# The capacity factor of wind

Guest Post by John Morgan. John is Chief Scientist at a Sydney startup developing smart grid and grid scale energy storage technologies.  You can follow John on twitter at @JohnDPMorgan.

A lot of ink is spilled on wind intermittency, and not necessarily based in data.  So I have extracted and analyzed a high resolution dataset of a year’s worth of Australian wind power for a number of interesting properties.  I previously wrote about the capacity factor as a limit to the share of electricity that wind and solar can acquire, so I also ask how wind capacity factor changes with time, place and season.  In particular, how does it change during sunlight hours and what does it mean for the capacity factor limit on renewable energy penetration?

## Australian wind fleet data

The Australian Energy Market Operator (AEMO) publishes data on all generators connected to the National Electricity Market (NEM) grid, which covers the eastern states including Tasmania, but excludes Western Australia and the Northern Territory.  The data includes power generation every five minutes for every generator for the last year, their capacities as registered with the grid operator, and more.  It is not very accessible, being in the form of thousands of SCADA data files, many of which contain errors.  But with a bit of work the data can be extracted.  Here, for instance, is the output of all grid-connected wind farms at five minute resolution over one year:

## Wind capacity factor

Here is the top level summary of the Australian wind farm fleet over the last year:

The nameplate capacity is the total capacity of all wind farms – 3753 MW.  But the whole fleet only manages 3238 MW at peak.The whole is less than the sum of its parts – half a gigawatt less in this case. Why is this?

The fleet is comprised of wind farms distributed over a large area of eastern Australia.  To achieve maximum theoretical power the wind would have to be blowing at the optimum speed for each wind farm, at all wind farms, simultaneously.  This is a statistical improbability and quite possibly a hydrodynamic impossibility, as it would require a high velocity correlated flow field over very large distances.

So while we often hear that the wind is always blowing somewhere, it is equally true that it is always not blowing somewhere else, and the fleet output never achieves full capacity.  Australia in theory has 3753 MW of wind capacity, but this will never be realized in practice.  Similarly, statements like: “The US added x GW of wind capacity last year”, overstate the capacity addition because the new wind build is unlikely to ever produce its maximum power in full correlation with the rest of the fleet.

In other words, national capacity statistics overstate the potential output of wind.  The flip side of this is that the capacity factor limit underestimates the potential for wind penetration.  We can push the penetration of wind a bit higher than the capacity factor – generation would start to exceed demand at 33% share, rather than 29% share.

## Wind correlation times and the synoptic scale

Over what distances are wind farm outputs correlated?  Its actually easier to ask, over what period in time is wind power correlated?  This information is contained in the wind power autocorrelation function, which we can calculate from the dataset:

The autocorrelation function tells us how long the influence of a particular state of wind persists.  If its windy now, for how long will it remain windy?  Surely for the next five minutes.  But will it still be windy tomorrow?  The autocorrelation function is a “memory” function that tells us how long wind “remembers” how hard it was blowing.

The autocorrelation function decays in about 40 hours (since we have 5 minute data the x-axis is in units of 5 minute “lag”s).  This means wind, on average, bears no relation to its output 40 or more hours ago.  Wind has a “correlation time” of about 40 hours.

Its interesting to interpret this as the time for a body of moving air to pass over a windfarm.  If we knew how fast it was moving we’d know how big it was.  Wind resource maps suggest a velocity of about 7-8 ms-1, so that interpretation suggests a wind correlation distance of about 1200 km – the “synoptic scale”.  This seems a pretty reasonable estimate of the size of weather systems and can in fact be done for a single wind farm with a similar result.  Its remarkable to be able to pull large scale geographic information out of just the power fluctuations of a single wind farm!

http://www.seabreeze.com.au/Photos/View/2871107/Weather/Australia-wind-energy-map/

If we wanted to cover intermittency we would need to ensure our wind fleet is dispersed over distances of 1200 km and more, so that the output of at least some of its wind farms will be uncorrelated.  This smooths the output of the wind fleet, reducing maximum output below the nameplate capacity, but increasing the amount of energy that can be integrated without having to spill, store or manage excess generation.

## Wind power ramp rates

Wind output is constantly changing and requires the rest of the grid to be flexible enough to ramp up power or shed load to balance wind fluctuation.  This rate of change is just the time derivative of wind power.  The plot below shows this “acceleration rate” throughout the year.  It’s a normal distribution, the symmetry showing that wind power picks up as fast as it drops off, and that the grid needs to be responsive at a rate of 20 MW per minute, in both directions, to cover most conditions.

As more wind is added, the flexibility of the rest of the grid will have to increase proportionately – double the wind energy would require about 40 MW/min ramp rate.  But this additional ramping ability must be delivered by the shrinking dispatcheable generator sector.  So the intrinsic flexibility of the rest of the grid must increase, and faster than in simple proportion to wind penetration.  Practically that means increasingly strong pressure to shift from coal generation to gas as wind share grows.

## Low wind days

Lets look at the distribution of low wind days.  We can ask, for how many days was wind output below some level?  For instance, we can find 29 days in which output was below 10% of capacity, and 127 days below 20% capacity.  127 days is, incidentally, pretty close to the number of weekends and annual leave of most Australians – Australian wind is obviously governed by Australian workplace awards!

The plot below shows the number of days below a particular output level.  Interestingly, the daily average power output never exceeded 75% of capacity, or 2810 MW, almost 1 gigawatt less than installed.  The fleet was never totally becalmed, but the lowest recorded day in the year saw output of just 2.7%.

Also of interest is the number of consecutive low wind days.  This affects the strategies we might use to cover wind outages – whether we store energy in batteries, or with pumped hydroelectricity, or shed load, cut in gas generators, or coal.  For instance, of the 29 days of wind output below 10% of capacity, 15 are single isolated low wind days, and then there are 7 pairs of 2 day long low wind runs.  If we look for sequences of days with less than 20% output, we find 2 runs of 5 low wind days.  The full distribution is shown below.

The number and distribution of low wind days show that while wind contributes energy, it does not provide capacity.  Alternative generation capacity must be available to meet the near absence of wind about one day in ten, and for two or more days in sequence.  But many of these low wind events are of just a single day duration.  This is a difficult timescale for coal plants, so again, increasing wind penetration drives the residual mix towards gas.

## Wind capacity factor by month and day

To get a handle on wind seasonality we can look at monthly output and capacity factors.  Each point in the plot below is the average power output for a day in the year.  The coloured blobs show the distribution of power output in each month.  Also shown is the capacity factor for each month.

The nameplate capacity factor varies from month to month (30%±5% covers it). Every month has low wind days and high wind days and everything in between with little seasonal structure.  The winter months have more high wind days, but they also have more low wind days, and one cannot confidently assert the monthly CF variation is greater than noise, in this year.

We can see this in a box plot of daily capacity factor – the data distribution is very wide and a capacity factor of 25% is consistent with the data for every month.  The highest daily capacity factor for the whole fleet was 75%, and the lowest was 2.7%.  These maximum and minimum output days both occurred in winter, when solar power is at a minimum.

## Wind capacity factor by hour

We can push this through to a still finer grain by looking at wind output by hour of the day.  The following plot shows the average capacity factor by hour of the day, for each month.  We can see if wind picks up or drops off in any consistent way through the course of a day.  The summer months show some daily pattern, perhaps, but the rest of the year does not:

Does the wind output drop when the sun is shining?  It would be convenient if it did, as it would allow more solar  power on the grid.  Lets nominate solar hours as 10 am – 4 pm, and compare solar hours with non-solar hours.

There is no difference between wind capacity factor when the sun is high in the sky and when it is not.  Wind does not cooperate with solar by subsiding in the middle of the day.  Possibly wind blows harder when clouds block sunlight.  Unfortunately I don’t have a dataset for solar PV output and can’t test this.  My guess is that the number of days and the number of sites at which such anticorrelation occurs is not large enough to shift the average output of the total fleet enough to change the overall picture.

## What does this mean for the capacity factor threshold?

As explained in detail by Jenkins and Trembath, it is increasingly difficult to build more wind or solar capacity as their market share approaches their capacity factor (CF) because they will then, at times, be producing energy in excess of demand.  The economic drag incurred by dealing with surplus generation by storage, curtailment or demand reduction undermines the economics of building additional capacity.  The capacity of wind and solar is thus limited to be roughly numerically equal to 100% of grid demand.

In “Less than the sum of its parts” I argued that adding solar to the mix actually reduces the combined amount of wind and solar energy that can be added to the grid.  This is because solar competes with wind for share of capacity, but contributes less actual energy due to its lower capacity factor.  Building solar thus reduces the maximum amount of renewable energy we can get onto the grid.

You can get around this if wind and solar generate at different times of the day, or year.  But from the data above we can say that wind does not drop during the day or pick up at night, to any significant degree.  The capacity factor of wind during “solar” hours is the same as during “non-solar” hours.

Turning to the seasonal variation, its possible wind has a higher capacity factor in winter when solar output is low, but the evidence of the last year is not compelling.  The lowest wind capacity factor in the year was actually in the winter month of June, and January in high summer was one of the higher producing wind months.  The winter months have more high wind days, but they also have more low wind days.

If there is some seasonal synergy between wind and solar, its not particularly strong, and the contention that the maximum share of renewable energy is achieved by building wind and not solar seems sound.

But the capacity factor threshold does require an adjustment.  Recall the peak wind output was only 3238 MW, less than the nameplate capacity of 3753 MW.  So we could build more capacity without fear of excess generation.  Instead of spillage or storage being required at 29% wind share, we can accommodate a more generous 33% share.  This greater share of wind energy is possible due to the geographic distribution of wind smoothing out some of the peaks.

## Conclusions

There’s a lot of information in noise.  Deducing the size of large scale weather systems from the power fluctuations is pretty cool, as is seeing the signature of spatial distribution of wind farms in a one-dimensional time series.  Notably, a national wind fleet will not achieve full output due to geographical smoothing, but this smoothing also increases the capacity factor threshold for wind share a bit, from about 29% to 33%.

As expected, intermittency means wind contributes energy but not capacity to the grid, meaning wind acts as a fuel saver for fossil plants, which must increasingly shift to gas rather than coal as wind penetration grows, to accommodate higher ramp rates.

The capacity factor does not show strong consistent variation across hours, days or months, and share of renewable energy is limited as Jenkins and Trembath describe.  There is little evidence of a synergy between wind and solar in the Australian grid, supporting my earlier conclusion that a combination of wind and solar can displace less fossil energy than wind alone.  If we really wanted to push towards maximum renewable energy, we would build wind and not solar, and variable renewables share could grow to about 33%.

## Data

Five minute data for all generators can be extracted by parsing the SCADA data files in this directory.  Data goes back a little over a year.  Older data is not available – AEMO appear to delete the oldest files on this page on a daily basis.

AEMO lists all generators connected to the grid, by technology here, in the spreadsheet “Registration and Exemption List”, in the tab “generators and Scheduled Loads”.  Each generator has a unique identifier, the DUID, allowing it to be located in the SCADA files.

The SCADA files contain a number of errors – in many files the output of many generators is double counted.  A corrected data set was created by filtering out duplicate generator entries.

The data was extracted and analysed with python code using the excellent SciPy scientific python tools, iPython notebook, pandas data analysis library, with MatPlotLib and Seaborn data visualization libraries for plotting.

1. Hi John,

Excellent post, as usual. Thank you. There’s much to discuss. Here’s a few initial comments.

If you haven’t already seen it, I expect you would be interested in Joe Whealey’s excellent analysis of the CO2 Emissions Savings from Wind Power in the NEM in 2014 http://joewheatley.net/emissions-savings-from-wind-power-australia/

Second, your capacity figure of 29% for the period Oct 2014 to Sep 2015 is identical to the figure Wheatley got for the NEM for calendar year 2014.

Third, some comments on this paragraph:

If we wanted to cover intermittency we would need to ensure our wind fleet is dispersed over distances of 1200 km and more, so that the output of at least some of its wind farms will be uncorrelated. This smooths the output of the wind fleet, reducing maximum output below the nameplate capacity, but increasing the amount of energy that can be integrated without having to spill, store or manage excess generation.

Wind farms in the NEM are dispersed over a triangular area of about 1200 km east-west by 800 km north-south. And sometimes there is no electricity generate by any wind farms. For example, in May 2010, there were 75 5-minute periods when wind farms generated zero power; some of this time they were drawing more power than they generated, up to a maximum of 4 MW (from memory).

The amount of wind that has to be spilled is effected mainly by local grid constraints rather than the total wind generation in the whole grid.

Fourth, I’d also mention an excellent series of posts on Energy Matters for readers who may not have seen them. A summary of the 24 posts is here http://euanmearns.com/the-renewables-future-a-summary-of-findings/ with links to each of the 24 previous posts. The last few are particularly interesting.

Fifth, regarding:

This is a difficult timescale for coal plants, so again, increasing wind penetration drives the residual mix towards gas.

True. And greatly increase the wholesale cost of that electricity.

Sixth,

… we would build wind and not solar, and variable renewables share could grow to about 33%.

If wind’s share of generation increased to 33% (I realise you are talking about wind+ solar share), the CO2 emissions abatement effectiveness of wind generation would decrease to well below 50%. At 20% wind energy penetration, the CO2 abatement effectiveness would be about 60%; that means the CO2 abatement cost would be about 67% higher than is generally claimed. Therefore, at 33% wind share of electricity generation, CO2 abatement effectiveness may be around 40% and the CO2 abatement cost about 2.5 times higher than generally calculated. See the chart in: “What’s the cost of CO2 abatement with wind turbines”: http://www.onlineopinion.com.au/view.asp?article=17447&page=0

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2. Peter Lang

If you cared to read the article then you would not claim the low CO2 abatement figures for wind power that you claim.

I have discussed this with you before and you yourself supplied a graph that clearly showed that your claims were unfounded.

Instead of just second guessing what you feel or think it would be much more productive to just post your beliefs that you base your strange CO2 abatement factors upon. And moreover present them in some kind of calculation.

John Morgan clearly states that to integrate wind you need peak power plants based upon natural gas. As natural gas emits roughly 50% less CO2 than a coal fired power plant then the logical assumption is that if the utilities decides to introduce peak power plants and take coal power offline then you have 100% abatement effect for the added wind power times the capacity factor and 50% for the added peak power natural gas power plants times their capacity factor provided the wind power does not go to waste at times with near 100% capacity factor.

Now you claim that John Morgan has got it wrong when he assumes that wind power can go slightly over the realized average capacity factor in Australia at 29% and supply 33% of the electricity without substantially overshooting production.

Both solar and wind is rapidly improving capacity factors and will be doing so in the next decades as a simple consequence of technological improvements. Wind turbines grow and reach higher altitudes with stronger and steadier wind and solar installations are rapidly moving from predominantly roof integrated to utility scale solutions and in utility scale solutions tracking, cleaning, maintenance, inverter/module ratio optimization is common, which increase the capacity factor.

If you over provision with electricity from a variety of low carbon sources then you can much easier make sure that you at all times can meet the electricity demand but you will also end up with un utilized electricity that is in excess and therefore cheap. John Morgan wrote an excellent piece about Synfuels. If we do not start producing Synfuels we will never be able to stop the ongoing climate catastrophe. Electrons are electrons and the final Synfuel will be of equal quality irrespective of its origins. What matters is that the origins are cheap enough and does not entail pollution including excessive GHG emissions.
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3. Has anyone done an analyis of the correlation or lack thereof, between solar and power demand?

Far from the equator there is little solar available in winter while demand is quite high, so solar is rather useless there. However, I would expect that many regions at lower latitudes would ,minimal seasonal variation & have the daytime peak in demand roughly match the peak output from solar power. So there would be some optimal mix of solar & something steady like nuclear to minimize the need for storage & overbuilding of the power supply. If this is so, then to move away from fossil fuel use many regions should build nuclear & solar and avoid installing wind.

But maybe even the most consistently sunny areas have too many cloudy or dusty days, or the peak demand is in the late afternoon & evening, so solar would be less useful than I think.

So can anyone provide a link to such an analysis?

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4. Hi Jim Baerg

It is not for all nations to handle nuclear and nuclear is at present too expensive compared to wind and solar and the gap is widening fast. As an example the solar capacity doubled in just one year in USA last year http://ensia.com/features/will-natural-gas-dim-solars-shine/ and the cost of solar is expected to halve within the next five years.

The widening gap problem can change but will probably require a departure from the classic LWR concept.

Some nations such as Bahrain, India, Turkey and more with high insolation are however also building nuclear capacity but in general nuclear is not befitting unless the country has a skilled work force and the strong academic tradition required to handle complex nuclear technology.

Any child can handle PV and not very adept organizations can handle wind turbines.

Nuclear is also a very time consuming technology where the time from the investment is considered to the power plant begins operation can be very long. Most new power capacity in equatorial countries are needed asap and solar and wind is very fast to get up and running.

Another consideration is the lack of sufficient water supply, which put a cap on nuclear unless there is abundant water resources and preferably seawater. Solar and wind are not dependent on water supply as they are not thermal power plants that require cooling water.

As for the updated scenario analysis you ask for links to I think you can expect it to be very difficult to find because the cost of wind and solar is dropping so fast along with the cost of storage that 2-3 years old studies are already inaccurate. EIA is famous for getting it wrong again and again http://rameznaam.com/2015/06/30/solar-cost-less-than-half-of-what-eia-projected/

Anyway for a complete shift away from fossils you need much lower electricity prices because Synfuels that are price competitive with oil products based upon crude oil require a huge expansion in cheap carbon light energy forms.

Developers of new nuclear technology should aim for sub US cent per kWh without subsidies because that is where the price point begins to make it feasible to keep fossils underground.

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5. You say ‘If we really wanted to push toward maximum renewable energy we would build wind and not solar, and varible renewable’s share would grow to about 33%’. A good thing you put in ‘variable’. In fact if we wanted to push toward maximum renewable energy (of both variable and dispatcheable) we’d have solar hot water on all households, waste to energy plants for every 300-500,000 tonnes of non-recyclable waste production in regions and city fringes, and biomass to energy plants of every type (including biogas, advanced biofuels, small to mid-scale CHP).
This could allow us to move (by 2030) up past 50% overall renewable share of energy on a final energy basis, and around 30% of electricity share, with a significant retirement of coal-fired plant.
In this scenario we’d freeze wind capacity expansion about where it is (because further expansion only necessitates ever greater installed capacity fo gas-fired plants) and maximise solar PV. And (quietly forgetting about the very high cost per MW-e actually produced from solar PV) we’d be getting the renewable electricity cheaper than from the mix of wind and the necessary added shoulder and peaking gas-fired plants.
To use my usual reference of Sweden, there they are past 50% final energy from renewables (with over 35% from biomass), and less than 2% of the country’s final energy is from wind (and it is not that they don’t have good wind resources).

I’d be keen for you to do a follow up on your current post that analyses the actual GHG emissions reduction/MW-e produced that added capacity of wind results in (i.e., at present installed capacity, at say 8000 MW installed, and at 17,000 MW installed), and also the real capital cost per MW-e produced by wind at these same installed capacity totals when all added balancing gas generation and associated gas pipeline and grid infrastructure requirements are taken into account.
just as an example, I am aware of a local wind farm in planning in Victoria where the developers say the total capital cost for the erected turbines plus all ancillary works of substations, supply line, roading, trenching, etc., will be $650 million for a 300 MW capacity and 1000 GWh/yr output. Many other wind farms will have comparable total capital costs without adding the external costs. Yet wind power is being marketed to us as ‘the cheapest source of renewable electricity’. I suggest that this whole aspect is not getting enough attention. BNC MODERATOR As per BNC Comments Policy, please supply refs to back up your contentions. Thank you. Like 6. Andrew 1. Assuming we do use biomass as you recommend why can’t that be used as backup to wind and solar rather than gas. Like 7. Thanks for this research John. In my book, The Power Makers’ Challenge, I have an appendix on wind power which covered some of the material you have presented here. My research showed that in some locations the mean wind speed was just under 7 m/s (25 km/hr) and occurs 10% of the time. Not all sites would have such a high mean wind speed but 7 m/s is thought to be the required profile for a ‘good’ site. Some would argue this is the minimum for commercially viable wind power. Looking at your image for Australia above there seems to be very few locations with mean wind speeds of 7 m/s on much of the east coast and practically none in Queensland and Northern Territory. Where does this leave Diesendorf’s research showing the viability of 100% RE? Like 8. Peter Farley, The answer is because the cost of electricity would be prohibitive if we attempted to use biomass to back up for wind power when wind is a large proportion of electricity generation. the back up generators need very high availability – e.g. around 98% like gas – but would have low capacity factor. The cost of logistics and of storing biomass fuel at the power stations to enable them to operate with such high availability would be prohibitive. This is explained here: https://bravenewclimate.com/2012/02/09/100-renewable-electricity-for-australia-the-cost/ In my response and questions to Mark Diesendorf here: https://bravenewclimate.com/2012/02/27/100-renewable-electricity-for-australia-response-to-lang/#comment-152532 And the cost of 100% renewable electricity in the NEM using biofuel as back up is compared with the cost of mostly nuclear here: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.363.7838&rep=rep1&type=pdf (see Figure 6 for cost comparison, Figure 5 and 7 for CO2 emissions avoided and estimate of the transmission capital cost and cost of electricity. Like 9. Whether Nuclear ,Water,Wind or Whatever Humans must start living and Governing to the fact that we only have one Earth and we have to live in balance with what is. Not some new Technology which allows for Human over abuse to carry on a bit longer! CHF Like 10. to Peter Farley, ‘biomass’ actually covers everything from sewage to landfill gas to urban wood wastes and the organic fraction of solid municipal wastes as well as agricultural resiues, organic food processing residues (including abbotoir wastes) and woody biomass from all sorts of forestry and plantation activities. Elsewhere the dry end of these feedstock materials are fuelling either heat plants or combined heat and power plants and these have little ability to ramp up and down fast and obviously the economics of sitting at a production of 30-40% of rated capacity are lousy. These are the bioenergy forms that can be replacing coal plants of various sorts. Some forms of biomass do have capacity to provide a fast ramp up/down and these are basically the various biogas sources – landfill gas, sewage, and other putrescible wastes. All you need in this case is the adequate capacity of pressurised gas storage tanks. Starting up a gas engine and getting up to full output only takes seconds. Australia might at present have 120-150 MW installed capacity (output of 700 GWh in 2011 and it be maybe 1000 GWh now). With some stimulus and technical support this could be lifted towards 2-3000 MW within 15 years. There are many wastes that can be used for production of biogas. Grass silage (including unpalatable grasses and weeds), straw pellets, food residues, abbotoir wastes and chicken manure/litter are the most available. Best economics are when there is also a sale and commercial use for the heat. It is possible to produce methane from woody biomass, or pyrolysis oil from any ligno-cellulosic material, or synthesis gas from dry municipal wastes, and so the availability of gas fuels or liquid fuels produced from sustainably and economically available biomass (and not remote and dispersed forestry harvest residues) can be increased using what is already available. All of this is now mature technology in commercial use in developed countries, and what the utilisation of biomass is depends on the economics – and within this some of these options do require aggregation of very large volumes of quite low density and low value feedstocks, and usually the capital cost of this large volume plant is high (but rarely higher than that of one single large wind farm). BNC MODERATOR As per BNC Comments Policy, please supply refs to support your assertions. Thank you. Like 11. Thank you for this great article John Morgan. Also thanks Peter Long. How can we get our message to COP21? The Third World has hijacked the United Nations climate talks [COP] to push their own agenda unrelated to Global Warming [GW]. They want to tax the US. http://unfccc.int/resource/docs/cop6secpart/l05.pdf Authority comes out of a gun. The Third World does not have the authority to tax the US. Forget about hijacking the climate talks and concentrate on fighting GW. “Developing” countries have to shoulder just as much of the burden as the US. If The Third World does not share the burden equally and reduce ‘s CO2 output, it is The Third World that will die first. The answer is NO but Hell NO! The US will not fight GW alone. The Third World must use Third World money to shut down coal fired power plants and replace them with nuclear power plants. Do not expect the US to pay for what they must do. The way to prevent The Third World from making CO2 is to leave them in the stone age. ANS Nuclear Cafe & COP6 http://ansnuclearcafe.org/2015/10/28/the-power-of-nuclear-energy/ Global Warming and the EPA plan to mitigate: http://unfccc.int/cop6_2/ CONFERENCE OF THE PARTIES Sixth session, part two Bonn, 16-27 July 2001 Agenda items 4 and 7 page 8: 2. Article 6 project activities The Conference of the Parties agrees: 1. To affirm that it is the host Party’s prerogative to confirm whether an Article 6 project activity assists it in achieving sustainable development. 2. To recognize that Parties included in Annex I are to refrain from using emission reduction units generated from nuclear facilities to meet their commitments under Article 3.1. http://unfccc.int/resource/docs/cop6secpart/l05.pdf FCCC/CP/2001/L.5 English Page 13 Issue: Nuclear Description: Can emission reduction units and certified emission reductions be generated by nuclear power projects? Options Option A No mention of the possibility of using nuclear facilities for generating ERUs and CERs. Option B FCCC/CP/2001/2/Add.2, page3 – Recognizing that Parties included in Annex I are to refrain from using nuclear facilities for generating emission reduction units and certified emission reductions. There must be more documentation on this. COP6 was in Germany, where the “Green” party has an outsized influence because it is necessary to be allied with the Greens to form a coalition government. The tail wags the dog. There is a lot more nonsense in those same documents, like the third world taxing the first world, which is not going to happen. Unfccc is not serious about GW at COP6. Will COP21 be any different? Let’s hope so. In the mean time, we need to straighten out the politicians. Like 12. John Morgan: Recommended reading: Read this on first to see why we need a week’s worth of storage.: “A Nation-Sized Battery” http://physics.ucsd.edu/do-the-math/2011/08/nation-sized-battery/ by physics professor Tom Murphy http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/ Pump Up the Storage” To store a week’s worth of energy as pumped hydro, for the US, we would have to lift Lake Erie half a kilometer skyward per Tom Murphy. Book: “Green Illusions” by Ozzie Zehner: A complete renewable energy system for the US would cost 1.4 QUADRILLION dollars. My estimate for the cost of a battery for the US is$0.5 QUADrillion. 5 times 10 to the eleventh power. About 29 times GDP. How I got it: Fairbanks has a battery that can last 7 to 15 minutes. They paid $35 Million for it. Fairbanks has 30,000 people. That is$1167 per person. Multiply by 400 million people. Divide 7 minutes into a week. Multiply that by the number you got before. You get half a quadrillion dollars. Batteries are out. I did not account for price going up as resources are depleted.

See: Fairbanks Daily News-Miner – “GVEA s Fairbanks battery bank keeps lights on”
http://newsminer.com/view/full_story/12739242/article-GVEA-s-Fairbanks-battery-bank-keeps-lights-on?

To go with renewables only, you need a whole week’s worth of battery power for the whole world because Europe can have a long cold cloudy calm winter. The batteries can run down over several months.

My list of references is too long to put here.

John Morgan: Since batteries rely on chemistry, they aren’t going to improve by the required factor of a million any time soon.

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13. Jim, this piece goes somewhat to your query on solar vs demand, with reference to summer in South Australia, which is when the greatest electricity demand is experienced: https://theconversation.com/summer-on-the-nem-12635

The effect of household PV penetration (which is expressed as a drop in demand, visible on the graphs therein) has been to shift the demand peak from 3-4 pm to 5-6 pm. Fortuitously, this appears to coincide with peak wind production in the hotter months (Nov-Mar) as seen in the hourly analysis above (sea breezes?). Maybe this will enable eking out a few more percent of PV penetration.

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14. I am presently doing some work in Sudan. if you look at the GHG emissions of Sudan you’ll see on some sites a per-capita figure of 0.3 tonnes. I’d be suggesting that it is closer to 1 tonne. India is put as 1.7, Indonesia is 2.6. Most countries in Africa and Asia have per-capita GHG emission levels of below 3 tonnes. The idea is that they are helped to stay below this level, as the real offenders like the USA, Canada, Australia, etc., also bring their levels down.

Yet Sudan and these other countries are heading off to COP 21 with each delegation carryiing a list of the ways they are intending to reduce GHG emissions. The reality is that these counties already with very low per-capita emissions don’t need to look at reductions (though certainly at changing to higher efficiency systems particularly for biomass use).
The critical point is that they have many ways of sequestering major amounts of atmospheric carbon and that they can be assisted to do this. Sudan is only one of the many sub-saharan countries that have the capacity and the land available to replant tens of millions of hectares to forest including wide-spaced agroforestry plantings. And that this can be done with only beneficial results including for food production. The actual cost per tonne of CO2 sequestered would be minimal. Sure they should do it anyway, but a well designed system would be just acting as a catalyst to national efforts towards this end, not a substitute for national effort.
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Please note that BNC Comments Policy requires that commenters provide quality and preferably peer review references to support their contentions. This applies on all but the Open Thread where rules are somewhat relaxed.

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15. Please note that BNC Comments Policy requires that commenters provide quality and preferably peer review references to support their contentions. This applies on all but the Open Thread where rules are somewhat relaxed.

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16. Hi John, in my book “The Power Makers’ Challenge”, I have an appendix on wind variability which covers some of the work you have done here. In that appendix I had a typical mean wind speed of just under 7 m/s (25 km/hr) occurring 10% of the time. Not all sites have such a high mean wind speed but 7 m/s is thought to be the required profile for a ‘good’ site. Some would argue this is the minimum for commercially viable wind power.

Looking at your map of Australia, much of the total country, particularly eastern and central locations do not have mean wind speeds that would be attractive to wind farm builders. Given that much of the population lives near the eastern coast, there must be some serious restrictions to how much wind power can deliver electricity demand to populations in Sydney and Queensland for example.

This must put into question the practicality of 100% renewable energy if one of the major RE technologies, i.e. wind, is not available locally for perhaps more than half the population that currently rely on coal.

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17. John

That is a fascinating post, however all sources of power generation have a capacity factor of less than 90%. As you point out availability is also a key variable

For example coal in Australia is around 58% capacity factor but about 90%+ availability. According to the latest French data their nuclear is running at 67% CF YTD, again probably 95+% availability. Hydro in Australia is well over 95% availability but averages around 15% CF but is lower this year. Gas is 95% + availability significantly less than 30% utilisation. Even Nuclear in the US which averages about 90% CF varies from 95%+ to around 70% or less availability on a seasonal basis.http://www.eia.gov/nuclear/outages/

Therefore you need significant excess capacity in any known grid scenario. In almost all grids the optimum mix has some sort of storage to minimise over-investment in slow ramping generators and the running costs of spinning reserves. They also have considerable fast ramping capacity

The tricky question is how we integrate them and what is the lowest cost reserve capacity.

I have seen graphs that show that in Europe solar and wind are largely complimentary and others that show they are not, although I think some of the differences between the two are due to the resolution of the time scale and the use of more or less grid integration between countries.

To determine the amount of storage and the optimum capacity factor one needs to understand the demand as well as supply and even the location of the generators. For example west facing solar farms on the western edge of the grid are much more useful for reducing peak demand on hot days than solar roofs in SE Qld. A combined cycle gas plant in North Qld. is of limited help with peak demand in SA or Tasmania.

Also with regard to time. Obviously solar is not available at night but demand is lower so it is much easier to meet demand from hydro, wind and biomass

I am not suggesting that either of the following is the best scenario but in the Australian NEM context here are two (of many) do-able, reliable 98% non carbon electricity options

We could install 50-60 GW of nuclear and keep the hydro, but the optimum nuclear scenario is probably about 35-40GW of nuclear + hydro + 20-30GW of of storage + 8-10GW of gas/biomass to cover extended nuclear outages/non optimal renewable weather.

Or we can build 40-50GW of wind, with the same conventional hydro, 10GW of biomass and 40GW of fixed solar + 10GW of tracking with the existing 10GW gas together with 25GW of storage.

In both cases we could operate quite safely with gas contributing <3% of annual demand and therefore negligible GHG and eliminate 99% of other pollutants.

In both cases if thermal storage and load shifting was encouraged the electrical storage can be reduced to about 15-20GW

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Martin.
The Australian data is based on 70m mast height. Most new turbines are available with mast heights from 80-110m and a few up to 140m. Depending on the terrain, wind speeds at 120-140m can be 15-20% higher than at 70m.

Current class 3 designs are optimised for 6m/min wind speeds and there are models for even lower wind speeds.

Low wind turbine designs are optimised for some production at medium to low speeds rather than peak production at strong winds. This means the Su kW/sq.m of swept area is falling whereas previously a high Su was considered a mark of high efficiency I think the best number was around 2.5, It is now trending towards 6. The
effect is that capacity factors are climbing so that the NREL predicts CF will reach 60% or more in large areas of the US
http://apps2.eere.energy.gov/wind/windexchange/windmaps/resource_potential.asp#states
Taking these three trends together there is ample area of Australia for the 13-15,000 wind turbines we would need. By comparison the area covered by the NEM (not including outback areas) is about 4-5 times the area of Germany and they already have nearly 28,000 wind turbines. Or Texas which is about half the area of the NEM is aiming for similar wind capacity

This is not a suggestion for 100% or even 60% wind, it is just that the technical/economical share for wind is noticeably higher than it was even 3 years ago

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19. Peter Farley,

We could install 50-60 GW of nuclear and keep the hydro, but the optimum nuclear scenario is probably about 35-40GW of nuclear + hydro + 20-30GW of of storage + 8-10GW of gas/biomass to cover extended nuclear outages/non optimal renewable weather.

Or we can build 40-50GW of wind, with the same conventional hydro, 10GW of biomass and 40GW of fixed solar + 10GW of tracking with the existing 10GW gas together with 25GW of storage.

When you consider the economics, the renewable scenario you suggest is out of the question. There is much on this on previous threads on BNC and elsewhere. A very god recent series of threads for EU and EU countries is summarised in a final post on Energy Matters here: “Renewables Future – A Summary of Findingshttp://euanmearns.com/the-renewables-future-a-summary-of-findings/ . AEMO also investigated the option of 100% renewables and reported in 2012 or 2013 from memory. They said it was technically feasible but costly, and buried in the text were many caveats such as the cost would be higher than stated in the report.

I do not agree with the capacities you suggest for the largely nuclear option. I’d suggest the least cost option to provide electricity with about the same emissions intensity as France’s electricity (i.e. less than 10% of Australia’s) is about 20 GW nuclear running at about 90% capacity factor (i.e. 18 GE average output with scheduled shut downs timed for periods of lower than average baseload), plus about 20 GW of gas plus about the current capacity of wind and solar. Peak demand in the NEM is about 32-35 GW (varies from year to year) so these capacities would give around 20% capacity reserve. The gas and hydro would run at low capacity factor so emissions from gas would be low. If more hydro or pumped hydro is economically viable then it should and would be developed, but it is not even close to being viable at the moment.

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20. Re the asertion that ‘all power generation plants have a capacity factor of under 90%’, the CF of waste to energy plants is generally above 95% and similarly for landfill gas and sewage gas-fuelled generator systems, and so is level with their availability.
In general WTE plants in Europe operate on some form of arrangement where the power produced has to be accepted, as they operate 24/7 for all but 1-2 weeks of the year. http://www.cewep.eu/m_1069

Similarly the anaerobic digesters taking in city sewage and other main industry putrescible waste streams, and their CF may be somewhat higher than for WTE plants. Biogas fuelled generators drawing from larger landfills and sewage anaerobic digestion systems or AD systems at round-the-clock food processing plants fit into this category. Similarly in Europe many larger biogas-fuelled generating plants with only the minimal gas storage within the reactor and may run at up to 98% CF.

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21. Peter Lang.

“I’d suggest the least cost option to provide electricity with about the same emissions intensity as France’s electricity (i.e. less than 10% of Australia’s)”.

From memory Australia’s emissions intensity for electricity is 850gms/kWh, France achieved 40gms in 2014 so their emissions are less than 5% of ours.

http://www.rte-france.com/en/eco2mix/chiffres-cles-en

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22. Thanks John Morgan for some facts.
The Capacity Factor that you refer to is very important and I think that it is being misunderstood by some contributors. What is being said here is that the total installed capacity for wind is 3752 MW and the peak amount of power generated was 3238 MW. It is not stated how long this peak was achieved for. It may have only been for 5 minutes according to the data that was analysed. John Morgan further says that it is basically impossible for the wind generation system to ever exceed this ratio of 86 percent (3238 MW / 3752 MW). This is an inbuilt inefficiency in a wind generating system.
The capacity factor that others are talking about is plant availability.
With Coal, Gas, Biomass, Diesel, Nuclear, Hydro, Geothermal etc when I call for full power I get the name plate capacity for a defined period of time with Certainty. Because these are all machines they require maintenance and they will never achieve 100 percent availability but when they are available they will give me 100 per cent of name plate capacity.
It is also important to note that the raw data is provided in 5 minute intervals. Grid managers are expected to supply 100 percent of demand on a minute by minute basis.

Blacking out any section of the grid due to a lack of supply is just not acceptable. One might regard certainty of supply as a determinant of a Developed Economy.

I remember watching a TV documentary about the North American Electricity Grid. They were showing the system control room in California and talking about the amount of wind power being generated and showing all the wind turbines in the Colombia River Valley revolving around majestically.
However, within the hour the supply of wind power fell from 2GW to 200mw.
I remember thinking to myself that there must have been a conversation going on somewhere in California similar to a Star Trek Movie.

Kirk ‘Scotty give me everything you’ve got now !!!!!!’

Scotty ‘ Aye captain I already am ! I canne give ye any more!!!!!!’

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23. Thanks everyone for the very interesting discussion in the comments here, all very thought provoking contributions!

Peter Lang, great opening comments, all well put and well taken.

Jim Baerg, I don’t know of any such analysis of solar and demand but the latitudinal variation is an interesting question.

I would really have liked to have included analysis of solar in this post at the same level as wind. Unfortunately, most solar in Australia happens behind the meter, as rooftop PV, so most solar generation does not get reported out to AEMO. The solar data that is reported by AEMO comes from grid scale solar farms, of which there are only a few operating, and not very large. So any solar analysis based on AEMO data would really just be a couple of sites – not enough to draw any broader insight from, so I chose not to analyse it.

Solar PV data that includes rooftop solar does exist, but is created by a process of inference and modelling rather than direct measurement, and, more importantly, is a proprietary product that I’m not about to pay for. If anyone has any suggestions as to where to find a complementary dataset for Australian solar at a similar resolution to this wind data please let me know.

Edward Greisch, you might be interested to read my previous piece on batteries: The Catch-22 of Energy Storage https://bravenewclimate.com/2014/08/22/catch-22-of-energy-storage

I should note the obvious qualifications: this data is for Australia, and other parts of the world may show different patterns. Within Australia, most wind is installed in South Australia, so this data is weighted with a high representation from a particular region in the coastal southeast. As wind penetration grows in other states different patterns may emerge (or disappear).

The 29% (or 33%) capacity factor of wind is in fact an unrealisable upper bound on wind penetration. I focus on that bound, set by overgeneration, in this post for reasons of clarity. But there are of course many other limiting factors, some of which have been mentioned in discussion. In particular, Jesse Jenkins and Alex Trembath in their article suggest that only 55%-60% of grid energy could be replaced by variable sources, due to the need to retain significant synchronous generator contribution for frequency control. This means VRE share will struggle to exceed 60% of capacity factor. If that figure is reasonable, then wind would be limited to about 20% (with no solar).
http://thebreakthrough.org/index.php/voices/energetics/a-look-at-wind-and-solar-part-2

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24. To Peter Lang

I stand corrected, I had assumed peak demand was in the order of 50 GW, so both quantities are oversized. Scaling the installations down and using current costs and allowing for the lower O&M costs of renewables the investments are of a similar value. According to the latest figures I have,renewables would be cheaper, but other posters on this site of course disagree violently.

Re capacity factors, you may not accept my figures but they are not my figures, they are from the US Energy Information Agency, The French Energy Directorate and the US NREL .

The question is, which technology will have the faster learning curve. The market, today does not agree with your choice, but in two or five years who knows.

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25. To Andrew Lang,

I did not say all power plants, I said all power sources, I probably should have been clearer and said all significant power sources. Minimum demand on the NEM seems to be 20% or less than peak so if a source of infinite reliability exceeds 20% of the demand some of it must be dialed down reducing capacity factors.

This is why France’s Nuclear power system runs at 70% or so CF at 75% or so of total generation. In the US where generation is only a bit under 20% of the total, CF is around 90%. According to my sources at the highest levels in the NRC, French technology was generally regarded as being at least as good, if not better than in the US so it is not technology differences that account for the difference in nuclear CF. if the US makes a significant increase in nuclear, its CF will also trend down .

I am not against biomass, in fact I think it is a key part of the system but it shouldn’t be mandated in preference to all other low carbon solutions. Requiring that MSW generators get preference is just as objectionable, if not more so than demanding other generators shut down so wind power gets to sell all available generation at a high price.

While in Australia there are places where heat and power are required, there are many fewer opportunities to economically use the waste heat than in Europe so the optimum amount of biomass is probably lower than in Sweden.

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26. Interesting post John … especially the cool bit about weather patterns. Your collection of posts and those of Jenkins and Trembath constitute a powerful demonstration that renewables can only ever be a smallish part of a total solution … not the whole story.

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27. Peter Farley,

According to the latest figures I have, renewables would be cheaper, …

Re capacity factors, you may not accept my figures but they are not my figures, they are from the US Energy Information Agency, The French Energy Directorate and the US NREL.

I don’t know what figures you are using, for what year, what proportion of each technology, what learning rates, for what grid, etc. You have to define the assumptions, use figures that are consistent for all scenarios and all technologies, define the demand profile, and calculate costs applicable for the capacity factors you’ve used in your analyses not the capacity factors used for calculating LCOE for comparing across technologies. If you don’t layout all your assumptions and do analyses on an equivalent basis, the numbers are meaningless. You also need to include grid capital and O&M costs for all technologies.

You can calculate costs for Australia for each technology for the capacity factor for the scenario you are analysing using the AETA calculator which you can obtain from here: http://www.industry.gov.au/Office-of-the-Chief-Economist/Publications/Pages/Australian-energy-technology-assessments.aspx

You can estimate grid costs for each technology using this (or go to the OECD source document linked): http://www.energyinachangingclimate.info/Counting%20the%20hidden%20costs%20of%20energy.pdf

If you run these CSIRO calculators you’ll find that nuclear is a much cheaper option than renewables to achieve major cuts in CO2 emissions.

MyPower: http://www.csiro.au/my-power/

The basis of estimate, method of calculation and assumptions are explained.

Here is a neat chart plotting countries CO2 emissions intensity versus cost of electricity: http://canadianenergyissues.com/2014/01/29/how-much-does-it-cost-to-reduce-carbon-emissions-a-primer-on-electricity-infrastructure-planning-in-the-age-of-climate-change/ (go to slide 10 in the slide presentation). Countries with a high proportion of nuclear have much lower GHG emissions intensity and cost of electricity than countries with a high proportion of intermittent renewables. (Also note the irony in slide 14 – which is what you are advocating).

If you want to make a persuasive argument that renewables can substantially reduce Australia’s GHG emissions intensity of electricity, you have an enormous task ahead of you.

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28. Just a quick question for John Morgan. The minimum wind speed has been mentioned for wind turbines. I have heard that there is also a maximum speed at which Turbines stop operating for mechanical reasons. Do you have any information in relation to this?

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29. To avoid getting caught in the mis-construed pro-con discussion of capacity factor applied to power capacity (% of MW nameplate power delivered over a long period), industry participants would be better served if they spoke about energy (in MWh) rather than power (in MW). Electrical engineers, market participants and investors care about MWh because that is the unit they get paid for. Knowing a solar, wind, biomass, hydro, gas or coal-fired plant’s annual energy production in MWh allows for an apples-to-apples comparison, and dividing capex or opex or revenue by the MWh production figure gives pundits an appropriate metric for useful discussion. Better to avoid talking in MW and capacity factors . . it just confuses people.

