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Future Nuclear Renewables

The Catch-22 of Energy Storage

Pick up a research paper on battery technology, fuel cells, energy storage technologies or any of the advanced materials science used in these fields, and you will likely find somewhere in the introductory paragraphs a throwaway line about its application to the storage of renewable energy.  Energy storage makes sense for enabling a transition away from fossil fuels to more intermittent sources like wind and solar, and the storage problem presents a meaningful challenge for chemists and materials scientists… Or does it?


Guest Post by John Morgan. John is Chief Scientist at a Sydney startup developing smart grid and grid scale energy storage technologies.  He is Adjunct Professor in the School of Electrical and Computer Engineering at RMIT, holds a PhD in Physical Chemistry, and is an experienced industrial R&D leader.  