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30. Geoff Russell

I think you jump the gun.

Capacity factors is on the rise for wind power and solar power as well. So the future number is not 29% penetration or 33% penetration corrected for the Australian wind distribution. Peter Farley has already linked to the the recent NREL study that anticipate wind capacity factors up to 65% by just moving the hub height to 140 meters to 80 meters. A lot of other technologies that is also increasing wind capacity factors is constantly being developed, tested and integrated in new wind turbines. And some even as retrofit to older wind turbines. The number of researchers and engineers that work with refining wind technology and the number of major industrial corporations in the business suggest that the competition is strong and progress will continue.

Cost for both wind and solar is coming down fast and is projected to keep doing so for a long time. The drop in the cost of wind energy dropped last year to only 6% “year on year” after five consecutive years with average 15% cost drop. As solar now has a larger marketshare measured in capacity sold, wind power is forced to press margins.

Storage is a big thing in USA among venture capitalist and also a focus for government grants. The benchmark for storage is to become cheaper than fracking gas peak power plants. John Morgan is an expert in the field so he could probably evaluate whether or not the optimism among storage developers is justified and whether the $100/kWh threshold will be breached in this decade. Simpler storage where you do not store electrons but just convert electricity to products or heat is also a feasible strategy and probably one that John Morgan studies being an entrepreneur within smart grid technologies. The obvious long term target for the wind and solar industries and indeed any industry fiddling with CO2 light electricity generation technology is to out compete crude oil, coal and gas altogether. John Morgan has written a well argued piece on this very subject here on Brawenewclimate and the concept has been around for many decades. What is different now is that wind and solar is now so cheap that the concept is becoming more and more realistic. Nuclear too can potentially reach out for the needed sub US cent price point per kWh. Ps. The article is well researched and very matter of factly about the present conditions in Australia but the theoretic framework provided by Jenkins and Trembath is not too impressive. Like 31. To Peter Farley, I accept your point. But the scope for Waste to energy (fuelled by non-recyclable flammable municipal wastes) is of the order of 1500 MW-e in Eastern Australia. This may or may not rate as ‘significant’. But it is certainly a fuel source in constant supply and is an unusual power source in that of all sources it is the least able to be flexible in output due to the requirement for furnaces to be operating within very tight parameters – so it is even more ‘baseload’ than brown coal-fuelled plants. But since this power source fully displaces coal-fired plants it is in a diferent category to wind power which does not displace fossil fuels, from the viewpoint of receiving some set feed-in tariff payment. Regarding the use of heat generated, since each WtE plant is unlikely to be producing over 100 MW of heat (and strangely you don’t hear the term ‘waste heat’ in most of Europe as sale of heat is a major part of the revenue stream of such plants) it is quite feasible to have this go to supply heat needs of nearby industry that have a year-round requirement for it – regardless of our latitude, paper recycling, biofuels production, food processing, industrial laundries, and many other industries, are presently under pressure due to increasing cost of natural gas. For many it is their main input cost along with labour. Like 32. John Morgan, “Possibly wind blows harder when clouds block sunlight. Unfortunately I don’t have a dataset for solar PV output and can’t test this. My guess is that the number of days and the number of sites at which such anticorrelation occurs is not large enough to shift the average output of the total fleet enough to change the overall picture.” It sounds as if when you made that guess you were unaware that it’s usually sunnier when air pressure is high and windier when air pressure is low. Yet I posted that objection last time. Did you miss it? “The economic drag incurred by dealing with surplus generation by storage, curtailment or demand reduction undermines the economics of building additional capacity.” You don’t deal with surplus generation by demand reduction, you deal with it by demand induction! Do you consider that to be an economic drag? Or an economic boost? “The capacity of wind and solar is thus limited to be roughly numerically equal to 100% of grid demand.” Didn’t I explain last time why this was not so? If we accept it going over demand 1% of the time, the decline in profitability is likely to be less than 1% (though it’s hard to predict, as more money is made at times when prices are high than when they’re low). But the capacity would have to increase by far more than 1% to exceed demand. I remind you of what I said last time: I suggest you have another look at the graph you got from Hirth: it clearly shows the combination of wind and solar depressing prices less than wind only at the same overall market share. So if Hirth is right, surely that proves that your original argument is wrong? I also remind you of something else I said last time: there is no Catch22 of renewable energy storage. I am still willing to debate this with you at a site of your choice, though preferably not this one as the mods here are so overenthusiastic that they wouldn’t even let me say what I really thought of it. BNC MODERATOR As per BNC Comments Policy please supply references for your contentions. BNC is a science based blog which expects that commenters support their opinions with links/refs/data. Otherwise it is just your opinion not fact. Thank you. Like 33. Andrew All systems are subject to the law of diminishing returns or lower incremental value whichever way you want to express it. If there was one 6MW wind turbine or one 50MWe waste to energy plant on the system all its power could be absorbed whenever it was generating. Similarly if there was one 1.1GW nuclear power station in the Hunter Valley it would have little difficulty selling its power, however once the capacity of any source increases there would be more and more likely that on some days it cannot sell its power, that is not a big problem for open cycle gas or existing hydro because their daily fixed costs are very low. It is a big problem for coal, even bigger for wind and very large for nuclear because their ongoing capital and overheads are very large. Lets assume for the sake of the argument that we have 2GW of biomass 1GW which is running @90-98% CF and the rest load following to some extent so the average output is 1.5GW. Then we have 8GW of hydro and there are a few plants which can be expanded and one or two more which can be built so we have 10GW peak of hydro. Then if wind farms use high Su turbines and are spread over a wider area then we can count on 3-4GW of wind. Peaks occur in the late afternoon and so we can only assume 2-3GW of solar so now we have a total of renewables of around 18GW so if the peak demand is 25 we need 7-12 GW of nuclear or storage of some sort to cover the peak. Whatever technology you use, you get to a point where further investment in a particular type of technology becomes uneconomic. Nuclear and biomass have a higher value because they are dispatchable but even so, no-one is going to build a nuclear, biomass or geothermal plant to cover the last 5-10% of peak demand so you have a choice of gas, hydro or storage. There is no single metric that you can use to find the best solution. Even if wind or solar LCOE was half the next best choice it doesn’t cut it if there is no wind one night. The LCOE of open cycle gas is very high yet people build plants and make money because of their fast ramping, high value peak output. Hydro is great except for the next big drought and nuclear is great as long as demand is highly predictable 10-15 years out and no-one finds a generic fault in the fleet of SMR’s you installed 10 years ago and energy efficiency and LED lighting don’t blow away you spring and autumn demand. My premise is that Low carbon is essential, distributed generation is good, “Short time to light” is good. Scalability is good. LCOE is important and technological variety is also good. Of course high availability is critical and that favours gas, biomass and nuclear whereas scalability, and time to light favour wind and solar. Like 34. Interesting analysis John, thanks for sharing. I also spend a bit of time looking at wind data, and notice I have a few differences to you. It would be good to clarify them. The main point of difference is that I get an average capacity factor for the period (1/9/2014-31/8/15?) of 32.6%, compared to your 29% value. I think there are a couple of reasons for this discrepancy. I notice you have an nameplate capacity of 3753 MW. This seems a little on the high side – the AEMO generator list (link below) totals 3667 MW of wind. However AEMO’s list includes Codrington, Hepburn, Toora, Windy Hill & Wonthaggi, which as far as I’m aware, AEMO doesn’t provide the data for these (though please let me know if you have found this data). Are you including these wind farms (67 MW) in your installed capacity, but not in the average power output calculations? In calculating the average capacity factor, you’ve assumed the entire 3753 MW was installed for the entire year. However, several wind farms were still under construction during the year of interest, and thus weren’t at full power for the full year. These wind farms were Portland, Bald Hills, Boco Rock, Gullen Range, & Taralga. I’ve estimated the installed capacity of these projects for each month of the year in question, and once I’ve averaged the 12 months, I get an average installed capacity that is 150 MW less than the final installed capacity. Also, thanks for making the point that when looking at rule-of-thumb penetration limits for renewables, the fact that the entire fleet of wind is never at full power simultaneously means the capacity factor rule-of-thumb can likely be exceeded without curtailment. This is also important for solar, as the Australian fleet output for solar also rarely exceeds 75%, as indicated in live output from the live solar output from APVI. Moreover, I think once you incorporate solar output to the wind output, the max combined output will be significantly less than the max wind output added to the max solar output. Indeed, for the year in question, the max output of wind occurred during July. Presumably solar output will peak during the months of Oct-Feb. The peak wind output in these months is about 16% less than the July wind peak during this year of interest. http://www.aemo.com.au/About-the-Industry/Registration/Current-Registration-and-Exemption-lists http://pv-map.apvi.org.au/live#2014-11-23 regards, Dave Osmond Like 35. Peter Farley, My premise is that Low carbon is essential, distributed generation is good, “Short time to light” is good. Scalability is good. LCOE is important and technological variety is also good. Of course high availability is critical and that favours gas, biomass and nuclear whereas scalability, and time to light favour wind and solar. These are a statement of your personal beliefs and preferences. They are not those demonstrated by preferences expressed through market choices and they are not the requirements of the electricity system. The primary and secondary requirements of the energy system are: Energy supply requirements The most important requirements for energy supply are: Energy security (refers to the long term; it is especially relevant for extended periods of economic and trade disputes or military disruptions that could threaten energy supply, e.g. 1970’s oil crises, world wars, Russia cuts off gas supplies to Europe). Reliability of supply (over periods of minutes, hours, days, weeks – e.g. NE USA and Canada 1965 and 2003) Low cost energy – energy is a fundamental input to everything humans have; if we increase the cost of energy we retard the rate of improvement of human well-being. Policies must deliver the above three essential requirements. Lower priority requirements are: Health and safety Environmentally benign Why health and safety and environmental impacts are lower priority requirements than energy security, reliability and cost This ranking of the criteria is what consumers demonstrate in their choices. They’d prefer to have dirty energy than no energy. Electricity is orders of magnitude safer and healthier than burning dung for cooking and heating inside a hut. The choice is clear. The order of the criteria is demonstrated all over the world over thousands of years – any energy is better than no energy. Nuclear can meet these requirements much better and much cheaper than non-dispatchable ‘renewable’ energy. Renewables cannot make much of a contribution to meeting the requirements or to reducing global GHG emissions. (For more see the links in my previous reply to you). Like 36. Dave Osmond, Dr Wheatley’s analysis of the AEMO data for calendar year 2014 gave an capacity factor of 29%. I understand his analysis used the average installed capacity of wind farms in operation in 2014. His analysis was done for a submission to the the Senate Select Committee on Wind Turbines. You can access it from the Senate site, Submission No. 348 http://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Wind_Turbines/Wind_Turbines/Submissions , or more easily from his web site: http://joewheatley.net/emissions-savings-from-wind-power-australia/ Anyone interested in the topic of this thread is encouraged to read read this very thorough and excellent analysis. Like 37. Wheatley’s analysis has the same issue. He used the installed wind capacity at the end of 2014, 3394 MW, and assumed it was available for the entire year. As it turns out, an average of only 3105 MW was available, if you average the values for each of the 12 months. This brings the average capacity factor up to 31.2% Like 38. Some more comments on Dr Wheatley’s paper. I agree Wheatley’s paper is very thorough. Unfortunately it is highly misleading, and I also believe it to be fundamentally wrong. The paper claims wind is only 78% effective in reducing emissions. This is because the paper claims wind power makes up 4.5% of generation, but only reduces emissions by 3.5%. However, this effectiveness is highly misleading. Any new power station is likely to displace other generation with the highest marginal cost, which in most cases is gas. Consider building a new near zero-emission generator (wind, solar or nuclear) in Sth Australia (which is the state that has seen the most wind built). This generator is likely to mostly displace gas generation (the highest cost generator in SA), with an average CO2 intensity of about 0.6 tCO2/MWh. If this new generator supplied 1% of NEM demand, it would reduce emissions by about 0.7%. According to Wheatley’s definition, it would have an effectiveness rate of about 70%. In comparison, Wheatley’s determination that NEM wind was 78% effective illustrates that it actually did quite OK. To have effectiveness greater than 100%, you would either need coal to have a higher marginal cost than gas, or you’d need some other mechanism to reduce coal generation instead of gas. I also believe Wheatley’s paper to be fundamentally wrong, as it uses correlation analysis on a 5 minute time scale to determine what wind is displacing. However, what wind displaces on a 5 minute timescale is completely different to what it displaces over the longer term. On a 5 minute basis, Wheatley determined that wind displaced 5 times more gas than coal. This is not surprising, coal generation is unlikely to respond to short timescale fluctuations in the wind. However, the figure in the following article illustrates the long-term changes are completely different. There’s been very little trend in gas generation in SA since 2005. In contrast, there’s been a very strong decline in coal as it is displaced by the rapid increase in wind generation. So at the risk of appearing to contradict what I said in the previous paragraph, it appears that wind has successfully displaced coal in South Australia. Obviously this was helped by the declining quality and availability of coal in SA. http://www.businessspectator.com.au/article/2015/6/11/energy-markets/sa-coal-killed-wind-and-solar-origin-ceo-says-agl-should-worry Like 39. Dave Osmond, Thank you for that information. I see the first line of Section 2.1 of Wheatley’s report says: Wind provided 8.7TWh in 2014 or 4.5% of total energy generated. SCADA data is available for 34 wind farms with total installed capacity of 3394MW I understood that figure was the average installed capacity for calendar year 2014. You may be correct and the figures is not right, but I’d like to be able to check for the source data for myself. I haven’t found the installed capacities and commissioning dates on the “Registration and Exemption List” you linked here: http://www.aemo.com.au/About-the-Industry/Registration/Current-Registration-and-Exemption-lists . Can you give me a link to the source data for the installed wind capacity at start of 2014 and the capacity that was added and the commissioning dates through the year? Or a schedule of the installed capacity by month through the year, or whatever the basis was for the calculation of 3104 MW average installed capacity through calendar year 2014. For capacity factor we need the installed capacity of wind farms, not just those that are available. We have to be consistent with how capacity factors are estimated for all other technologies. Like 40. Dos74 — Linking to a subscriber only article is not helpful. Like 41. Sorry, here’s a link to the figure of the article. Y axis is proportion of SA demand coming from each type. Peter Lang, I will hopefully be able to provide the information you’re after tomorrow. Like 42. Tony Carden, I have heard that there is also a maximum speed at which Turbines stop operating for mechanical reasons. Do you have any information in relation to this? Good question, and I’m not across the details of the mechanical engineering of wind turbines so I have no particular insight. I imagine both the bending moments of the blades at the point of attachment to the nosecone, and the unbalanced axial loads transferred to the driveshaft and bearings, must become enormous as wind speed increases. I’d also be interested if others know more about this. Like 43. If you google “turbine power curve”, plus the name of the turbine, and look at the images, you should be able to see what the shut down (cut-out) speed is for various turbines. Most turbines cut-out at speeds of around 20m/s for a Class III turbine, and 25 m/s for a Class I turbine, and somewhere in between for a Class II turbine. Class I turbines are designed for windy sites, generally with an average wind speed > 8.5m/s, while Class III turbines are typically for sites with average speed < 7.5m/s (Class II turbines obviously between those 2 values). This brings us back to the point that Jens S and Peter F have been making. There have been rapid developments in Class III turbines in recent years, in addition to a general move in the industry from Class I to Class III turbines. This is because new sites are generally less windy than those developed a decade ago. A Class III turbine will achieve a much higher capacity factor than a Class I turbine at a given site, as it will have a higher swept area to generator size ratio. It will achieve rated capacity at a lower wind speed. This also means it has a lower efficiency at the higher wind speeds, but at a low wind speed site, this is less important. There is a lot less force on a turbine if it is shut down at higher wind speeds, so this means that a Class III turbine can be made cheaper, lighter and less strong than a Class I turbine, obviously at the cost of generating less power at these higher wind speeds. Like 44. Tony Carden my understanding is that all turbines have an rpm that is the limit at which blades start to feather – this is reached usually around windspeed of13-15 m/s, and at around 25 m/s they will brake and stop. So rated output of the nameplate capacity is being produced at this rpm (often around 15-16 rpm but differs for each make and rotor diameter). This information is given by the manufacturer along with the curve of output against windspeed. Like 45. Aidan Stanger, It sounds as if when you made that guess you were unaware that it’s usually sunnier when air pressure is high and windier when air pressure is low. Yet I posted that objection last time. Did you miss it? Indeed I did not, for I responded to it on that thread here. I heard on that thread that wind and solar are anticorrelated across: *summer / winter *day / night and afternoons / mornings / midday *and with weather. These were offered without data. The data above shows first two contentions are wrong. You are now advancing the third, again without data. I would say that you are guessing too. Yes, there are windy storms and calm sunny days. There are also sunny days with wind (like today), and days and weeks where the rain sets in and wind is low. There are advancing storm fronts that drive wind in sun ahead of a breaking storm. Where is your data to show wind and sun are anticorrelated, at what time resolution, and for what fraction of the time? How do you determine that this happens for a significant fraction of the time? Does it rain more in the afternoons, or at night time, or midday? If so, there’s no correlation between wind and rain because the day-by-hour analysis shows nothing. Maybe cloudy rainless wind occurs to a sufficiently large degree to shift the conclusions. But now you’re relying on weather to cooperate with your argument. I don’t buy it. Bring me the data. You don’t deal with surplus generation by demand reduction, you deal with it by demand induction! Do you consider that to be an economic drag? Or an economic boost? Quite so. I meant to write “demand management”. Good catch. I regard it as an economic drag, because you are asking energy consumers to behave contrary to their default energy usage. This is the grid requesting a service from controllable loads, and the owners of such loads request payment for this service. “The capacity of wind and solar is thus limited to be roughly numerically equal to 100% of grid demand.” Didn’t I explain last time why this was not so? Not in any way I found compelling. I’d point out that I have not dwelt on limits that cut in before this 100% demand share either, in particular the requirement to spill (etc.) well before 100% of demand is reached by wind and solar in order to retain sufficient share of synchronous generation for frequency control. I remind you of what I said last time: I suggest you have another look at the graph you got from Hirth: it clearly shows the combination of wind and solar depressing prices less than wind only at the same overall market share. No, it doesn’t. I explained how this worked in this comment. Hirth’s data does not show wind and solar depressing prices, it show depressing value factors of wind, and wind and solar in combination. It is not presented in a way that allows a direct test of the thesis, but I was able to slice the data through two data points that did allow such a test, which I annotated the graph with, and which do support the thesis. the mods here are so overenthusiastic that they wouldn’t even let me say what I really thought of it. Your last comment on that question was deleted as abusive before I saw it. Quite frankly I was grateful to the mods for sparing me from having to read it. Like 46. Dave Osmond Instead of assuming that wind compete against natural gas power plants you should understand the point that John Morgan makes about the needed natural gas back up for wind power. And if this is not convincing you should look at the actual development in markets with wind power penetration closing in on the capacity factor limitation also argued by John Morgan. In these market the power generation that is made obsolete when wind power is introduced is slow coal power plants. Peter Lang and others argues that wind power has an issue with grid integration cost whereof some of these grid integration cost should be directed to peak power plants. Logically the attribution of cost and the attribution of CO2 abatement effect should follow each other. If you follow logics and the real life observed decline of coal power plants capacity factor when wind penetration rise with associated natural gas peak power plant penetration then you should factor the combined wind/gas CO2 abatement effect in as 100% of what the substituted coal power plants consumed minus the CO2 emission from the wind/gas solution. The usual decision making when coal power plants are being made obsolete is to take those coal power plants that has the largest running costs offline first, which is almost always the oldest and least effective coal plants, so the CO2 abatement effect is almost always higher than the average CO2 emission from coal power on the grid where wind/gas substitute coal power. Coal power plants that ramp up and down fast has considerably lower than achievable efficiency. With wind/gas on the grid coal power plants can most of the time be driven with less variation and slower ramp up and can even be moth balled in seasons where their output is not required. These better driving strategies for coal power plants further increase the positive result of a logics and fact based CO2 abatement calculation. Finally and very relevant many places on earth the pull on fresh water reserves and seawater resources release any GHG they may contain including water vapor and especially for fresh water the cooling water consumption may impact hydropower and or irrigation and thus respectively decrease hydro power output and limit carbon capture in plants and soil. On the down side coal power plants are run by businesses that could not care less about CO2 abatement so they will always try to supply all they got when there is are a margin to be earned. Further if the waste heat is used for district heating or process heat they may have obligations that oblige them to run even at times where they have negative margins on the electricity they can sell. In conclusion your comment about the unlikely achievability of more than 100% CO2 abatement effect is probably wrong. Wind/gas can achieve more than 100% CO2 abatement effect in real life conditions. As for your comments about the actual capacity factor I do not think that there has been any attempt to tinker creatively with the numbers. I think John Morgan is fully aware of the development in wind power and the ongoing increase in capacity factors as well as the accompanied decrease in LCOE since his business focus upon innovations within grid scale storage and smart grid. Ps. Thumbs up for your correct thrashing of the Wheatley paper where you indadvertedly deliver some of the logical arguments supporting why we in the marketplace see a rise in wind/natural gas and a decline in coal power, which both I and John Morgan have already made. Like 47. John Morgan, The correlation between sunshine and high pressure is easily explained: in low pressure conditions the air rises, therefore cools, therefore clouds form as the water vapour in the air condenses. Whereas in high pressure conditions, air falls, therefore warms, so it’s not conducive to cloud formation and clouds can even evaporate. Is that clear enough or do you require a link? The link between wind and low pressure I’m not quite so clear on. Wind is stronger where the pressure gradient is stronger. The pressure gradient is usually stronger in low pressure conditions. I admit I’m not sure quite why that is, but the relationship is clear – see http://scialert.net/fulltext/?doi=jas.2011.2712.2722 “Does it rain more in the afternoons, or at night time, or midday?” In equatorial regions it rains more in the afternoons because of convectional uplift. Elsewhere I’m not aware of any difference. “I regard it as an economic drag, because you are asking energy consumers to behave contrary to their default energy usage. This is the grid requesting a service from controllable loads, and the owners of such loads request payment for this service.” The way I see it, it’s an economic boost, because it gives electricity consumers the opportunity to save money by changing their energy usage pattern to take advantage of cheaper electricity. Why do you not see it like that? “Not in any way I found compelling. I’d point out that I have not dwelt on limits that cut in before this 100% demand share either, in particular the requirement to spill (etc.) well before 100% of demand is reached by wind and solar in order to retain sufficient share of synchronous generation for frequency control.” But many of the wind turbines do synchronous generation. And synchronous generation isn’t the only means of frequency control. Some places use flywheel storage for that purpose (I’m not going to hunt the link right now, but I can find it tomorrow if you’re interested). I expect it’s also possible to do it purely electronically; are there any electrical engineers here who can confirm or refute that? “Hirth’s data does not show wind and solar depressing prices, it show depressing value factors of wind, and wind and solar in combination. It is not presented in a way that allows a direct test of the thesis, but I was able to slice the data through two data points that did allow such a test, which I annotated the graph with, and which do support the thesis.” If the proportion of solar really is “matching” then you pointed out that 10% wind + 10% solar depresses the value factor more than 10% wind alone. Which is so obvious that I’m surprised you thought it needed highlighting. But if you look at the same RES market share, you’ll see that the Solar and Wind curve is above the Wind Only curve; it depresses the value factor less. Were the Less Than The Sum Of Its Parts hypothesis correct, the Solar and Wind curve would be below the Wind Only curve, as it would depress the value factor more. Like 48. David Osmond, Thank you for your comment. Critiques are valuable. However, I think you have misunderstood what CO2 abatement effectiveness means. It is “ratio of % CO2 emissions savings to % wind power generation”. Another way to think of it is: if the average CO2-e emissions intensity of the grid is 1 t/MWh and wind energy saves 0.8 t/MWh, the abatement effectiveness is 80%. If wind energy saves 1.2 t/MWh, as would be the case if it displaced generation from high emissions intensity brown coal generation, the abatement effectiveness would be 120%. Abatement effectiveness decreases as wind energy penetration increases – unless there are significant other factors changing the dispatch order of the technologies in the grid. ERCOT is an example where this has been occurring. The abatement effectiveness of wind has been increasing because the cost of gas has been reducing relative to the cost of coal. So there has been a move towards gas generators becoming the baseload generator and coal becoming the intermediate generators. Coals is ramping and cycling more in ERCOT now than was the case when gas was more expensive. However, that is not the case in Australia, and unlikely to happen any time in the foreseeable future. In fact gas prices are projected to increase, not decrease relative to coal. Your chart of proportion of South Australia’s generation from each type of generator (i.e. fuel type), shows declining coal proportion as wind proportion increases. But this is not a plot of abatement effectiveness. A plot of abatement effectiveness for these years would almost certainly show that effectiveness decreases as the proportion of wind generation increases. This is significant because it means the estimates of CO2 abatement cost are underestimates and increasingly so as wind penetration increases. The chart of Herbert Inhaber analysis of many earlier studies of CO2 abatement effectiveness shows the shape of the curve, although we now know there were problems in the Inhaber analysis such that the curve is too low, but the shape seems to be supported by the growing evidence from recent studies such as Wheatley’s for Ireland and Australia and Daniel Kaffine et al. for various US grids. Ref: “CO2 avoidance cost with wind energy in Australia and carbon price implicationshttps://bravenewclimate.com/2011/05/21/co2-avoidance-cost-wind/ Wheatley’s analysis demonstrates the importance of analysing the whole grid, not just South Australia in isolation. Wind power in South Australia is mainly backed up by cycling and ramping of relatively efficient (high cost) black coal power stations in NSW, rather than brown coal in Victoria. This explains why wind power generation abates less than the average intensity of the grid. Like 49. Hi Peter Lang, this is not exactly what you are after, but hopefully it’s sufficient. If you go to the link below, it will show you wind farms operating on Dec 31, 2014 for which AEMO data is available. It contains all the wind farms in the AEMO register, except Codrington, Hepburn, Toora, Windy Hill & Wonthaggi, for which, as far as I’m aware, AEMO doesn’t provide data. That is 35 wind farms with an installed capacity of 3601 MW. Note the AEMO list has Boco rock (BOCORWWF1) listed twice, I have ignored that duplication, though included the full capacity of 113 MW. On Dec 31, the anero web site also excludes Bald Hill, which isn’t yet generating. That leaves 34 wind farms with an installed capacity of 3493 MW. If you go back to the beginning of Dec, you will also see Taralga disappear, as it also wasn’t yet generating. I am guessing Wheatley also excluded this wind farm. That leaves 33 wind farms with an installed capacity of 3386 MW, not quite the same as what Wheatley quotes, 34 wind farms with a total capacity of 3394 MW, but the installed capacity is very close, and the Boco rock WF duplication may explain the mismatch in wind farm number. Now if you go back to Aug 2014, you will also see Boco rock disapear, as it is not yet generating. Now we are down to 3273 MW. Hopefully this is enough to tell you Wheatley’s value is not an average installed capacity for the year. To explain how I calculate the installed capacity each month for wind farms under construction, for each month I determine the max generation, according to AEMO data, and add 5%. If this is greater than the official registered capacity, then I use that instead, and continue to use that for thereafter, considering that farm is now fully commissioned. To give you some reassurance, it is rare for a modern wind farm to not reach 95% of its installed capacity in any month once it is fully commissioned. I calculate an installed capacity of 2819 MW at end Jan, 2014, and 3396 MW at end Dec, 2014. The 12 month average for 2014 I get to be 3105 MW. At the end of Jan 2014, the following wind farms were not yet generating or at full capacity. Bald Hills, Boco Rock, Gullen Range, Mt Mercer, Snowtown 2 Nth & Snowtown 2 Sth Some more information Like 50. Hi John Morgan, You have an afternoon bias in your definition in solar hours of 10am to 4pm. Remeber AEMO time is AEST, and does not include daylight savings, so the peak hours should be centred approximately around noon, although solar data from SA will shift that somewhat to after noon. As your diurnal plots indicate, wind output often picks up in the afternoon after 2pm. If you remove your afternoon bias, and define solar hours 10am-1:59pm or 9am-2:59pm, then you will start to see wind farm output during non-solar hours exceeding those during solar hours. The SA solar data justifies a slight bias to the afternoon, so perhaps 10am:2:59pm or 9am:3:59pm could be reasonable. Also, my analysis of AEMO data since 2008 indicates wind output is greatest during the months of July, Aug & Sep (CF~37%), and least during the months of Mar, Apr & May (CF~30%). The peak wind months certainly help offset most of the poor solar months in winter. But obviously it would be nice if the wind in May was more productive. I suspect this will be the problem month if we aim to get most of our electricity from wind and solar. Like 51. David Osmond, Thank you for that explanation. I am not able to download all the required data from AEMO so I cannot check what Wheatley used. But I did ask him if the capacity factors were calculated on the basis of end of year capacity or average capacity for the year and he replied it was average capacity for the year. He was getting all the data from AEMO. He would have correctly used the capacity from commissioning date, and not have subtracted periods where they are out of operation for whatever reason. But we can always make mistakes and there are many errors in AEMO data too. Like 52. Further points about capacity factor It is obvious that any excess capacity is an economic drag, but the focus in this debate seems to be on generation rather than demand. To meet peak demand there has to be some capacity that is not fully used all the time The current Australian grid plus rooftop solar averages a bit under 47% CF. Without rooftop solar it is almost exactly 50%. Almost all assets are the same, cars, trucks, railway lines etc. very few are used at even 90% capacity. Returning to energy and looking at individual sources nobody seems too upset that hydro CF is around half that of wind because the operating costs are low and the despatchability is high. OCG has very low capital costs very high ramp rates (up and down) but again has a capacity factor anywhere between 10 and 20%. Again nobody complains too much Conversely when a coal power plant falls below 55% CF or nuclear below about 70% it becomes very difficult to service the fixed costs, interest, staff, depreciation, maintenance, security and the end of life clean up trust fund. If we plan for peak demand at 35GW with say 8 GW of hydro running at 80% and 5GW of wind and +10GW solar running @5% and biomass at 1.5 @ 85% on a hot still afternoon then we need 26GW of other plus a reserve of 3-4 so alternative sources have a total of 30GW. Lets say that is all nuclear we then have an annual capacity at their respective capacity factors of 9Tw.hrs hydro (15%), 11 TW.hrs wind (30%), 12 TW.hrs solar (70%), 10 TW.hrs biomass (85%) and 240 TW.hrs of nuclear (90%) i.e generation of 280-290TW.hrs. However the system only needs about 190TW.hrs so we can’t in fact reach the capacity factors above. Even if we reduce the biomass by half and in the next parliament we get approval to go nuclear, by the time the first plant is started wind and solar will already reach or exceed the above capacity. The marginal cost of output from wind and solar is much lower than nuclear so either the nuclear plants will give power away or they will generate about 150-160TW.hrs of power therefore having a capacity factor of 60%. So the sensible thing to do is to build about 20-23GW of nuclear @85-90% and 7-10GW of storage/enhanced hydro. Of course now that we have storage on the system the marginal cost of delivering wind and solar to storage is lower than the marginal cost of nuclear so there is an incentive to build more wind and solar and even less nuclear so the optimum number and generation contribution of nuclear falls further. All this assumes the worldwide trend to de-industrialisation and higher energy efficiency does not continue or in fact accelerate, which is the most likely scenario. It also assumes continued economic growth in Australia. If a company was borrowing money for a 7-10 year project with a 30 year payback after that time there are some big ifs to overcome. Like 53. For those interested in further information on wind farm capacity factors in Australia. AEMO has provided capacity factors for Sth Australian wind farms in its historical market information report. Fig 7 indicates the average capacity factor for Sth Australian wind farms was 32.7% (not weighted by project size). It also indicates that the average CF was 31.8% during summer and 34.8% during winter (36.2% if you ignore some extremely low CFs resulting from wind farms not yet fully constructed). http://www.aemo.com.au/Electricity/Planning/South-Australian-Advisory-Functions/South-Australian-Historical-Market-Information-Report Like 54. David Osmond, Fig 7 indicates the average capacity factor for Sth Australian wind farms was 32.7% (not weighted by project size). Thank you for the link. It is for several financial years with no total given for SA. I presume you have averaged the numbers but you didn’t say for which year. Wheatley calculated the capacity factor of wind power by state for calendar year 2014 on page 10, http://joewheatley.net/wp-content/uploads/2015/05/sub348_Wheatley.pdf as: Capacity factors at regional level were 19%(NSW), 35% (TAS), 31%(SA) and 28%(VIC). The capacity factor figure you quoted and Wheatley calculated for South Australia are fairly close and I think arguing about such small differences here is distracting from the important, policy-relevant points which I would summarise as: Average capacity of factor of wind in the NEM was about 30% in 2014 CO2 abatement effectiveness of wind in the NEM in 2014 was 78%. This is consistent with the abatement effectiveness in other girds (e.g. ERCOT) with similar proportions of coal,gas and wind generation and similar wind energy penetration. CO2 abatement effectiveness decreases as wind energy penetration increases. – Estimates of CO2 abatement cost that assume wind power generation avoids the average emissions intensity of the grid are incorrect. They underestimate CO2 abatement cost in inverse inversel proportion to CO2 abatement effectiveness – e.g. if CO2 abatement effectiveness is 50%, then the CO2 abatement cost is underestimated by a factor for 2 (i.e needs to be increased by 100%.) This last point is the important policy-relevant issue. Like 55. Some commenters have been querying moderation rules. Please avoid posts that are convoluted, irrelevant (Off Topic -there is a separate thread for these) repetitious or circular. Do not offer as fact what are simply opinions about complex matters.To avoid this provide scientific data, links, refs to support your arguments. Remain civil throughout. Rudeness will not be tolerated. Thank you. Like 56. Peter, you suggest that we are only dealing with small differences in capacity factor. However you then quote Wheatley’s claim that wind farms in NSW had a capacity factor of 19%. This clearly illustrates the misleading way he has calculated the capacity factor. The average capacity factor for the NSW wind farms that were fully operational during all of 2014 (Capital, Cullerin, Gunning & Woodlawn) was 29% in 2014. The only way you could get 19% for NSW is by including both Gullen Range and Taralga wind farms in the totals, and ignoring the fact that Taralga only started to generate in the final month of the year (and even then, less than 25% of the project was operational), and Gullen only reached full capacity in December. And you repeat Wheatley’s claim that wind is only 78% effective at reducing emissions. A claim which is based on 5 minute correlation analysis suggesting wind displaces 5 times more gas than coal. This claim looks highly dubious after looking at South Australia’s generation since 2005, which indicates wind has displaced much more coal than gas in that state. Perhaps I can summarise some relevant policy points of my own average capacity factor of wind generation in the Australia is 34%, based on data from 2008 till end Oct 2015 the average capacity factor of wind in winter is above average at 37%, which will help complement the low capacity factor of solar in those months data from South Australia has demonstrated that wind can primarily displace coal generation, albeit with the help of interconnector flows from Victoria even with energy penetration rates of 33%, 5 minute variations in wind generation in South Australia are still less than 5 minute changes in demand, and significantly less than the reserve required to cope with the sudden and unexpected loss of a large coal or gas power station in that state. For that last point, see Fig 12 in the South Australian wind study report. http://www.aemo.com.au/Electricity/Planning/South-Australian-Advisory-Functions/South-Australian-Wind-Study-Report Like 57. David Osmond, The only way you could get 19% for NSW is by including both Gullen Range and Taralga wind farms in the totals, and ignoring the fact that Taralga only started to generate in the final month of the year (and even then, less than 25% of the project was operational), and Gullen only reached full capacity in December. I accept Wheatley’s have used incorrect capacity factors or he may have obtained incorrect data from AEMO. But at the moment you haven’t provided the correct data I’d need to be able to send him before I could ask him a question. I can’t just post a comment on his web site telling him he’s wrong. Can you provide the capacity factors for wind generation in each state of the NEM for 2014 and provide links to the AEMO sources to support the figures you provide? I need to be able to reproduce the figures you provide. And you repeat Wheatley’s claim that wind is only 78% effective at reducing emissions. A claim which is based on 5 minute correlation analysis suggesting wind displaces 5 times more gas than coal. This claim looks highly dubious after looking at South Australia’s generation since 2005, which indicates wind has displaced much more coal than gas in that state. I did respond (nicely) to this point in an earlier reply to you. I’ll try to be clearer. I think you have misunderstood what CO2 abatement effectiveness means as used in Wheatley’s analysis. It is defined and explained in Wheatley’s submission and I quoted the definition in my previous comment. Your comment about 5 minute data suggests you not understand how analyses of CO2 emissions avoided by fluctuating-power, intermittent generators are done. These analyses have to use short period data. The shorter the better. 1-minute data would be even better. [However, as an aside, because the 5-minute data is MW as-generated, rather than MWh sent-out and measured at the regional nodes, which is the basis for all the commercial settlements and for AEMO’s calculations of CO2 emissions from the NEM generators, it would be better to use the latter because it is energy. But this data is commercial in confidence and not publically available. It was not available for this study. However, Wheatley estimate any error caused by this would be less than 1%. ] Your “highly dubious” assertion is your opinion, unsupported by evidence. You haven’t provided what you believe is the correction required nor what you believe the correct values are. If you want to make a constructive critique, it would be more valuable if you detail what corrections need to be made to the analysis and quantify what you believe is the error. It would help if you said how much difference your suggested revisions would make to the CO2 abatement effectiveness of wind generation in the NEM in 2014. The fact that the calculated CO2 abatement effectiveness in the NEM at 4.5% wind energy penetration is similar to that calculated for ERCOT by Daniel Kaffine et al. when wind energy penetration was 4.7% is a reasonable reality check on Wheatley’s estimate for the NEM. Furthermore, the NEM and ERCOT abatement effectiveness figures fall on the trend line with the figure for Ireland, i.e. 53% effective at 17% wind energy penetration. All in all, the Wheatley calculation of 78% CO2 abatement effectiveness for the NEM at 4.5% wind energy penetration, looks reasonable. It’s recognised, of course, there are always uncertainties, and it would be excellent to reduce them. Wheatley’s report points out what he believes are the main causes of uncertainty in the analyses and what could be done to reduce them. The main one is to get better CO2 emissions data for the few power stations that are responsible for most of the ramping and cycling for backing up for wind power variability. You could gain a fuller understanding of the analyses by reading Wheatley’s peer reviewed paper on his study for Ireland “Quantifying CO2 savings from wind power”: http://www.sciencedirect.com/science/article/pii/S0301421513007829 or the free pre-submission version here: http://joewheatley.net/how-much-co2-does-wind-power-save/ . You may also find the Sustainability Energy Authority of Ireland (SEAI) modelling study, which was done in response to Wheatley’s study, of interest. You can download it from here: http://joewheatley.net/quantifying-co2-savings-from-wind-power-redux-ireland-2012/ Perhaps I can summarise some relevant policy points of my own I don’t regard your points as policy relevant. What do you believe is the abatement effectiveness in each year (not average for 5 years); please provide links so your figures can be reproduced. It is the abatement effectiveness that is policy relevant because that’s what we need to understand so the errors in the estimates of CO2 abatement cost can be corrected. See the chart here: http://www.onlineopinion.com.au/view.asp?article=17447&page=0 Like 58. Two typos in my previous comment: Opening sentence after first quote should read: “I accept Wheatley may have used incorrect capacity factors …” This paragraph was intended to be a quote: And you repeat Wheatley’s claim that wind is only 78% effective at reducing emissions. A claim which is based on 5 minute correlation analysis suggesting wind displaces 5 times more gas than coal. This claim looks highly dubious after looking at South Australia’s generation since 2005, which indicates wind has displaced much more coal than gas in that state. Like 59. Dos 74 Thanks for that information. As the newer wind farms have better technology (i.e lower Su – higher CF) then the average CF will increase. So in 7-10 years if we have 7 GW wind @ average 37% then generation is more than 22TW.hrs per year which knocks out another$5-6b from the required investment for 95-98% carbon free electricity

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60. I have to agree with Peter Lang.

I also think it is unhelpfull in these discussions to use examples from areas that are only part of a Grid. In the graph of SA , I notice in the graph the Interconnector.

When is the Interconnector used?

I am guessing, but I think it is at times of Peak Demand.

There is no Interconnector for the Australian Grid. It runs from north of Cairns to West of Adelaide.
In terms of Grid management and whole of Australia solutions it is generally of little interest to me what is going on in Denmark, Portugal or Scotland because for a start they all represent a very small part of a very big grid.
Examining Ireland on the other hand is useful because it is an island nation like Australia. The management of the Irish grid can give Australia an insight into how to manage VRE’s to ensure grid stability, etc

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61. David Osmond,

You’re right about capacity factor discrepancies. I counted capacities for all wind farms listed as registered participants in the AEMO Registration and Exemption list. This includes Codrington, Hepburn, Toora, Windy Hill & Wonthaggi. However, as you point out, these are not reporting data, so I should remove them from capacity calculation.

The Registration & Exemption list gives the DUID (Dispatch Unit Identifier) by which the generator is identified in the SCADA files. But it is incomplete and does not give a DUID for several wind farms. I managed to find them in the data, all except for Portland wind farm, which I have now found with the DUID PORTWF. Portland energy is not included in the data, so I need to add that in.

Note that there were other problems with the AEMO data – I mentioned in the article many double entries from wind farm energy records that I found at a late stage and had to detect and filter out.

When I make these adjustments there will be a modest increase to the capacity factor that will probably align with the value you calculated. I’ll ask Barry to update the article when I do that.

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62. David Osborn,

You have an afternoon bias in your definition in solar hours of 10am to 4pm.

Yes, but I did play around with the the bounds of the solar period and found the calculated capacities were quite insensitive to the the exact hours chosen. Here is the plot redone for the periods you suggest:

There’s essentially no difference between these plots, and the 10am-4pm plot in the article, and the conclusions drawn therefrom remain the same.

This incidentally is partly why I think the anti correlation between wind and solar due to weather is probably weak – if the day/night capacity factor calculation is robust towards moving the solar window around by many hours, the less profound influence of weather is also unlikely to shift the weight of the pattern significantly.

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63. Sorry, mucked up the markdown formatting for the images. There are at

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64. As I am associated with the electricity industry in South East Qld I am aware that the impact of solar PV on this section of the grid has been to move peak demand from (4pm -6pm) to (6pm – 8pm).

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65. Peter Lang, I apologise, I missed your reply to me yesterday morning, and did not read it before I replied in the evening. Never-the-less, I feel that you do not seem to understand my criticism of the Wheatley paper. In Table 2.2, Wheatley indicates than 1 MWh of wind in SA displaces just 0.06 MWh of brown coal in SA, but 0.320 MWh of gas. However we know that coal generation in SA has reduced rapidly in the last decade, as wind generation has rapidly increased, and gas has had very little trend. Indeed coal generation is due to cease completely early next year and the owner of the coal generators blamed the rise of renewables in part for the decision to close the power stations. In light of this, how can the Wheatley figures that suggest wind in SA has displaced a negligible amount of coal in SA be considered credible?

Wheatley obtained his figures by using 5 minute correlation analysis. However this analysis completely misses any longer-term decision making by the owners of generators, or indeed any other long-term trends.

Please let me try an analogy. I suspect there is a very poor correlation between 5 minute demand in Victoria, and 5 minute brown coal generation. The brown coal generators often produce at a near constant level regardless of demand. However we cannot use this correlation analysis to deduce that brown coal generation does not significantly contribute to meeting demand in Victoria. However this is similar to the logic leap that Wheatley uses to determine that wind generation in SA displaces very little coal generation in SA.

Let me also try a thought experiment. Let us suppose that next year we build a nuclear plant in SA. A 520 MW nuclear plant running at 90% capacity factor would generate 4.1 TWh of power in SA, matching almost exactly the contribution from wind in 2014 according to Wheatley.

This nuclear is most likely to primarily displace the high marginal cost SA gas generation, namely from Osborne & Pelican Pt, and probably also some from Torrens A & B. These have an average emission intensity of about 0.6 tC02-e per MWh. If demand on the NEM remains similar to what it was in 2014, then this nuclear plant, producing approximately 2.1% of the 194 TWh NEM generation, would have saved approximately 1.4% of NEM CO2-e emissions. According to the definition in the Wheatley paper, nuclear is therefore 69% effective. Wind at 78% is suddenly looking not so bad in comparison.

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66. Dave Osmond,

Thank you for your reply. I do understand your criticism and I’ve understood it each time you posted it. I replied each time and explained that I believe your criticism is invalid. I’d respond that you do not seem to understand the meaning of CO2 abatement effectiveness and its relevance for estimating the CO2 abatement cost of fluctuating-output, intermittent generators.

If you want to see the trend of how CO2 abatement effectiveness changes over time you need to calculate it for each year and chart CO2 abatement effectiveness of wind generation against time, similar to the chart you’ve posted of generation by technology/fuel type in South Australia.

You also seem to not understand that we have to analyse the emissions avoided by wind across the whole NEM, not just in South Australia.

The Wheatley analysis is an analysis of empirical data. We have to go where the numbers take us. If there are errors in the analysis method or input data we should certainly try to find them and report them to Wheatley. However, I suggest the criticisms you’ve raised so far about 5-minute data versus multi-year trends are invalid criticisms of his analysis, the results and the very important policy implications of those results.

I’ll leave aside discussion of your thought experiments. The Wheatley analysis is of empirical data. Thought experiments should be tested using dispatch models such as used by SEAI in their analysis of emissions avoided by wind in all of Ireland grid for year 2012.

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67. Thanks kindly John Morgan for responding for my comments, and for taking the time to look at other solar-hours definitions.

Regarding your comment that the anti-correlation between solar and wind is weak, it should be pointed out that even a zero correlation is still a good result. Obviously wind is positively correlated with other wind, and solar positively correlated with other solar. However if there is no correlation between wind and solar, then the chance of a few days of very poor solar resource coinciding with a few days of very poor wind resource is greatly reduced.
And as I’ve posted elsewhere, wind does tend to be more productive during winter than summer, which is very helpful.

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68. I would like to clarify a few issues.

The key policy-relevant issue is: what is the CO2 abatement cost with wind generation and how does it change as wind energy penetration increases?

Many analyses show that CO2 abatement effectiveness decreases as wind energy penetration increases. I’ve provided links to Wheatley’s empirical studies of Republic of Ireland and of NEM, SEAI’s modelling study for all of Ireland grid (for a different year than Wheatley’s study), and mentioned Kaffine’s empirical study of ERCOT and Inhaber’s analysis of many earlier peer reviewed studies (and mentioned his curve is too low).

Wheatley’s figure of 78% CO2 abatement effectiveness of wind power generation in the NEM in 2014, when wind energy penetration was 4.5%, is the best figure we have. Nothing said in the comments on this thread has given any valid reason to doubt the 78% figure.

Dave Osmond has said that the capacity factors stated in Wheatley’s report understate the true capacity factors because they overstate the average installed capacity of wind power in 2014. This criticism may be correct and I am waiting for David Osmond to provide data and sources so the capacity factors can be recalculated and corrected if they are wrong.

It is important to note however, the state average capacity factors play no part in the calculation of CO2 emissions saved by wind generation or in the calculation of CO2 abatement effectiveness. Therefore¸ any changes to the state average capacity factors will not change the 78% CO2 abatement effectiveness figure nor will they change the corrections needed to CO2 abatement cost estimates (which are significantly understated). [The only capacity factor relevant in the calculation of emissions avoided is the capacity factors of the thermal generators that cycle and ramp in response to changing wind power output – see equation 3.2, p21 http://joewheatley.net/wp-content/uploads/2015/05/sub348_Wheatley.pdf ).

This chart shows the relationship between CO2 abatement effectiveness and the correction required to estimates of CO2 abatement cost if the estimates were based on the assumption that wind power generation abates the grid average emissions intensity.

Source: http://www.onlineopinion.com.au/view.asp?article=17447&page=0

One last point, the CO2-e abatement effectiveness in the NEM in 2014 would be 75% (instead of 78%) if it was calculated on the same basis as is used in the EU and USA. The Australian estimate is based on emissions intensities using both combustion CO2-e emissions (Category 1) and fugitive CO2-e emissions (Category 3), whereas in EU and USA the calculation is done using combustion emissions only.

I’d also like to add that I greatly appreciate Dave Osmond’s critique. CO2 abatement effectiveness is very important and very few people have an appreciation of how important it is for estimating CO2 abatement cost. As a result, CO2 abatement cost is being significantly understated in most if not all estimates. It is important to get those who do the estimates to understand this concept. However, it is important that the numbers presented in analyses such as Wheatley’s are correct. Therefore, critiques like Dave Osmond has contributed on this thread are very valuable. I’ve appreciated the exchange on this important policy relevant issue.

I’d also thank John Morgan again for the post and BNC for facilitating such discussions.

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69. “The chance … is greatly reduced”. Occasional probability eventually becomes near-certainty of zero-zero power. If we dont want every near-record cold snap to take out a near-record harvest of our frail citizens, the entire capacity would have to be duplicated in despatchable power – probably all OCGT (gas).

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70. Hi John Morgan, just a few more comments about the diurnal analysis of wind. For the 1 year of data corresponding to the 1 year you used, I have wind being ~4% less productive than average during the middle of the day during the ‘solar hours’. I agree there is not a great deal of difference if you shift the solar hours around by an hour or so, so apologies for sending you off on that wild goose chase. Using 5 years of data (from Jan 2010 to Jan 2015), I get wind being about 5% less productive during the middle of the day.

Obviously solar is massively more productive during the solar hours, perhaps ~300-400% more productive than the 24 hour average.

Meanwhile, electricity demand during the solar hours is about 5% more than the 24 hour average.

What I am getting to, in a very round-about way, is that demand is lower during the night than during the day. We don’t necessarily want wind to be completely anti-correlated with solar, producing primarily at night and little during the day. Obviously we want the combination to add up to something that closely resembles demand. That may mean that wind produces only a fraction more during the night than during the day, which is what we are seeing.

Having said all that, I am a firm believer that battery storage will take off in the next decade, and in the next couple of decades the NEM will have of order 100 GWh of battery storage which will help us to match supply and demand over the course of a day.

However matching supply to demand on a daily, weekly or seasonal basis will be much more challenging if we rely on a high penetration of wind and solar. So when analysing correlations between wind and solar, I think it will become more important to do this on these longer timescales, rather than on hourly timescales.

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71. Dave Osmond,

Battery storage is an order of magnitude more expensive than pumped hydro and pumped hydro is not viable at current prices. So I see little chance that the optimistic claims about battery storage are likely to become a reality. Furthermore, 100 MWh storage can have negligible impact on making wind and solar a viable alternative to dispatchable power supplies – which is what is needed.

There are interesting links on energy storage here:
Energy Matters The Renewables Future – A Summary of Findings http://euanmearns.com/the-renewables-future-a-summary-of-findings/

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72. Roger, I certainly agree that there is a strong possibility that there will be days of the year with simultaneous low wind and low solar. So this will require substantial back-up. Bear in mind the NEM currently has ~11 GW of gas generation, about half of which is OCGT, plus another ~8 GW of hydro.

So the NEM already has a fair bit of potentially useful back-up for a high penetration renewable grid.

However if we sensibly combine wind and solar, their lack of correlation, or perhaps small negative correlation will reduce the amount of time that this back-up is required, compared to a wind-only or solar-only scenario.

Obviously it would be nice to reduce the required capacity of back-up generation. But reducing the amount it is used is certainly a worthy achievement,

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73. Of that 5 or 6 GW of OCGT in the Oz grid, much of that rapid-despatchability is already committed. Around where I live (off the NEM), crushing plants at mines throw 10 MW of demand on and off. When the OCGTs are winding up to back up the sudden demand, they are not available to back up a sudden loss of supply.

Any spare capacity in Oz’s OCGT fleet will eventually run out as already committed. At some point in the growth of wind-and-solar, stability of the grid will require a matching growth of OCGT. Renewables require us to continue to use and emit fossil carbon, when we should be zeroising our emissions.

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74. Dave Osmond,

I get the impression your advocacy for wind and solar is putting the cart before the horse. You seem to have a chosen solution “wind and solar” and are trying to find any arguments you can to justify them being the needed solution.

But why take that approach. Why not start with the requirements of the electricity system and then, without prejudice, compare options for meeting the objectives at least cost. When you do this, if one of the requirements is to greatly reduce the CO2-e emissions intensity of electricity (e.g. to about equivalent to France’s), then around 20 GW of nuclear plus gas and hydro is the least cost way to deliver the requirements. See main requirements in previous comment on this thread: https://bravenewclimate.com/2015/11/08/the-capacity-factor-of-wind/#comment-432133

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75. Peter Lang

I agree with your approach but based on the market results around the world in the last year or so it is unlikely that nuclear would get to 20GW. Even the CEO of Southern Co. which is building the Vogtle plants in the US will not admit to any desire to build more nuclear even with GHG abatement credits http://www.bloomberg.com/news/articles/2015-10-27/what-killed-america-s-climate-saving-nuclear-renaissance-

Existing hydro and gas is probably not enough in a drought year and 20GW nuclear is far too much in mild nights or at least half the weekends so the capacity factor of the nuclear will be in the order of 60-70% and we will need another 4-6GW of Gas or nuclear for peak drought demand, if it is gas, emission targets are weakened and if it is nuclear the capacity factor is down and cost per MW.hr is up.

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76. Thanks for your kind words this morning Peter Lang.

To respond to three main distinct parts to your posts.

Capacity factors. It appears that John Morgan and myself are likely to soon be in close agreement on CFs for Sep 2014-Sep 2015. My main point for arguing this is that many people seem to think wind capacity factors in Australia are in the 15-30% range, and moreover believe wind penetration rates on the NEM will never exceed the wind CF. To those people I hope you now understand that the national annual average wind CF in Australia average around 30%-37% (there’s variation from year to year, and note that CFs from the relatively modern wind farms in WA are the highest in the nation, not that that helps us on the NEM). I also hope that people realise that it is easy to calculate a misleadingly low CF for wind farms if you do not allow for the fact that a wind farm may have started generating in the 2nd half of the year (ie, generation data may not represent a full year of operation), and also that a wind farm often starts generating once just a handful of turbines are operating, and there is sometimes up to a year delay before the final turbines start generating (ie, the data may not represent a complete year of operation from the entire project).

To those who believe that penetration rates from wind or solar will never exceed their CF, please note that instead of using CF, you should instead use annual average power/ annual maximum power. This is a point John Morgan made in the article above. For distributed, NEM-wide wind, maximum power is likely to be atleast 10% lower than installed capacity. For residential solar, NEM-wide maximum power is likely to be atleast 20% lower than installed (DC) capacity. And note that a small amount of storage or curtailment can (if required) easily reduce the maximum power output further, and that demand is significantly higher than average when PV hits max output.

And finally, although many of the best, windiest sites may have already been developed, modern Class III wind turbines with high hub-heights and large rotors can achieve higher CFs than these existing wind farms in their windier sites (ie, lower turbine Su as Peter Farley has mentioned).

Peter Lang, I cannot provide a link to an AEMO document indicating that Wheatley’s CFs are wrong, particularly for NSW. I have simply downloaded the data from AEMO as John Morgan did, and have analysed the data for myself. If you want to message Wheatley, I suggest you ask, when calculating the CFs for NSW (and for the entire NEM), if he allowed for the fact that Taralga only started generating in December 2014, and also that Gullen was under construction for most of the year, and only reached full capacity in December.

Wind CO2 abatement effectiveness. I don’t think I can add to my previous comments regarding Wheatley’s paper, other than to agree that wind C02 abatement effectiveness is likely to decrease with wind penetration rate. I believe Wheatley’s paper is fatally flawed in calculating the current effectiveness of wind on the NEM. Long-term South Australia data clearly shows that wind has displaced far more coal generation in SA than gas generation, in clear contradiction to Wheatley’s paper. And regardless of whether Wheatley’s calculation of abatement effectiveness is wrong or not, an appropriate follow-up question is if any alternative generation could be more effective in abating CO2 in a market where current coal generation is cheaper than gas generation.
Battery costs. You are most likely right that pumped hydro storage costs are cheaper than current battery storage. However, for pumped hydro to be economic using price arbitrage, it must use price differentials on the wholesale electricity market. On a typical day, you are likely to only get a $10-$30/MWh price differential to work with.

However, we currently have over 1.5 million homes with roof-top PV, a number that continues to grow rapidly. Many of these households, in the next year or two, will no longer have access to gross feed-in tarrifs, and will find themselves producing excess generation during the day for which they only get paid ~6c/kWh, while later on in the evening they will be charged ~30c per kWh for grid electricity. They have a ~$240/MWh price differential to work with. With battery pricing proposed for the next year, this is likely to be economic. One million homes times 10 kWh battery is 10 GWh of battery storage. This is enough to reshape the diurnal NEM generation profile. To put this in context, on Jan 16 last year, NEM demand hit a multi-year peak of 33 GW. Average demand for the day was about 27 GW. About 50 GWh of storage could have reduced that daily peak to the daily average of 27 GW, a saving of 6 GW of peaking generating capacity. About 30 GWh of storage could have reduced the daily peak to 29 GW, saving 4 GW of generating capacity. Like 77. John Morgan, I have done some quick analysis comparing timing of low wind generation days with low solar generation days. For this analysis, I have looked at 2 years of solar and wind data, Nov 2013-Nov 2015. For solar generation data, I have used daily generation data from the PVoutput.org website, collecting data from a variety of systems in the NEM state capitals. I combined them by weighting their output in proportion to state demand. Average CF of my data was 17.7%, which is probably on the high side (NEM average residential is more like 15.4%). For wind generation, I used all NEM wind farm data. Average CF was 31.3%, a little on the low side as I hadn’t fully corrected for all wind farms under construction. I define a low generation day as one where the average daily CF was less than 10%. 4.3% of days were low generation according to the PV data. 4.7% were low generation according to the wind data. If you add the wind output to the solar output (in a ratio of 60%:40% solar:wind by installed capacity), and recalculate the daily CFs (average=23%), then you find that less than 1% of days are low generation when you use a mixture of wind and solar. This means that it is quite rare for a day to have both very low solar generation and very low wind generation. Indeed, only about 1/5 of the low solar days were also low wind (or vice-versa). This emphasises the point of some research I’ve previously done, and also matches up with AEMO, UNSW and BZE renewable studies. Storage requirements for a high-renewable penetration electricity grid in Australia will be much lower if you use a good mixture of wind and solar, rather than letting one or the other dominate. Like 78. Peter Farley based on the market results around the world in the last year or so it is unlikely that nuclear would get to 20GW. Even the CEO of Southern Co. which is building the Vogtle plants in the US will not admit to any desire to build more nuclear even with GHG abatement credits: http://www.bloomberg.com/news/articles/2015-10-27/what-killed-america-s-climate-saving-nuclear-renaissance- Existing hydro and gas is probably not enough in a drought year and 20GW nuclear is far too much in mild nights or at least half the weekends so the capacity factor of the nuclear will be in the order of 60-70% and we will need another 4-6GW of Gas or nuclear for peak drought demand, if it is gas, emission targets are weakened and if it is nuclear the capacity factor is down and cost per MW.hr is up. Peter Farley, There are many points you’ve raised in previous comments that I’ve refuted but you didn’t acknowledge so we could bring them to closure. So, there is little point raising more points until they’ve been brought to closure. I’ll make some quick responses to your latest comment: it is unlikely that nuclear would get to 20GW That comment is baseless because you don’t state the time frame you are referring to. If we want to cut GHG emissions it is inevitable we’ll have to convert our electricity system to largely nuclear. Renewables cannot make much of a contribution. We’ve had that out on other threads. Hydro can make only limited additional contribution, so best to assume we stick with what we’ve got. France commissioned most of its nuclear capacity over about 20 years; we could too if we wanted to after about 10 years lead time to first reactor in service – i.e. about the same as UAE is scheduled to take from first deciding to go nuclear (in 2007) to first reactor scheduled to be in service by 2017, and fourth by 2020 (they are running on schedule). So, we could have 20 GW in operation in under 40 years from now if we wanted to. Existing hydro and gas is probably not enough in a drought year I said nothing about “existing gas”. In fact in a previous reply to you on this thread I said about 20 GW of gas. Refer back to the comment here: https://bravenewclimate.com/2015/11/08/the-capacity-factor-of-wind/#comment-432004 and “drought year” is irrelevant because hydro storage lasts us through decades of low rainfall years. I am not suggesting more hydro capacity be built because it is not economically viable at the moment and potentially viable sites are limited in Australia. Its share will shrink over time. The rest of the last paragraph is incorrect – see this: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.363.7838&rep=rep1&type=pdf Like 79. I think that there is another important fact to consider. There are also upper limits on how much wind is useful. For example if Australia has 30GW of wind capacity, from the facts that John Morgan has analysed we can expect to get approx 10 GW generated in a year. But we also need to consider the peaks generated. On some days and we do not necessarily know the time of day when it will occur we may generate 25.8 GW at peak (86% of 30GW from John Morgans figures above). If the amount being supplied by VRE’s at a given point in time exceeds total grid demand what do we do with it. Shut down all our Base Load power to use the so-called free power from VRE’s. Like 80. Dave Osborne, I hope you now understand that the national annual average wind CF in Australia average around 30%-37% No, I don’t accept those numbers. Until I see evidence to the contrary, I accept the numbers in Wheatley’s report. I’d need to see the data to support your figures and links to the sources so I can check for myself and so Wheatley can reproduce them. I’d also need to know the calculation has been done correctly, not confusing availability with capacity which should be from the commissioned date. At the moment I have more confidence in Wheatley’s analysis than yours since you cannot produce the evidence to support your nimbers. However, as I’ve already explained, the state-average capacity factors are not relevant to the calculation of CO2 emissions avoided by wind generation or the CO2 abatement effectiveness. So the argument about a couple of percentage points is down-in-the-weeds distraction from what is relevant. I believe Wheatley’s paper is fatally flawed in calculating the current effectiveness of wind on the NEM. Long-term South Australia data clearly shows that wind has displaced far more coal generation in SA than gas generation, in clear contradiction to Wheatley’s paper. You’ve repeated that four times now, and each time I’ve explained that you do not understand what “CO2 abatement effectiveness” means. The long term trend you are referring to is irrelevant for calculating the CO2 abatement effectiveness. I am wondering if you’ve read my replies to you where I explained this? I’d urge you to read the links I provided so you can get to understand what this is all about. At the moment you clearly do not understand it. Like 81. Hi Tony, your point is very valid. If wind is generating more than we need, then it is very easy to curtail the wind farm output. Obviously it affects the LCOE if this wind goes to waste, so hopefully we wouldn’t have to do it too often. Fortunately it is not too often that wind across the country is all producing simultaneously. Moreover, hopefully we will be able to use existing pumped hydro storage or other future storage devices to take some of the excess. Like 82. Peter Lang, I certainly can’t deny that I am pro-renewables. However I am also open to nuclear. There are many countries in the world that will struggle to go mostly renewable, and for their sake I hope nuclear proves to be a worthy option. However I don’t believe Australia is one of those countries. We have so much plentiful & economical renewable potential. However, if 3 things happen then I will likely join you in barracking for nuclear. if China starts to roll out nuclear generation economically, timely and safely at a more rapid rate than it rolls out wind and solar (in terms of delivered GWh/y). If any country is able to roll out nuclear quickly and economically, then it is China. If they can’t, then I don’t fancy our chances. if a Western democracy follows in China’s path, and also rolls out nuclear economically, timely and safely. And by economically, I mean at a rate that is competitive with wind and solar prices in Australia. And for this point, I mean a current or future example. Evidence from last century will not persuade me, there seems to be too many examples of over-time and over-budget nuclear at the moment that I wonder if a democracy can repeat what was achieved a few decades ago. if I can see compelling evidence that Australia will struggle to gain a large majority of its electricity from renewables. Like 83. The example I quoted is purely hypothetical. But it is meant to show what can happen when people start advocating large percentages like 50 percent for generation from renewables. In Australia, renewables effectively means VRE’s. Any significant hydro is very limited near our population centres. Some of the more senior contributors may remember the Franklin Gorge in Tasmania. Whilst not a hydro project, purely water supply, the Traveston Dam project in South East Qld was extremely politically unpopular and failed to start. One of the other factors that gets very little attention is transmission line losses. Whilst certain section of the Grid do not have to consider these losses overmuch. In Qld, NSW and WA they are a significant factor. John Morgan’s maps show significant wind resources near the tip of Cape York. I have tried to find figures on transmission line losses but have not been able to do so. The distances and the quantity of power which is transmitted makes the Australian grid unique. I doubt that resources like Cape York offer any economic opportunities for the Australian Grid. Like 84. I have just posted a comment in Open Thread 23 about Nuclear power development in China. It would be worth your while to have a look. In short, they will have 20GW built by smoko. Like 85. Peter Lang, let’s go through Wheatley’s process point by point so we can work out exactly where our disagreement lies. Abatement effectiveness. I don’t think we have any disagreement on this point. I agree with your statement above “It is “ratio of % CO2 emissions savings to % wind power generation”. How do you calculate the CO2 savings? Model CO2 emissions with and without wind, and calculate the difference. How do you model the ‘no wind’ scenario? Which generators would have picked up the slack if there was no wind? It seems to me this is where our disagreement lies. As I understand it, Wheatley uses regression analysis on the 5 minute data to work this out. This is where I believe his error lies. Please correct me if you believe me to be wrong on this point. Like 86. Dave Osborne, I’ll try another approach to explain why the chart you posted says nothing about CO2 emissions avoided or CO2 abatement effectiveness. I expect you believe that the wind bars on the chart represent the proportion of emissions saved. They don’t! Unless you know the CO2 abatement effectiveness of wind power generation you cannot convert the proportion of wind generation to the CO2 emissions avoided. The chart you posted is not about wind’s effectiveness; it’s about the Renewable Energy Targets effect on the proportion of generation from renewables, at least the ones picked out for special favouratism. The RET is a very bad policy, IMO. It is an example of government ‘command and control’ intervention that distorts the market. The first objective of the legislation is to impose more renewables, not to reduce CO2 emissions. (a) to encourage the additional generation of electricity from renewable sources If South Australia was an isolated grid, so that other states were not backing up for wind power variability, South Australia’s CO2 abatement from wind farms, at 27% penetration, would be in the order of$100/tonne – refer Submission 259, p3. http://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Wind_Turbines/Wind_Turbines/Submissions

In Comparison, the RET Review summarised estimates of the abatement cost of the Large Scale Renewable Energy Target (LRET)3 at $32-$70/t CO2. These estimates, however, are likely underestimated as the analyses do not appear to take effectiveness into account, or at least not fully. If the economic analyses do not take effectiveness into account, and if effectiveness decreases to 53% by 2020, the estimates of abatement cost would nearly double to $60-$136/t CO2 with effectiveness included.

To put these abatement costs in context, the ‘carbon’ tax was $24.15/t CO2 when it was rejected by the voters at the 2013 Federal election. The current price of EU ETS carbon credits and the international carbon credit futures are: • European Union Allowance (EUA) market price (10/3/2015) = €6.83/tCO2 (A$9.50)
• Certified Emissions Reduction (CER) futures to 2020 (9/3/2015) = €0.40/tCO2 (A$0.56) Therefore, the LRET in 2020 could be 2 to 5 times the carbon tax, which was rejected by the voters in 2013; 6 to14 times the current price of the EUA; and more than 100 times the price of CER futures out to 2020. Clearly, the RET is a very high cost way to avoid greenhouse gas (GHG) emissions. The 53% effectiveness mentioned in the quote is from Wheatley’s study for Ireland at 17% wind energy penetration. For South Australia at 27% wind energy penetration, a fairly similar mix of technology fuel types as Ireland, and assuming South Australia is an isolated grid, the CO2 abatement effectiveness would be around 40% to 45%. At 40%, the CO2 abatement cost would be around$80-$175/tonne. That’s three to seven times the ‘carbon tax’ that was rejected by voters at the last election. I hope you can appreciate why CO2 abatement effectiveness is such an important, policy-relevant concept to understand. Lastly, There are many countries in the world that will struggle to go mostly renewable No large industrial economy can go mostly non-hydro renewables. This has been explained over and over again on BNC https://bravenewclimate.com/renewable-limits/ and also in the posts I linked here: http://euanmearns.com/the-renewables-future-a-summary-of-findings/ . There’s no point in trying to repeat all that here. Like 87. ‘In Australia, renewables effectively means VRE’s’ This prevailing ignorance of the potential for biomass to provide significant electricity is a testament to over a decade of lobbying against development of electricity from biomass by the Greens on federal and state policy formation. We are so far behind other OECD countries in this as well as BRIC countries in our development of this most readily available renewable energy source it is a national embarrassment. So at present we have 800 MW of installed capacity that is mostly capable of high CFs in the order of 80% plus. This equates to around 3000 MW of installed solar capacity on a CF basis or about 1800 MW of wind capacity. It is a fact that we are not seeing this production from biomass in the AEMO figures as much of it is used by the industries where it is generated – the sugar mills, Australian Paper, Visy, etc. These also use the vlauable co-product of heat and this use displaces use of natural gas or other fossil fuels. A recent report by the CEFC identified in the short term this could be bio-electricity generating capacity could be doubled to 1600 MW capacity. Other reports by Bioenergy Australia, CSIRO and RIRDC give estimates of 17% to as high as 30% of present electricity base needs (so about 3000 to 6000 MW) coming from available and unutilised biomass or biomass sources that could be stimulated as a result of integrated farming systems. Like 88. My apologies Andrew for forgetting about Bio-Mass. I am sure that it has a role to play in future energy and environmental solutions. As you have acknowledged it can not provide 100% of our future energy needs. Unfortunately I find the Windies and solar PV proponents believe that their favorite is the solution when the scientific facts say otherwise. Like 89. Peter Lang, I have previously provided evidence that Wheatley did not use the average installed capacity for wind during 2014. I will make another attempt to do so now. But to begin with, you say that we should only be using wind farm capacity which should be from the commissioned date. If everyone did this, then I would not be having these arguments. Wind farm commisioning dates are when the wind farm is complete. However wind farms start generating well before the commisioning dates, as they like to get revenue as soon as possible, as soon as any turbines can be connected to the grid. AEMO publish this pre-commisioning data, and it is because people are using this pre-commisioning data to calculate CFs that they are getting these low CFs. However it is difficult to find the commissioning dates, so it is understandable that people just use all the data without working out if it is pre-commissioned or not. Even I don’t bother, however I do make the effort to estimate the installed capacity for each month prior to commissioning. However for the purposes of the rest of this email, I will not make these pre-commissioning adjustments. Now getting back to the installed capacity used by Wheatley. He says he used 34 wind farms with an installed capacity of 3394 MW, which you have said that he claims is the average installed capacity for 2014. The AEMO registered generator list (link at end of post) has 40 or 41 wind farms listed with 3667 MW of registered capacity. BOCORWF1 is listed twice, with 2 different installed capacities (the correct value is the sum of the two values, 113MW). Confusion about the number wind farms relates to if you count Boco rock once or twice. AEMO does not provide data for 5 of the listed wind farms, Codrington, Hepburn, Toora, Windy Hill & Wonthaggi. John Morgan agrees with me on this point, and is also why the http://energy.anero.id.au/ website does not list their data. Weatley also mentions “Note that some smaller non-scheduled generation is omitted from the SCADA dataset”, which is no doubt refering to these wind farms. These 5 wind farms total 67 MW, so we are now down to 35 or 36 wind farms, and 3600 MW total capacity. Bald Hill wind farm first connected to the grid around midnight on Jan 29, 2015. For evidence of this, download the AEMO PUBLIC DAILY SCADA file from AEMO for Jan 2015 from the link below, then open the Jan 28-29 file. Search for “BALD”. You will see an entry for BALDHWF on 29/1/2015 at 0:00. There is no data prior to this time or date. http://www.nemweb.com.au/REPORTS/ARCHIVE/Daily_Reports/ Bald Hill is 107 MW. Thus we are down to 34/35 wind farms with 3493 MW registered capacity as of Jan 28, 2015 Taralga WF (TARALGA1) first connected to the grid on 11/12/2014. Again, this can be verified by downloading the PUBLIC_DAILY file from AEMO for Dec 10-11. It first appears at 11/12/2014 at 0:05. Taralga is also 107 MW, so we are now down to 33/34 wind farms with 3386 MW of registered capacity as of 10/12/2015 Boco Rock (BOCORWF1) is 113MW, and AEMO files indicate that it first generated on 29/8/2014. I could continue further back in 2014, but that is not necessary to make my point. Thus, to summarise the timeline of installed capacities: Date, Registered Capacity, # of Wind Farms 28/8/14, 3273 MW, 32 or 33 10/12/15 3386 MW, 33 or 34 28/1/2015 3493 MW, 34 or 35 Note that these figures include the full installed capacity for the wind farms connected to the grid. It does not include any downward revision estimates for pre-commissioning installed capacities. It is clear that Wheatley’s figure of 3394 MW is not the 2014 average. His CF values are wrong and too low http://www.aemo.com.au/About-the-Industry/Registration/Current-Registration-and-Exemption-lists Like 90. Dave Osborne, Thank you for going to the trouble of extracting this data. Unfortunately I could not send it to Wheatley in the form it is in. It is unclear to me and I expect would be unclear to him too. I don’t understand what you believe the average capacity factor should be nor where to get the data to reproduce it, so clearly it would be confusing and unpersuasive to Wheatley too. He extracted the data from AEMO and it would have to be shown what the correct average capacity factors are for each state and why his are wrong. I’d suggest the presentation of the data should clearly lay out the capacity by state at the start and end of 2014 and say the dates when capacity was added during the year (by state). Furthermore, since the state average capacity factors are irrelevant for calculating the CO2-e emissions avoided and the CO2-e abatement effectiveness, I am reluctant to raise this issue with him unless it is absolutely clear – and important. I suggest, if you want to you, you could post a comment on his web site here: “Emissions savingfs from wind power: Australia” http://joewheatley.net/emissions-savings-from-wind-power-australia/ Like 91. David Not sure that you fully understood my point. When wind generation exceeds the systems ability to use it the Capacity factor of wind is reduced. So there is an optimal point for wind generation beyond which the capacity factor is reduced and the cost of wind generation per kw as a consequence will keep increasing. Like 92. Tony Carden, You are correct. The quantities escalate rapidly as wind penetration increases. There is a good explanation of the effects in this very interesting analysis: “The difficulties of powering the modern world with renewables “Figure 3: UK electricity demand and wind generation with wind supplying 50% of demand, February 2013” Like 93. Peter Lang, you wrote “I expect you believe that the wind bars on the chart represent the proportion of emissions saved”. You expect wrongly. My plot of the generation sources for South Australian electricity were not to demonstrate wind’s abatement effectiveness. They were to demonstrate the fatal flaw of Wheatley’s paper. That is that each MWh of wind in SA displaces only 0.06 MWh of coal generation in SA, but 0.32 MWh of gas generation in SA and 0.63 MWh of imports. Like 94. Dave Osborne, That’s not a fatal flaw. It’s not a flaw at all. It’s irrelevant. NSW generators are doing a large part of the cycling and ramping to back up for the wind power fluctuation in South Australia. That is, NSW electricity users are paying for the high cost of backing up for South Australia’s wind power. Your comments demonstrate you haven’t carefully read or haven’t understood the paper. They also suggest you haven’t read the back ground papers I provided links for. Here’s another example from an earlier comment that clearly demonstrates you haven’t read carefully or haven’t understood this paper and the Wheatley paper of his Irish study. How do you calculate the CO2 savings? Model CO2 emissions with and without wind, and calculate the difference. Models are one way. They commonly give too-high values for emissions avoided and for CO2 abatement effectiveness. The other way, which Wheatley’s analysis uses is empirical analysis of historical generation and emissions data. He explains both methods have their benefits and limitations. Modelling is used for projecting and scenario analysis. Empirical analysis gives you the actuals – the ‘truth’ if you like – of what actually occurred. This is important for validating and calibrating the models. Please read the links I’ve provided in previous comments: Wheatley, 2013; Kaffine et al., 2013; SEAI, 2013. There is no point discussing this any further until you understand. Like 95. Surely the main reason for the transition to non carbon power sources is to reduce GHG emissions. Real world data shows that intermittent renewable energy generation (like wind) with low capacity factors and requiring backup from fossil fuel generation does not reduce GHG emissions. For example Germany, which by the end of 2014 had installed; • 38GW of Solar producing 33TWh (or 6%) of electricity with a capacity factor of 10%. • 36GW of Wind producing 57TWh (or 10%) of electricity with a capacity factor of 18%. This intermittent energy infrastructure is backed by gas and a new fleet of load following coal burning power stations to provide power when the sun and wind are unavailable. The results are: Germany CO2 emissions from electricity generation are 576 gms/kWh compared to France with 40 gms/kWh. See http://www.rte-france.com/en/eco2mix/chiffres-cles-en https://en.wikipedia.org/wiki/Energy_in_Germany While German renewable generation has dramatically increased, CO2 emissions from electricity generation are virtually unchanged since 1997 at about 365Mt per year. http://www.indexmundi.com/facts/germany/co2-emissions German electricity prices are almost twice as high as France. http://ec.europa.eu/eurostat/statistics-explained/index.php/Energy_price_statistics Unfortunately almost every pledge to COP21 plans to use renewable energy to reduce emissions and if the result is the same as Germany, then emissions BAU will continue for decades to come. Like 96. For those who think French power generation is cheaper than Germany page 6 of the following document shows that year ahead French wholesale power prices are around E38 vs E33 for France. http://www.cre.fr/en/content/view/full/13404 Frances oldest current generator was commissioned in 1979 it latest in 2000 i.e 20 years not 10 to reach current capacity http://www.world-nuclear.org/info/Country-Profiles/Countries-A-F/France/ These generators supply about 450TW.hrs per year i.e they added 22 TW.hrs per year. China’s wind generation increased from 45TW.hrs in 2010 to 160TW.hrs last year i.e 28TW.hrs per year. From 2009 to 2014 Nuclear output rose from 97 to 125 TW.hr or about 6 TWhrs per year. http://www.world-nuclear.org/info/Country-Profiles/Countries-A-F/China–Nuclear-Power/ Like 97. Tom Bond, can you do us a favour and stop using the term ‘energy’ when you are meaning ‘electricity’. In the renewable energy area there are major advances in supply by the renewable energy sources in Europe (and some countries obviously more than others), but overall the contribution of renewable sources of energy is far greater than of ‘energy’ from nuclear reactors (the utilised part of which only consists of the electricity produced, and the vast amounts of heat produced are entirely ‘wasted’. So the energy that is produced from renewables in the EU and many other countries in commitments of various levels at COP 21 are actually fairly meaningful once you stop seeing it all only as being about electricity (which as we all know is only 25-30% of final energy). Like 98. Dave Osborne, I’m looking for help with Portland Wind Farm. I have a DUID of PORTWF which I take to be Portland Wind Farm, reporting in my generation data. PORTWF is not listed in the Reg & Exemption list, so there is no registered capacity figure available. Wikipedia tells me PORTWF has capacity of 195 MW. But, that includes the first stage of YAMBUKWF. So I can’t assign a capacity of 195 MW to PORTWF or I’d be over counting. Also, the peak instantaneous generation for the year from PORTWF was 18.6 MW which seems a bit low for a wind farm of that size. Do you know what PORTWF represents, how it relates to YAMBUKWF, and what its registered capacity is? Like 99. John Morgan check out the website http://energy.anero.id.au/wind-energy. Using this you can zero down to the Portland wind farm (producing almost zero at present), or any other producing wind farm suppling the eastern grid. Like 100. Thanks Andrew. That gives YAMBUK at 30 and PORTWF at 164, for a total of 194 MW. Ignore the 18.6 MW figure I mentioned; that was just in a 3 day sample I use for testing, not the whole year. Like 101. It seems to me that if you want to claim that wind emits CO2 you should also bundle the cost of wind and peak power gas backup but on the other hand also attribute the CO2 abatement effect of wind/peak power plants and silence intermittence argument. Wind and peak power plants outcompetes high marginal cost electricity generators, which nearly always will be older coal plants that perform below average and thus also use more coal to produce electricity. The CO2 abatement can therefore in praxis be more than 100% of the CO2 emitted from average coal fired plants because they range between 30% conversion efficiency and 47%. And the peak power plants can also back up all other power generators including nuclear or high efficient coal power plants that thus achieve higher capacity factor. I full well understand the need for backup for wind but any other electricity generation technology also frequently requires backup. The intermittence of wind and solar is as predictable as weather forecasts. Nuclear and coal power will to the contrary scram every once in a while and especially nuclear will on occasion be out for weeks, months or even years. How much backup does nuclear require? There has been one post here at BNC that has argued the historic evidence of wind powers CO2 abatement effect. https://bravenewclimate.com/2010/09/01/wind-power-emissions-counter/ If you want to calculate the CO2 abatement cost after carefully assessing the CO2 abatement effect then at least in USA there are no other source of new electricity generation that is anyway nearly as cheap as wind power and no electricity generation technology that is cheaper than wind/peak power plants. Like 102. Tom Bond said: “Real world data shows that intermittent renewable energy generation (like wind) with low capacity factors and requiring backup from fossil fuel generation does not reduce GHG emissions” Considering that the backup must be OCGT rather than CCGT, one might add: “requiring backup from fast-responding but inefficient fossil fuel generation”. Like 103. Re Germany vs France 1. Correction to my post above German wholesale electricity prices are now 10% lower than France, France’s prices are predicted to rise over the next 10 years and Germany’s are predicted to continue to fall. 2. Germany is building 8GW of new coal but retiring 14GW and there is now an expectation that not all of the 8 GW will be completed http://www.renewablesinternational.net/new-german-coal-plant-worth-one-euro/150/537/89142/ Tom Bond and Roger Clifton. If anyone was proposing solar or wind as the solution then you are right OC gas is not very efficient. However If you have a five factor system. Wind, solar, biofuel, hydro and gas, then some proportion of the gas can be CC while fast response hydro and some of the biomass can cover the short term fluctuations leaving CC Gas to run most of the day on high demand days. While wind and solar are intermittent they are predictable over an hourly timeframe particularly over a wide area so there is plenty of time to ramp other sources. The addition of some storage or changing the operating regime of the hydro so that is the last used resource allows further optimisation of the CC gas plants because during short term demand dips or early in the demand rise or later as demand is falling the CC plants can be used to recharge storage. While bulk battery storage is clearly uneconomical, local battery storage at substations can have a very high value in smoothing local fluctuations and avoided grid costs. That is why Energex etc. are installing batteries today. Finally grid control of movable loads such as hot water, pool pumps, many cooling loads etc. can act as very low cost pseudo storage, absorbing excess wind and solar and dropping off when other demands are high. All of these techniques mean that the contribution of an energy source can, in fact, exceed its capacity factor just as coal does in China. 70% of electricity but a little over 50% CF and nuclear does in France 75%+ of generation, 68% CF Like 104. If you have a five factor system. Wind, solar, biofuel, hydro and gas, then some proportion of the gas can be CC while fast response hydro and some of the biomass can cover the short term fluctuations leaving CC Gas to run most of the day on high demand days. Oh yea, right. “Five factor system” required 2-5 times the capacity and investment to do the same job as nuclear (and don’t forget the many times higher grid costs). You’d need >100 GW of capacity in you “five factor” system as could be done with 20 GW nuclear at 90% CF plus 20 GW gas at about 13% CF to meet NEM demand profile analysed by EDM http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.363.7838&rep=rep1&type=pdf You really do need to crunch some numbers instead of continually making wild unsupported assertions. Like 105. Roger Clifton, why do you think backup must be OCGT? Isn’t it only the single shaft designs of CCGT that are unsuitable? And how long will we continue to ignore the alternative of fuel cells? Like 106. David, I am not sure that people read what is posted on these threads. But further and relevant to this thread. There is a rule of economics that relates to the overall growth of an industry and that is the law of ever decreasing rates of return. Put simply wind generation will expand until net returns from wind generation become zero (marginal revenue = marginal cost). It is obvious to me that there are some contributors to this thread who have a much more intimate knowledge of the Wind Industry than I do so please feel free correct me. When wind energy sites are proposed, presumably, they are evaluated on the net amount of electricity that will be delivered to the grid. That calculation must include an estimate of transmission line losses as well as the cost of the transmission line itself. Both are directly related to the length of the transmission line . So if we assume that this is the logical process then the sites that are currently in use already have the best rates of return and the consequent highest capacity factors. Consequently it is not logical that just because the existing capacity factor for wind is 33.3% that as we add additional wind generation that this capacity factor will remain the same. Capacity factor will inevitably go into decline and continue to decline. ( I have decided to use this figure 33.3% for simplicity irrespective of the discussions between dos74 and Peter Lang) Like 107. Tony Carden, Thank you for the good points. I’ll add a few. Wind power is not economic without subsidies and effectively ‘must-take’ regulations now. All future construction would stop if the subsidies and effective mandating were stopped. The most obvious subsidy in Australia is for Renewable Energy Certificates. They are priced around$35-$40/MWh. That’s around 1.5 to 2 times the cost of electricity from our existing coal fired power stations that wind is being forced by RET and subsidies to replace. The RET effectively mandates that utilities must buy renewables. If they don’t buy enough, they are fined around$93/MWh for every MWh deficit below what they are required to buy.

You also mentioned grid costs, The grid costs for renewables at 50% penetration are around 50 times higher than for coal and 25 times higher than for nuclear. See approximate grid level system costs (in $.MWh) at 50% penetration Nuclear 1.8 Coal 0.9 Gas 0.5 Onshore Wind 45.2 Offshore Wind 45.3 Solar PV 74.8 These are my linear projection from the grid level system costs at 10% and 30% penetration summarised by Nicholson and Brook http://www.energyinachangingclimate.info/Counting%20the%20hidden%20costs%20of%20energy.pdf from OECD/NEA, 2012, report System effects in low-carbon electricity systems: http://www.oecd-nea.org/ndd/reports/2012/system-effects-exec-sum.pdf These costs are not charged to the wind energy generated. some increase the wholesale cost of the dispatchable generators and some add to the grid costs and are passed on to consumers in the price of electricity. These amount to another subsidy for wind of around$45/MWh at 50% penetration.

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108. To Tony Carden

You are of course right about the economics. Often the best sites for the technology of the day are used first.

However as many people have pointed out the technology is improving and mast heights are increasing so the US fleet capacity factor has increased from 25.4% in 2005 to 32.7% in 2015. This average includes the old plants.

The 29 newest wind farms have an average capacity factor of 37.8% so the technology improvements have more than compensated for the slightly poorer sites.

Of course this problem applies to any technology. the first canals in the British midlands made their owners an absolute fortune with ROI of 30%+ for decades. The last canals built went broke so no more were built.

Similarly for nuclear plants which rely for their economy on very high utilisation once they exceed minimum grid demand there will be more and more times where they cannot sell all their capacity so the “position” of the next nuclear plant to come onto the grid will be worse than the first. No-one really knows where the nth plant can’t sell enough power to justify its construction falls in the market Peter Lang says it is the 20th GW. I think it is somewhere between 0 and 12-15GW, but I am sure we will all be proved wrong.

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109. To Peter Lang

You seem to have a problem with different rates of technological progress.

The link to the Canadian presentation has France in the low CO2/ Low Cost quadrant and Germany in the high cost High CO2. However as I have pointed out and posted the link twice, German wholesale costs are now significantly lower than France and the cost differential is increasing so France is still keeping CO2 low but moving to the high cost while Germany is low cost and its CO2 is trending (very slowly) down.

Secondly you use inflated costs for wind based on a 2012 paper yet contracts from Canberra to India to Chile and the US and Brazil are cheaper per delivered MW.hr than anyone is offering for nuclear. This takes into account the differing capacity factors. If nuclear is so attractive why aren’t US power operators planning to build more plants. there are 5 under construction with zero planned after that, yet they are adding a nuclear power plants worth of wind every quarter

Using real capacity factors for current technology at high penetrations you need 2-2.5GW of wind for one GW of nuclear but nuclear is 1.5-3 times the price per MW. Then both technologies need storage or gas backup. Nuclear needs hot spinning reserves because of the unit size of the plants, wind doesn’t need hot spinning reserves but needs more storage.

I will agree that the capital cost of a renewable system today may be 15-30% higher than a nuclear system. however the downward cost trajectory for renewables is much more clearly understood than it is for nuclear. Meanwhile the nuclear proponents completely neglect the fact that O&M for nuclear is around A$30 per MW.hour whereas wind is A$5-10 and solar is even lower

To reach the idea that renewables are much more costly than nuclear there is an unfounded number of 40 times the grid costs to integrate renewables to the grid than nuclear

The proposal is for 20 GW of nuclear when for more than 50% of the time there is not 20GW of demand on the grid and the merit order effect will ensure that existing wind, solar and hydro will get preference to nuclear. It may be possible to link 20GW of Nuclear to the grid but it is not possible to get 85% CF. unless there is 10-15GW of storage built as well so the business case overestimates the sales from nuclear and overestimates the economies of scale for building while not accounting for storage costs and therefore significantly underestimates the cost per MW.hr of nuclear power,

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110. Comments here are starting to veer off topic. This thread is specifically about wind capacity. If you wish to discuss such topics as nuclear vs wind vs solar, costs pertaining etc you should move to the Open Thread. As BNC does not have the capacity to move comments between threads further OT comments will be deleted. It may pay to keep a copy of your comment so that you can re-post in the correct thread, if asked to do so.
Thank you.

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111. Peter Lang, you seem blind to potential flaws in Wheatley’s empirical analysis. You seem to think that empirical analysis provides the ‘truth’.

You suggested that I clearly didn’t understand Wheatley’s work when I said his analysis modelled the difference between CO2 emissions with or without wind.

Perhaps it is yourself that needs to read and understand his paper more carefully. His Australian paper says “Operational emissions savings can be defined as the difference between the observed emissions and what emissions would be in a no-wind scenario, all else being equal. This quantity can be investigated empirically”.

Wheatley’s empirical method uses regression analysis to determine correlations between wind generators and other generators. Once you have performed the analysis, you then set wind to zero in the relationship, and that gives you a model of what would be happening without wind. You are then able to calculate the differences in CO2 emissions between the two scenarios.

However, if you perform the empirical analysis on 5 minute data, as Wheatley did, then you miss any longer term relationships – such as a decision by the owner of a coal power station to shut down prematurely, in part due to the growing penetration of renewables.

To quote your words, ‘there’s no point discussing this any further till you understand’.

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112. Dave Osborne,

However, if you perform the empirical analysis on 5 minute data, as Wheatley did, then you miss any longer term relationships – such as a decision by the owner of a coal power station to shut down prematurely, in part due to the growing penetration of renewables.

In one of my early comments, I said a good, constructive critique of Wheatley’s paper, and others that use similar methods to estimate emissions avoided by wind power, would be very valuable and most welcome. Unfortunately, none of your various attempts to criticise it are not a valid criticisms. Your critique are not of Wheatley’s analysis or paper at all. You are proposing a different analysis. You are stating what you believe would be a more interesting (from your perspective) analysis of long term trends of wind displacing coal generation. Your analysis is not about emissions avoided by wind or CO2 abatement effectiveness at all. It’s about how effective the RET and other incentives have been at forcing wind power to replace coal power. It’s a different issue altogether.

If we want to know the long term trends in emissions avoided by wind power generation and the CO2 abatement effectiveness, then we need to repeat Wheatley’s analysis for each year, then chart CO2 abatement effectiveness by year, as Kaffine did for ERCOT. When you do that you find that the displacement is due to the changing relative costs of the technologies – after incentives!

You’ve mentioned that 5 minute intervals are not appropriate. You are wrong. This clearly demonstrates you don’t understand the analysis. To determine emissions avoided by wind generation with lowest achievable uncertainty we need to use the shortest period available – not more than 30 minutes and the shorter the interval the better. You haven’t understood that key concept yet. Some argue 1 minute would be best.

Regarding you comment modelling you are really stretching the meaning of model.

I asked you to explain what exactly is the error(s) you think you have identified in Wheatley’s paper? Specifically I asked:

Which number?
In which table or figure?
What do you say is the correct number that should replace what you think is the wrong number?
Why do you say his number is wrong and what is the basis for your calculation of what you think is the correct number?

You haven’t answered those questions. Until you do, I Am unlikely to take any more of your repetitive, unsupported assertions seriously.

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113. Regarding capacity factors, costs and cost of carbon abatement it might be worth looking at the latest Lazard analysis https://www.lazard.com/perspective/levelized-cost-of-energy-analysis-90/.
Because wind is so cheap now you eliminate carbon and save money by investing in new wind vs new coal.

According to Lazard. Total cost of nuclear based on contracted rather than actual cost of Vogtle is double the recent costs of new wind

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114. Total cost of nuclear based on contracted rather than actual cost of Vogtle is double the recent costs of new wind

Wind does not make a grid.  Wind supplies energy, not capacity.  It does not supply frequency control.  Many wind turbines cannot provide reactive power either.  When you add up all the costs of the things required to actually make a grid work, 100% nuclear is far cheaper than 100% wind.

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115. Peter Lang, recognising a limitation in a report doesn’t in any way demonstrate failure to understand it.

It’s very rare for a single result to provide all the information you need. Short timescale measurements show the instantaneous effects of wind power, but don’t always show the long term trend, particularly when it involves large step changes such as the shutting down of coal fired power stations.

It is disingenuous to attribute wind power’s replacement of coal power to the RET, as the RET itself has no direct effect on whether it’s coal or gas that the wind power is replacing. But more wind power in the system creates economic conditions that favour gas over coal, even though it may not be discernible from a short timescale analysis;

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116. Below a certain minimum capacity factor (CF), wind-backed-by-gas emits more than two-stage gas generation alone.

When supply must be increased (by power P) by gas alone, the gas usage would be
P/Ec , where Ec is the gas-to-power efficiency of CCGT

If that same power were to be generated with wind backed by dedicated OCGT,
the average power generated would be PCF from wind plus P(1-CF) from gas
and the average gas usage would be
P/Eo*(1-CF), where Eo is the gas-to-power efficiency of OCGT.

The gas usage and thus the emissions would be the same in the two scenarios when the two usage terms are equal:
P/Ec = P/Eo*(1-CF)
It follows that the minimum capacity factor to make any reduction of emissions is
CF = 1 – Eo/Ec

The efficiency of gas generation depends very much on the plant, however open cycle is approximately two thirds the efficiency of closed cycle gas plant. In that instance,
CF = 1 – 2/3 = 33%

Below the minimum capacity factor, wind farms induce more emissions than they save. How much available land in reach of the grid achieves wind of this minimum quality?

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117. To Engineer Poet.

I agree 100% wind is a silly idea, just as 100% nuclear.

A couple of technical points.
Frequency control is about short term response to spikes/dips. Wind is very good at responding to dips in demand, blades can be feathered in seconds, obviously not so good at spikes unless deliberately running below capacity but that applies to all generators.

While nuclear is more predictable, it is not good for frequency control, even if there is spare capacity, ramp rates are measured in hours not seconds, that is why France has gas, hydro and still uses coal and imports from Germany to cover peaks.

It is true that many older wind turbines cannot supply reactive power but the power converters on many new turbines which will be the vast bulk of any new fleet can supply reactive power even if the turbine is not turning http://www.energy.siemens.com/co/pool/hq/services/renewable-energy/wind-power/service-solutions/optimization-tab/Reactive-Power-at-no-Wind_flyer.pdf

On nuclear cost, see the latest contract in Argentina, which is by far the cheapest published cost for nuclear in the world http://www.businessspectator.com.au/news/2015/11/18/china-wins-21b-nuclear-plant-deal-argentina

A$21b for 2GW of capacity. With 20% equity @ 12% ROI and 80% debt @ 6%. Lifetime 85% CF and$A30/MW.hr O&M, power works out at A$132 per hour. This does not appear to include pre commissioning financing costs. It also does not include the cost of spinning reserves for frequency control or fault backup, decommissioning costs nor grid reinforcement. This is a thought experiment for Australia. Assume all existing generation is retired over the next 10 years and completely replaced, while droughts eliminate hydro If we built a 100% nuclear grid it would need 36-38GW to cover peaks with reserve. However at 195 TW.hr demand, utilisation would be 58-63%. Using a 20% lower average cost than Argentina’s latest contract, the cost per MW.hr would be about A$155-175 not including fast response backup or any grid re-inforcement. Canberra is contracting wind at a little over half that figure.

An alternative analysis focussing on the capital cost.
Adding 10% for higher labour and cooling costs in Australia and deducting 25% average learning curve effect i.e. the last unit is half the cost of the first one. The capital cost for the nuclear scenario with 3GW of OC gas is about $320-360b. On a 45 year payback with weighted average cost of capital of 7.5% the annual cost of interest and depreciation is about$26b plus another $6b or so in O&M including the small amount of gas used. i.e an annual total cost of$32b for 195 TW.hrs of power

If we built 55 GW of wind and 35GW of pumped storage, the capital cost would be about $92b and$70b respectively. Using a 20 year life for wind and 70 year life for pumped storage, the annual interest and depreciation charges are $9b and$5.3b respectively and the O&M costs are around 0.8-$1.5b so the total annual cost is$15 to $16b for the same 195 TW.hrs. or about A$80-$90 per MW.hr which is consistent with or higher than costs being contracted all around the world today This analysis is biased toward nuclear because a) Weighted average cost of capital for wind and storage is likely to be lower than for nuclear because of reduced construction risk and shorter “time to light”.and the applicability of the storage element to any generation technology including nuclear b) higher capacity factors in new wind and a wider spread of wind farms over the NEM will reduce the need for long term storage as well as reducing the optimal number of turbines c) I have used current costs for wind and storage vs significantly discounted costs for nuclear d) Because of the effect of discounting on future cash flows, increasing the service life for a wind turbine just from 20 to 25 years has almost double the effect on the lifetime cost than increasing the life of a nuclear power station from 45 to 60 years e) As operation, maintenance, security and decommissioning are a much larger proportion of nuclear (20-25%) than they are of wind+ storage (<10%) the cost of nuclear will rise over time at about twice the rate of the annual cost rise of wind f) Once a nuclear plant is ordered you have to hope that the technology won’t be disrupted for 45-50 years by yet another new generation of nuclear, 60%CF wind or whatever. A wind turbine has broken even about 15 years after the project agreement is signed. h) On premises thermal storage and load shifting is usually much cheaper than pumped storage In spite of all those concessions to nuclear, a nuclear system in Australia still works out to have an annual cost double that of wind and storage. Like 118. Is that really the best nuclear can do, PeterF? China apparently plans to punch reactors out at less than$1.5 billion a pop: http://www.firstpost.com/world/china-to-invest-78-bn-to-build-110-nuclear-power-plants-by-2030-will-overtake-us-2471414.html

There’s not much to be done in the short term about the labour cost differential (though by 2030 you’d expect a fair bit more automation in this sphere), but surely we can work out a way to piggyback off the Chinese economies of scale?

Also, what was the basis for your estimate of a flat $2 billion per GW for pumped storage? Like 119. To engineer poet Wind does not make a grid nor does nuclear. I posted a long reply which has disappeared,however a) windfarm electronics from Siemens Vestas and GE are designed to provide reactive power even if the turbine is not running b) Generators can only help with frequency regulation by ramping rapidly. Ramping down easy for wind up hard. Nuclear is too slow in both directions. Re cost: newest cheapest contract signed (not delivered) in the world is in Argentina is A$21b for 2GW. That works out in the most optimistic scenario @$132/MW.hr. Around the world wind is being contracted between A$40 and A$100 per MW.hr. This includes the effects of the lower CF for wind. A 100% nuclear grid including reserves will have 34-38GW of nuclear with 2-3GW of something else fast. Based on the Argentinian priceless 25% for the learning curve the capital cost is A$320-360b. Depreciation and interest @7.5% weighted average cost of capital and 45 year payback annual cost is $23b/yr O&M about$5b total $28b per annum for 195 TW.hrs 55 GW of new wind and 35 GW of pumped storage at current cost is$162b. Allowing a similar learning rate as for nuclear it is $132b. on the higher figure and 20 year life of wind and 70 on storage gives annual costs of$13.5b plus around $1.1b O&M i.e. <$15b/yr. i.e. a little over half the cost of the nuclear system

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120. Roger Clifton

A class 3 turbine at 6,5m/s and an Su of 5 about where the very latest wind designs are, will average 41% CF A shorter blade turbine with Su 4.3 and wind speed 7m/min will average around 45%.

The NEM covers about 500,000 sq.km. modern wind farms are spaced about 2.5 units per sq km. Therefore we need 5500 to 6,000 sq km or 1% of the NEM.

Average wind speeds across the NEM at 50m vary from 4.3 to 9.6m. About half the area is over 6m/min the top 10% is above 7m/min. Now new turbines are available with mast heights up to 155m where wind speeds are usually 10-20% higher than @ 80m.

Thus even the 6m/min areas @80m/min can achieve 7m/s + Thus in theory we have about 250,000 sqkm where CF can be above 40% and as I said we need about 5-6,000 sq km so

A CF above 40% is commonly available with current generation turbines
B We have about 50 times as much land as we need for high performance wind system

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121. Roger,
Am I correct in saying that it is your contention that the minimum acceptable capacity factor for Wind Generation is 33%, because at capacity factors below this OCGT would be more effective at reducing GHG emissions.

Regards Tony Carden

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122. b) Generators can only help with frequency regulation by ramping rapidly. Ramping down easy for wind up hard. Nuclear is too slow in both directions.

Nuclear has no impediment to simply bypassing steam directly to the condenser, allowing a ramp rate limited only by the thermal stress on the turbine.  It’s just that nobody’s asked for this capability yet.  If you can’t ramp wind up, you have to have something else ABLE and RUNNING to do that instead.  Generally that means a turbine that’s started and burning fossil fuel.  If we had lots of interruptible load we’d use that instead, but aside from pumped storage these things are scarce on the ground.

Re cost: newest cheapest contract signed (not delivered) in the world is in Argentina is A$21b for 2GW. I had to look up the exchange rate, which is AU$1 = US$0.7174 ATM. This makes roughly$7200/kW delivered.  What this ultimately costs depends on interest rates and capacity factor.  Amortized at 5% over 20 years I get about 7¢/kWh for the cost of money; O&M will be a few cents more.  This is quite competitive.  Once the plant is paid off it will have another 40-80 years of useful life ahead of it.

Around the world wind is being contracted between A$40 and A$100 per MW.hr. This includes the effects of the lower CF for wind.

“Wind” isn’t delivered firm power.  Wind is closer to fuel, which must be converted to delivered firm power at considerable extra expense.

Working that backwards, AU$40/MWh at a CF of 35% yields revenue of AU$123/kW/year.  Using your implicit cost figure of AU$92B/55 GW (roughly$1670/kW) and 7.5% interest, amortization costs $132/kW/yr. The only way to make this up is with huge subsidies. In short, a MASSIVE distortion in the market to force wind into it regardless of usefulness. Like 123. PeterF, Your posts contain many figures and quotes. However, many are irrelevant factoids because they do not compare like with like. Your comments would be more persuasive and readers would be more likely to read the links if they were to recognised authoritative sources. Your comments would be more persuasive to me if they: begin by defining the essential requirements of the system (e.g. energy security, reliability of supply and low cost of electricity); then state the year your cost projections are for; then compare option on the basis of the total wholesale cost of electricity and CO2-e emissions avoided (from the system); you may also want to compare the total system resources needed (steel, concrete) etc. and the EROEI (but this is secondary, compare the cost of electricity for the various options that meet requirements first. If you do this you’ll find the ‘mostly nuclear’ option is much cheaper than a ‘mostly renewables’ option. Here are some examples of such analyses (the first three are for Australia and using Australian Government projected costs (these are what the government uses for policy analysis): Renewables of Nuclear electricity for Australia – the costs http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.363.7838&rep=rep1&type=pdf (Figure 6 for costs, Figure 5 for CO2 emissions intensity, Figure 7 for cost of the transmissions system additional to the existing system) CSIRO eFuture http://efuture.csiro.au/#scenarios CSIRO MyPower http://www.csiro.au/my-power/ Decarbonizing UK Electricity Generation – Five Options That Will Work http://euanmearns.com/decarbonizing-uk-electricity-generation-five-options-that-will-work/ The last one listed above does not have costs, but you might learn a lot from it – and get a better understanding of why many of the contributors here are saying that intermittent renewables cannot contribute much – they can provide only a small component of global electricity, let alone global energy, and therefore can make only a small contribution to reducing global GHG emissions. Like 124. Tony Carden asked for clarification. Yes, if the ratio of the efficiencies of OCGT and CCGT were 2/3, then a wind farm (backed by OCGT) with a capacity factor less than 33% would be a worse emitter than if it were replaced by CCGT. Other values for the efficiencies would give a different minimum capacity factor. However, the formula derived above is quite general. It measures the minimum useful capacity factor of any intermittent source (wind, solar, lightning…) in terms of the carbon efficiencies of its backup source compared to the source they replace. The sources can include the various coal generators. Note that the formula is about emissions only if carbon efficiencies are used. (In the above, two asterisks intended as multiplication signs have vanished, interpreted by the webpage as a command to render the intervening text in italics!) Like 125. To Engineer Poet US O&M costs this year are US$24/MW.
hr http://www.nei.org/Knowledge-Center/Nuclear-Statistics/Costs-Fuel,-Operation,-Waste-Disposal-Life-Cycle. This does not include long term waste storage or plant decommissioning.

If plant Vogtle in the US which is owned by an existing nuclear operator has a weighted average cost of capital of around 7% when US long term bond rates are 2/3rds of ours how will anyone finance a nuclear power plant in Australia at 5%. Grid operators are allowed to earn 8-10% on poles and wires. Any financier in their right mind is going to want a substantially higher premium for a long life inflexible asset so a correct weighted cost of capital for Australia is probably well over 10%.

Being optimistic Over 45 years payback the cost of capital and depreciation on an $10.5b investment at 7.5% WACC (very hopefull) is$820m per year At 85%CF that is a cost per MW.hr of $110 + 24/0.71 =$144/MW.hr.

$40 per MW.hr for wind includes the capacity factor why are you dividing it by 35% As I have pointed out on numerous occasions no matter what technology you use you have a choice of low penetration and high capacity factor eg US nuclear 19% and 90%CF or high penetration and lower capacity factor France Nuclear 77% and 68% YTD. If you try for 100% of anything without massive storage the maximum capacity factor is around 60-65%. In Australia to cover peaks with a 10% reserve you need 35-38GW of generation. With 195 TW.hrs demand the Capacity factor will be around 60% which forces up the cost of the nuclear grid to around$180-$200 per MW.hr. Dumping steam to ramp down is not cheap you are spending all the costs and generating less power. Unless you are dumping steam all the time you still don’t have a fast ramp up capacity. If you have pumped hydro for ramp management, fault backup and peak shaving which is what Japan has (in fact 29GW of pumped hydro to support 58GW of Nuclear) then the cost of the pumped hydro has to be added to the cost of nuclear. On the other hand you build a few less nuclear plants so lets say its a wash on costs In the wind case I added 35 GW of storage and added the finance depreciation and operating cost. That gives a total cost of power of just under$80/MW.hr including operation and maintenance of both the wind turbines and the storage. This is based on current costs not future 60% CF wind turbines which will not only be cheaper per generated MW.hr but reduce storage requirements even further

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126. This does not include long term waste storage or plant decommissioning.

Both are trivial cost per MWh. Waste storage is around $1/MWh and decomissioning is around 0.01/MWh. See IEA, 2010, Tables 3.7a and 3.7d (at discount rate used in AETA, i.e. 10%), and p43: “Where no data on decommissioning costs was submitted, the following default values were used: – Nuclear energy 15% of construction costs; – All other technologies 5% of construction costs.” Footnote #8: “In the median case, for nuclear plants, at 5% discount rate, a cost of decommissioning equivalent to 15% of construction costs translates into 0.16 USD/MWh once discounted, representing 0.2% of the total LCOE. At 10%, that cost becomes 0.01 USD/MWh once discounted, and represents around 0.015% of the total LCOE” WNA, 2014, ‘Decommissioning Nuclear Facilities’ (“0.1 to 0.2 cents/kWh”) http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Decommissioning-Nuclear-Facilities/ Like 127. Another Question for John Morgan. Do you know at what point that the electricity produced is metered. I am trying to get some idea of what has been allowed for transmission losses. Regards Tony Carden. Like 128. Peter F You are confusing me again how can you store 35GW. Like 129. To Peter Lang. The nuclear costs are already double wind +storage so it doesn’t matter whether storage and decommissioning are zero. However the indications from the few plants that are being decommissioned around the world is that the industry supplied estimates of$300-$500m per plant will be woefully inadequate. To Tony Carden: Roam consulting found in 2012 in a report for AEMO hundreds of sites throughout the NEM suitable for pumped hydro, restricting them to 500MW+ …….. 68 total schemes have been identified, with an assumed capacity of 500 MW each. If all these schemes are built, the installed capacity of new pumped storage would be 34 GW…….. As I have said all along a sensible policy will include thermal storage and load shifting + existing hydro and 1-5GW of batteries, primarily used for grid optimisation but available for backup. In reality, for the next 30 years at least, there will be some residual gas which may only have 5-10% utilisation so supplying perhaps 2-5% of the annual demand but dramatically reducing the investment in new generation . In addition, according to the BOM there is always wind on very hot peak demand days so there will be some wind. Taking all these factors into account you probably only have to build 15 to 18 GW of storage. Of coarse most of these measures can be applied to reduce the amount of nuclear required as well but the ratio of cost of nuclear to cost of wind will not change a lot Like 130. Peter Farley, The nuclear costs are already double wind +storage so it doesn’t matter whether storage and decommissioning are zero. That is so far from the reality it’s unbelievable. Even with an ideal storage site on El Hierro island wind and storage are not viable. You do need to challenge your beliefs. Do common sense reality checks. If the incentives were removed, there’d be no more wind and solar. To make significant cuts to global GHG emissions, the world needs a substitute for fossil fuels. Renewables cannot do much. The facts are that renewables cannot meet the requirements (read the links posted in previous comments). They cannot supply more than a small proportion of global electricity, let alone of global energy, let alone future demand as it continues to increase. But nuclear can. The fact you frequently confuse power and energy and miswrite units demonstrates you do not understanding the subject. I’d suggest you read the links I and others have posted, understand them and then ask questions. I fully recognise that nuclear is not financially viable in Australia at current prices. But neither is wind or solar (or energy storage at the capacity that would be required to enable these technologies to meet requirements). If we mandated and subsidised nuclear to the same extent that applies to wind and solar, nuclear would be much cheaper (on a properly comparable basis). The LCOE of generation plus grid show clearly that nuclear is a much cheaper option than wind and solar (plus backup and/or storage) at the levels of penetration that would be needed to make a substantial reduction in GHG emissions (see the cost of generation for different proportions of technologies in the CSIRO calculators I linked – I compared five scenarios here: http://forum.onlineopinion.com.au/thread.asp?article=17320#306282 ; add grid costs from the OECD study or Nicholson’s and Brook’s condensed version (linked in an earlier comment). Clearly, nuclear is much cheaper than renewables – and that’s using optimistic learning rates for renewables and no learning rate for nuclear. Add the risk that renewables cannot do the job by 2050. I estimated that risk to be$54/MWh based on applying the social cost of carbon to the probable undelivered GHG emission reductions.

Even at the high cost of nuclear in the developed countries, nuclear is still by far the least cost way to make major reduction in GHG emissions intensity of electricity. I’ve provided links to authoritative sources in previous comments. You didn’t respond to them.

Furthermore, you have totally misunderstood the ROAM Consulting desk study into potential pumped hydro sites. Probably none of them are viable. If they were we’d have been building them long ago.

Your comments demonstrate you have little understanding of the subject; that together with the fact you won’t listen, won’t read links provided and don’t acknowledge when you have misunderstood, means it’s a waste of time trying to explain anything to you.

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131. Nuclear better than renewables

Nuclear power is better than renewable energy in all the important criteria. Renewable energy cannot be justified, on a rational basis, to be a major component of the electricity system. Here are some reasons why:

Nuclear power has proven it can supply over 75% of the electricity in a large modern industrial economy, i.e. France, and has been doing so for over 30 years.
Nuclear power is substantially cheaper than renewables
Nuclear power is the safest way to generate electricity; it causes the least fatalities per unit of electricity supplied.
Nuclear power has less environmental impact than renewables.
ERoEI of Gen 3 nuclear is ~75 whereas renewables are around 1 to 9. An ERoEI of around 7 to 14 is needed to support modern society. Only Nuclear, fossil fuels and hydro meet that requirement.
Material requirements per unit of electricity supplied through life for nuclear power are about 1/10th those of renewables
Land area required for nuclear power is very much less than renewables per unit of electricity supplied through life
Nuclear power requires less expensive transmission (shorter distances and smaller transmission capacity in total because the capacity needs to be sufficient for maximum output but intermittent renewables average around 10% to 40% capacity factor whereas nuclear averages around 80% to 90%).
Nuclear fuel is effectively unlimited.
Nuclear fuel requires a minimal amount of space for storage. Many years of nuclear fuel supply can be stored in a warehouse. This has two major benefits:

• Energy security – it means countries can store many years of fuel at little cost, so it gives independence from fuel imports. This gives energy security from economic disruptions or military conflicts.

• Reduced transport – nuclear fuel requires 20,000 to 2 million times less ships, railways, trains, ports, pipelines etc. per unit of energy transported. This reduces shipping costs, the quantities of oil used for the transport, and the environmental impacts of the shipping and the fuel used for transport by 4 to 6 orders of magnitude.

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132. 2.1 Nuclear cheaper and lower emissions than renewables
Renewables v Nuclear: Electricity Bills and Emissions reductions by technology proportions to 2050

The CSIRO ‘MyPower’ calculator shows that, even in Australia where we have cheap, high quality coal close to the main population centres and where nuclear power is strongly opposed, nuclear power would be the cheapest way to reduce emissions: http://www.csiro.au/Outcomes/Energy/MyPower.aspx

MyPower is an online tool created by CSIRO that allows you to see the effect of changing the national ‘electricity mix’ (technologies that generate Australia’s electricity) on future electricity costs and Australia’s carbon emissions.

Below is a comparison of options with different proportions of electricity generation technologies (move the sliders to change the proportions of each technology). The results below show the change in real electricity prices and CO2 emissions in 2050 compared with now.

Change to 2050 in electricity price and emissions by technology mix:

80% coal, 10% gas, 10% renewables, 0% nuclear:
electricity bills increase = 15% and emissions increase = 21%
0% coal, 50% gas, 50% renewables, 0% nuclear:
electricity bills increase = 19% and emissions decrease = 62%.
0% coal, 30% gas, 10% renewables, 60% nuclear:
electricity bills increase = 15% and emissions decrease = 77%.
0% coal, 20% gas, 10% renewables, 70% nuclear:
electricity bills increase = 17% and emissions decrease = 84%.
0% coal, 10% gas, 10% renewables, 80% nuclear:
electricity bills increase = 20% and emissions decrease = 91%.

Source: CSIRO ‘MyPower’ calculator

Points to note:

• For the same real cost increase to 2050 (i.e. 15%), BAU gives a 21% increase in emissions c.f. the nuclear option a 77% decrease in emissions (compare scenarios 1 and 3)

• For a ~20% real cost increase, the renewables option gives 62% decrease c.f. nuclear 91% decrease in emissions (compare scenarios 2 and 5).

• These costs do not include the additional transmission and grid costs. If they did, the cost of renewables would be substantially higher.

3. Conclusion:

Nuclear is the least cost way to significantly reduce the emissions intensity of electricity.

The difference is stark. Nuclear power is far better.

But progress to reduce emissions at least cost is being thwarted by the anti-nuclear activists.

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133. Do you have a reference for that report

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134. Thank you foe that reference Peter Lang. It is as I expected another example of Peter Farley not understanding what he has read. As this discussion seems to me to be going off topic I will be reverting to OT 23 unless someone posts some in formation specifically about the capacity factor of wind.

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135. It looks as though the UK is becoming concerned with the high grid costs imposed by low capacity, intermittent generators like wind.

The UK Secretary of State for Energy and Climate Change, Amber Rudd sets out a new direction for UK energy policy.
https://www.gov.uk/government/speeches/amber-rudds-speech-on-a-new-direction-for-uk-energy-policy

She says; “In the same way generators should pay the cost of pollution, we also want intermittent generators to be responsible for the pressures they add to the system when the wind does not blow or the sun does not shine.”

This direction may explain the interest in developing the pumped storage potential in the UK.

The Quarry Battery Company (QBC) carried out a UK-wide geographical survey that identified suitable sites with low planning risk for some 15 GW of new pumped storage capacity.
http://www.powerengineeringint.com/articles/2015/11/pumped-storage-project-developers-aim-to-boost-capacity.html

Rudd also quotes David McKay; “Climate change is a big problem, it needs big technologies. As the former Chief Scientist at DECC, David Mackay, said: “If everyone does a little, we’ll achieve only a little. We must do a lot. What’s required are big changes.”

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136. Tom Bond,

Thank you for the link. Unfortunately, it doesn’t give the important figure, i.e. the energy storage capacity (in GWh). It gives the cost at $244 million for 99.9 MW, say$2.5/W. That could supply about 20% capacity factor if powered by reliable baseload power at night but very much less (probably less than 10% on average) idf powered by intermittent renewables (the ideal El Heirro pumped storage facility powered by wind power shows the very low capacity factors achieved in practice).

At 20% capacity factor the cost per average power delivered would be $2.5/20% =$12.50/W.
At 10% capacity factor the cost per average power delivered would be $2.5/10% =$25/W.
Add that to the cost of wind at say $2/W at 20% capacity factor sent to storage (note you’d need enormous overbuild before this could be achieved from excess wind power) =$10/W
Wind + storage = $10/W +$25/W = $35/W Compare the new plants being built in UAE: 5,400 MW for$20 billion (all up project capital cost) = $3.7/W at 85% capacity factor =$4.36/W

This very simple cost comparison shows wind + storage is around seven times more costly than nuclear to provide reliable power ( $35/W versus$4.36/).

It’s actually much worse than these figures show because:
1. the amount of storage capacity available in quarries is negligible, so next to useless for storage energy from intermittent renewables

Enormous over build of wind would be required before you’d get sufficient excess energy generated by wind to achieve 20% capacity factor from stored energy from wind generation (i.e. at 75% pumped storage round trip efficiency would require about 27% excess capacity factor from wind).
By the time wind is at sufficiently high penetration to produce an excess generation of 27% capacity factor, the CO2 abatement effectiveness of wind would be down to very low because fossil fuels back up is still required or you’d have to turn the whol of England into quarries (look at what’s happening on El Hierro Island – they are having to use the diesel generators to pump water – how ridiculous is that?).
Add the expected monetary value of the risks that intermittent renewables cannot meet requirements by 2050.

This is a quick post, so could contain significant errors, but the general message is correct. Storage cannot make intermittent renewables viable.

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137. Hey Tom,
You are pinching my references. I had already posted this one in OT23. I have just also posted another reference from The Washington Post

Thank you very much though for the reference to the pumped storage report. I notice with interest your comment re low planning risk.

I believe apart from economics, the biggest issue in Australia for pumped storage will be planning approval if the mood of the electorate is the same as it was for the Franklin Gorge and Traveston Dam projects. Mind you Nuclear is going to face a bigger challenge in this area though.

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138. Tony sorry about that, I found this reference and thought it may be of interest to BNC readers, I had not noticed your post in OT.

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139. No problems Tom, I posted some references on this thread and got a slap on the wrist for being off topic so I have been very careful where I put my posts since.

Regards Tony Carden

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140. Tom,

Thank you. I wrote some of those posts. In this one https://bravenewclimate.files.wordpress.com/2009/08/peter-lang-solar-realities.pdf I showed the costs and the area that would have to be inundated to supply the NEM’s 2010 demand profile if all the power was generated by PV at a single location in NSW and energy stored in pumped storage reservoirs with 150 m average elevation difference between upper and lower reservoirs. This is sometimes called a limit analysis or a “book-end” analysis. It is useful to define limits. But it does not claim to be realistic. Recognising this, the results are interesting.

The capacity factor of the solar PV power station, for which we have 2 years of actual ½ hourly data, was as low as 0.8% for the worst days and about 9.4% during 3 months of winter.

The minimum system cost is with 30 days pumped hydro energy storage (about 70 Sydney harbour volumes of water to be pumped up 150 m each day and released each night). This would require 8,000 square kilometres of pumped hydro reservoirs and 3,000 square kilometres of PV panels, total 11,000 square kilometres innundated.

The capital cost of the system was estimated at $2,800 billion. The minimum system cost using Sodium Sulphur batteries would be$4,600 billion.

From the conclusions:

The capital cost of solar power would be 25 times more than nuclear power to provide the NEM’s demand.

The minimum power output, not the peak or average, is the main factor governing solar power’s economic viability.

The least cost solar option would emit 20 times more CO2 (over the full life cycle) and use at least 400 times more land area compared with nuclear.

Government mandates and subsidies hide the true cost of renewable energy

Some of the figures are out of date now, but updating them would not change the conclusions.

A second post, https://bravenewclimate.files.wordpress.com/2009/08/peter-lang-solar-realities.pdf, estimates the cost of constructing a large pumped hydro scheme joining the existing Tantangara and Blowering reservoirs in the Snowy Mountains scheme. The schemes is 9 GW power and 400 GWh energy storage capacity. The revised estimated cost is about $15-20 billion (increased as a result of reviewers’ comments but not updated in the post). The reviewers’ comments are included at the end of the post and should be of interest to anyone interested in what is considered by engineers during the pre-feasibility investigation for hydro projects. There are also many excellent comments on the thread. Some include analyses which explain why intermittent renewables and pumped hydro are not feasible. Like 141. Peter Lang I am not anti nuclear in high density markets. I have never said the China the US or Europe should not build them or Japan re-open theirs. However you have not shown any current evidence that anyone is building new nuclear plants with a delivered cost per MW.hr anywhere near the A$90 per MW.hr for wind available in Australia.

You throw around an 11MW grid on El Hiero as proof of the failure of wind plus storage. a single small windfarm with almost zero diversity and low CF turbines. The exact opposite of a modern distributed NEM wide system in Australia. Even so it was never in fact expected to be by the builders until the lower reservoir can be enlarged. http://www.bbc.com/news/magazine-34424606.. You accuse me of selective facts … Pot… kettle..
I point out that the 29 newest windfarms in the US have 39% capacity factors and you say it is a …factoid…. and persist in using 25-30% in your calculations. In the meantime the largest manufacturers have announced new turbines with 8-10% higher annual output again than those installed last year.
I give you the current utilisation of French nuclear power plants and you ignore it. I give you the maximum utilisation of a 100% nuclear grid in Australia is around 60% you ignore it
You completely deny the practical evidence from South Australia that wind has actually displaced coal even more than gas while imports from Victoria have fallen.
EROI is a useful metric but not the only one but again you misuse it. According to Siemens GE etc. your EROI figures for wind are completely out of date. Siemens is claiming between 20 and 30 and GE is saying their next generation units which are actually being tested today will be as high as 50
You don’t seem to be able to grasp the concepts of interest and depreciation or weighted average cost of capital. The annual interest and depreciation on an $10b investment (current cost) at a mythical 5% interest rate on a 20 year payback. (your figure) is$800m. that is $107 per MW.hr. @85% utilization Using an optimistic 7.5% it is$132 PLUS O&M at $30. Please explain my error You talk about nuclear providing energy security and completely ignore the costs of building and operating the nuclear fuel fabrication and reprocessing plants in building your independent Australian nuclear network The cost of integrating renewables into the grid is mainly storage you are double counting when you add grid integration costs to storage. The CSIRO site you refer to is no longer available however, contracts issued this year for wind in Chile, India, the USA, South Africa and China are all lower cost than nuclear, You say we cannot generate enough energy from renewables but wind power output alone in the US this year and China next year will exceed Australia’s entire electrical demand Like 142. PeterF, This discussion is off topic for this thread. I shouldn’t have replied previously. But anyway I realise there is no point me replying to you. Your comments demonstrate you don’t understand power and energy basics – such as the units – and your comments are a jumble of irrelevant factoids and questions that don’t compare like with like in any meaningful way. You’ve misunderstood or misrepresented much of what I’ve posted in comments above. And you don’t understand even when told repeatedly – for example capacity factor of wind farms is not the capacity factor of wind power delivered to the system, and reduces as penetration increases (read the links I and others have provided and please stop repeating nonsense after you’ve already been told). Comparisons and options analyses have to be done on a properly comparable basis. I refer you back to my previous comments, e.g.: begin by defining the essential requirements of the system (e.g. energy security, reliability of supply and low cost of electricity);  state the year your cost projections are for and the constraints and assumptions that are to be used for the options comparison,  compare options on the basis of the total wholesale cost of electricity and CO2-e emissions avoided (from the system);  We’ve been told not to post off topic comments on this thread. Like 143. The point of the original article was that wind was not economical with penetration above the capacity factor. The CF was claimed to be about 30% and the implication was therefore that nuclear was the only answer to a decarbonised electricity generation system. I pointed out that it is not so simple that renewables + storage is cheaper than a 100% nuclear grid. You referred to various papers you have prepared over the years which are clearly outdated, for example in your example of solar + storage you used a capital cost of$5m/MW for solar. Current costs for utility solar are about 10% of that. Similarly you estimates for CF for solar, length of transmission lines, area of solar farms and CF of solar were all unduly pessimistic, not to mention the fact that no-one in the world would seriously propose a solar+ pumped storage grid. Have you heard the term “Straw Man”

You say that nuclear uses two orders of magnitude less resources yet a nuclear power plant uses 800,000 tonnes of concrete. 850 wind turbine foundations use 350-400,000 tonnes for the same annual generation.
http://www.nei.org/Master-Document-Folder/Backgrounders/Fact-Sheets/Nuclear-Power-Plants-Contribute-Significantly-to-S.

I have updated my calculations to reflect corrections you have made based on new information eg. Argentina and reduced my cost of nuclear but for Australia it still does not add up.

A. Please point out the error in my latest calculations with the appropriate maths not references to out of date calculations

B. Please demonstrate a grid configuration with 90% or more nuclear generation with better than 65% CF.

C. In your secure local nuclear energy calculation please include all costs of the domestic nuclear fuel cycle

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144. To Tony Corden

I am afraid if you look back through the posts, all of us have mixed power and energy. At least I stick to units relevant to the grid

You asked how we could store 34GW. I could have been pedantic and asked you what you meant. I agree that storage is measured GW.hrs not GW. However when we are considering peak capacity, Power is the relevant unit, that is why I quoted the 34GW number from ROAM,

I agree that none are viable at the moment, the only way storage or nuclear will be viable in Australia is if a significant reduction in carbon emissions is mandated by regulation or a large carbon price

When we are considering annual capacity, delivered energy is the key, that is why mixing 85% CF and 100% nuclear does not add up.

I am very hopeful that Molten Salt reactors may be viable particularly for “burning” current nuclear waste. I am all for continuing research, however if it fails what do we do.

If we install renewables now, we reduce emissions gradually (see South Australia) and at less cost than current generation nuclear (see Argentina). In 7 or 8 years time when we are approaching 30% wind and 10-15% solar, then we can retest the economics of whatever the best nuclear option the Chinese have come up with.

It may be that we have a 20-50% nuclear grid in 15 years time but on current trends I doubt it

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145. Peter Farley,
I believe that you are missing the point. John Morgan has provided factual data based on independent data to show that the current capacity factor of wind operating in Australia is 30%. I do not place a lot of weight on what the salespeople from GE, Siemens etc are saying until it is proven in the field.

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146. Peter Farley,
Again you miss the point, with pumped hydro, both GW and GW.hrs are equally important. 35 GW.hrs with 5GW of generating power means the system will run for 7 hrs at 100 % capacity factor. If we were to use all of our existing wind capacity to fill the pumped hydro reservoirs it would take 35 hrs, based on John Morgan’s figures.
Do you know how many litres of water are required to produce this amount of power? Where is this quantity of water available from?

If I was to be pedantic I might point out that my surname is spelt CARDEN.

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147. To Tony Carden

My humblest apologies for miss spelling your name.

I cannot repeat often enough that I am not anti-nuclear. I am pro low carbon and at the currently available state of the art the way to go is renewables. If MSR’s work at lower cost than renewables great. I do agree with most of the Harvard video except to say that the increase in actual generation (i.e MW.hrs not MWs) is almost an order of magnitude faster in both India and China for renewables rather than nuclear

At peak demand times it does not matter how many GW.hrs of storage you have if you cannot deliver it. That is why the power of the system is important. I pointed out that there is plenty of evidence that 35GW of peak storage power can be installed.

You obviously did not read the Roam report because all the water is sourced from existing water bodies with new small ponds located either above or below. It does not consider turkey nest dams by the sea which other reports have recommended, it does not consider plants of less than 500GW capacity, It does not consider thermal storage, load shifting, augmenting existing hydro, power to gas etc etc etc

I am not relying on GE or Siemens for capacity of windfarms but US and Australian data. You have many instances above from correspondents other than me to show that the 29% figure is understated and that the capacity factor of new windfarms is higher than old ones. Australia has around 4GW of older technology windfarms. By definition any windfarms built in the future will have newer technology and higher capacity factors and in the final scheme they will be the majority of the farms so the total system capacity factor will be between 37 and 45%

Nuclear proponents on the other hand are relying exclusively on salesmen for nuclear because no-one has built a new nuclear plant in the last 10 years where the LCOE is less than A$140 per MW.hr. No-one has yet to give any evidence how a 90-100% nuclear grid can be operated economically without large storage and/or exports and thermal backup (see Japan/France) If you had read my post you would have also noted that I said that the 35GW storage power was a thought experiment and that in a balanced system we probably needed about 15-18GW of peak capacity storage and even that would not all be pumped hydro. There are three difficult questions that no-one has answered for any future generation scenario. a) What is the future demand. Electrical demand all around the developed world is trending down. Even in China growth has fallen from 10-13% per year to 1-3% and many of the new coal powered stations in India, China, the US and Germany are losing money now or will face large losses when they open because demand is lower than forecast b) What is the expected rate of change of the technologies. After all, the IEA predicted in in 2002 that by 2010 there would be 8GW of solar and 50GW of wind. Actual result 42GW of solar and 200GW of wind. In 2009 it forecast coal demand in 2015 of 5.54b tonnes and 2030 about 7b. It will be around 5.3b this year but it is already falling to be on track for around 4b in 2030 c) In any economically viable scenario there will be a need for a lot more storage/demand management both in power and energy. How will this be achieved Perhaps we should bend our minds to answering these questions rather than each backing our own hobby horse BNC MODERATOR Please move this discussion to the Open Thread as it is OT here. Tony has posted his reply there. Thank you. Like 148. No I did not read the Roam report because you did not provide a link to it. I would be happy to read it if you would be kind enough to provide the link. Like 149. Thank you Peter I have replied to this on OT23 as this ahas nothing to do with the Capacity Factor of wind. Like 150. Returning to the capacity factor of wind. There are a number of metrics which while useful guides are not set in stone. For example source penetration vs capacity factor. The current capacity on the NEM is 44GW, peak demand is 32GW or 72% of capacity. The overall Capacity Factor is 50%. Even a 100% available system with just the mandatory minimum reserve cannot be more than 60% CF because of the ratio of peak to average demand. Spilling wind or solar is economically inefficient but so is not running an expensive thermal plant below capacity. That is why all grids rely on hydro and/or storage of some sort to optimise the use of thermal plants. The next factor is the demand profile. Many correspondents assume maximum demand has to be available at any time of the day or night and therefore solar is useless for reducing maximum demand. This is not the case, maximum demand is on very hot (therefore windy) afternoons and evenings. If utility scale solar is placed on the western side of the grid, there will always be a significant renewable contribution to the peak. There will be still nights where there is no wind or solar output but demand then is much lower than peak so the backup power does not have to equal the peak demand. The third factor, which has always been a key consideration in grid planning is diversity. The more widely distributed power sources are, the more evenly distributed is their contribution to the grid. John has hinted at this saying that the optimum wind contribution can be 33% even if the Capacity Factor is 29%. This is based on a wind sector occupying only about 15% of the area of the grid. If wind was more evenly spread throughout the whole grid then the optimum contribution may be 1.2 or 1.3 times the capacity factor. The combination of diversity and demand correlation can mean that even higher penetration of solar and wind can be economical. Then there is the question of rising capacity factors. If we build 15,000 class III/IV wind turbines on 155m towers in the best 2% of the NEM area they can reach 65% CF so theoretically all the generation could be wind with existing hydro augmented by some 12GW of solar, with thermal storage, demand management and about half our current gas power stations running 1-200 hours per year. Peak demand could be met by wind turbines running @ 25% of capacity, solar @20% hydro @85% 4GW of gas, 2GW of biomass, wave, geothermal etc. 1.6GW of demand response and only 5GW from storage. Of course if there were hot north winds then the wind @65%and solar @10% would cover all the demand with the hydro, gas and storage just supplying frequency control Finally it all depends on costs, In the current grid, when the carbon tax was removed brown coal increased even though it is technically very inefficient. It still drove some high efficiency combined cycle gas and black coal out of the market. In the future grid, if storage is cheap you build generation capacity equal to 105-110% of annual demand and a lot of storage. If generation is cheap you build generation equal to 200% of average demand (like now) and a lot less storage. Therefore the optimum mix is not a technical constraint, it is cost driven. There is enough room on the NEM to build 100’s of GW of both wind and solar without impacting more than 1% of farm lands so there is not a space or capacity constraint as there is with hydro, it is just a question of money. Like 151. Peter F, As usual you are mixing misunderstanidng the meaning of the terms. Most readers here fully understand them. You also frequentely make comparisons tha Like 152. Peter F, I’d urge you background yourself on the basics: BNC has excellent background papers here: https://bravenewclimate.com/renewable-limits/. Many of your comments suggest you misunderstand and conflate the meaning of terms, such as capacity factor. Most readers here understand them, what they mean and how for example the capacity factor of dispatchable technologies is due mainly to what proportion of the time they are dispatched, not their availability. For example, OCGT might have an average availability of 98% and a capacity factor of 1% to 10%. You also frequently make comparisons that are not fair comparisons, for example comparing LCOE of dispatchable and non-dispatchable technologies. These are not equivalent or comparable. If you want to compare dispatchable and non dispatchable technologies you need to compare on the basis of system costs to meet the same requirements (e.g. demand profile). To do that you need to add the cost of back-up and/or energy storage and grid costs for the technologies you want to compare are equivalent; i.e. dispatchable. David Benson posted a link on Open Thread 23 to an excellent report by JP Morgan Deep decarbonisation of electricity grids https://www.jpmorgan.com/cm/BlobServer/Brave_New_World_-_Annual_energy_piece.pdf?blobkey=id&blobwhere=1320687247153&blobheader=application/pdf&blobheadername1=Cache-Control&blobheadervalue1=private&blobcol=urldata&blobtable=MungoBlobs Like 153. To Peter Lang As usual you misread what I have said. If you read all my earlier costings they include the cost of storage for renewables and often favour nuclear by not including fast ramping support or spinning reserves. I have read the JP Morgan report and their analysis is excellent in its breadth and scope. However their argument is not nuclear vs renewables but how much of each. Even with their assumptions which they themselves acknowledge are highly uncertain, they suggest the optimum is probably 40-45% solar and wind, 5-10% hydro 10-15% gas and 35-40% nuclear. This is for California not for the world My comments: In favour of nuclear I think costs may fall quicker than they suggest. Also I think that their contention that storage is and will remain more expensive than renewable proponents hope and to that extent I will modify my costs per unit of storage. However on the other hand, their capacity factor for new wind is clearly too low. In the Australian case, AEMO has demonstrated that the amount of storage required on the Australian grid appears to be much lower than in other jurisdictions because, system wide, we have much shorter intervals of low wind, low solar than Germany and probably California because of higher average insolation, higher average wind speeds in the required locations and the greater East West spread. A few minor points that probably don’t make a huge difference to the overall balance. JP Morgan dismiss CSP on the basis of the poor initial performance of Ivanpah but performance there has almost doubled over the last few months. They also dismiss offshore wind in Germany but the Germans seem to believe that the higher CF of offshore wind (around 50% in newest farms) reduces the need for high cost backup and is therefore cost effective Like 154. Yes, typical. So bioenergy disappears from the options again even though it is providing 10% or more of baseload electricity in Germany, Austria, Sweden, Denmark, Brazil and a few other more intelligent countries. This is typical of you engineers, you opt for the most high tech and technically sexy, high cost and complex solutions, and blithely ignore the renewable option that provides jobs, social and environmental benefits, and long term flow-on economic benefits to rural and regional economies. In the meantime we have just had high winds causing wind farms in SA and Vic and maybe Tas to shut down just as they get to over 90% CF. Have a look at Snowtown 1 & 2, and Lake Bonney 1, 2 & 3 over the last 24 hours on http://www.anero.id.au. In Vic the Macarthur wind farm and Morten lane and a few others have done the same thing. The anero site lets you look back in time a day and see just how shakey the management of these sites was in this situation. Suddenly up to 1000 MW of supply just disappeared out of the AEMO system within Vic and SA over maybe15-30 minutes. Bald Hills in eastern Vic was similar and some of the NSW sites were doing something similar a bit later on. If you look at the AEMO supply and pricing site you can see for each of SA, Vic and NSW that the pricing due to this wind influence was all over the place from minus$40/MWh up to plus $250. And this is when we only have about 3700 MW as opposed to the projected 8000 MW or more by 2020. Like 155. < blockquote>As usual you misread what I have said. If you read all my earlier costings they include the cost of storage for renewables … < blockquote> All your earlier costings are irrelevant because they are not like with like comparisons. It’s been pointed out to you over and over again. However their argument is not nuclear vs renewables but how much of each. Even with their assumptions which they themselves acknowledge are highly uncertain, they suggest the optimum is probably 40-45% solar and wind, 5-10% hydro 10-15% gas and 35-40% nuclear. That’s your (mis)interpretation. The JP Morgan report does not compare a range of alternatives from low to high nuclear and low to high renewables. So your point is not valid. What you can draw from the analysis is that nuclear is a much cheaper way than renewables to reduce GHG emissions. However on the other hand, their capacity factor for new wind is clearly too low. That’s disingenuous. As the proportion wind energy increases the capacity factor of wind decreases (due to increasing spillage). They report makes that point. Like 156. Eyeballing from the chart on p24, ‘Learning curves for power generation technologies’, the end of the solid lines (i.e. year 2000) I interpret: Nuclear capital cost = EUR 4,600/kW Wind capital cost = EUR 1,000/kW Nuclear capacity = 350,000 MW Wind capacity = 11,000 MW Nuclear plants have a life expectancy of 2x to 3x wind farms. And nuclear plants have a capacity factor about 3x wind farms. Therefore, an investment in W of nuclear capacity supplies 6x to 9x the energy that an investment in a W wind farm capacity supplies. That is, EUR 4,600 invested in nuclear would supply the same total energy as EUR 6,000 to EUR 9,000 spent on wind farms. But it’s much worse than that, because the wind farm also needs backup and energy storage to enable it to be comparable to the reliable, dispatchable energy supplied by a nuclear plant. It worse still when you compare the CO2 emissions avoided with and without nuclear. Nuclear power displaces baseload generation. A MWh of electricity generated by nuclear avoids all the emissions of the coal fired plants it displaces. The CO2 abatement effectiveness of nuclear is greater than 100%. In contrast, the CO2 abatement effectiveness of wind power is much less than 100%. Various studies suggest CO2 abatement effectiveness declines to about 50% when wind power supplies about 20% of the electricity (Wheatley, 2013 and Wheatley, 2015). It continues to decline as the proportion of wind power increases. At 50% CO2 abatement effectiveness the CO2 abatement cost is double what it would be if 100% effective, http://www.onlineopinion.com.au/view.asp?article=17447&page=0 . Like 157. Andrew, I do not agree with the zealots who take ideological positions and say we will have 100% renewables or 100% Nuclear. So where Bio-Mass stacks up surely use it. Surely there will be places where wind is the obvious choice etc. Indeed in 200 years time someone may still be running a coal fired power station. Thank you for your comments about the current Wind Performance, you have actually confirmed some points that I made in this discussion around the 9th and the 10th of November about what was the max speed that wind turbines operate at and what happens when the wind stops. At the risk of repitition: Kirk ‘Scotty give me everything you’ve got now !!!!!!’ Scotty ‘ Aye captain I already am ! I canne give ye any more!!!!!!’ Like 158. JP Morgan report, p2: Transmission costs excluded. We exclude investments in transmission infrastructure often required to accompany large amounts of renewable energy capacity, which could substantially increase the estimated cost of high-renewable systems. Wind capacity factors may also degrade with a large wind build-out since the most optimal sites are often developed first. Like 159. @dos74, You are dismissive of the regression analysis based on 5-min generation data (“misleading”, “fatally flawed”, “fundamentally wrong” etc). I think you are mistaken. John Morgan’s post shows the value of the high frequency data. You are correct that the annual capacity factors quoted in the overview section of my report use installed wind capacity at year end. As you have emphasised more than once, this is not a good approach when installed wind capacity has changed significantly during the year. Of the 34 wind farms included in the report, 3 were commissioned during 2014. CF for NEM becomes 29.8% when these wind farms are excluded. At regional level, CFs become: NSW 23% (19%) SA 32% (31%) TAS 35% (35%) VIC 28% (28%) (Values based on year end capacities are in brackets.) The substantive part of my report deals with the calculation of emissions avoided. This is unaffected by the definition of capacity factor. The emissions avoided calculation makes use of the full 5-min WPG time-series as an explanatory variable. CFs are simply never used. Like 160. To Andrew Lang Sorry I was a bit tired and sloppy I should have said biomass/gas not just gas. Like 161. To Peter Lang You forgot the O&M and security costs O&M of nuclear is 10 times that of renewables. Ontario Power has the largest security force in Canada outside the Canadian military, mainly dedicated to protecting nuclear power plants. Again you use outdated numbers, the nuclear lifetime generation is now around 2 x wind not 3. Nuclear power capacity in Europe today 120,000MW, Wind 130,000 MW. Like 162. Peter F, Again you are not comparing like with like and are quoting factoids that are irrelevant, You forgot the O&M and security costs O&M of nuclear is 10 times that of renewables. Ontario Power has the largest security force in Canada outside the Canadian military, mainly dedicated to protecting nuclear power plants. No one is forgetting that. It’s included in the FOM costs. Clearly you have negligible understand of the subject, and don’t understand how to do like with like options analyses. Again you use outdated numbers, the nuclear lifetime generation is now around 2 x wind not 3. Nuclear power capacity in Europe today 120,000MW, Wind 130,000 MW. Gen III+ uclear plants are expected to last over 60 years. Wind plants are viable for about 20 years on average. But all these silly factoids are just nit-picking Irrelevancies in the context of the huge gap between the mostly nuclear and mostly renewables cost of electricity, CO2 abatement cost and CO2 abatement effectiveness. You continually avoid the key important criteria: cost of electricity from the system, CO2 abatement cost, CO2 abatement effectiveness. Like 163. PeterF says that nuclear power capacity in Europe today is 120 GW, and wind capacity 130 GW. Maybe, but proper comparison requires you to multiply them by their respective capacity factors. If they were 90% and 30% respectively, Europe’s nuclear average production would be 108 GW and wind average production would be only 39 GW. If you multiplied by availability for baseload, the score would be 108 to 0 Is that all that their years of hot air have achieved? I wonder that we will come to witness the collapse of Germany’s heavy industry, while Europe’s zealots crow victory for a cause that the world has meanwhile forgotten. Like 164. Joe Wheatley, Thank you for that clarification. To those who have been raising the issue, as I expected it is a trivial change. A lot of hot air about nothing. And it makes absolutely no difference whatsoever to the values of CO2 emissions avoided by wind power in the NEM in 2014 or the CO2 abatement effectiveness of wind power. Like 165. Peter F, again do you have any references to support your figures Like 166. Thank you Joe Wheatley. I had asked a question of John Morgan in relation to the point of metering of the output of the Wind generators. Would you be able to provide any information in this regard. Like 167. To Tony Carden: The world Nuclear Association for nuclear http://www.world-nuclear.org/info/Country-Profiles/Others/European-Union/ and the European Wind Association for wind. The calculation of Nuclear power output for China in 2010 was based on 85% CF of installed capacity at that time. BNC MODERATOR Please note that comments may be held in the moderation queue for some time as moderators are volunteers and not available 24/7. Thank you. Like 168. Roger Clifton, Yes!@. Furthermore, reportedly Europe has spent almost 1 trillion euros on renewables. A huge cost for arguable negative benefit, since advocating for and spending money on renewables has delayed genuine progress by decades. If not for that anti-nukes scaremongering over the past 50 or 60 years, global GHG emissions would be around 10%-20% lower than they are and we’d be on a fast trajectory towards much faster emissions reductions by 2030 and 2050. That’s what their obvious obstinacy in the face of the blindingly obvious facts has caused. Like 169. Peter, Again your references are either wrong, not on point, completely irrelevant or non existent. Repeatedly you have forced me to read material that is wrong. You are making these numbers up. As when i challenged you on the cost of pumped hydro storage in Australia you admitted that you had no idea. But previously you had claimed to have costed various scenario’s using pumped hydro. I have taken a decision that all of your comments are disingenuous and i do not wish to engage with you any more. Like 170. To Peter Lang Your earlier post was about capital cost and capacity factor not total cost. You also quoted the figures about installed capacity. I merely corrected your post. You project future reliability and life of Gen III reactor plants when none are fully operational and assume that wind turbines won’t last any longer than their initial minimal design life. I agree that nuclear plants should last 60 years although many Gen II plants have been closed well short of that so let’s say we reach 55 years average life. Similarly many wind turbines have operated for 30 years not their 20 year design life. In addition a number of those that have been replaced have been replaced due to technical obsolescence rather than old age. This is common with rapidly evolving technology (see computers, phones, earlier generation jet planes, machine tools etc.) It is true that the EC wide capacity factor of wind is 1/3rd the capacity factor of nuclear (EU wide 82%). however the capacity factor of wind is improving so that new offshore farms are already registering around 50% and new onshore about 35%. In addition all the major manufacturers are announcing high Su turbines, 155m masts, new control systems etc so that many onshore medium wind sites which weren’t even worth building on 5 or 6 years ago will reach capacity factors of 40% by 2018. Meanwhile the UK, Germany and Belgium are increasing the proportion of high CF offshore so by about 2025 the European CF will be around 32-35% whereas it is unlikely that the nuclear CF will change significantly So making a reasonable assumption that average life of wind is 25 years (25% offshore) and the weighted CF of new plants is 40% x.75 + 50% x.25 =42.5% then the lifetime output of new nuclear is 55/25 x 82/42 = 4.2 x wind not the figure of 9 you used None of this says we should go 100% wind and I have never advocated that. It simply says that wind and solar will be a significant part of the zero carbon mix with biofuels, hydro and storage. In other countries (eg Portugal and New Zealand) large amounts of hydro, geothermal, wave or tidal may be important. Then in some countries there will be nuclear maybe as high as 77% in France or Belgium although France has passed a law aiming for 50% nuclear. This is unlikely to be achieved but it is likely that the nuclear generation % will fall. My argument from the start is that the cost of nuclear in Australia will be higher than other countries due to hot cooling water, lack of, or cost to build nuclear infrastructure, higher construction costs and summer peak demand. Meanwhile Capacity Factor will be lower than in other grids because we can’t export off peak and import at peak like France does. Conversely our capacity factor of wind and solar will be higher because we only need to use the best quality wind regions in 1-2% of the Grid and average insolation is about 50% higher than Germany For both technologies we will be using much more efficient and cheaper equipment because we don’t have much of the old stuff. Because of the length of the grid we have a much higher diversity in generation so the grid wide consistency of generation means that the use of storage and backup will be still be essential but used much less and therefore will be a lower proportion of the cost than in a high renewable grid in California or Germany. Another complicating factor is the payback time either in money or energy. While nuclear has a high ROI/ROE if it lasts 50 or 60 years, but it starts from a long way back. (800,000 tonnes of concrete vs 380,000 tonnes for example) so that if Lockheed’s new fusion reactor suddenly became viable in 2030, we would have a whole fleet of nuclear power stations which had still not recovered the money or energy embedded in them and the fuel cycle, while the wind and solar generators would have recovered their embedded energy and be well on the way to recovering most of their money. If nuclear costs fall as fast as you think they will and renewables and storage don’t fall as fast as they have been, then nuclear might make up half the Australian grid. On the other hand current “overnight” costs of equipment that can be ordered today suggest that there will not be any nuclear. see The Australian Power Generation Technology Report Like 171. Peter Farley, Your earlier post was about capital cost and capacity factor not total cost. You also quoted the figures about installed capacity. I merely corrected your post. I haven’t a clue what you are referring to since you didn’t quote. However,since nearly everything you’ve said on this thread has been disingenuous or just plain wrong, I suspect this assertion is disingenuous, misrepresentation, incorrect, irrelevant or out of context too. You made a comment earlier referring to the JP Morgan report and mentioning the high uncertainties. Yes of course there are great uncertainties with the predictions. However, we know nuclear can do the job. It’s proved it can in France. But there is no evidence that non-hydro renewables can do the job for most of the world. So there is much greater uncertainty attched to the projections of 80% renewables than there is to 80% nuclear. Like 172. However their argument is not nuclear vs renewables but how much of each. Even with their assumptions which they themselves acknowledge are highly uncertain, they suggest the optimum is probably 40-45% solar and wind, 5-10% hydro 10-15% gas and 35-40% nuclear. Where do they suggest the optimum proportions? The tables on p9 and p15 of the JP Morgan report show that: Energiewende with 35% nuclear instead of 0% nuclear, would be 79% the cost of electricity and 28% the CO2 abatement cost. Caliwende with 35% nuclear instead of 0% nuclear, would be 82% the cost of electricity and 36% the CO2 abatement cost. This trend suggests that cost of electricity and CO2 abatement cost both decrease as the proportion of nuclear increases and the proportion of wind and solar decreases. The JP Morgan report does not optimize the technology mix to minimize cost of electricity or CO2 abatement cost. If it did, the cost trends in the tables on p9 and p15 suggest the nuclear proportion for least cost electricity (especially once you include grid costs) would be similar to France plus gas, any additional viable hydro and a relatively small proportion of wind and solar (like France is now). France has demonstrated what is achievable with a high proportion of nuclear power; i.e. relatively low cost of electricity and very low emissions intensity. France’s nuclear power has been supplying 75% to 80% of electricity for about 30 years, helped by having good hydro resources. Without the hydro resources, gas would be required for most of the load-following in a system that meets requirements and is optimized for minimum cost of electricity and minimum CO2 abatement cost. The CO2-e emissions intensity of electricity in France will increase if it reduces the proportion of electricity generated by nuclear and increases the proportion generated by intermittent renewables. The CO2-e emissions intensity of electricity in France is 8.6% of Australia’s and 14.5% of Germany’s (IEA, 2014, http://www.oecd-ilibrary.org/energy/co2-emissions-from-fuel-combustion-2014_co2_fuel-2014-en . If France reduces its nuclear proportion and increase its wind and solar proportion it will have to also increase thermal generation proportion for back-up, therefore increasing the emissions intensity of its electricity. Your assertions that capacity factor of wind will increase as penetration increases are wrong, by a wide margin. The JP Morgan report explains it and I’ve given you references explaining this in a number of previous comments. Also, you have not provided relevant, valid evidence demonstrating that a large proportion of renewables can supply electricity and cut emissions more cheaply than a large proportion of nuclear. Like 173. Peter Lang — Yes, that is an important reminder. Like 174. Peter Lang So many misinterpretations of what I have said. You accuse me of not giving references yet you clearly do not read them when I do I have never said that the US China or Europe even Germany should not use nuclear If you look at the costs in the JP Morgan report on P20 wind is far cheaper than Nuclear, and so is solar PV, biomass and geothermal and surprisingly even solar CSP so it seems to me that it is logical that you would include as much of those as possible in the grid to lower the overall cost of power. Only when you run out of economical hydro, geothermal and biomass would you consider nuclear as residual load i did not say wind CF increases because of its increased penetration. Obviously if the technology remained the same, CF would decline as penetration increased (just as it does with nuclear coal or any other source above a certain threshold but that is not the case. I said wind CF is increasing because of vastly improved technology, for example typical annual output from a new turbine installed in Germany in 2008-10 was about 2-3GW it will be 10-13GW for one installed in 2017 . Further as the number of full load hours increases, cost of grid integration is lowered. Changes to the electronics allow them to supply re-active power even if they are not turning, further reducing grid integration costs As usual it is you who doesn’t want to understand the technology or the economics How many times do you have to be told 1. that France’s wholesale electricity generation is more expensive than Germany’s according to France’s electricity directorate 2. France’s current nuclear CF is less than 70% and would be lower if they could not dump off peak power on neighbours with more flexible generation. You don’t answer the basic question of how does anyone justify building nuclear power plants to provide shoulder and peak demand when their utilisation of the last plant will be about 5% or if the load is shared evenly all plants will have to make money at 60% utilisation. You assert that if France increases wind and solar its carbon intensity will go up. That is not a fact it is a guess. If wind and solar allow France to make better use of its hydro, carbon intensity can go down. You don’t know I don’t know but as nuclear is covering the base load the liklehood is that more renewables can actually lower the carbon intensity Like 175. However their argument is not nuclear vs renewables but how much of each. Even with their assumptions which they themselves acknowledge are highly uncertain, they suggest the optimum is probably 40-45% solar and wind, 5-10% hydro 10-15% gas and 35-40% nuclear. Where does the JP Morgan report suggest those optimum proportions? Like 176. Peter Farley is using un-referenced and likely falsified numbers. Example: Another complicating factor is the payback time either in money or energy. While nuclear has a high ROI/ROE if it lasts 50 or 60 years, but it starts from a long way back. (800,000 tonnes of concrete vs 380,000 tonnes for example) His claims are completely opposite to reality. He asserts e.g. a 2:1 disadvantage for nuclear, while a very quick search on my part found not one but two references (with sources cited) showing roughly a 4:1 disadvantage for wind. As usual it is you who doesn’t want to understand the technology or the economics Says the poster who is either deluded or a foul propagandist. I strongly suggest that BNC put Peter Farley on moderation, and delete any further comments giving un-cited claims. Just remove his flow of nonsense from the forum; make him either start talking sense or go elsewhere. Like 177. Hi Joseph Wheatley, thanks for taking the time to respond to my comments of your paper. I’m not sure how many of my previous comments you have read, but let me summarise three issues I have. Capacity Factor. Thanks for redo-ing your capacity factor calculations taking into account the 3 wind farms which had not commenced generation by the beginning of 2014. I presume you are talking about Bald Hill, Taralga, & Boco Rock. Please note that I used the words “commenced generation” rather than “commissioned”, as I believe this is what you meant, though happy to be corrected if I assumed wrongly. To clarify the difference, a wind farm is commissioned when it has finished construction, which may be a few months or even a year after it first starts generating. For a fair analysis of capacity factor, I believe you also need to exclude wind farms that were still under construction during during 2014. This also includes Portland, Gullen Range, Snowtown Nth & Sth, & Mt Mercer. If you remove these wind farms, then the overall NEM capacity factor for wind increases to 30.4%, and NSW’s CF increases to 29.1%. Misleading use of carbon emission abatement effectiveness. This is not so much a criticism of your paper, but rather a criticism of how others have interpreted your result. Your paper calculated that wind farms had an abatement effectiveness of 78%. In a comment above, Peter Lang said “Nuclear power displaces baseload generation. A MWh of electricity generated by nuclear avoids all the emissions of the coal fired plants it displaces. The CO2 abatement effectiveness of nuclear is greater than 100%.” I previously pointed out that a new nuclear power plant in Australia was more likely to displace gas generation, which has a higher marginal cost than coal. I suggested that a nuclear plant in SA would be most likely to displace gas generation with a carbon intensity of about 0.6 tCO2/MWh, which would give it an abatement effectiveness of 69%. My point is that people like Peter refer to your calculation of abatement effectiveness, and insinuate that their preferred technology would do much better. It is highly misleading to refer to wind’s abatement effectiveness, without acknowledging that this is highly influenced by the marginal cost of generation of other generators on the network, and that other new generators may not do any better than wind. Five minute regression analysis does not indicate longer-term trends of carbon abatement effectiveness. When I first read your paper, I was very impressed. It seemed to be a highly comprehensive analysis of wind’s abatement effectiveness. However, after some more thought, I came to believe that it is fundamentally flawed. Please correct me if any of the following is wrong, but my understanding is that your paper uses 5 minute regression analysis to determine, amongst other things, that 1 MWh of wind in SA displaces just 0.06 MWh of brown coal generation in SA, and 0.320 MWh of SA gas generation. From this result, and similar results from the other states, you were able to determine what generation would have occurred in the absence of wind (on a 5 minute basis), and therefore calculate the emissions saved by the wind. However, five minute regression analysis misses any longer term trends and decision making by other generators. As an example, in the last few years, one of SA’s coal power stations (Playford B) has stopped producing power, and the final remaining coal generator (Northern) is scheduled to close early next year. The owner of the generators blamed in part the rise of renewable generation in the state for the closure. If you look at the long-term trend in generation in SA (I have posted the image twice in earlier comments), it is clear that wind generation in SA has primarily displaced coal generation, and there has been very little trend in gas generation over the same period. This has not been picked up in your 5 minute correlation analysis, which suggests that wind in SA displaces 5 times as much gas as coal in SA. Clearly coal generation does not react over this short period to changes in wind output, but that does not mean wind doesn’t displace coal in the longer term. So I believe your paper may prove a reliable predictor of wind’s abatement effectiveness over the short term (hours, days and possibly even weeks), but it is a very poor predictor of wind’s abatement effectiveness in the longer term (months & years). Like 178. dos74 This is not so much a criticism of your paper, but rather a criticism of how others have interpreted your result. Your paper calculated that wind farms had an abatement effectiveness of 78%. In a comment above, Peter Lang said “Nuclear power displaces baseload generation. A MWh of electricity generated by nuclear avoids all the emissions of the coal fired plants it displaces. The CO2 abatement effectiveness of nuclear is greater than 100%.” I previously pointed out that a new nuclear power plant in Australia was more likely to displace gas generation, which has a higher marginal cost than coal. Your comment is not relevant to Wheatley’s analysis and is not a valid criticism of it. Wheatley’s analysis is of historical empirical NEM data for 2014. You are surmising, presuming, assuming about what might be if, if, if. The empirical analysis is not used for that. For what you want, you need to use a modelling approach like SEAI did for Ireland. Your reference to my comments, which were a response to another poster, are irrelevant in the context of critique of Wheatley’s paper. You have conflated two separate discussions, made your own assumptions and misrepresented what I was talking about (which was about the J. P. Morgan paper on Germany and California). I do not appreciate the misrepresentation and disingenuous comments. I don’t understand why you don’t understand that Wheatley’s analysis is about 1 year, not multiple years. If you want long tern trends you need to repeat the analysis for several years. Then you have to assign causes to the changes, such as effects of government interventionist policies, and changing relative costs of generation technologies over time as in ERCOT where gas prices have come down significantly. I’ve told you all this several times and you still either don’t get it or refuse to accept it. I’ve also told you the reason wind is replacing coal in SA is because of the RET which effectively mandates renewables and subsidises them through the REC’s. Wheatley’s analysis does not explain the reasons for the displacement of one technology by another, it just estimates how much emissions were avoided by wind generation and what the CO2 abatement effectiveness was for the data analyses. The fact you haven’t acknowledged your misunderstanding about why the analyses have to be done using short period data (5-minute power output from each generator unit) suggests you still have not understood the analysis. I again urge you to read Wheatley’s 2013 paper of the Irish study, SEAI report and the Kaffine et al. report of ERCOT 2007-2009. There is no point asking Wheatley to explain the analysis if you won’t take the trouble to try to understand it. http://joewheatley.net/how-much-co2-does-wind-power-save/ http://joewheatley.net/quantifying-co2-savings-from-wind-power-redux-ireland-2012/ Emissions Savings from Wind Power Generation in Texas Author(s): Daniel T. Kaffine, Brannin J. McBee, , Jozef Lieskovsky https://www.iaee.org/en/publications/ejarticle.aspx?id=2509 Like 179. Peter, I apologise for quoting you out of context in my above comment, and for giving any impression that you were talking about nuclear abatement effectiveness in Australia. Your comments on the long-term abatement effectiveness of wind in Australia illustrates that you do not understand my criticism of Wheatley’s paper. If one was to repeat Wheatley’s analysis in Australia in the years 2009, 2010, 2011, 2012 & 2013, I’m sure that we would again find that wind generation does not (anti) correlate with coal generation, with the implication that wind generation does not displace coal generation. It will show this, despite a clear long-term trend of wind displacing coal. You seem to be under the impression that I think 5 minute analysis is irrelevant to wind’s carbon abatement effectiveness. That is not the case. I am merely stating that using only 5 minute regression analysis and ignoring analysis based on a slower timescale can provide some highly misleading results. I repeat my previous analogy. I am confident that brown coal generation is not well correlated to demand in Victoria on a 5-minute time-scale. However, this does not mean that brown coal does not make a significant contribution to meeting Victorian demand. Like 180. dos74, Peter, I apologise for quoting you out of context in my above comment, and for giving any impression that you were talking about nuclear abatement effectiveness in Australia. Thank you for the correction/clarification. Appreciated. Your comments on the long-term abatement effectiveness of wind in Australia illustrates that you do not understand my criticism of Wheatley’s paper. I think your criticism is invalid and irrelevant to this paper. The paper is an excellent contribution to our knowledge base of the CO2 abatement (in)effectiveness of wind power. Your complaints are not about the paper. They are about a different analysis altogether. Why don’t you do that analysis yourself? Look at the SEAI report for an example of a method. Analyses over several years would show trends in emissions avoided by wind generation and CO2 abatement effectiveness in the NEM. More accurate and frequent CO2 emissions data from the generators involved in cycling and ramping to back up for wind power would improve the estimates and reduce the uncertainties (95% confidence intervals on the estimates). If one was to repeat Wheatley’s analysis in Australia in the years 2009, 2010, 2011, 2012 & 2013, I’m sure that we would again find that wind generation does not (anti) correlate with coal generation, with the implication that wind generation does not displace coal generation. It will show this, despite a clear long-term trend of wind displacing coal. Who cares what wind anti-correlates with (unless you have preconceived ideas about good and bad ways of generating electricity). My interest is in the highlighting the very serious issue of assuming that wind power is 100% effective at savings emissions. It is nowhere near that, as Wheatley’s analysis highlights and quantifies. But that is the assumption that underpins most of the analyses of the emissions avoided by wind generation. I would suggest that belief is what is underpinning you apparent belief that wind replacing coal in SA is necessarily a good thing. Furthermore the CO2 abatement effectiveness of wind power gets worse as wind energy penetration increases. So the CO2 abatement cost with wind is much higher than recognised. The result is that wind is a very high cost way to reduce GHG emissions. Those who are genuinely concerned about achieving deep cuts in GHG emissions should stop advocating for wind power, renewable energy and government interventions in the energy market to implement bad policies, such as the RET. … I’m sure that we would again find that wind generation does not (anti) correlate with coal generation … This is something you seem to be concerned about, but why? It seems to me that you think it is a good thing that unreliable, intermittent, high cost, highly subsidised wind power is displacing reliable, dispatchable, low-cost coal generators, presumably because you assume that by doing so you are avoiding the emissions that coal would have caused. Wheatley’s analysis shows that is not the case. Coal power stations in other states do the cycling instead. What is relevant is the CO2 abatement effectiveness of wind in the NEM, not what is happening in SA, nor which particular generators in which state are being forced to close down by the RET. Like 181. dos74, As an aside, Referring to the graph that you posted on November 10 on this thread. From the years 08/09 to 13/14 Wind as a percentage grew from 14% to 28%. In the same period Supply from the interconnector grew from 2% to 12%. Do you think that there is a relationship in the similar amounts of growth of electricity supply from the two sources? Also do you know what is the source of supply for the interconnector i.e. coal, gas, hydro, solar??, wind. Like 182. BNC MODERATOR Your latest post was again off topic on this page. Please re post on the Open Thread as you have been previously advised several times. Like 183. Hi Tony, between 08/09 and 13/14, both coal and gas generation in SA has reduced. In total, they have reduced at a faster rate than wind has increased. It seems that economics have favoured increased imports rather than maintaining local gas or coal generation. I think it’s as simple as that. Imports into SA are from Vic, which is predominantly brown coal generation. At first glance this would suggest that the imports are primarily brown coal, though it’s not as simple as that. The brown coal generators are often run at near constant load, and their output does not generally correlate to whether SA is importing or exporting. One would suspect that the increased generation supplying SA from Vic is coming from sources other than brown coal. So I’m afraid the answer is complicated. Wheatley’s analysis probably provides some clues, but once again I don’t believe it will provide the full story, as it is based on 5 minute regression analysis and does not capture slower relationships. Like 184. David, i apologize if I have your name wrong. Surely, to correctly evaluate Wind etc we have to consider its impact on the total system i,e, The NEM, and measure the total changes in system inputs and outputs that occur from Wind or whatever. This is why I am particularly interested in reports from places like Ireland where it is possible to measure the system inputs and outputs as a whole. Robert Hargraves mentions the results for Ireland. It is towards the very end of the video, about minute 38, referenced here Hargraves states that Ireland was expecting to reduce GHG emissions by 12% by installing wind farms. After installation and remeasurement the reduction was only 3%. Like 185. The Robert Hargraves statement in the video is probably a misunderstanding. I suspect he was referring to 53% effective at 17% wind energy penetration from the Wheatley empirical study. Wheatley’s posted a comment on the SEAI report here: http://joewheatley.net/quantifying-co2-savings-from-wind-power-redux-ireland-2012/ In part he says: The Sustainability Energy Authority of Ireland (SEAI) have a new report which looks at CO_2 emission savings from wind energy in 2012. The electricity grid is simulated using \frac{1}{2}-hourly system demand, known outages, and inter-connector flows as boundary conditions. One simulation is done using actual wind generation in 2012 while another sets wind generation to zero. The difference in total CO_2 corresponds to emissions savings. The SEAI study was carried out using off-the-shelf PLEXOS dispatch modelling software. [Table summarising the SEAI results] The savings for RoI is far lower than SEAI’s earlier number 0.49tCO2/MWh. In terms of “effectiveness”, 1 MWh of wind generation displaces the CO_2 equivalent of 0.65MWh of average thermal generation. The earlier SEAI number corresponds to approximately one-for-one displacement. So this is a big change. SEAI’s simulation findings can be compared to results based on empirical estimates. … The NI CO_2 savings number is much lower than found by SEAI. In fact, SEAI’s 2012 savings of -0.8tCO_2/MWh is hard to understand, because only \approx \frac{1}{3} of NI generation came from coal. Simulation and empirical approaches each has advantages and disadvantages. Both are sensitive to imperfections in the wind generation/system demand dataset. However SEAI make a number of claims about the 2011 empirical method results which seem to me to be wrong. … Points to note: SEAI’s study is a modelling exercise, not an empirical study of actual data. SEAI did their study in response to Wheatley’s analysis, but did not analyse the same year or same geographic area so the results are not directly comparable. SEAI has had to revise downward (very significantly) it’s claims about emissions avoided by wind generation. It also now recognises that CO2 abatement effectiveness decreases as wind energy penetration increases. Wheatley has pointed out likely errors in the SEAI analysis and also pointed out the SEAI misunderstood or misrepresented his analysis. All in all, Wheatley’s analysis has stood up to all attempts to discredit it since it was published (nearly 3 years ago). I suggest it is an important contribution to our understanding of the true effectiveness of intermittent renewable energy. Especially significant is that Wheatley’s results are consistent with others and together they provide a persuasive case that CO2 abatement effectiveness decreases with increasing wind energy penetration. CO2 abatement effectiveness may be around 60% in the NEM when wind energy penetration reaches 15%. That would mean that CO2 abatement cost with wind would be 67% higher than estimates that assume wind energy is 100% effective (i.e. the standard assumption in most analyses). To clarify the significance of this, if the estimated CO2 abatement cost is$60/t CO2 on the assumption effectiveness is 100%, then the estimate should be corrected to $100/t CO2 (i.e.$60/0.6).

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186. http://www.theenergycollective.com/jessejenkins/2259541/can-market-fixes-overcome-declining-value-wind-and-solar-high-market-shares

I found this explanation of the energy market and particularly the declining value of wind and solar at high penetration rates easy to understand and I quote.

“But once wind and solar have displaced all fossil fuel-consuming resources at a given moment, adding more wind and solar won’t deliver much value. The additional savings of pushing nuclear, hydropower, or even other wind or solar generators off the market at that time is virtually nil. We just don’t save any more fuel (or other operating costs).”

This supports John’s conclusion that variable renewables have an upper limit on market share.

Particularly if the aim is to reduce CO2 emissions.

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187. John,

A very interested post.

As you say, there is no point in providing many times overcapacity of a renewable resource such as wind or solar if the generation from all the capacity is correlated. But the reverse of this is that it is worth providing additional renewable capacity if generation times are expected to be anti-correlated, or perhaps just uncorrelated to what you already have.

On the matter of wind and solar together there are a few comments.

Firstly the analysis of both wind and solar on the German grid gives different conclusions to yours.

From the document the nameplate capacity of 35.6 GW of solar and 32.5 GW of wind in October 2013. The points all seem to represent hour slots. At no point does the total exceed 36 GW, and there are very few points higher than the installed capacity of either solar or wind.

The implication is that in Germany at least you can go higher than the maximum capacity factor of wind or solar in configuring total wind + solar renewables capacity without significant renewables overcapacity.

One caveat is that Germany is not an ideal place for solar and solar capacity factors are likely to be much lower (10-12%) than in Australia. Wind capacity factors in Germany may also be lower, which makes it easier for German wind and solar to be anticorrelated (there are just more gaps).

Secondly the analysis of wind capacity factor by month does not take into account one mitigating factor. In Europe and the USA and presumably Australia the typical demand tends to peak during the day. Germany used to have peaks at midday and then an evening peak.

Although solar has a lower CF (capacity factor) than wind – in the range of 10-25% (maybe 30% in places), the solar generation is never at off-peak demand times. So you can afford to configure solar + wind to provide some measure of total overcapacity during peak hours. Then wind capacity could be configured to provide a little more than average demand outside hours with significant daylight.

Provision of 3 or 4 hours of storage, either battery, or maybe provision of some CSP (Concentrated Solar Power) with hot salt storage to cater for the evening peak would clearly also increase the total proportion of solar without wasting significant wind power.

It would be very interesting if John could take into account the daily demand curve and solar generation daily curve in some future analysis.

Thirdly, the cost has to come into it. Assuming that the CCGT backup you need is a fixed capital cost, the cheaper wind and solar is, the more you can afford to overconfigure wind and solar to provide higher levels of CO2 abatement, even if you do throw more more power away (or better, find a productive use for it such as Power to Gas [syngas]). In particular once the LCOE cost of wind and/or solar gets below the fuel (and other true variable costs) of CCGT then you can start overconfiguring. And the IEA are saying that by 2050 solar LCOE costs may get as little as 1.5 US cents / kWh.

Fourthly capacity factors of wind and solar are expected to rise. For wind, the towers will be taller and the rotors bigger, but the generator size may not increase. This captures more wind energy, and throws more away at high wind speeds but also increases generation at lower wind speeds as a fraction of nameplate capacity.

For solar one trick is to overconfigure what are now becoming increasingly cheap panels relative to the harder to reduce costs of the rest of the system. For fixed tilt systems you might also face the panels further to the rest which would not increase the capacity factor, but might make more of a dent in the evening peak.

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188. The implication is that in Germany at least you can go higher than the maximum capacity factor of wind or solar in configuring total wind + solar renewables capacity without significant renewables overcapacity.

It is recognized you can do it from a purely technical point of view. The point is, it is very costly.

To be financially and economically viable we need the cheapest solution that meets requirements. The main requirements are reliability of supply and cost.

The excellent ERP 2015 report ‘Managing Flexibility Whilst Decarbonising the GB Electricity Systemhttp://erpuk.org/wp-content/uploads/2015/08/ERP-Flex-Man-Full-Report.pdf considered the relevance of weather dependent renewables in Germany to the GB electricity system. The lessons are relevant to other isolated electricity systems, such as the NEM.

At the end of 2014 Germany had 36 GW of wind and 38 GW of solar, with a peak demand of over 70 GW. So at first sight it might be thought that Germany is already tackling issues associated with intermittency that the GB system will have to face if the UK also aims for significant production from renewables. However, closer examination shows us that Germany is not in the same position and the solutions currently employed there are either not possible or unpalatable for the GB system.

Therefore Germany does not provide much evidence on how the GB system could deal with high penetration of renewables, as:

• Its production from wind and PV is still quite low compared to scenarios explored here

• Although well short of having surplus renewables generation it chooses to export a lot of production so that high carbon plant runs baseload

• Most of its immediate trading partners (with the exception of the small Danish system) have not yet constructed large amounts of wind and PV

• Germany benefits from being a small part of a very large synchronous system

Virtually all lines of evidence show the least cost way to make large reductions to the emissions intensity of electricity is with a large proportion of nuclear and little or no weather dependent renewables. The ERP analysis is an excellent, recent example. It shows that the least cost way for the Great Britain electricity grid to achieve the same emissions intensity as France (i.e. 42 g/kWh in 2014) would be for GB to install 32 GW of nuclear and no more weather dependent renewables (e.g. wind and solar). http://erpuk.org/wp-content/uploads/2015/08/ERP-Flex-Man-Full-Report.pdf

By the way, as has been pointed out to you on several other threads where you have made similar arguments, the low or negative statistical correlation of wind and solar is almost irrelevant for capacity planning because there are periods where there is zero or near zero generation from wind and solar. Such periods can last for days, and weeks, and below average output can last for months. Energy storage is prohibitively expensive.

In short, renewables are not the answer to substantially lowering the emissions intensity of electricity – nuclear is (see Figure 14 in the ERP report).

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189. @ Peter Davies, 26 December 3015:

Figure 5 on Page 14 plus the associated text provide an eloquent demonstration of the of the interaction in UK of new wind and new nuclear when modelling reductions in carbon intensity.

In round figures, in order for the UK to reach its National Renewable Energy Renewable Action Plan goals by combinations of new wind and nuclear generation capacity and to meet the CCC target carbon intensity of generation of 50 g/kwh, the model’s outcomes range between (for UK and subject to modelling assumptions)
• 22GW new nuclear plus 28 GW new wind or
• 30GW new nuclear plus 20 GW new nuclear.

This is an example of where 28 GW nameplate of new wind displaces 8 GW of new nuclear. I have not worked back to an “energy sent out” basis, but even that would be uncomplimentary to wind.

The study, of course, is much more detailed than this simple comparison. The discussion of “No new nuclear” indicates that an infinite addition of new wind will fall very much short of the target.

Further,“…although renewables output in Germany is less than half of demand for nearly all of the time, much of the renewables production (typically half) is exported to its neighbours rather than displacing the highly emitting lignite plant. Figure 3 illustrates this well”.

In similar manner, SA’s grid is only part of the much larger Australia NEM. It is outrageous to draw conclusions about the effectiveness or otherwise of SA’s wind farms without considering the power flows to and from the remainder of the NEM which, as in Germany, support rather than reduce lignite power stations and thus do little to reduce system-wide carbon intensity.

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190. @singletonengineer (26 Dec 2015)

Fig 5 from http://erpuk.org/wp-content/uploads/2015/08/ERP-Flex-Man-Full-Report.pdf is also very interesting. What it shows is that around 70GW of new wind alone can abate 50% of the current UK CO2 emissions. This is an estimate from continuing the top curved line, not from the linear extrapolation given by the second (straight) line down.

However, the chart itself is a very crude calculation, with 3 weaknesses.

It does not include solar as well as wind, and the Fraunhofer chart in my post above shows that wind and solar are anti-correlated in Germany, and therefore presumably UK. Therefore you can achieve a higher abatement of CO2 by including solar in the mix, without significantly increasing the costs.
It is very obvious to anyone that thinks about it a little that just increasing the quantity of a single correlated type of variable generation has limits. However, these limits and the cost effectiveness are significantly higher if more than one type of variable generation is included (e.g. both wind and solar). Mostly the exercises that set out to prove that nuclear is essential or the most cost effective solution fallaciously compare only with increasing quantities of wind from a single location (northern Europe) – and usually existing onshore wind with low capacity factor instead of the likely move to more offshore wind which is likely to have a capacity factor exceeding 50% in the future. Further, the inclusion of North African wind (uncorrelated with the North Sea area) further reduces renewables generation gaps.
It shows only the effects of new nuclear, not those of additional storage or demand response solutions, which are mentioned as alternatives in the text. Some of the industrial demand response solutions, such as new aluminium smelters, provide a significant degree of load flexibility, enabling demand to be increased or decreased at the drop of a hat (or a drop in the wind).

You have to assume we are looking at a 2030 solution, so the strong implication is that two major changes in demand will have happened by then, irrespective of the 2030 solution chosen for UK power generation.

A) Industrial demand response implementation will be well underway by then.
B) Land transport will be mainly electric vehicles EV’s) by then

The wholesale switch to EV’s will depend on battery prices, and charging network implementation, but all the evidence is that batteries will be below the magic $150 / kWh in the late 2020’s, which is considered the magic figure for straight purchase costs to induce consumers to buy EV’s on purchase price comparisons alone. With the simple and obvious change to regulation to ensure EV charging can be controlled by the grid, this will provide a significant measure of demand response flexibility in domestic electricity use. The effects of the demand flexibility in both these areas, for just wind alone, would probably straighten the line in figure 5, leading to 133 g / kWh with just wind implementation, and considerably lower when anticorrelated solar is added. By 2050 (or more likely earlier after the Paris ambition to restrict rises to 1.5 degree C) UK generation has to get to zero carbon emissions, not 50g / kWh. The point about Germany not modulating lignite generation output to complement renewable generation but choosing to export instead is irrelevant. By 2030 there will be no hard coal or lignite generation left in UK or Germany, and the technology filling in the gaps left by wind and solar will be fast start CCGT which is capable of starting in 20 minutes or less, and, once started, capable of the required ramp rates, particularly with some help from national pumped hydro schemes. UK government (whose energy policy seems in some disarray at present) did announce it was shutting coal and would ensure orders for replacement CCGT stations, though it might find it has to subsidise the new CCGT stations somehow before it gets bids to install them. Everyone understands that this CCGT generation is likely to have a low load factor by 2030. However, the absolute CCGT capital costs are also very low, so this is going to make little difference to the costs of units of power supplied. In https://www.worldenergy.org/wp-content/uploads/2013/09/WEC_J1143_CostofTECHNOLOGIES_021013_WEB_Final.pdf the capital cost of UK CCGT is estimated as 0.76M$/MW, whereas, if the same capacity of onshore wind and solar PV together is deployed (which it would be to get high levels of CO2 abatement) the capital cost currently would be 1.5M + 1.6M = 3.1M $/MW. The backup costs are thus some fraction of 20% of current total capital costs – in this scenario where CCGT might be generating some 40-45% of the time, the fraction would be 0.5, so the backup for wind and solar adds some 10% additional cost. If the CCGT is already there and we keep existing nuclear, then the back-up cost is even lower than this. As wind and solar get much cheaper and fall below CCGT fuel and variable costs) towards 2030 and particularly 2050, the absolute capital cost of CCGT stays the same. But the overall capital costs are lower and since gas fuel is expensive, the LCOE price reduces. In conclusion the ERP report seems to have focused on a couple of extreme solutions to UK’s problem (mostly wind, mostly nuclear or some combination of just these two), whereas the cheapest and most effective solution will encompass multiple renewal generation types (biomass, solar, wind), industrial process and domestic EV demand response, expansion of pumped hydro storage, interconnection to Norway’s huge pumped hydro potential and interconnections to Iceland’s dirt cheap hydro and geothermal power potential. Although ERP is a respected body, on this occasion they appear to have missed the mark somewhat, although the report does say “A much deeper examination of the issues raised within this report is needed. ERP’s modelling and analysis has only begun to scratch the surface and ERP does not have the resource or capabilities to take this work much further.” In short it does not appear to add very much to what is currently known about the UK power grid because of a very constrained analysis which really only states the obvious problems instead of exploring the full continuum of combinations of solutions which will provide an efficient system. Like 191. In response to my comment : “The implication is that in Germany at least you can go higher than the maximum capacity factor of wind or solar in configuring total wind + solar renewables capacity without significant renewables overcapacity.” Peter Lang on 26 Dec 2015 said : “It is recognized you can do it from a purely technical point of view. The point is, it is very costly.” By 2030 there will be a significant capability for demand response, such as flexibility of +/- 25% in certain large-impact industrial processes such as aluminium smelting, and in domestic EV charging (EV’s will be pervasive for land transport by 2030). This means that demand can be increased (or reduced) instantaneously using Smart Grid technologies so ensure that virtually all variable renewable generation will be used to satisfy demand, even when a degree of renewables overcapacity is provided. This can be achieved within the capabilities of the existing UK transmission grid which itself is already overconfigured to maintain continuous operation when generation problems require a switch to alternative generation locations. In this context there is virtually no wasted renewable generation and thus it is no longer costly to provide some overcapacity of the total of wind and solar generation combined. You have to look outside the current grid implementation to examine the advantages of Smart Grid approaches which will solve a number of issues which high levels of renewables generation would cause on the current UK system – but which would not be present on the expected 2030 or 2050 UK grid implementations. Like 192. Fig 5 from http://erpuk.org/wp-content/uploads/2015/08/ERP-Flex-Man-Full-Report.pdf is also very interesting. What it shows is that around 70GW of new wind alone can abate 50% of the current UK CO2 emissions. This is an estimate from continuing the top curved line, not from the linear extrapolation given by the second (straight) line down. True. But 31 GW of nuclear alone can abate 90% and at much lower overall system cost (as shown in Figures 11 and 14). Nuclear can do9 the job, but weather dependent renewables cannot. Furthermore, building weather dependent renewables delays significant progress and means emission will be higher in 2030 and 2050 than if we do not waste money building them but focus on building the least cost solution now. However, the chart itself is a very crude calculation Given the nonsense analyses you’ve been doing yourself and trying to justify on other web sites, this comment must be intended as sarcastic, yes? Like 193. Peter Davies, By 2030 there will be a significant capability for demand response, Demand response is taken into account in the ERP analysis. The ERP analysis was done by an expert groups who understand the electricity system and know what they are doing. As you have admitted elsewhere your career has been in IT until recently and you are now now studying for a PhD in nano energy storage. There is an enormous amount you could learn by asking question on Brave New Climate. But I’d recommend you take that approach asking. Like 194. The low capacity factor of weather dependent renewables is only one part of what is important and relevant for policy analysis. It is just one of the many issues that in total mean weather dependent renewables cannot supply a large proportion of global electricity and therefore cannot make a large contribution to reducing global GHG emissions. Many lines of evidence show this, for example: Non-hydro renewables have not managed to do so to date in any large electricity grid, (hydro cannot help; its capacity growth is limited so its share of global electricity generation will decrease over future decades). Growth rates of wind and solar over 25 years have achieved just 3% (wind) and 1% (solar) of global electricity supply. Over 25 years, wind power has grown at just 1/6th and solar at 1/18th the rate nuclear grew at. The recent growth rates, which are off a near zero base and are driven by enormous incentives, are not an indication of future growth rates. Signs are the recent growth rates may have already peaked. The cost of electricity and CO2 abatement cost is much higher for wind and solar when all costs are properly included and a proper comparison is done. Adding more intermittent renewable technologies adds cost but does not remove the need for nearly full backup capacity or high cost energy storage. Industrial countries with a high proportion of non-hydro renewables have high cost electricity and high CO2 emissions intensity. For example, compare France (with a high proportion of nuclear) with Germany (with a high proportion of wind and solar). Germany’s electricity prices are twice France’s and its CO2 emissions intensity is 6x France’s. Wind and solar are not sustainable – their ERoEI is insufficient to enable them to power modern society and reproduce themselves. The cost of energy storage that would be needed to make intermittent renewables capable of providing reliable power make intermittent renewables prohibitively expensive – at least five times the cost of nuclear. CO2 abatement effectiveness decreases as penetration increases – e.g. to around 50% CO2 abatement effectiveness at 20% penetration. The weight of evidence shows a large proportion of nuclear power is the cheapest way to make large reductions to CO2 emissions intensity of electricity. Like 195. Peter Davies — Aluminum smelting is considerably less flexible than it appears you think it is. Like 196. Peter Lang You make a lot of claims that has no foundation in links or proper analysis. You can create 100% carbon free energy supply not only to the electric grid but for all purposes. Synfuels has previously been suggested by the author in this brilliant article. https://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/ Or you could power district heating via heat pumps and heat storage, or stop using natural gas and oil for heating and start using solar thermal and or heat pumps. Or you could use the trick described in the article where the middling of wind power allows slightly higher penetration according to the author. Besides no one plan to shut down existing hydro power plants or to stop using biomass and both can provide some power production that can regulate the match between demand and supply. More exotic forms of renewables such as OTEC and geothermal are base load power plants with capacity factors on par with Nuclear. Modern wind turbines have much larger capacity factors than average installed wind turbines so the intermittence is actually decreasing. You might want to read the article and address your critique directly to the author. As for the growth rates of solar, wind and nuclear it could be very interesting to see links that support your claims if such links indeed exists. Here is what I found if we try to choose the golden age of nuclear vs the most recent numbers available for wind and solar. http://www.worldnuclearreport.org/The-World-Nuclear-Industry-Status-52.html Graph number four gives a good representation of the growth in nuclear power plants. http://cleantechnica.com/2014/09/04/solar-panel-cost-trends-10-charts/ The links shows the development up to 2012 whereafter the market exploded with even high growth rates which increased the capacity by 77% in total 2013 and 2014. http://cleantechnica.com/2015/04/02/global-solar-pv-capacity-ends-2014-177-gw/ Your speculation that “The recent growth rates, which are off a near zero base and are driven by enormous incentives, are not an indication of future growth rates. Signs are the recent growth rates may have already peaked.” are very confusing. In USA the cost of coal for production in an average performing coal power plant is$0,022/kWh with the current coal prices that has broken down the value of the coal companies to a tiny fraction of previous market valuation. The price of coal does not include delivery of the coal, staff at the coal power plant, depreciation, interest, decommission cost, insurance or anything else needed to run a coal power plant.

The average 20 year wind PPA contract in USA was in 2014 $0.023/kWh or if you include the PTC$0.035/kWh.

Your CO2 abatement philosophy is unintelligible to me. I suggest you read these analyses because they are likely to influence the business decisions going forward http://oilprice.com/Energy/Coal/Goldman-Sachs-Peak-Coal-Is-Here.html or the European counterpart http://www.businessgreen.com/digital_assets/8779/hsbc_Stranded_assets_what_next.pdf http://www.nrel.gov/docs/fy15osti/63604.pdf

2014 was most likely the year where coal peaked and the main reason why is that it is no longer economically viable in most parts of the globe simply because wind and solar now define grid parity.

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197. @David B Benson

“Aluminum smelting is considerably less flexible than it appears you think it is.”

Sure it is – at the moment. However, have a look at what Trimet is proposing :-

http://www.bloomberg.com/bw/articles/2014-11-26/germanys-trimet-aluminium-turns-smelting-tanks-into-batteries

http://www.resourcereports.com/wind-power-germanys-new-record-trimets-storage-experiment/

http://www.trimet.eu/en/presse/pressemitteilungen/2015/2015-09-17-2014-2015-financial-year-voerde-and-france-successfully-integrated

Currently, at the request of grid managers, electrolytic aluminium smelting cells can be turned off for 2-4 hours, depending on the rate of cooling, and then turned back on before the contents solidify around the anode (which would spell trouble). They only do this for hard cash.

Trimet is proposing to run its cells at a rate such that the power can be changed by up to +/- 25% almost instantaneously to assist in controlling short, medium and long-term fluctuations to the electricity supply. It is conducting preliminary trials.

Now it is true that other companies do not have to follow suit, but the requirement to do this is likely to become pretty pervasive and there is absolutely no technical reason why this technique should not be pervasive. The issues are around grid policy issues and financial rules for demand management. But these problems are soluble.

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198. @Peter Lang

“Demand response is taken into account in the ERP analysis. The ERP analysis was done by an expert groups who understand the electricity system and know what they are doing. ”

The ERP report mainly just assumes about demand response what you don’t like, which is that demand response effectively eliminates the inefficiencies of large scale wind and solar, meaning they can be cheap sources of CO2 abatement (133 g / kWh with 60 GW of wind capacity) because no power is thrown away. The report also points out that demand response does not help solve the problem of gaps with reduced wind and solar power of more than 24 hours, which is hardly new news.

Demand response is not taken into account specifically in any of the modelling work. In fact, the ERP report specifically says it is excluded.

Unfortunately, the ERP analysis uses DECC prices for commissioning in 2016/7 when doing calculations for a 2030 grid with plenty of wind and solar installed well after this date. Probably by 2030 and certainly by 2050 onshore wind costs will reduce by 40% (based on a 10% reduction per doubling of global wind capacity), and solar PV by 60% or more (18% per doubling). See http://www.irena.org/DocumentDownloads/Publications/IRENA_RE_Power_Costs_2014_report.pdf . That is assuming no technology breakthroughs. The IEA estimate solar PV could be as low as 1.5 cents / kWh by 2050.

Some of the conclusions of the report are thus very suspect because the method section says they are optimising for costs (which are based on current DECC pricing). The pricing data is only available from the references and not from the body of the report – which is not very helpful, and the only pricing reference is for the DECC prices referred to.

As a result, one of their conclusions is that hydrogen as a storage mechanism is too expensive because the efficiency is low (round trip power to gas to power around 42%, or better if heat output is included for community heating). However, this does not take into account the price reductions in solar because that was outside the scope of the prices considered. If solar power in southern Spain is 1.5 US cents per kWh by 2050 then, assuming a 1.5 cents / kWh for HVDC transmission lines to London, the fuel costs of renewable hydrogen in UK for CCGT backup become 7 cents / kWh. CCGT + renewable hydrogen is thus clearly a viable reliable zero emission generation technique for filling the long renewables gaps.

The authors do say they have barely scratched the surface of the modelling which must be done and suggest follow-up activities, some of which are likely to take place at my college (Imperial College London).

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199. The 2015 ERP report Managing Flexibility Whilst Decarbonising the GB Electricity System http://erpuk.org/wp-content/uploads/2015/08/ERP-Flex-Man-Full-Report.pdf analyses the costs of reducing CO2 emission from electricity in GB with different mixes of electricity generation technologies.

I’ve interpolated from the charts the CO2 emissions intensity and the electricity cost increase that would be needed to achieve them. The cost increase is from the baseline which is the electricity cost of the existing system with a 70/t CO2 carbon price added. The report states that a £70/t CO2 carbon price would not be sufficient to drive the changes in the electricity system needed to achieve the CO2 emissions reduction targets.

I’ve eyeballed from Figures 5 and 6 some values of CO2 emissions intensity for different mixes of wind and nuclear in the GB electricity system. The fourth column is eyeballed from Figure 11 (left chart); it is the change in total system cost per MWh above the baseline. The rows are ordered by decreasing CO2 emissions intensity. The columns are: ‘Wind, GW’; ‘Nuclear, GW’; ‘CO2, g/kWh’; ‘TSC, % change’.

Wind, GW Nuclear, GW CO2, g/kWh TSC, % change
56 0 180 8.0%
30 10 140 3.2%
56 11 100 11.4%
30 20 60 7.7%
56 18 50 ~15%
42 20 50 11.0%
0 31 50 ~3.0%
0 32 40 ~4.0%
0 35 25 7.7%

For comparison, France’s CO2 emissions intensity was 42 g/kWh in 2014 http://www.rte-france.com/sites/default/files/bilan_electrique_2014_en.pdf; Britain could achieve that with 32 GW of new nuclear and 0 GW new wind.

The table shows the least cost options to achieve the greatest reductions in CO2 emissions intensity of electricity is with mostly nuclear and little or no wind. GB could achieve the same emissions intensity as France with 32 GW of new nuclear, 0 GW of new wind for a ~4% real increase in cost of electricity.

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200. “The requirement to do this is likely to become pretty pervasive”. You could equally proclaim the imminent collapse of Western industrialisation. However it is unwise to say it so complacently.

On this website we have witnessed the deaths of more than a thousand unnecessary evacuees from Fukushima proclaimed as a triumph by the renewables movement. In both cases it is triumph for self-righteousness, bigotry and malice.

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201. Peter Davies,

Your comments are simply ‘arm waving’, baseless assertions about relative trivia. You have not stated how much difference your trivia would make. It’s a common diversionary tactic to throw up unsupported, baseless assertions as you are doing here and have done on other web sites. Unless you can provide a link to a better, more thorough, more complete, more competent analysis of the GB system, and showing the technology options mixes and true cost of achieving the emissions targets by 2030, you should admit you are barking up the wrong tree trying to argue that weather dependent renewables and your nano storage are a viable option. They are not!

Weather dependent renewables cannot supply a large proportion of global electricity. Many different lines of evidence show this, as summarized in my previous comment: https://bravenewclimate.com/2015/11/08/the-capacity-factor-of-wind/#comment-440447 .

I suggested on another web site you’d make a much greater contribution to the good of humanity if you changes the subject of your PhD from nano storage to nuclear energy.

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202. @ Peter Davies,
The first of those links seems to imply they’ve found a way to make the electrolysis process run backwards, but I can’t understand how they could possibly do so with a graphite electrode. Are they using something else?

If they’re not, even varying the reaction speed is cause for concern because of the amount of CF4 produced.

@ Peter Lang,
“Wind and solar are not sustainable – their ERoEI is insufficient to enable them to power modern society and reproduce themselves.”
No matter how many times you say that, it will never be true. ERoEI is of critical importance in the early stages of research for renewables when even producing positive net energy is a challenge, but solar and wind power are way past that stage now. ERoEI is also of some importance with fossil fuels, as supply is limited. But for wind and solar, with unlimited supply and strongly positive net energy, ERoEI is irrelevant to the needs of modern society. What counts is cost, and most of the cost is unrelated to energy input.

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203. Peter Davies — Thank you for the information about Trimet. But this won’t help here in Washington state where the last two aluminum smelters are closing at the turn of the year.

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204. Peter Davis’s comments re demand management and aluminium smelters contains nothing new.

Australian aluminium producers have long offered limited demand reduction, at a price, via their contracted generator. Unfortunately, the details are commercially sensitive and thus are not on public display.

However, 50% reduction for an hour or more is in the correct Australian ballpark.

Many other loads are capable of similar management, given favourable commercial environments. Think: Turning blocks of domestic refrigerators, freezers, air conditioners and pool pumps off for an hour when the market price for electricity is high.

Demand management may be a step in the right direction, but can it ever be the solution to the problem, given Jevon’s paradox?

This thread is/was about capacity factor. Demand management is historically a tool for managing unplanned outages (ie breakdowns), peaks and troughs in demand. To ask demand management to extend its role to accommodate the poor capacity factors which are part and parcel of wind or other weather-dependant terchnologies is hypothetical but not practical in the real world.

I suggest that this discussion be continued either on an OT or on a thread discussing demand management, if one exists.

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205. @Aidan Stanger

“The first of those links seems to imply [Trimet have] found a way to make the electrolysis process run backwards, but I can’t understand how they could possibly do so with a graphite electrode. Are they using something else?”

Aidan, you are clearly not used to manufacturer marketing speak which the press seems to pick up on because it sounds good! What Trimet are proposing is to run with an average nominal load / electrolysis rate of 100%. When wind power is plentiful and cheap they increase that to 125%. When there is very little wind or solar power then they reduce the rate to 75%. Effectively they are claiming they are acting as a battery, sometimes absorbing excess power, sometimes releasing it, but this is always relative to a nominal load which is ongoing!

“If they’re not [using something other than a grahite anode], even varying the reaction speed is cause for concern because of the amount of CF4 produced.”

From a quick google and scan for the CF4 gas emissions there seems to be no mention that CF4 emissions are rate dependent, but rather more dependent on the process used to electrolyse the aluminium oxide. It also seemed to imply the gases were normally captured (or the operators get free dry cleaning and the atmosphere gets yet more greenhouse gases). I’d be interested to read anything on rate dependence if you have a favourite link.

I was talking to a PhD student at my college who was working on the possibility of provision of similar load rate variation for other industrial processes which are large-scale users of electricity, so aluminium smelting, though likely the first, ought not to be unique.

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206. @Tony Carden

“I notice that you have a little IF in your statement about solar and a time frame of 2050. I argue that IF the Chinese can solve the technical issues of a Thorium Molten Salt Reactor by 2050 which they seem to have some confidence of doing, then the world of energy production and electricity generation will be revolutionized forever.”

Absolutely there’s an “if”. There’s no doubt solar PV prices will tumble in future, but no-one really knows where they will end up by 2050. Notably the IEA usually underestimates the progress of renewables so it is unusual for them to make an optimistic-looking guess on 2050 solar PV such as 1.5 cents / kWh.

Solving the technical issues of Thorium Molten Salt Reactors, or fusion reactors for that matter, by 2050 would indeed be a great technical achievement, but the problems of nuclear fission have more to do with a poor public perception than anything else, regrettably. If wind and solar can meet the requirements at a reasonable price then the public have a choice if both come to pass.

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207. Peter Davies –

So the statement that ” It can then resell the power when demand is at its peak” is just inaccurate reporting? Fair enough – that did always seem to be the most likely explanation, and certainly the simplest.

I don’t really know much about CF4 emissions from Al refining, but ISTR reading elsewhere on this site that its formation depends on voltage, which I’d expect to be what controls the reaction speed unless they vary the number of electrodes in use.

I am now aware of any other industrial processes that use both fluoride electrolytes and graphite electrodes.

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208. I do not see that the issue of Nuclear Power having a poor public perception should deter the scientific community from advocating the facts as they stand, especially when that poor public perception is a result of misinformation, disinformation, and just plain lies.

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209. @Peter Lang

The average 2014 Nordpool spot price for electricity is approximately $0.03/kWh http://www.nordpoolspot.com/Market-data1/Elspot/Area-Prices/ALL1/Yearly/?view=chart The reason behind the drop from 2010 to the present is mainly fast dropping wind power costs but there is also an annual variance because the precipitation varies the output from the hydropower and the influence from solar during the summer months. Polen, Germany, Holland and UK plan more HVDC connections to Nordpool, which will increase demand and thus the average spot prices while also decrease price spikes and limiting the few hours annually where the spot price is negative (producers pay to produce power). Nordpool electricity is at least a factor 4 cheaper than electricity from Hinckley Point £92.50/MWh ($0.137/kWh) and Nordpool is not inflation regulated 35 year into the future as Hinckley point.

The 1.400MW NSN link has been contracted for €1.5 billion which is €0,933/MW. http://nsninterconnector.com/latest-news/ and the 3.200MW Hinckley Point is budgeted at €24 billion, which is €7,5/MW. https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_station

UK is paying A FACTOR 8 MORE FOR HINKLEY POINT electricity generation capacity with around 98% availability than for the NSN link access to always ready dispatchable capacity and unlike Hinckley Point or for that matter any nuclear power plant a HVDC transmission connected to Nordpool can ramp up to 100% and down to minus 100% and do it very fast.

The NSN link flexibility will provide UK with the option to increase their own wind capacity and as the article states geographic spread will middle wind power and allow a larger share of the power generation.

Your belief that UK cannot be powered by renewables seems without any sort of rooting in reality and your ideas about cost of energy generation as presented by you appear to be purely fictional because you do not link to a specific market price as available at Nordpool.

Since Nordpool is the largest free electricity market in the world and you not seem to understand what electricity costs and how it is traded I decided to give you this older introduction. http://www.ft.dk/samling/20091/almdel/epu/bilag/354/882165.pdf

Unless you have a PPA or a FIT you are forced to sell at the spot market. In the last few years thermal power plants of any kind have been under a huge pressure because in the Nordpool region selling electricity is unprofitable and their protected access to sell district heating is under siege by electricity driven heat pumps that can produce heat cheaper and move more power consumption to electricity.

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210. @Tony Carden

The problem you have is that the very word “nuclear” causes a problem. A significant fraction of the population associates nuclear with nuclear bombs (which are not exactly a good sales pitch for the world “nuclear”), and have heard of Three Mile Island, Chernobyl and Fukishima. With PR like that, you don’t really need disinformation, misinformation and lies to turn people off.

Take “nuclear magnetic resonance imaging” as an example. Hospitals used to have departments with such titles. To the best of my knowledge no-one has ever tried to make propaganda against NMRI (nor tried to sell it to the public for that matter), but the very inclusion of the word nuclear has caused enough issues that for the last 15 or 20 years the word “nuclear” has been dropped to give the name MRI (magnetic resonance imaging). Apparently the public felt much safer using it after the rename.

So the best way to make nuclear power more popular would be to rename it. “Fission power” probably would not hack it either.

And it’s the fact “nuclear” is in the name which means that no country has yet got political agreement to the location of a nuclear waste repository.

As for educating the entire world population so they no longer get negative vibes from the word “nuclear”, good luck with that!

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211. I agree ignorance is bliss!!

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212. So, no negative vibes associated with undeliverable, high cost, less safe, unworkable, unreliable, weather-dependent, obtrusive so-called renewable wind and solar power either?

Unpalatable as some terms are, in the long run the whole truth beats half-truths.

It is difficult to analyse fine distinctions when slogans and preconceived notions are permitted to dominate discussion, especially discussions about expensive, difficult, multi-decade electricity options.

“Nuclear power” and “fission power” at least are able to be clearly defined and hence understood. Tell me again how the term “renewable” applies to the myriad abandoned solar and wind junk-farms for which photos are available online. Google: “abandoned wind farm image”.

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213. My statement was said with a deep tone of irony.
I am glad that you have rejected it and I really do agree with you.
What is called for here is LEADERSHIP.
In fact, I am deeply disappointed that in the enlightened 21st Century, a Phd student would advocate the path of ignorance as opposed to the challenge of enlightenment.
Thankfully the genius of Nikola Tesla and others like Barry Marshall was not daunted by the fact that their science was not popular.

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214. My research has revealed that over the past 20 years, the world has spent $367billion on subsidies for the renewables, especially wind for a return of 2.8% of the world’s electricity and with no measurable reduction in greenhouse gas [CO2] emissions. How’s that for fiscal irresponsibility? I know that it will offend you Peter Lang and anyone else for that matter. The renewables have been a scandalous wasteful folly, inspired by the Greens and other environmental groups and further development of them, especially in South Australia should be terminated. Thanks John Morgan for your study which sits very well with one done by a friend of mine in 2013.I included a summary of his study in the submission I sent to the Scarce Royal Commission. As Barry knows, I’ve been an advocate for nuclear power for Australia and speaking for it since 1998. And if any of the commenters on this blog remain anxious about Australia going nuclear then you need to ask yourself just one question. ” Why are 32 countries, including Japan again, continuing to generate 12 % of the world’s electricity in 436 reactors. Those countries and 17 others are building 70 reactors right now, 174 reactors are firmly planned and 301 proposed for the future? Those are April 2015 World Nuclear Association figures. Incidentally, I asked Ian Lowe why all that nuclear build in July 2013 at the ATSE nuclear conference. Lowe responded with 150 countries aren’t building nuclear reactors. And that from an Emeritus professor??? Aaarrrgghhh!!! Like 215. @Terry Krieg “My research has revealed that over the past 20 years, the world has spent$367 billion on subsidies for the renewables, especially wind for a return of 2.8% of the world’s electricity and with no measurable reduction in greenhouse gas [CO2] emissions. How’s that for fiscal irresponsibility? ”

Since the world energy expenditure has averaged over $4 trillion pa over the last 20 years, then in that time over$80 trillion has been spent on energy. $367 billion, while notable, represents less than 0.5% of this total. The purpose of renewables subsidies is to nurture immature technologies to the point where they reach volume installation, allowing mass production efficiencies to kick in. The aim is for the new technology to get to volumes where it needs no subsidies and reduces overall energy costs. In the case of wind and solar, grid parity is about to be reached. Before 2030 we will be making significant cost savings from these technologies. By 2050 any investment in subsidies for wind and solar up to 2020 will be repaid handsomely by much reduced electricity prices and zero CO2 emissions for electricity generation. And that’s the way new energy technology is developed. Like 216. @ Peter Davies: Peter chose to compare expenditure on renewables against the total market and came up with a nonsense figure of 0.5%. As a percentage of market share of, say, 2%, that subsidy is seen for what it is: a loading of 25%. Peter’s post then degenerated into arm-waving and motherhood statements, capped off by an unreferenced affirmation about reaching grid parity – whatever that may be in his world. The term “grid parity” has been used at one extreme to refer to bid prices in the wholesale market, exclusive of system services such as frequency control and transmission services from boondocks to somewhere near a customer. At the other extreme it has been used, in relation to rooftop domestic solar, to retail rates at the meter, but still with an assumption that the domestic supply is a “must take” generator and that all others are subject to curtailing during times of excess generation capacity. Without a reference which is sufficiently detailed to ensure that terms have meaning, statements on such matters as “grid parity” are meaningless. Meanwhile, the capacity factor of wind remains essentially unchanged, it is backed up almost everywhere by one or more of: . Open cycle GT, which is almost universally the case; . Pumped storage or other hydro, which are geographically limited, environmentally challenging and, in the case of pumped storage hydro, come with an 80% (I’m being generous here) round trip energy efficiency. Given that in Europe pumped hydro represents less than 5% of total installed capacity and is further limited by the volume of the upper pondages and transmission system constraints, how effective can pumped hydro ever be at backing up a system with, say, 50% wind power? . Next door neighbour’s load-following nuclear power, as for example, Germany’s imports from France; or . Good old (or new) lignite power operated as baseload plant while the surplusses of wind are pushed into the wider European grids, resulting in half of the renewables not being used where they are generated (Germany) but instead diffused throughout adjacent countries, in order to maintain system stability in the face of unreliable weather-dependent diffuse power sources such as wind and solar. What, I wonder, are Peter’s answers to the stability issues which are demonstrated, time and again, by Germany’s pattern of exports of renewables and imports of stable power from neighbouring countries, all the while maintaining year-on-year increases of CO2-e emissions? As Professor Julius Sumner Miller famously said frequently more than 50 years ago, when science was considered to be a suitable subject for popular TV programs, “Why is it so?”. Why is it so, that despite receiving 25% subsidy/support, coupled with “must run” market access, plus hugely favorable press, globally and over several decades the wind power industry that meets its own stated goals? Could it be that there are limits that simply cannot be overcome? Where are the real groundbreaking, undeniable successes from the hundreds of billions of dollars spent? The purpose of subsidies is not as Peter stated. It is not to support limited technologies for decades, despite clear evidence of inability to ever meet the twin goals of cost and performance. Subsidies are for achieving goals. Greater subsidies must be used to achieve greater goals. Global subsidies must achieve global goals, in this case, a contribution to climate stability through reduction in global carbon emissions. Why is it not so? Like 217. Why is it so that, despite receiving 25% subsidy/support, coupled with “must run” market access, plus hugely favorable press, globally and over several decades, the wind power industry has failed to meet its stated goals? Like 218. …subsidies for the renewables, especially wind for a return of 2.8% of the world’s electricity… Since the world energy expenditure has averaged over$4 trillion pa over the last 20 years, then in that time over $80 trillion has been spent on energy.$367 billion, while notable, represents less than 0.5% of this total.

Very broadly, 2.8% capacity achieved after 0.5% renewable investment would merciful and madness not to promote.

I cant appreciate were the passion comes from to rile against minutiae of renewable power issues.

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219. @singletonengineer

Peter chose to compare expenditure on renewables against the total market and came up with a nonsense figure of 0.5%. As a percentage of market share of, say, 2%, that subsidy is seen for what it is: a loading of 25%.

Wind subsidies are an investment for the future. The point of wind (and solar) power is to make future huge and cheap reductions in CO2 emissions. It is nonsensical to quote the cumulative subsidy levels against current global capacity costs at the precise point where wind is just reaching grid parity. This is precisely the point in time where all the subsidy costs of wind have been incurred, but very few of the savings have been realised.

If you project forward to 2030 or 2050 then wind power may generate up to 60% of global electricity, and do so very cheaply. At that point the subsidies of 0.5% of global energy expenditure will be repaid many times over by the benefits.

It seems strange you are prepared to ignore the huge initial government technology research and subsidies for nuclear power development, but are not prepared to do the same for wind power.

The US congress seems to have it about right (and I never thought I would ever say anything nice about the current US congress). The wind energy PTC will remain at 30% this year (2016), gradually tapering off over the period 2017-2019 and expiring in 2020. Thereafter wind is expected to save money for USA utility customers.

However, US onshore wind is at grid parity in some windy places in the USA with no subsidy.

The solar ITC will remain at 30% until the end of 2018, then taper down to a continuing value of 10% in 2022.

Peter’s post then degenerated into arm-waving and motherhood statements, capped off by an unreferenced affirmation about reaching grid parity. The term “grid parity” has been used at one extreme to refer to bid prices in the wholesale market, exclusive of system services such as frequency control and transmission services from boondocks to somewhere near a customer. At the other extreme it has been used, in relation to rooftop domestic solar, to retail rates at the meter, but still with an assumption that the domestic supply is a “must take” generator and that all others are subject to curtailing during times of excess generation capacity.

Unfortunately the term “grid parity” represents different things in different countries. In the USA the grid / utility is generally responsible for new transmission, and in some states must contract for the cheapest generation. In the UK the wholesale generator pays for the grid connection. I’ve no clue what happens in Australia. Hence the definition drives the contractual process – like it or not, and thus the definition of grid parity varies by country.

Being super precise about what grid parity is does not help matters either. The key thing is whether installing wind turbines and solar over 20 or 30 years into a national grid is a cheaper solution overall than nuclear, taking into account the other grid changes which must be made. Wind does require the presence of CCGT for period of calm, but if your grid already has plenty of this then you do not have to pay for more. Existing quantity presence of despatchable hydro and pumped hydro similarly should be factored in. The costing exercise should be a comparison between final systems, not a comparison between components.

As far as rooftop solar is concerned, we are not really talking about “grid parity” but just consumer cost savings against the retail price. A lot of distribution costs will be incurred whether rooftop solar generates power or not, though rooftop solar tends to generate at peak times and save some of the costs of electricity from peaking plant.

Wind and solar is generally “must take” in most places because, once the capital investment has been made, the overall incremental cost to society of wind and solar power is close to zero, whereas for fossil fuel generation the incremental cost includes fuel which is a major component of cost. This ought to be an obvious point.

Meanwhile, the capacity factor of wind remains essentially unchanged

http://cleantechnica.com/2015/05/26/new-wind-turbines-capacity-factor-increase-40-60/

The trend towards a higher ratio of turbine blade area swept to generator capacity is bound to push capacity factors higher. Historically this was around 2 m2/kW, but some future turbines are likely to operate at > 6m2/kW. Another factor pushing CF higher is taller towers.

The net of this is that onshore wind in good places already gets up to 40% capacity factor, but the trend towards higher rotor sweep areas to generator capacity is likely to push this up to a maximum of 60%. This does increase the area per turbine, but there is sufficient room in the USA for these. I’ve not researched Australia, but it seems to have plenty of room and a sparse population so my guess is that area per onshore wind turbine is not an issue.

[Wind Power] is backed up almost everywhere by one or more of:
. Open cycle GT, which is almost universally the case;

. Pumped storage or other hydro, which are geographically limited, environmentally challenging and, in the case of pumped storage hydro, come with an 80% (I’m being generous here) round trip energy efficiency. Given that in Europe pumped hydro represents less than 5% of total installed capacity and is further limited by the volume of the upper pondages and transmission system constraints, how effective can pumped hydro ever be at backing up a system with, say, 50% wind power?
. Next door neighbour’s load-following nuclear power, as for example, Germany’s imports from France; or
. Good old (or new) lignite power operated as baseload plant while the surplusses of wind are pushed into the wider European grids, resulting in half of the renewables not being used where they are generated (Germany) but instead diffused throughout adjacent countries, in order to maintain system stability in the face of unreliable weather-dependent diffuse power sources such as wind and solar.

Theargument saying grids can never cope with 50% or more of wind power applies only to current grids – not future ones. Getting to 50% will take time, and by the time we get there the grids will have changed out of all recognition. There won’t be any coal or lignite generation. Germany’s neighbours will have their own wind power and Germany’s thermal plant will all be fast-response CCGT. UK says it will get rid of coal by 2025 and install more fast-response CCGT soon, though there seems to be a bit of an issue with how this will be financed since the current wholesale electricity price is too low to allow any new generation to be profitable without subsidy.

For Europe, Norway has huge hydro storage (84 TWh – equal to more then 10 days of European generation), but no pumped hydro. See http://ahk.de/fileadmin/ahk_norwegen/Dokumente/Presentasjoner/wasserkraft/Design_of_Future_Pumped_Storage_CEDREN_Killingtveit.pdf . But someone has to agree to pay for the conversion. Here’s a document outlining the possible total European pumped hydro potential – https://ec.europa.eu/jrc/sites/default/files/jrc_20130503_assessment_european_phs_potential.pdf which comes up with around 80 TWh in total, with a few caveats.

However, this pumped hydro potential is probably not enough, which is why the Germans are expecting to supplement it with renewable hydrogen for electricity storage (from electrolysis of water, used in fuel cells or hydrogen-compatible CCGT – http://www.power-eng.com/articles/2010/07/hydrogen-fuelled-combined-cycle.htmlthen ), at an end-to-end efficiency of around 45%.

What, I wonder, are Peter’s answers to the stability issues which are demonstrated, time and again, by Germany’s pattern of exports of renewables and imports of stable power from neighbouring countries, all the while maintaining year-on-year increases of CO2-e emissions?

Where is the hard evidence that Germany’s wind power exports destabilise the surrounding country grids? Link please, showing some power flows causing a problem, not just an arm-waving assumption. Germany does not export power without contracts, and these have specific terms in them.

German CO2 emissions from power generation are generally on the way down, although it could make life a bit easier for itself if it slowed down the decommissioning of nuclear a little.

Germany exports more than it imports, and has reduced its recent CO2 emissions in every year but one. Although they commissioned some new coal/lignite plants a few years ago, some of these will no longer be completed, and others are expected to replace older, less efficient coal/lignite plants reducing CO2 emissions for the same electricity output from coal generation.

Why is it so, that despite receiving 25% subsidy/support, coupled with “must run” market access, plus hugely favorable press, globally and over several decades the wind power industry that meets its own stated goals?

Perhaps you would tell us what these goals might be as a quick Google search does not produce anything specific.

My version of the goal is that the subsidies were always intended to bring wind to a volume where the LCOE and other costs of wind were competitive with other forms of generation.

The USA DoE seems to be setting a national goal of 20% penetration of wind power by 2030 and saying it can be done with no more than 0.5 cents / kWh integration costs – http://energy.gov/eere/wind/20-wind-energy-2030-increasing-wind-energys-contribution-us-electricity-supply . Texas will probably be at 50% by then.

Where are the real groundbreaking, undeniable successes from the hundreds of billions of dollars spent? The purpose of subsidies is not as Peter stated. It is not to support limited technologies for decades, despite clear evidence of inability to ever meet the twin goals of cost and performance. Subsidies are for achieving goals. Greater subsidies must be used to achieve greater goals. Global subsidies must achieve global goals, in this case, a contribution to climate stability through reduction in global carbon emissions. Why is it not so?

The purpose of subsidies is to get wind power into volume production, enabling wind power to compete effectively once subsidies are withdrawn. For onshore wind we are pretty much there (UK has withdrawn onshore wind subsidiesl, though maybe a little early). Offshore wind might take another decade. From the Lazard’s chart above, the subsidies have achieved exactly that.

So that is indeed a real groundbreaking success story – wind power reaching LCOE prices competitive with fossil fuel generation, with the US DoE estimating addition grid costs of 0.5 US cents / kWh to cope with every increasing levels of wind.

However, the real success story is yet to come as countries expand wind production to levels in the range of 20-50% of electricity production by 2030.
BNC MODERATOR
Your comment is very long winded, so much so that it is unlikely to be read in full. It would be better to split the post. You also veer off topic – please move to the Open Thread to discuss anything other than the post’s title. Thank you.

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220. 1755 words! Is someone being paid by the word?

I have neither the time nor the patience to read in detail, let alone to respond in detail to a scattergun spread of affirmations, misrepresentations, avoidance and off-topic red herrings. I am probably in breach of one or more site rules because I decline to list and debate each of them one at a time.

Two points, though:

One, Germany does indeed export half of its wind+solar power instead of winding back its brown coal generation. I didn’t say that by so doing, the adjacent nations’ grids have been destabilised, however I do believe that Germany is only able to absorb the output from its huge wind fleets due its being able to offload the peak production (indeed, half) to its neighbours. The Austrians, Czechs and possibly the Poles might have an opinion about potential destabilisation, otherwise, why the proposal to separate the German/Austrian market and why is expensive phase shifting equipment being installed by some of Germany’s neighbours?

Two, discussion about the need to define the term “grid parity price”, has led nowhere. We still don’t know what Peter Davies means when he uses it, and I suspect that he doesn’t want us to know.

John Morgan’s excellent post concerned the applicability of Jenkins and Trembath’s findings to the limits of penetration of wind power in the existing Australian NEM grid, in the light of the most detailed data currently available. It is about engineering and statistical analysis of operational data, not about costs, prices, economics or aspirational goals.

If Peter seeks to discuss the economics of wind power, there are several threads on this site, including the Open Thread, for this.

I thank Peter for providing us an excellent example (or ten) of why long comments deserve tight editing and why limits to the number of comments (or words) per person, per day might be a good thing.

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221. BNC MODERATOR
Unfortunately, neither Prof Brook or the volunteer moderators have time to to edit, count or limits words on comments. I have advised PD to split comments and make sure they are in th correct thread.
I think that few would read such a long comment anyway and I have advised him so.

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222. @ apasser:
Your key statement is false in two ways.

“Very broadly, 2.8% capacity achieved after 0.5% renewable investment would merciful and madness not to promote.”

2.8% of electrical energy is less than 1% of total global energy consumption. Like must be compared with like.

The 0.5% figure relates to subsidy. To this must be added all of the developer’s costs to arrive at the investment.

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223. @apasser queried our passion over “capacity”.

As used here, “capacity factor” is the ratio of the average power produced by a wind generator (whether turbine/farm/region) versus its maximum power production. It is about 30%. The passion arises because the un-replaced 70% inevitably comes from fossil carbon emitters. The emitters cannot be eradicated as something bad, while the wind production it backs up is considered a necessary “reduction” of fossil carbon.

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224. There is so much evidence to show that weather dependent renewables are ineffective, cannot meet requirements and very expensive, where does one begin?

El Heirro Island’s 100% renewable project. The aim was to supply the island’s electricity with 100% renewable energy. The island has an ideal situation for pumped hydro with a volcano providing a free upper reservoir with 600 m of hydraulic head. It’s built 11.5 MW wind capacity and 11.3 MW pumped hydro capacity. So far it’s a failure.

Since full operations began the 11.5MW wind farm has run at an average capacity factor of 13.2% and the hydro plant at an average capacity factor of 1.5%.

Renewables generated 30.7% and diesel 69.3% of electricity. http://euanmearns.com/el-hierro-renewable-energy-project-end-2015-performance-review-and-summary/

As an example of the conviction to twaddle by renewable energy advocates look at this amazing article by ScottishScientist: “World’s biggest-ever pumped-storage hydro-scheme, for Scotland?” (and also note his responses to comments): https://scottishscientist.wordpress.com/2015/04/15/worlds-biggest-ever-pumped-storage-hydro-scheme-for-scotland/. This project could never get off the ground (explained in my comment here: https://scottishscientist.wordpress.com/2015/04/15/worlds-biggest-ever-pumped-storage-hydro-scheme-for-scotland/#comment-189 The LCOE is >10 times the LCOE of nuclear. What rational investor would invest in such a scheme and what rational buyer would buy renewable energy at 10 times the cost of nuclear?
The same author advocates solar thermal in the Nabib Desert (Western Africa on the tropic of Capricorn) to power Europe in winter. Again the cost is 10 times the cost of new nuclear in Europe. http://euanmearns.com/blowout-week-104/#comment-14264
One of the common responses is to say these are single technology solutions and not relevant because multi RE technology solutions are cheaper. Nonsense. The excellent ERP 2015 report puts that argument to rest http://erpuk.org/wp-content/uploads/2015/08/ERP-Flex-Man-Full-Report.pdf . UK could achieve the same emissions intensity as France – i.e. 42 g/kWh in 2014 – with 32 GW of new nuclear and no new weather dependent renewables. According to the report, the cheapest way for GB to reduce its emissions to meet its 2030 emissions targets is with all or near all new nuclear and no new weather dependent renewables. Pumped Hydro is very expensive and ineffective. The worst option of all is to close existing nuclear if its life can be extended. It’s an excellent report, broadly applicable, with many valuable lessons for policy advisers.

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225. I second what Peter Lang said. That report is extraordinary – well written, authoritative (as in well referenced) and fact-filled.

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226. @Edward Greisch

I read your links with interest. We Danes spend very little on producing electric energy so whether or not we are parasites as your links suggest and dumb as is also suggested is up to you. The link quite correctly mentions that we make money from being the interconnect to Norway and Sweden. The average Nordpool electricity price is less than $0,03/kWh. The subsidies that are available for on shore wind are 25 øre/kWh on top of the market price, but with a cap at 58 øre/kWh for market price + subsidy. The subsidy is available until the turbine has produced an energy amount corresponding to 6.600 hours times the wind turbines rated power + the rotor area in m2 times 5,6 MWh, which is on average 6-8 years so for the remaining 17-19 years of the turbines projected design lifetime the wind turbine sells electricity hour by hour for what can be fetched at Nordpool. Throughout the entire lifetime there is an additional subsidy amounting to 2,3 øre/kWh ($0,0023/kWh).

Further wind turbines are curtailed without compensation when the Nordpool electricity price is negative.

The information is only available in Danish but for those of you who want to check with google translate here is the link to the official administration that handles the energimarket in Denmark. http://www.ens.dk/undergrund-forsyning/el-naturgas-varmeforsyning/elforsyning/elproduktion/stotte-vedvarende-energi-2

To recap this means that the owners of wind turbines sell electricity in the first 6-8 years for a maximum of 60,3 øre/kWh ($0,088/kWh) whereas the average is around 48 øre/kWh ($0,07/kWh). And thereafter are left to the market forces, which provided the current Nordpool average continues will be around 21 øre/kWh ($0,03/kWh) Throughout the lifetime the average selling price will be (7 X$0,07/kWh + 18 X $0,03/kWh)/25 =$0,0402/kWh.

However as electricity prices are dropping fast this best case for the wind turbine owner will be significantly less. Based upon the difference between the Nordpool spot price average and the selling price you can calculate that there is a subsidy amounting to $0,01/kWh, which makes wind energy the least subsidized electricity production in Denmark with a very broad margin. No coal fueled power plant can ever produce electricity for$0,0402/kWh with the current market price for coal plus transport plus OPEX plus CAPEX – and most certainly not for 25 years.

I know most nuclear proponents would jump to the chance if you could sign a PPA for 25 year at four US cent per kWh.

The future wind LCOE is going to drop fast. Vestas is putting up a new 3,65 MW test wind turbine with 166 meter hub height to fetch stronger and steadier winds and the other Danish major wind power producer Siemens has announced that they expect to reduce the cost of wind by 40% within the next 10 years.

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227. @ Jens Stubbe

I have stated before that I find very few examples from Denmark relevant to the world problem of GHG emissions.

So, when is it forecast that Denmark will cease to burn any coal or gas for the purpose of electricity and heat generation?

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228. When will Denmark (with highest electricity prices in Europe) get it’s electricity prices down to those of France?

When will Denmark (with relatively high CO2 emissions intensity of electricity), get its CO2 emisisons of electricity down to the same as France (42 g/kWh in 2014 according to RTE figures)?

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229. @ Peter Lang

That is really a matter for the Danes and I really do not care what they charge for Electricity.

But there is one thing that should be clearly understood after the Paris talks on climate change. No longer is it good enough to embark upon GHG mitigation. What is required is GHG elimination.

At this stage GHG elimination is an impossible dream. There are a number of areas where there is no alternative but to burn fossil fuels e.g. Jet engines and Diesel engines. So in areas where the consumption of fossil fuels can be replaced by zero GHG emitting alternatives it should be done.

Jens Stubbe has told us how wonderful the Danish system using wind is hence my question of him or anyone for that matter.

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230. @ Tony Carden.
I suggest that Tony re-read the leading article on this thread. It concerns the limits to stability of grids operating with increasing proportions of weather-dependant wind power. It cites examples and statistical justifications for the proposition that current indications are that the practical limit is about the capacity factor of the generating plant. If this is correct, then it follows that major advances are necessary if wind power, in any configuration, is not to be limited in practice to much less than half of the total demand of the system, as measured in energy terms, not instantaneous.

It is not about whether there are unlimited pots of gold awaiting any project that claims to be potentially, but not quite yet, ghg-free. Nor, primarily about the cost of Danish electricity, although a significant tangential issue relates to whether and to what extent the Danish high wind turbine count and the highest or second-highest domestic electricity prices in the EU are cause and effect. Or whether fairies at the bottom of the garden are responsible for the high cost of Danish power.

Nobody has demonstrated that wind power in a grid can reliably be present at penetrations significantly above its capacity factor and, if so, how this can be achieved. Currently, and for reasons I can not fully explain, it certainly appears that the limitation is real and that thus efforts to reduce ghg emissions should recognise this as a limiting factor and which welcome the role of other, more reliable sources.

I’d very much like to read contributions that show where John’s conclusion is wrong and how additional wind penetration can be achieved reliably. Can it? How?

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231. My apologies to singletonengineer for cluttering up this thread, I was simply replying to earlier comments by others which I did not think were entirely on thread but I thought worth saying something about.

I do not need to re-read the lead article by John Morgan. I quite fully comprehend it.

In relation to your first paragraph I do not agree that
‘the practical limit is about the capacity factor of the generating plant’
The practical limit is the capacity factor of the wind.

John Morgan’s figures show that the capacity factor of the wind is 29 percent.

In relation to your second paragraph for many reasons which I intend to post in Open Thread 23 what happens in Denmark, in terms of the world’s efforts to reduce GHG emissions, is irrelevant. The production of Lego blocks is more relevant to the world certainly my grandchildren.

In relation to your third paragraph, I hope this extract from the above article assists.
‘As explained in detail by Jenkins and Trembath, it is increasingly difficult to build more wind or solar capacity as their market share approaches their capacity factor (CF) because they will then, at times, be producing energy in excess of demand. The economic drag incurred by dealing with surplus generation by storage, curtailment or demand reduction undermines the economics of building additional capacity. The capacity of wind and solar is thus limited to be roughly numerically equal to 100% of grid demand.’

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232. Mea culpa!

Apologies to Tony Carden. My comment a couple of posts upthread was not in response to his contribution(s). I am sorry for causing him to waste his time responding.

However, I do have a request for clarification of the final sentence of the Jenkins and Trembath quotation, “The capacity of wind and solar is thus limited to be roughly numerically equal to 100% of grid demand.”

The main point made by Jenkins & Trembath and supported by John Morgan is that the maximum practically achievable share of wind power in a grid will not exceed, over time, its capacity factor times the fleet capacity. I imagine that this could be true in the general case, eg coal, nuclear, renewables, although John’s work discussed only wind power.

Maybe someone else can explain what that J&K mean by:
“The capacity of wind and solar is thus limited to be roughly numerically equal to 100% of grid demand.”

Is it only the trivial point that at any time in a stable grid without storage:
Generation (Supply) = Demand >= (Wind + Solar)

What have I missed?

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233. @Tony Garden

As I mentioned the subsidies for fossil fuel electricity generation is much higher than for wind electricity generation in Denmark and also locked by law that protect the right to supply district heating and natural gas for heating. The current energy minister was before the managing director of a powerful fossil lobby organization and the party he comes from was the same party that elevated Lomborg to fame. From what I read I think Australians also have to battle powerful fossil lobby groups to get rid of fossils.

Nordpool is the single largest electricity market in the world and very likely a model for other open electricity markets yet to come in the rest of the world.

Denmark is the birth place of modern wind turbine technology and a hot place for the development of the same, and since wind turbines are by far the cheapest new electricity generation it is also interesting.

Further and more to the point relative to the article that we are discussing the “capacity factor of wind” and how much wind that can be reliably integrated into the grid is also impacted by the way you build the infrastructure, which makes Denmark interesting.

Lastly more than 90% of all offshore wind turbines are from Denmark and the process of driving cost down is done in Denmark were the unsubsidized price seen over design lifetime is now around $0,06/kWh with capacity factors approaching 60%. Closing the 50% price gap between on shore and off shore wind will be difficult and perhaps impossible but wind at sea is more steady making it easier to integrate in the grid and less intrusive making it more acceptable for the public. Like 234. Perhaps it should read, “Installation of wind and solar is thus limited to a nameplate capacity roughly numerically equal to 100% of grid demand.” Like 235. Thank you, Roger. My thoughts, entirely. Like 236. The limiting point is when Peak (Wind + Solar) rise to equal Demand. Further additions of Wind and Solar capacity beyond this point destabilize the grid. Like 237. @Singleton Engineer The post is not in the least bit wrong for a grid not focused upon handling intermittent electricity generation. On the other hand it is feasible to focus attention on intermittent electricity generation and design an electric grid that can handle any percentage of intermittent electricity sources up to 100% but this will invariably become an economic question. As John pointed out greater geographic spread reduce intermittence and so does higher capacity factor. John has also in other article made the case for producing Synfuels when electricity is in excess. Heating, transportation and industrial processes can be electrified and more demand can be time shifted by smart grid technologies and ultra cheap storage such as heat storage. Biomass and municipal waste can either be burnt to produce electricity or be converted into methane or Methanol – all of which adds some dispatchable power to balance the grid. Finally as is already the case a few hours every year in the Nordpool area you can curtail wind power and/or a small amount of electricity storage could be connected to the grid. As for your theory then Denmark is part of Nordpool the worlds largest electricity market with an average cost of less than$0.03/kWh and new onshore wind currently sell for approximately including subsidies $0.04/kWh, which makes onshore wind the least subsidized electricity generation in Denmark. The high taxation on electricity is simply a concealed fossil fuel subsidy and fossil fuels enjoys many other other direct and indirect subsidies. Like 238. @ Roger Clifton, singletonengineer “Installation of wind and solar is thus limited to a nameplate capacity roughly numerically equal to 100% of grid demand.” That’s not true for the combined total of wind + solar when the two are anti-correlated with each other, as they appear to be in Europe. The economic losses for going above grid demand are not that big, even in the absence of storage. Further, if the wind price is low enough compared with the alternatives (e.g. nuclear) it is not true even for wind alone when you have two completely independent regions generating wind power. e.g. North Africa (from the trade winds) and the North Sea (Northern Europe). If the capacity factor of both areas was 50% then you can provide 75% demand coverage from wind. Curtailing or using the extra for something else when the total from both regions is more than demand is an economic calculation and depends on relative prices (which for wind power will only reduce). The technical aspects of grid control powered only by wind require you to have advanced wind turbines which are generally run at slightly less than full capacity (blades slightly feathered) so you can ramp up capacity from some wind farms if necessary. Other short term cycle control equipment may also be required. The general trend is for the minimum generation from mechanical generators with high inertia to be lowered progressively as time goes on because there are other means of accomplishing the same thing. However, for a system with no storage capability, the quoted constraint would be true for just North Sea wind generation. This isn’t a realistic scenario anywhere, however, as it will always be wind + solar. Like 239. @singletonengineer After just having praised the article I did find one example of less thoughtful extrapolation. “As more wind is added, the flexibility of the rest of the grid will have to increase proportionately – double the wind energy would require about 40 MW/min ramp rate. But this additional ramping ability must be delivered by the shrinking dispatcheable generator sector. So the intrinsic flexibility of the rest of the grid must increase, and faster than in simple proportion to wind penetration. Practically that means increasingly strong pressure to shift from coal generation to gas as wind share grows.” The capacity factor of wind has been ever growing and will continue to do so for a good deal of years to come simply because wind turbines scale and improve. Higher hub height means stronger and steadier winds. Higher capacity factor means less variation in output and slower variation in output, so despite the shrinking dispatcheable generator sector it won’t have to ramp more up and down. Solar and energy efficiency improvement also contribute to less ramp up and down ability. Solar generally tend to cater for the higher energy demand during working hours and for increased air condition usage and energy efficiency such as LED lighting caps the demand peaks. The shift from coal to gas is not because coal power cannot ramp up and down but because coal power plants are most efficient when driven as base load. Gas power plants are cheaper to build and can thus make do with lesser utilization as long as there is high paying demand at least in some minimum time over a year. Like 240. Peter Davies urges us to be reassured that sometimes wind and solar anti-correlate. However we’re not interested in when they do supply together, but when they don’t. We seem to the only people staring at the fact that most of the time wind and solar do not supply anywhere near capacity and indeed, sometimes they do not supply at all. Why should the responsibility for the capacity factor of wind fall onto the grid operator? It is only the “must-take” provision that makes trouble for the people trying to provide a reliable power supply. If that provision were instead dismissed, and replaced with say, a hefty carbon tax, the problem of intermittency would fall on the wholesaler. It would be an engineering challenge, not a salesman’s pitch to an unwilling buyer. In Australia, the grid operator accepts bids from a range of wholesalers to guarantee supply of 30 MWh across the next five minutes. It’s automated. In order to draw up their bid, a consortium of wind farms, solar farms and open cycle gas turbines could then negotiate among themselves as to their confidence to supply, the price they would pay each other, and when to shut down the spinning turbines and their capacity to bid during unfavourable weather. If the carbon efficiency of the wind+solar exceeds the carbon inefficiency of their backup, they might make a profit. Like 241. @ Jens Stubb I have replied to you on Open Thread 23 as I fear that I may run Off Thread Like 242. @Roger Clifton The “must take” provision makes sense at the moment when wind and solar penetration are low virtually everywhere. But as soon as you start getting solar and wind power exceeding demand at a particular time of day, then it makes sense to change the rules so that some wind / solar generation can be curtailed (after all fossil fuel generation sources, despatchable hydro etc.have first been curtailed). It doesn’t really make sense to remove individual unit scheduling responsibility from the grid operator, purely because the grid operator is the the one party who knows everything that is going on and can make the best decision for the grid as a whole. A bunch of generators of different types could get together to synthesise a type of generation which has different and more desirable characteristics than any of the individual generators. But to make better decisions than the grid operator on the use of the individual generating and storage plants they would have to duplicate all the grid operator data feeds. It’s possible, but does not seem to be a particularly efficient way to do it. Further, smart grids will make significant use of demand response to flex demand up and down to offset as much of the variability of wind and solar as possible. It seems unlikely this would be used efficiently unless under the control of the single grid operator. There are also problems with the most efficient use of storage. The problem with storage is self-cannibalisation. The ideal is that you have enough storage that the price of electricity does not vary very much between periods when there is plenty of wind and solar power and periods where there is a deficit. But if storage has to make money from arbitrage (selling when prices are high and buying when low), then it would be unprofitable if such price parity were close to being achieved. One solution (not the only one) is that storage is contracted by the grid operator under completely different terms from generation, and the costs are then distributed across all electricity users. It comes down to the regulations governing the monopoly grid operator. These are not set in stone and governments can change them if that is the right thing to do. At present the regulations tend to suit 20th century grids rather than mid 21st century smart grids. They will need significant changes at some point and there is a lot of work being done on this as well as on the technologies themselves. Like 243. The “must take” provision makes sense at the moment when wind and solar penetration are low virtually everywhere. Why? Why does it make sense to impose “must take” provisions for high-cost, low-value weather-dependent renewables? Wouldn’t it be far more rational and objectively justifiable, if the aim is to reduce global GHG emissions, to impose the “must-take” provision on nuclear instead? (as well remove the mass of impediments already imposed)? Like 244. Peter Davies seems to argue against a regulated monopoly, AEMO, which basically runs a rational market via dispatch order for the various generators, based on price and within the physical constraints of availability, transmission capacity and ancillary services. He argues in favour of selected participants in that marketplace being granted priority entry to the market, regardless of price, due entirely to the fact that they are intermittent. Not because of the carbon savings that they represent, because his rules do not rely on carbon emission reduction, only that the sources be weather dependent and thus unreliable. The argument is not that in operation they are zero carbon emitters – because that would necessarily result in support on equal terms for nuclear power. Not on the basis price of avoided carbon emissions, because that would imply a carbon market and all that comes with it, winners and losers and the ability for cheaper external sources of carbon reduction to be utilised by those generators which are locked into carbon emitting fuels. John Morgan’s discussion paper at the head of this thread demonstrates the inescapable practical limits of variable weather-dependant power sources. It has demonstrated that 100% market penetration is an unreachable dream, unless with mammoth (infinite?) overbuild. It has demonstrated the futility of continuing a discussion which is repeatedly dragged back to an irrational starting point, one where the mathematics of atmospheric CO2 emissions and costs are ignored. Like 245. @ Peter Davies, “The problem with storage is self-cannibalisation. The ideal is that you have enough storage that the price of electricity does not vary very much between periods when there is plenty of wind and solar power and periods where there is a deficit. But if storage has to make money from arbitrage (selling when prices are high and buying when low), then it would be unprofitable if such price parity were close to being achieved.” But that’s only a theoretical problem with storage, and will not become an issue until we have an extremely large amount of it (if ever). Self cannibalization’s far more likely to be a problem for renewable electricity generation (e.g. when the wind’s blowing it depresses the electricity price so it’s harder for wind turbines to be profitable) and storage can mitigate that problem. Like 246. @singletonengineer The issues with an all-renewable grid are not technical or economic, but regulatory – how to incentivise everyone correctly to get the required behaviour. It is very clear how to put together a cost-effective grid using only wind and solar renewables plus pumped storage hydro for storage where geographically feasible and renewable hydrogen powering compatible CCGT generation for the rest of the backup. You don’t need infinite renewables. You need the anti-correlation between (one load’s worth of capacity from each of) wind and solar to get you to around 70% time period coverage (50% + 30% CF’s respectively). Then pumped hydro (at 70% efficiency) and renewable hydrogen (45% efficiency) powering CCGT backup to cover the remaining 30% of the time. To store into the pumped hydro capacity you need 1/0.7 = 1.4 times as much additional renewables energy as you will generate from pumped hydro. To store via renewable hydrogen it is 1/0.45 = 2.2 times as much as you need to fill the remaining gap. For 100% renewable hydrogen backup (no pumped hydro) assume 50% wind and 30% solar CF, 70% direct load coverage with 10% spare generation available. The 30% gap x 2.2 = 66%. Subtract the 10% already going spare, and the storage need is for 56% extra renewables generation at a solar PV capacity factor of 30%. Assume a constant load, and we can generate all we need from 1 x wind and 3 x solar – each times the same nameplate capacity as the constant load needs. This can produce 50% + 3 x 30% = 140% renewable power compared with the 100% power the load consumes. Thus an overconfiguration of solar nameplate capacity sufficient to produce 36% extra energy is adequate for an all-renewables system. i.e. wind + solar at 50% and 30% capacity factors have to deliver 136% of the load between them. The 36% comes directly from the extra factor of 1.2 (=2.2 – 1) you lose via the renewable hydrogen cycle times 30% gap. If you have some pumped hydro this overcapacity comes down because the efficiency is higher. By 2030-2050 (at the point you will be switching residual natural gas CCGT to renewable hydrogen CCGT) the wind LCOE will be lower than current coal LCOE, and solar PV LCOE will be of the order of 2-3 US cents / kWh. Thus the direct renewable generation is very cheap and the 40% solar overconfiguration adds only 0.8 to 1.2 US cents / kWh. Electrolysis equipment and hydrogen storage costs very little by comparison with the rest (it doesn’t have to do very much). CCGT capital costs will be almost as low as they always have been (with a small uplift for hydrogen-compatible operation) as it is mainly CCGT fuel that dictates the cost. Nuclear costs in western nations have always gone up with time, so it’s not at all clear it can compete with an all-renewable solution. See Joe Romm’s article as to why nuclear is not the complete solution – http://thinkprogress.org/climate/2016/01/07/3736243/nuclear-power-climate-change/ . Once you do the sums, singletonengineer’s claim of infinite renewables capacity requirement comes down to just over a third of extra electrical energy generation required to support the storage / backup in one particular example of an all-renewables grid. Like 247. What an all-renewables grid would require in the US, if built to the projections of Mark Jacobson (per analysis by the Clean Air Task Force provided to James Hansen): 1,670 offshore wind farms the size of the 468 MW Cape Wind array (92 per coastal state) 2,400 Tehachapi-size wind farms (705 MW each ) onshore (or about 50 per state) 27,000 megawatts of wave machines (zero exist today) 227 Gigawatts of concentrated solar plants (or 580 Ivanpah-sized plants at 392 ME each, or 10 plus per state) to produce energy, and an additional 136 GW (7 per state) just for storage 2,300 GW of central solar PV plant, or 1,200 times more central PV capacity than exists today Additional 469 GW of solar thermal storage, or roughly 1.5 times the capacity of US coal http://csas.ei.columbia.edu/2015/12/29/wanning-workshop-beijing-charts-year-end-comments-2/ Some notes: Transmission not included in the above analysis. Renewable energy is not made using magic fairy dust. The Ivanpah solar facility, which displaced threatened species of desert tortoise, is a mega death trap for birds: http://www.desertsun.com/story/news/environment/2014/04/07/birds-going-smoke-brightsource-energys-ivanpah-project/7448299/ A search engine search will enable you to watch solar power scorching birds on video. Scaling brings resistance. The Cape Wind facility has gone approximately nowhere after 15 years of effort; the promoters put a brave face on it by noting it is mired in litigation: http://www.nawindpower.com/e107_plugins/content/content.php?content.14675 More analysis of Jacobson’s plan is slated for release late this winter or in the spring (N. Hemisphere). Like 248. The issues with an all-renewable grid are not technical or economic, but regulatory – how to incentivise everyone correctly to get the required behaviour. What is the “required behaviour”, and why? Is it to meet electricity system requirements or some people’s irrational, nonobjective, ideological belief? Like 249. @Frank Jablonski What you don’t say, but should, is that Mark Jacobson’s proposed US electricity grid would replace all energy use in the USA by 2050, not just supplying the current electricity grid demand. Here’s the Jacobson source article : https://web.stanford.edu/group/efmh/jacobson/Articles/I/USStatesWWS.pdf For that reason my rough calculation spreadsheet above shows it generates each year considerably more than four times the 2013 US annual TWh electricity consumption of 4,066 TWh from http://www.eia.gov/electricity/annual/html/epa_01_02.html . It would require about 0.5% of the USA surface area for machinery and facilities and another 2.4% for spacing between wind turbines which could be used for other purposes. That’s total land use, not additional land use, since energy. The question the US states citizens will ask themselves is whether they would prefer to live close to a nuclear plant, of which there would be a number in each state, or whether they wish to devote 2.9% of the land area of the USA to an all-renewable energy solution. Like 250. @ Peter Davis. After a very long string of assumptions and guesses, Peter arrived at a situation where the most variable of the variable supplies are presumed to be able to be absorbed into storage such as pumped hydro (Where? What cost?) and hydrogen. I just happens that I have some experience with electrolytically produced hydrogen and with H2 storage… and with three hydrogen fires, one of which blew apart the cladding off the building which contained it. First, electrolytic H2 production does not lenditself readily to spikes and troughs in electicity supply – it works best on steady load. There may be techniques foradapting to fluctuating loads, combined with either none or little power at all, but I have not seem them described. These bones need to be fleshed out. Second, current H2 economics are very much in favour of production by stripping hydrogen from a feedstock of natural gas. If I really want hydrogen in large quantities, as is the case for existing power turbines, the cheapest method is not to manufacture on-site by electrolysis even when the marginal cost of electricity is essentially equal to the cost of coal, ie 2 or 3 cents per kWh. Thus, on the basis of reduced cost and reliability and even safety, bottled hydrogen is frequently preferred even when almost-free power is available and an existing facility is on site. Third, given the safety implications of hydrogen storage, I would far prefer to live adjacent to a nuclear power station than next to a hydrogen production and storage facility at a scale of hundreds of MW average. Like 251. As so often happens, the (interesting) discussion has drifted far from the topic of this thread. At least the moderator and I would appreciate continuing on the latest open thread. Where, by the way, various commenters may find some value in what I have contributed… Like 252. Moderator, Can we have a thread entitled something like “Discussions on all renewables versus all nuclear grids” please? That seems to be the scope of the topic we all wish to discuss, but the information gets very diluted with other stuff on the open thread 23. Like 253. Would Peter D bring more than hopes and wishes?I’d appreciate some facts. Meanwhile, John M’s excellent, factual and substantiated article cannot be discussed on its merits? Someone’s joking. Like 254. @singletonengineer I’d appreciate some facts. I have neither the time nor the patience to read in detail….. Make up your mind. Do you want blow by blow refutations with factual links to put you right on those things on which you are misinformed, or would you prefer to conduct the debate at a summary level? Like 255. Step 1: Agree the topic for discussion Step 2: Can you answer ‘yes’ to the first three boxes here? http://twentytwowords.com/a-flowchart-to-help-you-determine-if-youre-having-a-rational-discussion/ Step 3: if you answer ‘yes’ to the questions in those three boxes, then we can agree to have a discussion about the topic, provided the following rules are obeyed: Do not introduce new arguments while another arguments has yet to be resolved Do no move onto another argument if it is shown that a fact you have relied upon is inaccurate Provide evidence for your position or arguments Do not argue that you do not need evidence I’d suggest your suggested topic is too poorly defined. I’d suggest one of the following: Which electricity system would supply cheaper electricity: all nuclear or all renewables generation? Which is the cheaper option to reduce GHG emissions intensity of the electricity system: All nuclear or all renewables Like 256. @Jens Stubbe You state that “The capacity factor of wind has been ever growing and will continue to do so for a good deal of years to come simply because wind turbines scale and improve. Higher hub height means stronger and steadier winds. Higher capacity factor means less variation in output and slower variation in output, so despite the shrinking dispatcheable generator sector it won’t have to ramp more up and down.” Even if what you are saying is true, the over CF of wind installations will only marginally increase unless existing installations are “repowered” and/or the overall capacity of wind installations for a grid are greatly expanded (which then leads to over capacity further leading to REDUCED capacity factor due to the need to curtail). In either case, there would seem to be considerable cost involved, especially if existing nameplate wind capacity is close to the average grid demand. BTW Can you please provide a source that gives some indication of how capacity factor of a turbine scales with hub height? If the increased tower costs were also available, that would be a great help. Also, can anyone advise how you are able to create a post “in reply”? Like 257. Hi Greg, I can help with your request of estimating the effect of hub height on capacity factor. It will vary from site to site, and from turbine to turbine, but the following rule of thumb gives a very approximate estimate. A 10% increase in hub height will yield approximately a 2% increase in energy. A 20% increase will yield approximately a 4% increase in energy, etc. So if a turbine has a capacity factor of 30% at a hub height of 80m, then at a hub height of 112m it will have a CF ~ 32.4% (ie, a 40% increase in height will increase energy by about 8%). The following may help you make your own estimate. Many wind turbine manufacturers show graphs of annual energy production (AEP), vs site average wind speed. I’ve copied a link to one from Vestas at the link below. This is based on an assumption of the wind speed distribution, which varies from site to site, but the assumed Rayleigh distribution is as good an assumption as any if you don’t have measurement data. To convert AEP to capacity factor, divide by 8766 and again by the turbine capacity (in MW). Next you need to estimate how the wind speed changes with hub height. The wiki link below will help with this. Like 258. @dos74 Thanks Dave Osmond. I checked your links but using the most favourable assumption about the atmospheric stability (alpha = 1/7), I only get a 1.37% increase in wind speed with each 10% of height increase and the AEP for the turbines appear to increase in a slightly less than linear manner with wind speed, making 1.37% increase in CF the outer limit for each 10% of hub height increase. The Wikipedia article suggests that offshore wind farms would only see a 1.05% output (and hence CF) improvement per 10% increase in hub height. Is there something I am not factoring in to fall so far short of the 2% that you provided? Like 259. @Greg Khan BTW Can you please provide a source that gives some indication of how capacity factor of a turbine scales with hub height? If the increased tower costs were also available, that would be a great help. Greg, The Capacity Factor (CF) is actually to do with project economics, rather than a straight technical issue to do with hub height, as should become clear if you read below. There is a very simple law about wind power output. Power output is proportional to the cube of the wind speed and to the square of the rotor diameter. The following charts gives an indication of the increase in wind speed with height due to less interference from surface friction and other effects : The wind speed on the simple top chart is generally too high for most sites. Using the top chart, as an example, the wind speed at 40m height is 16.2 m/s, but at 100m height is 18.5 m/s. The factor of the two wind speeds is 1.14, and the difference in power output is the cube of this, which is 1.48. So at 100m instead of 40m height you get almost 50% more power. Translating this to a capacity factor is complicated because other factors come into it. The wind is more consistent higher up, but the choice of turbine is going to make a huge difference to capacity factor. If you increase the ratio of rotor area to generator capacity, then you increase the capacity factor. This is often referred to as Specific Area Ratio (=Su in the PDF below) measured in m2 / kW. The higher the ratio for the turbine selected for a given site then the higher the capacity factor. See the last slide of this link – http://cf01.erneuerbareenergien.schluetersche.de/files/smfiledata/4/7/8/6/3/2/114bSWRcaseUSA.pdf . To get from hours of operation to capacity factor divide the Nh figure on the chart by 8,760 hours in a year. You can also think of it as reducing the generator capacity for a given hub height and rotor diameter, in which case you can see this reduces the cost, and reduces the maximum power output and average power output. But the capacity factor is higher because the generator is operating at a higher capacity and at maximum capacity for a higher proportion of the time, even though that maximum capacity is lower! In increasing the capacity factor by reducing the generator like this, you also collect less energy than you could for the land or sea area you use and for the rotor area. The recommendation is to site wind turbines 6 rotor diameters apart (in two dimensions) on land. Thus the energy available for a given land (or sea) area is independent on the rotor size, though it is still dependent on the hub height and turbine type chosen. So you can increase the capacity factor if you wish, and increasing the hub height makes the trade off between energy output and capacity factor easier, because there is more energy available at the increased height. However, the aim of the wind project is to make the best rate of return on the capital investment, not to maximise the capacity factor, so it is a question of balancing specific power ratio against project income and cost, and for a given hub height and turbine type (specific power ratio) there will be an optimum balance leading to a particular capacity factor. If governments gave a subsidy for higher capacity factors then you would suddenly find the capacity factor of new wind farms taking a jump, though the total power output might reduce. The expectation for offshore wind turbines in good locations is a CF of around 50% for maximum energy extraction, and as high as 60% with smaller generators. But offshore wind is expensive anyway and you might stick with 50% but more output. By contrast onshore wind turbines are cheaper to build and install. There is an expectation that the windiest sites in the USA could achieve 60% capacity factor with tall turbines with high area/ gen capacity ratios, and that there is enough very windy land in the USA to put them on (even though the power output per unit area reduces with the increase in capacity factor). See the presentation link above. There’s a lot more data in Bernard Chabot’s presentation (link above) as to how the onshore wind market in the USA is shifting to these taller, higher specific power ratio and therefore higher CF turbines. He’s a cross between an engineer and an economist, so well suited to discuss issues such as capacity factor, though the presentation can get a bit heavy in places. Like 260. Greg There are also mechanical limits to the maximum speed at which a wind turbine can operate i.e. they stop in gale force winds. Like 261. Greg To reply to a post simply click on the reply button at the bottom of the email you receive with the comment in it. Like 262. Greg Davies, A number of us have already discussed Mark Jacobson’s report on Open Thread 23. In short he has not completed the report. The storage element has not been finalized and is due for completion in 2016. Then I am an anticipating a cost estimate for this project. Until that is done his report is speculative as will be a lot of the comments. I will re-post this comment on Open thread 23 where it is appropriate to discuss off thread topics. Like 263. Hi Gred, the main reason for the discrepancy is that alpha=1/7 is not the most favourable assumption about atmospheric stability. As soon as you introduce stability (common at night), then the shear is likely to increase. In many sites, average measured shear exponents exceed 0.2, and even levels above 0.3 are not that rare. Moreover, if the ground is rough due to nearby forests or complex terrain, then this can also increase shear levels. However I agree that off-shore shear levels are much lower, and my approximate rule-of-thumb was meant for on-shore sites only. Like 264. Hi Greg, I just re-read your comment and realised that there is a larger reason for the discrepancy. You said that the speed-AEP relationship was slighly less than linear. This is wrong. Have a look again. In going from 6 to 7.7m/s, the Vestas AEP goes from 8,000 to 12,000 MWh. ie, a 28% increase in speed gives a 50% increase in energy. The relationship is steeper than linear. That’s the main reason for your estimate not matching my rule of thumb. Like 265. “a 28% increase in speed gives a 50% increase in” power. Well, yes. Theoretical power delivered is proportional to the sideways lift on the blade, which is proportional to the square of the relative airspeed. Eg, 1.25^2 = 1.56 Like 266. Actually, since power = force x speed of the blade, the power should go up as the cube of the speed. Like 267. Yes, theoretically the power increases in proportion to the cube of the wind speed. In practice, the turbine efficiency changes with wind speed. For example, once a wind turbine reaches rated power, any increase in wind speed does not increase power. And thus total energy (over a year, for example) is more likely to vary in proportion to annual average wind speed to a power of somewhere between 1.2 and 2. Like 268. @dos74 ” For example, once a wind turbine reaches rated power, any increase in wind speed does not increase power. And thus total energy (over a year, for example) is more likely to vary in proportion to annual average wind speed to a power of somewhere between 1.2 and 2.” That is the year by year behaviour after you have selected the wind turbine to install, when the wind varies each year from the multi-year average. With correct turbine selection you would expect the multi-year average of power output on different sites to correlate with the rotor swept area and cube of their multi-year average wind speeds, provided the wind farm economics rewards maximum annual energy and not a higher capacity factor. Like 269. Thanks to all those helping me fill my knowledge gaps. But some of the claims still do not seem to add up. The AEP graphs supplied by Siemens show that AEP increase with yearly average wind speed is clearly slightly less than linear in the region where they have plotted figures. For the Vestas V117 turbine linked, I assume that the graph is bounded because below an average wind speed of 6m/s, the capacity factor is so poor that the turbine would be uneconomical while above 8.75m/s, there would be too much time where the maximum operational wind speed of 25m/s would be exceeded. In both cases, I would assume Vestas would recommend a different turbine which would be similarly bounded but have its operating yearly average wind speed range shifted down or up to better suit the prevailing conditions. Now the power may well increase somewhere between the square and the cube of the wind speed but the AEP graphs supplied by Siemens are for average yearly windspeed. And since any decrease in wind speed would reduce the power by the same proportional amount (assuming the aerodynamic behavior of the blades does not change). So while the rate of increase in AEP from 0m/s to 6m/s is 1333MWh/(m/s) and from 0 to 8m/s is 1500MWh/(m/s), in the region of interest, the behavior is approximately linear with an offset: 2000MWh/(m/s) – 4000MWh If we take the case where the yearly average wind speed is 7m/s and the hub height is raised by 10% from the specified 80m to 88m, then the yearly average wind speed increases to 7.059m/s (assuming an alpha of 1/7) so the AEP rises from about 10000MWh to 10137Mwh which seems a trivial improvement. I use an alpha of 1/7 because according to the following Wikipedia page, a larger value would only apply if turbines were to be built in areas that had a high amount of obstruction (where the average wind speed would be worse than for clear areas). In fact, from the following page, 1/7 seem generous for on shore wind. https://en.wikipedia.org/wiki/Wind_gradient Peter Davies, you say “provided the wind farm economics rewards maximum annual energy and not a higher capacity factor”. Shouldn’t capacity factor be a baseline for assessing how a wind farm is built, given that most of the cost appears to be in the generator rather than the tower and base (not that those costs should be ignored). Or are the other costs, like of setting up transmission lines and maintenance, a greater factor so the AEP is given priority? Like 270. Hi Peter, the key to the issue is your last sentence: “provided the wind farm economics rewards maximum annual energy and not a higher capacity factor”. A turbine manufacturer could put an absolutely massive generator on the back of the wind turbine just so that it could continue to generate power efficiently during a 1 in 50 year wind storm event. They would also have to massively over-engineer the strength of the blades, gearbox, tower and foundations to cope with the huge loads that this would impose. In practice, they look at the wind statistics of the site, and decide that it is more economic to design the wind turbine so that it is most efficient at the most common wind speeds, and feather the blades to reduce loading at higher wind speeds with a resultant drop in efficiency. Google “wind turbine power coefficient Cp” to see what the efficiency of wind turbines look like as a function of wind speed. As a result, annual energy production is not proportional to annual average wind speed to the power of 3, instead the coefficient is generally somewhere between 1.2 and 2. Like 271. Hi Greg, Your assumption about Vestas recommending a different turbine if the average wind speed is below 6m/s or above 8.75m/s is partly on the money. I’d just add that if the site average wind speed was above 8.75m/s, then it may present loading on the turbine greater than what the turbine (blade/gearbox/tower/foundation) was designed for. The fraction of the time the wind speed is above 25m/s is likely to be trivial, and would only be a minor consideration. Although you haven’t linked to the Siemen’s AEP curve, I believe you may have made some minor miscalcs. The 10% increase in hub-height should increase the wind speed by 1.37%, or from 7m/s to 7.10 m/s. You quote a slope for the AEP curve as being 2000MWh/(m/s), so that increase in speed should boost the AEP by 192 MWh, a 1.91% increase. Thus the 1.37% increase in wind speed increases energy by 1.9% (ie, greater than linear, an exponent of approximately 1.4). Finally, turbines are generally designed to maximise project economics, which roughly speaking means maximising (generation/CAPEX). In practise, this means neither capacity factor nor generation is maximised, but the optimum lies somewhere in between. Like 272. Greg, I forgot to reply to your comment about using a wind shear exponent of 1/7. Although this is fine for many sites, there are undoubtedly many wind farm sites with a shear exponent greater than this. As I mentioned previously, stability greatly affects the shear exponent. The wiki page you linked to quotes an exponent of 0.4 for stable air above flat open coast. The wiki page below mentions the exponent can be above 1. Stable air is quite common during the night. Similarly, many wind farms are located in regions with forested areas nearby, and this can also increase shear exponent levels above 1/7 even without stability effects. https://en.wikipedia.org/wiki/Wind_engineering Like 273. @Peter Davies and Greg Kaan, Peter’s closing comment is very significant and lies at the root of the primary misunderstanding about the economics of wind power. “…provided the wind farm economics rewards maximum annual energy and not a higher capacity factor.” In some markets, the following happens: (1) Priority. Wind power may receive priority access to the market, ahead of other sources. Whenever wind can generate, it is permitted to do so. (2) Price. Wind power may receive preference over other sources, regardless of price – this might be in the form of a pre-set wholesale energy price which retailers must pay, regardless of lower bids from competing producers, which are typically either FF or nuclear. (3) Avoidance of paying for risks. Wind power providers may not be responsible for the costs attributable for “ancillary services”, primarily frequency control, which match the system output to demand. This generally involves a mixture of hydro and/or “spinning reserve”, which can be thought of as baseload style gas, oil, coal or fission fuelled plant operating at below their full capacity. The reserve capacity is typically at least equal to the largest generating unit in the system. Thus, in an unfair market, wind gets the benefits of “maximum annual energy” without any penalty for having low capacity factors. In a fair energy market wind power providers would bid for day-ahead supply like others and either provide at the bid price or pay someone else to do so in the event of inability to supply as bid.. Wind would carry the financial risks that arise from unplanned inability to supply, either via a direct market mechanism or by arranging, progressively through the day, for others to do so on their behalf. Like 274. Returning to the capacity factor of wind farms, the following report from Greenmarkets reports that the average capacity factor for wind farms on the NEM was 31.8 per cent in 2015, up from 30.9 per cent in 2014. Bearing in mind that WA’s large-scale wind farms have far higher CFs than the national average, this further supports that the average CF of wind farm CFs in Australia is generally in the range 31%-37%, with some variation from year to year. Indeed, using data from 2007 onwards, I have 2010 being the worst year, and 2007 the best year. http://greenmarkets.com.au/resources/review-of-the-nem-2015 Like 275. Now for the bad news, taken from the same report and regarding the NEM market: Carbon emissions intensity increased from 0.809 to 0.817 t/MWh last year. Greenhouse emissions increased by 2.2% in 2015. Despite the hype from the renewables sector, we are losing the emissions race despite 1% reduction in overall energy sent out in the NEM market. There is nothing at all to celebrate yet, despite claims of increasing CF for wind turbines. Like 276. 7.059?? How on earth did I come up with that figure. You’re absolutely correct, David – the wind speed increase should have been from 7 to 7.10 m/s. How embarrassment! So yes, I get the 2% increase for 10% hub height increase you suggested. Still, I can’t help but think that we must be approaching an economic scaling limit for this sort of improvement, given the leverage that the drag on the blades and nacelle must place on the footing and tower base. I guess that is why the turbine tends to get scaled up in power capacity as tower height is increased. As for wind shear, it seems logical that as the better, more cleared sites get used, then the more cluttered sites would demand higher hub heights since the larger wind shear would make lower heights ineffective. But I don’t see this leading to higher capacity factors since the increase in Hellman exponent would only make the bring the wind speed back up towards that of the uncluttered site as hub height increases. singletonengineer, you refer to certain widespread policies on renewable generation as being “unfair”. The costs (both economic and opportunity) that result from the distortions caused by these policies must be quantifiable. The NEM article is interesting and paradoxical – the displacement of gas generation by coal seems to defy the ramp requirements needed to cope with the increased penetration of renewable sources. This is especially surprising given that this occurred in SA as well as Qld and Victoria, And according to the ACIL Allen Emissions Report used as the basis for the CO2 emissions, they are estimated from power generated so any effects from ramping and spinning in reserve would not be accounted for. This could well have led to an even larger increase in CO2 emissions with the increased wind generation penetration if it behaved as John describes. Like 277. Greg Kaan, I generally speak english. What language lends meaning to: “…according to the ACIL Allen Emissions Report used as the basis for the CO2 emissions, they are estimated from power generated so any effects from ramping and spinning in reserve would not be accounted for. This could well have led to an even larger increase in CO2 emissions with the increased wind generation penetration if it behaved as John describes.” I was not discussing “what if” or “could well have led to”, which are unjustified idle musings, given the rules for reporting performance in the NEM. The paper that Greg Kaan cited presented actual numbers and they aren’t pretty. Wind power has not produced a reduction in any of emissions intensity, system stability or cost. What will it take to convince wind proponents to change their minds? Is ACIL Allen’s data wrong? In which case, why does Greg Kaan rely on selective citation drawn from the same source? John Bennetts +61 407 724 095. Come on, Greg. Phone me and have a chat if you wish. Like 278. @singletonengineer “In a fair energy market wind power providers would bid for day-ahead supply like others and either provide at the bid price or pay someone else to do so in the event of inability to supply as bid.. Wind would carry the financial risks that arise from unplanned inability to supply, either via a direct market mechanism or by arranging, progressively through the day, for others to do so on their behalf.” My understanding is that this is exactly what happens in the German day-ahead market. Providers quote for power in particular chunks and are then responsible for providing it. http://www.businessspectator.com.au/sites/default/files/styles/full_width/public/forecasting%20error.png?itok=CAeleBij Wind predictability is very good. It is generally better than 8% of rated wind capacity for 24 hours ahead, and better than 4% of rated wind capacity for 1 hour ahead. This is with the benefit of specialised weather forecasts. The forecasts do cost some money, so if you have large quantities of despatchable hydro available you might not have to bother. In Germany they treat is as a grid exceptional event if the forecast for wind power by time slot 24 hours ahead is worse than 10% of the rated wind capacity, and it doesn’t happen very often. When comparing wind predictability with CCGT or coal forecasting, then the size of CCGT generators is much larger than wind turbine generators. So if you lose one it makes much more difference. So the current time spinning reserve (not backup) requirement for wind power tends to be less purely because you are only going to lose 10 or 20 MW when you lose a couple of turbines to mechanical failure, whereas with CCGT or coal the generators are many 100s of MW. Like 279. Wind forecasting image from above with the correct URL (without suffix) : Like 280. John Bennets, here it is in plain english, then. If you read through the 2014 ACIL Allen Report used by the NEM to calculate the CO2 emissions “EMISSION FACTORS REVIEW OF EMISSION FACTORS FOR USE IN THE CDEII”, you will see from section 2.4 that they estimate average thermal efficiency and auxiliary consumption factors for each generator to produce an emissions factor and from this, they used the delivered electrical energy over the year (in MWh) to produce the estimated CO2 emissions for each generator. They key is the the average thermal efficiency used to calculate the emissions factor. If the average used is that for a steady output operation but in actual operation, there is considerable ramping up and down to match demand fluctuations, then the operational thermal efficiency will be lower than the steady state efficiency, particularly for coal (and to a lesser extent CCGT) plants. This will lead to a higher actual emissions factor which means the actual CO2 output will be correspondingly higher for the same delivered energy. Now from section 3 in the NEM report, hydro’s generated output fell in 2015 as did gas when compared with 2014. Meanwhile, wind and solar generated output increased as did brown and black coal. Now without knowing the instantaneous output from all sources over both years, I am reduced to musings but it seems reasonable to assume that in 2015, the larger generation capacity of wind and solar would almost certainly have created larger demand fluctuations for the other generators. And since coal plants made up a larger proportion of “dispatchable” generation capacity, it also seems reasonable to assume that these needed to ramp more often to cover the fluctuations which would reduce their thermal efficiency, leading to more CO2 being produced per MWh generated/delivered. This is what led me to propose that it is likely that the actual 2015 CO2 emissions are higher than that stated in the NEM report, since the same emissions factors are used for both years. I will call you later today to discuss this further Regards Greg Like 281. @dos74 Peter Davies, you say ‘provided the wind farm economics rewards maximum annual energy and not a higher capacity factor’. Shouldn’t capacity factor be a baseline for assessing how a wind farm is built, given that most of the cost appears to be in the generator rather than the tower and base (not that those costs should be ignored). Or are the other costs, like of setting up transmission lines and maintenance, a greater factor so the AEP is given priority? As someone pointed out, absolute maximum AEP would involve grossly oversizing the generator, so I should have said “a bias towards maximum AEP rather than a high CF”. Optimising return on investment is key criterion. The cost of the generator itself turns out to be small. The other AC components (transformer, power converter and grid connection) costs must be added in as these should also be proportional to the nameplate capacity, for maybe a grand total of 25%. That the total is so low is a surprise to me. Presumably if the price of copper and maybe other materials goes up the cost of these components rises as a proportion. Even though the AC side is a low fraction of the costs, there is still an optimisation in which the major decision is to select the model of wind turbine. There’s no point in incurring costs of a bigger generator for the same rotor size if the high wind speeds at which it will be required rarely occur in the location. Like 282. @singletonengineer, Why do you think a fair market would require supply to be determined a day ahead? Wouldn’t it be easier for the price to be determined in real time to match demand (which they can’t accurately forecast a day ahead)? Isn’t priority a good thing? Surely we should avoid a situation where we’re buying power from fossil fuels while forcing wind to curtail its output? Frequency control is needed anyway because of fluctuating demand. Isn’t it unfair to attribute the cost to wind power? Like 283. @ Peter Davies Would you be able to tell us what items might be in the OTHER section of the first chart that you give above, seeing that it appears to be the largest single section of wind turbine cost. I would also like to make the point that grid connection is a huge variable, the cost of which may preclude all other considerations. Like 284. Either Greg Kaan adopts the findings of the 2015 ACIL Allen report which he cites or he does not. Yes, ramping up and down while chasing increasing fractions of variable generation does have an impact on the carbon intensity of energy from the thermal power stations which are doing the work. The correct way to estimate this is not to guess from the 2015 report alone, but by reviewing statistics from previous years,maybe previous ACIL Allen reports. I agree with Greg that increased load following will indeed result in increased carbon intensity, if all other factors remain unchanged. That is not at issue. My concern is that, having cited the report and adopted some of its findings, it is a bit rich to then set aside those findings which are not supportive of wind power. That is cherry-picking. The figures I quoted from that report present a bleak picture of increasing emissions, despite increasing renewables. Maybe next year will be different, but that remains to be seen. The two primary goals are to reduce carbon emissions and to minimise energy costs. Neither is going to be met at the necessary scale via efforts to increase the capacity factor and penetration of wind – stronger measures are needed. Like 285. @ Aidan Stainger: Q1: “Why do you think a fair market would require supply to be determined a day ahead? Wouldn’t it be easier for the price to be determined in real time to match demand (which they can’t accurately forecast a day ahead)?” Instant action requires infinite speed. I say 24 hours, in order for the market to be orderly. “Real time” implies requiring instantaneous action by others, which is not possible except with real cost. Q2: “Isn’t priority a good thing? Surely we should avoid a situation where we’re buying power from fossil fuels while forcing wind to curtail its output?” That is a very shallow and selfish way to view the market. It implies an infinite value on avoided CO2 emissions, plus an implied assumption that wind power actually avoids emissions, which is debatable when its negative effects on other generators is considered. A rational, structured approach to costing both electricity and emissions, combined with a merit order approach to scheduling of generating plant is the smart way to go. Q3: “Frequency control is needed anyway because of fluctuating demand. Isn’t it unfair to attribute the cost to wind power?” I was not discussing fluctuating demand, which is a red herring. However, a case can be made in favour of wind carrying its own share of the response to variable demand, both up and down. It is irrational to permit wind power generators to freely and without penalty introduce additional variability to the system in the form of variability of supply. This results in additional costs for the other generators and for transmission and distribution operators who need to work together via either load following or load shedding to compensate for the additional variability that is attributable to wind. Like 286. @ singletonengineer Sorry but I did think that Greg Khan was making a valid point about using averages etc, as opposed to using say tons of coal burnt and/or the amount of gas burnt. I also did not get the impression that what Greg Khan was saying supported wind or solar. Further, the goal in terms of electricity generation is to eliminate the use of fossil fuels entirely, at minimal cost. I am not a zealot so I will settle for 90 percent of the world’s electricity generation coming from non fossil fuels by 2100. The science tells me that the major source of this generation will come directly from nuclear energy. PS That is unless we work out how to use the warp drive from the Enterprise. Like 287. We seem to gone off track again – maybe the issue of generation vs demand, last year’s CO2 emissions etc should be taken up in the open thread. In any case, I appear to have made a further error on the issue of capacity factor vs wind turbine hub height. Just to recap, the Vestas V117 was presented by Dave Osmond to me as an example of a turbine for analysis and I found that the AEP varied with yearly average wind speed in a largely linear manner approximately as AEP =2000MWh/(m/s) – 4000MWh in the yearly average wind speed range of 6.0m/s to 8.5m/s see https://www.vestas.com/en/products_and_services/turbines/v117-3_3_mw#!power-curve-and-aep I used the wind speed of 7.0m/s as an example and assumed a Hellman exponent of 1/7 to calculate that a 10% increase in turbine hub height would result in a 0.0959m/s increase in wind speed which led to the AEP increasing from 10000MWh to 10192MWh equating to about a 2% power increase. What I forgot was that the capacity factor depends also on the nameplate capacity of the turbine which is 3.45MW in the case of the V117. The original capacity factor was 10000MWh / 3.45MW * 24h * 365.25 * 100 which equals 33.066%. With the power increase from the 10% increase in hub height, then new capacity factor only rises to 33.701%. This increase of 0.635% with the 10% hub height increase is well short of the 2% rule of thumb I was provided so taller towers (with attendant wider bases, both suitably strengthened for the greater leverage) doesn’t seem to help much with the underlying capacity factor issue at the heart of John Morgan’s post. Maybe Jens Stubbe can shed more light on his claim of “The capacity factor of wind has been ever growing and will continue to do so for a good deal of years to come simply because wind turbines scale and improve. Higher hub height means stronger and steadier winds. Higher capacity factor means less variation in output and slower variation in output, so despite the shrinking dispatcheable generator sector it won’t have to ramp more up and down.” which I originally asked about. Like 288. Hi Greg An increase in capacity factor from 33.066% to 33.701% is an increase of 1.9%, or an increase of 0.635 percentage points. I tried to word my original rule of thumb to avoid this confusion, but it appears I wasn’t successful. “A 10% increase in hub height will yield approximately a 2% increase in energy” Like 289. @Tony Carden Would you be able to tell us what items might be in the OTHER section of the first chart that you give above, seeing that it appears to be the largest single section of wind turbine cost. The source didn’t give the breakdown of other, but some obvious things missing are customer acquisition costs (marketing), R&D and profit. I would also like to make the point that grid connection is a huge variable, the cost of which may preclude all other considerations. The latest US DoE LCOE document https://www.eia.gov/forecasts/aeo/electricity_generation.cfm puts average additional transmission costs at around 0.3 US cents / kWh for onshore wind and about double that for offshore wind. As a proportion of 7.36 that is 4% for onshore wind, so the 11% allocated in the pie chart appears relatively generous. If you are doing good things with a very long distance transmission, such as transmitting both solar and independent region wind power from North Africa to London or Berlin to complement North Sea region onshore or offshore wind, then you would expect significant transmission costs. Desertec were quoting 1 to 2 US cents / kWh over distances of 1,300 miles / 2,000 km. But you would not expect to spend this much unless renewables generation in total is exceeding 50% of supply. It’s only worth supplying wind from a long way away when it reduces the proportion of generation from storage. See http://www.desertec.org/concept/questions-answers/ . Why do you believe transmission upgrade costs might be more than 11% for wind in some cases? Like 290. Peter, I am not trying to be pedantic but in Australian conditions Grid Connection Costs can be significant. John Morgan included in his article above a map showing Australia’s Wind Resources. Here is the reference again http://www.seabreeze.com.au/Photos/View/2871107/Weather/Australia-wind-energy-map/ Many of the resources identified are at least 1000 klms from any significant population centre. The estimate for the current Australian Transmission line losses in the NEM is 10%. Therefore grid connection costs, let alone the resultant transmission line losses, may well exceed 11% in Australia. My reference to the Other costs is not a criticism of you but more of IRENA. Assuming that the pie and bar chart are drawn to some kind of scale then the Other costs are one of the largest components. My experience of presenting proposals to decision makers is that the first thing that they will target in a presentation is a large non-descript figure. I have had the phrase ‘In relation to the Other or miscellaneous costs what are the hooks in there.’ said to me before I started to break them down more informatively. Like 291. @ Pater Davies, 10 hours ago. The Desertec link failed for me. Like 292. DesertTec link worked for me just now. However, the concept failed to gain traction with the Spanish and so is moribund. For a live CSP project in the Maghreb, see what the Moroccans are doing. Like 293. @Greg Kaan “Maybe Jens Stubbe can shed more light on his claim of “The capacity factor of wind has been ever growing and will continue to do so for a good deal of years to come simply because wind turbines scale and improve.” There are three trends behind the ever growing wind capacity factor, which in turn grow AEP and limits both the required backup and the speed with, which the back up needs to ramp up and down. The first is simple because it is just about elevating the hub height to reach stronger and steadier winds. You can get a better grasp of it here. http://cleantechnica.com/2015/08/04/wind-could-replace-coal-as-us-primary-generation-source-new-nrel-data-suggests/ The second is equally simple to understand because the idea is to continue the ongoing development of bigger and bigger rotors. This article covers the timespan of some recent years http://www.nawindpower.com/issues/NAW1301/FEAT_05_Turbine_Advances.html The third is more complex because it involves interaction on wind park scale and over the entire lifespan of a wind turbine. The effects at play here are all minor with a few notable exceptions. Wind farm scale LIDAR technology enables the wind turbines in a wind farm to be individually yawned to reduce turbulence (3% higher AEP). Sharkskin structures on blades has been demonstrated to increase AEP by 6% but cannot be used due to cost mainly because of fast degradation. LIDAR based individual blade pitching, which is in its infancy because of cost involved and because the pitching action is too demanding for the standard pitching mechanisms. Plasma drive where the boundary layer over the blades is dynamically controlled by electrodes that subdue large vortices. Winglets with dynamic morphing characteristics that limits losses due to wing tip vortices. Generators with less friction. Dynamic and passive stabilization of tower movements. At some point in the future the capacity factor for onshore wind turbines will settle but what it will settle at will be very much dependent upon how the grid infrastructure is built and how the strategy will be for managing the grid. For instance there could be a very good case for over provision if the electricity becomes very cheap and more demand could be time shifted, and in such conditions could favor turbines with cheapest possible electricity generation cost over turbines with high capacity factors. Like 294. @ Tony Corden What is the source of your 10% figure? @ singletonengineer The Desertec link worked for me, though it was a bit slow loading. Like 295. Aiden, ‘As electricity flows through the transmission and distribution networks, energy is lost due to electrical resistance and the heating of conductors. The losses are equivalent to approximately 10 percent of the total electricity transported between power stations and market customers.’ Like 296. Thanks Jens. Dave Osmond helped me with looking into increasing hub heights and the calculations I came up with did not look very promising – around 0.66% increase in capacity factor with each 10% increase in height. This would not seem to be worthwhile unless the area around the wind farm was particularly cluttered making for high wind shear in which case, the area would seem to be a poor site for a wind farm in the first place. Do you know what the cost increases are as a function of rotor size? The greater weight of a larger rotor must require stronger gearboxes and bearings. Of course the larger rotor also demands a taller tower (which also helps with the capacity factor) which then needs to be more strongly constructed with a larger footing. There are also quite a few articles about bearing and gearbox failures and their prevention which means they must be already optimised to minimise contact areas in the interests of minimising friction for increased efficiency. Improvements in metallurgy and mechanical design will almost certainly be marginal since this is such an important area in many industries. Active blades to tune out vortices sounds very promising but they must be far more costly to make than the relatively simply constructed blades currently being used. The same applies to better controlled towers. Given that one of the concerns about low capacity factor is the cost due to the large overbuild, we really need solid figures on the costs required to achieve each incremental increase in turbine efficiency. As you have said, if the costs are low enough, we don’t have to worry about spillage/curtailment but everything seems to be leading to higher costs. As for time shifting demand, meaningful changes couldn’t be made in this area without being able to schedule the wind produced electricity with certainty. Since predictability is one of the issues demonstrated in John Morgan’s article, time shifting demand is not a practical solution. Like 297. @Greg Kaan Given that one of the concerns about low capacity factor is the cost due to the large overbuild, we really need solid figures on the costs required to achieve each incremental increase in turbine efficiency. As you have said, if the costs are low enough, we don’t have to worry about spillage/curtailment but everything seems to be leading to higher costs. There seems to be some confusion here about the trade off between AEP and capacity factor. The discussion above indicates that capacity factors automatically increase slightly with higher hub heights. These also give additional output power. But there’s always an optimisation available, because you can constrain the output power and get a higher capacity factor. This reduces costs slightly, but beyond a certain point this does not earn you more revenue, however, because it reduces, rather than increases the total units of electricity generated. So capacity factor is not the only thing to take into account. Like 298. @Tony Carden Many of the resources identified are at least 1000 klms from any significant population centre. The estimate for the current Australian Transmission line losses in the NEM is 10%. Therefore grid connection costs, let alone the resultant transmission line losses, may well exceed 11% in Australia. With the exception of Darwin, most of the large Australian cities I have heard of seem to be within spitting distance of reasonable wind resource except Darwin. Darwin has excellent solar resources so forget about wind there. Just because you have huge high quality wind resources available thousands of miles from anywhere does not mean you have to use them if reasonable wind in the required quantities closer to the population centres is available instead. Normally you would not include transmission losses in project costs, just the cost of building the extra transmission lines required to exploit a new generating resource. You would put them in as a reduced revenue item. Like 299. @Peter Davies, your point about proximity of mean wind resources in proximity to population centres misses that made by John Morgan in the original article, immediately below the link reposted by Tony Carden: “If we wanted to cover intermittency we would need to ensure our wind fleet is dispersed over distances of 1200 km and more…” This is where the requirement to transmit wind-generated electricity thousands of kilometres comes from. As you yourself said in a similar context above, ‘you would not expect to spend this much (on connection) unless renewables generation in total is exceeding 50% of supply…’, but isn’t that latter condition exactly what is being advocated? Like 300. Peter, Below is the reference to the wind map you have quoted. It shows the resources in better detail. https://www.finance.wa.gov.au/cms/uploadedFiles/Public_Utilities_Office/Energy_in_WA/Renewable_energy/mean-wind-speed-2008.pdf A more detailed examination of this map shows that a major part of the wind resources are off shore. Here is a reference to a report by The Australian Renewable Energy Agency. http://arena.gov.au/files/2013/08/Chapter-9-Wind-Energy.pdf From page 246 first paragraph ‘Australia has some of the best wind resources in the world. Australia’s wind energy resources are located mainly in the southern parts of the continent (which lie in the path of the westerly wind flow known as the ‘roaring 40s’) and reach a maximum around Bass Strait (figure 9.8).’ From page 240 first paragraph ‘Grid constraints – lack of capacity or availability – may limit further growth of wind energy in some areas with good wind resources, particularly in South Australia. In such areas, upgrades and extensions to the current grid may be needed to accommodate significant further wind energy development. Elsewhere,current grid infrastructure should be adequate for the levels of wind energy penetration projected for 2030’ Further from page 248 last paragraph ‘Factors that may limit development of wind energy on a localised basis are a lack of electricity transmission infrastructure to access remote wind resources, and the intermittency and variability of wind energy.’ Further here is a reference to a map entitled ‘Figure 9.18 Wind energy resources in relation to reserved land and prohibited areas and the transmission grid. A 25 km buffer zone is shown around the electricity transmission grid.’ There are many pristine coastal regions in NSW and Qld which appear to be good locations for Wind Farms. Good luck with that. Here is a reference to a report by the Australian Bureau of Statistics showing population densities. http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/1301.0~2012~Main%20Features~Geographic%20distribution%20of%20the%20population~49 The fact that you wish to contend my original statement is proving the necessity for making it. If the average grid connection cost is 11% then mathematically there must be installation that are over 11%. Australia is a major candidate for having grid connection costs above 11% based on the information above. There will be other situations that have similar issues. I am sorry but Solar is off topic. Like 301. That is a great correlation and justifies an investment in Wind purely for the purposes of Hydro conservation. Like 302. @duffer70 As you yourself said in a similar context above, ‘you would not expect to spend this much (on connection) unless renewables generation in total is exceeding 50% of supply…’, but isn’t that latter condition exactly what is being advocated? You do have a point, but it’s a littleless of a point than it might be! If you are using a second source of wind a long way away to fill in the gaps, then the transmission capital cost is incurred. To get up to the high levels of wind penetration you are now going to have twice the wind power. At a reasonable future 45% capacity factor for wind the 1200km remote wind farms will be filling somewhat more than 45% of 55% (gap) or about another 25% of the gap if wind power has a random time distribution (which it doesn’t in Europe). So effectively you now have 45%/70% of the long transmission line costs to bear averaged over all wind kWh. These costs are going to be significantly less than the cost of storage, and still only a faction of the US DoE LCOE of over 9 cents / kWh for nuclear so you are still saving. If, on the other hand, you believe wind power does not have a random time distribution, then you get less benefit from the remote wind but you have to assume the capacity factor is seasonally higher in the winter months and daily when the sun is not shining. That is also pretty good, because it means future very cheap solar PV power is going to be better anti-correlated with both local and remote wind. Either way, local and remote wind and local solar power can get up to a decent fraction of generation before you have to start implementing storage in a nearly all renewables Australian grid. Darwin looks as if it might need some nuclear though. Like 303. Do you have an idea of how much nuclear Darwin might need? Like 304. @Tony Carden Do you have an idea of how much nuclear Darwin might need? Not a lot, from the population statistics of the city itself in the link you provided. But I’m not familiar with the degree of industrialisation or the size of the surrounding population. If it was the only nuke in Australia, it would not be worth the bother. Like 305. @Mark Duffett I’m not following you here, in particular the second para. There are two cases. In Australia either solar anti-correlates with wind or it does not. If solar anti-correlates with wind, then it must anti-correlate with wind in both remote (> 1200kms) and local wind areas.That means that the wind in the remote and local areas must correlate somewhat. If solar does not anti-correlate with wind, then there is more chance that wind in two areas 1200 km apart is independent. This is not guaranteed but appears to be John’s finding from the correlation times. If the wind is independent with a capacity factor of C, then a crude sum says the chance of no wind in either place is (1 – C) * (1 – C). It’s not as simple as this, however, because wind is often blowing at intermediate speeds between maximum power output and zero power output, so the effect is better than you might expect. The question of installing wind and solar together is more complicated than you suggest. Firstly in the 2030-2050 timeframe both onshore wind and solar PV are expected to be very cheap indeed. Solar PV is expected by the IEA to be lower than 2c US/kWh. Maybe not in UK or Germany with no sun, but certainly in Australia. Wind a little higher, but below 4c / kWh in reasonable locations. The costs of an all-renewable grid are then determined more by the requirement to fill in the gaps with storage than by the cost of wind or solar power. In this scenario you have to optimise and it will be better to overconfigure wind and solar somewhat, to avoid more expensive stored power costs. Secondly most grids have a higher load during the (sunny) daytime rather than the nighttime, so it makes sense to configure solar PV as well as wind. There’s often an evening period after the sun goes down where load remains high, particularly domestic load. If this is due to a residual air-conditioning requirement then it may reduce somewhat. By 2030-2050 buildings are likely to be much better insulated. If it doesn’t reduce then there’s a role for solar CSP, heating salt during daylight, but not generating until the sun goes down – because it’s cheaper to generate with solar PV than solar CSP during the day. So the conclusion that wind and solar capacity is restricted by economics to peak load is too simple, predicated on current, not future, prices and not taking account of daytime bias of the load. And lastly I’ve no idea why wind should be more or less constant during 24 hours in Australia, but nowhere else (France, Germany, Texas). It seems odd. Most of the Australian population lives near the coast. During the day the land heats up faster than the sea surface and you get an offshore breeze, in the morning. Somewhere after noon the wind drops. Then in the evening you get onshore breezes as the land starts to cool down rapidly, particularly in cloudless skies. So you would expect a significant evening breeze. Where is it? Maybe it’s because Australia is big and nearly circular and there are lags in the effect because of the large distances which cancel out. But why doesn’t that apply in Texas? Like 306. About the daily cycle… In the absence of vertical mixing, the layer of air near the ground slows down overnight, so that it is often still in the mornings. With a clear cold night sky, it radiates its heat to space, forming an inversion layer that may persist all day. Most often, the mid-morning sun warms the ground, causing thermals to rise through the layer to the geostrophic wind aloft, diverting momentum downwards and clearing the layer. John Morgan’s graphs shows this effect in Nov-Dec-Jan-Feb-Mar, with the ground wind rising between 0600 and 1800. In each case, the ground wind dies off between 1800 and 2400 as the next evening’s calm layer develops. Like 307. @ Peter Davies, If solar anti-correlates with wind, then it must anti-correlate with wind in both remote (> 1200kms) and local wind areas.That means that the wind in the remote and local areas must correlate somewhat. Not necessarily. If it only anticorrelated with the wind in local areas, there could still be an overall anticorrelation. Like 308. The wind in the Mid-North region of South Australia is nicely anti-correlated with solar, as you can see from the average daily generation curve over a 3 year period below : And now the surprise – the South East of South Australia correlates (not anti-correlates) with sunlight : These are charts 3-2 and 3-4 from the “SOUTH AUSTRALIAN WIND STUDY REPORT 2012” (for which Word Press does not seem to accept the URL and has rejected the full post a few times, so will try it in bits). Like 309. Sorry I still can’t get the URL for the “SOUTH AUSTRALIAN WIND STUDY REPORT 2012”, so please Google the document. The wind in the Mid-North region of South Australia is nicely anti-correlated with solar, as you can see from the top average daily generation curve in my post above. My understanding is that South Australia represents half of all Australian electricity consumption and generation. Probably other Australian regions also have the same mix of wind profiles correlated and anti-correlated with solar PV. The only reason John reports no anti-correlation between wind and solar PV is that he, very reasonably, performed only the obvious analysis, aggregating together all Australian wind farms before doing the time analysis. Since there are regions with both anti-correlation and correlation, the two types of daily profiles cancel and you lose the information you were looking for. To spot the regional variation which gives strong wind / solar PV anti-correlation in the Mid North you have to analyse windy regions separately not together. Not only is there anti-correlation with solar in the Mid North region, but also a high wind capacity factor at night (in excess of 50% for some wind farms), which is ideal. Thus South Australia can achieve synergy of onshore wind and solar PV power by installing most of its wind farms in the Mid Northern region, probably at the cost of a few hundred km of transmission lines. Then it can incorporate another nameplate capacity of solar PV equal (or more) to the daytime peak load. If the solar PV capacity factor is 25-30% over the course of a year, then for only daytime hours the capacity factor over a year is actually 50-60%, since everywhere on earth averages 12 hours of sunlight per day. This combination of Mid North wind and solar PV can thus achieve a penetration of wind and solar PV power usefully and economically which is higher than the capacity factor of wind or solar PV alone. It would give something like a 45% (plus) wind capacity factor at night when load is low. During the peak day, the wind capacity factor of around a third is going to plug one third of the 40-50% gap left by solar, to give a 27-34% gap, which means 66-73% solar + wind coverage during the day, for the price of an excess of 50-60% of the wind power generated during the day. That means the solution can achieve high renewables penetration economically when wind and solar prices drop just a little below the cost of current fossil fuel generation, which is not likely to take too long to happen. In practice analyses for all four seasons are needed, rather than the equinox calculation above. But the principle stands. So it looks like the capacity factor of Australian wind does not represent a hard economic barrier after all, thanks to the emergence of new information on the daily profile of South Australia wind. Like 310. @Greg Kane You are wrong in concluding that capacity factors does not grow significantly with hub height. I think you better look it up yourself or assume these guys know what they are talking about. http://cleantechnica.com/2015/08/04/wind-could-replace-coal-as-us-primary-generation-source-new-nrel-data-suggests/ https://www.google.dk/search?q=wind+speed+as+function+of+hub+height&client=safari&rls=en&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjC9uXf3cLKAhWKFCwKHe9qAl0QsAQIRw&biw=1427&bih=696 The problems with bearings and gear boxes has absolutely no consequence for the PPA contracts signed because they all fix the cost of electricity for typically 20 years into the future. Usually the owners of the wind turbines sign insurance and service contracts that cover their risk exposure. The major wind turbine manufacturers tinker with adaptive pitch and none of them have products in the market. The main reason is that the idea only became practical when LIDARS became cheap. The challenge lies in the getting the mechanism, the predictive software and the LIDAR fine tuned to work consistently over the lifetime of wind turbines. As for dampened towers the concept is validated both in calculations and trials but has not found its way into mainstream turbines yet. This can change once wind turbines grow because the gains then become greater. Your assumption that you have to predict wind electricity production to make use of excess power is simply not correct. In the first place wind is predictable and in the second place excess power usage options can be entirely stand by options. Wind power is less than half the cost of coal power in North America and Europe (I realize that for some reasons wind is quite expensive in Australia and China) and the cost is going down fast so over provision with with high capacity factor turbines is very cheap irrespectively whether you decide to curtail the production or sell it of just above the marginal cost of operating the wind turbines. Like 311. “My understanding is that South Australia represents half of all Australian electricity consumption and generation” Whoa, no. I’d be surprised if it’s as much as a tenth (googles…yes: http://www.energymatters.com.au/energy-efficiency/australian-electricity-statistics/). This is fundamentally why SA has been able to achieve nominally high wind+solar penetration – it’s embedded in a much larger grid consisting largely of dispatchable baseload. “If the solar PV capacity factor is 25-30% over the course of a year” is also a gross overstatement, it’s barely half that: http://www.businessspectator.com.au/article/2015/9/11/energy-markets/how-do-power-generator-capacity-factors-vary-across-world Like 312. Why use the 2012 report? Here is a reference to the 2015 report http://www.aemo.com.au/~/media/Files/Other/planning/SAWR%202014/2015_SAWSR.ashx. Here is also a reference to AEMO http://www.aemo.com.au/Electricity ‘AEMO operates Australia’s National Electricity Market (NEM), the worlds largest interconnected power system. NEM infrastructure is comprised of both state and privately owned assets and is managed by a variety of entities under the overall direction of AEMO’ By large I think they mean geographically. I would suggest that you research this site. Like 313. When talking about the capacity factor of solar in Australia, it is important to note if you are talking about residential/commercial or utility scale. It is true that CF of residential solar in Australia (which represents the vast majority of Australia’s installation of ~4.8 GW) is around 15%-16%. However this capacity factor is based on the DC (panel) size of the system, and has a relatively low average due to non-optimal orientation, tilts and issues with shading. According the APVI website (link below) it seems that CF of commercial systems doesn’t do much better, with an average CF of 16%. However, utility scale solar is a different matter all together. It will usually be designed with optimal orientation, tilts, will have next to no shading issues, is probably located in a place with very good solar resource, and the CF will be based on the AC (inverter) size of the system. For example, the Nyngan solar has been at full power since June 2015, and in the 6 months Jul-Dec has had an average CF of about 26%. I’m not sure what the DC size is of Nyngan, but it is likely to be atleast 20% larger than the AC capacity of 102 MW. As an example, Royalla has an AC size of 20 MW, but a DC size of 24 MW. In the future, we may see more large utility solar with tracking, which will get even higher CFs than Nyngan’s ~26% (Nyngan uses fixed panels). http://pv-map.apvi.org.au/historical#4/-26.67/134.12 Like 314. Fair enough, however are you aware of any indications/drivers that will change the relative proportion of residential vs utility-scale PV in the foreseeable future, and thereby significantly raise the PV sector’s aggregate CF? Comparing http://www.bom.gov.au/web03/ncc/www/awap/solar/solarave/6month/colour/latest.ns.hres.gif with the long term average for the solar plant location (from the grid data at http://www.bom.gov.au/jsp/ncc/climate_averages/solar-exposure/index.jsp), it seems the Jul-Dec 2015 period has been on the high side of long term average daily insolation for the Nyngan plant location (possibly consistent with a strong El Niño), ~20 vs 19.45 MJ/m2. It will be interesting to see if that apparently small difference translates in linear proportion to PV output. The distance of good sites like Nyngan from markets also goes back to the transmission issues thoroughly canvassed above. Like 315. Peter Davies said “My understanding is that South Australia represents half of all Australian electricity consumption and generation” Whoa, no. I’d be surprised if it’s as much as a tenth Thanks, you are right. I had spotted the problem earlier from somewhere else which said the main Australia population centres were the South East and South West. 50% looks like the South Australia wind capacity as a fraction of the wind capacity in the whole of Australia. I did check the numbers added up to 100% before writing down the statement at the top!! Like 316. Duffer70, Australia often gets special mention as ideal for solar generation, so you would expect inherently pretty good capacity factors. The issue of transmission cost in sparsely populated Australia is likely to raise the capacity factors of utility-scale solar to be as high as possible. There are references to 20% overconfiguring of DC (panel) vs AC (inverter, lines) capacity for other countries. If the distances and thus transmission line costs in Australia are higher than elsewhere then you would expect more DC overconfiguration as the cost balance favours achieving a very good capacity factor. My guess would be 30-50% DC overconfiguration, particularly as panel prices continue to reduce. You would also expect 2 axis tracking arrays to be pretty standard in Australia, as this seems to be a finely balanced decision elsewhere. This would mean you end up wasting DC power around mid day, but the advantage is that you get higher power all the time the inverter and lines are not maxed out, including the beginning and end of the day. I read somewhere that 15% of Australian homes already have rooftop solar, which is already high. If you went to 6X this figure you would be nearly at 100%. City properties may not have sensible area of North-facing roof. Hence there is a very definite limit to residential rooftop solar, and the enthusiasts will have installed it already. Some wind sites at least are anti-correlated with solar PV. So you would expect the economic solar capacity fraction to be around the solar PV capacity factor of 25-30% as prices reduce. Rooftop solar is likely to max out well below this, so most of this has to come from utility-scale solar PV. Like 317. Slight correction to the above. The penulatimate sentence should read : So you would expect the economic solar electricity units generated fraction to be around the solar PV capacity factor of 25-30% as prices reduce. Like 318. Why use the 2012 report? Here is a reference to the [South Australian Wind Study Report] 2015 report… Having scanned it, the 2015 report does not break down wind generation daily profile into the 3 different regions of South Australia. The information that Mid North wind power is anti-correlated with solar PV power is thus only in the 2012 report for some reason. Like 319. The Eastern Australian grid, with the exception of South Australia, tends currently to have generation capacity located close to centres of population and to rely on radial transmission to remoter areas. Summer daytime peaks dominate in the remoter areas. Thus, eg for the large scale PV plant at Nyngan, it seems to me that it has the advantages of (a) high insolation figures and (b) feeding into the system closer to some of the load which otherwise would be towards the end of long transmission lines. The AEMO web site has good maps and system diagrams here: http://www.aemo.com.au/Electricity/Planning/Related-Information/Maps-and-Diagrams Additional supply from Nyngan feeds backwards to the city of Dubbo and thus potentially acts to reduce the peak flows needed from the existing base load generators to the east. This is a good thing, but may necessitate upgrading of control systems, switching and protection, perhaps also voltage correction. My point is that locating a moderate amount, ie a couple of hundred MW maneplate of PV at Nyngan at the end of the HV grid is not necessarily a bad thing and could well bring a suite of benefits. Like 320. Hi guys, I’ve been reading recently about some startups that intend to store renewable energy using thermal storage. For example, one has a website here: http://www.isentropic.co.uk/. They’re working on something called “Pumped Heat Electricity Storage” or something similar. Another is here: http://www.highview-power.com/. They’re storing energy using liquified air. There are also a few other approaches. It’s claimed that these devices they intend to build will allow roundtrip efficiencies of 60%+. In all cases they are using only abundant materials like liquified air. Does anyone see any drawback to the approach of thermal storage, or any reason why those ideas are unfeasible? Couldn’t that be used to overcome the intermittency of wind, at least somewhat? -Tom S Like 321. Tom S Perhaps it could, but why bother? Even if some not unreasonably expensive storage method is invented, it will still be an extra expense. Other things being equal we want a mix of energy sources that minimizes the need for storage & over building of the energy producing/collecting equipment. In the regions of the world where air conditioning is a bigger energy use than space heating, I expect solar would complement nuclear nicely by providing power just when demand peaks. I don’t see a situation where wind power is much better than a useless distraction. Like 322. Tom S, I can’t comment on Highview Power. Isentropic is a very promising technology, and they are going to a lot of trouble to make it efficient. Basically this means keeping the hot and cold gases produced separate from the lukewarm gas which filled the space before the hot and cold stuff gets there. I’ve seen a couple of presentations by researchers at the UK Energy Storage Conference analysing and modelling the Isentropic technology and advising on how to keep it efficient. For short-term storage of less than 24 hours it seems to be great, and potentially fairly cheap. But it isn’t appropriate for the situation where there are clouds and no wind for 2-15 days, and the hot and cold rocks have a chance to cool off. It’s the usual problem for long-term storage – you need some physical property that doesn’t degrade over time, like the potential energy in a mass of water at altitude in pumped hydro, or the chemical energy in hydrogen in power to gas using electrolysis and back to power using CCGT equipment or fuel cells. Short-term storage technologies like Isentropic may be able to reduce the gaps in wind and solar generation down from 30% to 10-15%, allowing pumped storage hydro to take it down to the 5-10% range at which point power to gas to power kicks in for the long-term or seasonal storage backup. Like 323. @Jens Stubbe Thanks for replying but your figures are still highly speculative. If you examine the NREL report that the CleanTechica article bases its predictions on, “Near future” turbine technology for a large portion of the 65% capacity factor predicted for the 140m hub height turbines. Plus the intermittency of wind generation is still not addressed and the massive transmission infrastructure upgrade required to transmit the remote inland generated power to the coastal usage centers is glossed over (as usual) in the CleanTechnica article. Increasing the capacity factor may utilise this infrastructure more effectively but it still needs to be built, along with the turbines themselves. BTW, I did look up wind shear effects and did some calculations on how increasing hub height would affect AEP and capacity factor and the 2% power increase per 10% hub height increase does not make hub height increase alone a major factor in the NREL prediction. All the discussion about storage for renewables ignores that storage also helps increase the capacity factor of current baseload thermal generators as well. If it was technically and economically feasible, it would have been done already Like 324. @Greg Kaan Greg, It looks like the CleanTechnica article has misinterpreted the NREL chart : My reading of this is that there is close to zero area of the USA where the “near future” technology wind turbines could achieve a capacity factor of 65%. That is because the purple line hits zero on the y axis at about 66% and is almost zero at 65%. The graph should be interpreted a little differently. It is showing that there is approximately 1.8m square km in the USA at which “near future” technology wind turbines could reach a 60% capacity factor or higher (but dropping to zero at 65%), and around 3m sq km at which they could reach a capacity factor of 50% or higher (i.e. an additional 1m sq km with a potential for capacity factors between 50 and 60%). The world expert on the “near future” or Silent Wind Power Revolution wind turbines is Bernard Chabot, and here is his latest presentation about the state of play in the USA. http://cf01.erneuerbareenergien.schluetersche.de/files/smfiledata/5/2/5/5/1/5/132SWRUSAq13.pdf The charts on pages 12 through 16 show how the turbines installed increased in sq m/kW as time went on, and this more than compensated for the fact that the more recent sites tended to have lower quality wind resource. The net was that capacity factors for new installations rose by around 3% per year. But if you think about it carefully, this is because there is less generator capacity for a given rotor diameter, which means overall the turbine generates fewer units of power, so you need a higher area to generate the same power. And the hub heights are higher, so a little more wind energy is available. Like 325. @Greg Kaan All the discussion about storage for renewables ignores that storage also helps increase the capacity factor of current baseload thermal generators as well. and this quote from the CleanTechnica article : Using ‘near future’ technology wind power’s CF will exceed the CF of both coal (61%) and natural gas (48%) achieved nationwide in recent years. These capacity factors of current baseload thermal generators were set by how much they are required to generate, not how much they could actually produce if the demand for it were there. So the CleanTechnica article comparing 65% (which should read 60% – see post above) potential capacity factor for “near future” technology wind against actual lower capacity factors for thermal generation is misleading. In other words thermal generators do not need storage backup because they can generate on demand and those in the USA are no-where near the possible limit. This is almost certainly a CleanTechnica misunderstanding rather than a problem with NREL documents. If it was technically and economically feasible, it would have been done already. That argument could have been applied to any one of a huge number of technology developments in the past which are now regarded as essential to modern life! Technology advances as time goes on, particularly if governments throw research and development money at an area because they know it will become important in the future. Not all such research bets come off, but some do and government usually gets a solution to a problem it needed to solve. Like 326. I only brought the Cleantechnica article as a link because it supports my claim that capacity factors are improving for wind power. The likelyhood of 65% capacity factor being an average value for US wind power is low though it is definitively not defined by technical limitations or limitations of wind resources. The defining properties will be economics where an optimal balance between rotor size and generator capacity will be sought. A large number of design variables have been tried and will be tried. As for the claim that the needed infrastructure is not accounted for then please bear in mind that wind is$0.035/kWh on an unsubsidized basis on average for 20 years PPA contracts in USA per 2014 with a strong trend towards still lower costs. This means there is room for quite substantial investments and much needed investments in the grid.

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327. In relation to the pingback.
Someone has had a light bulb moment.

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328. @Jens Stubbe

…bear in mind that wind is \$0.035/kWh on an unsubsidized basis on average for 20 years PPA contracts in USA per 2014 with a strong trend towards still lower costs

Jens,

Where have you found a reference to 3.5 c/kWh? The 2014 subsidised price average seems to be the 2.2 c/kWh PPA price on slide 49 of https://emp.lbl.gov/sites/all/files/lbnl-188167_presentation.pdf . To that you must add 2.3 c/kWh PTC, giving a total unsubsidised price of 4.5 c/kWh. Or is it a typo?

I agree about the trend to lower wind power costs, but wind isn’t quite at 3.5 c/kWh unsubsidised yet.

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329. John take the many years of your wind data and hourly demands and the AEMO fleet of generators and plug the data into the hdata and gdata files and run the RTS program I have written. It will calculate the LOLP every hour and you can see of those wind gaps are significant or not. The program is posted here in a zip file link inside this document: http://www.egpreston.com/RTS.pdf
I am using this program to study ERCOT, a 71,000 MW peaking system. It should work ideally for AEMO.

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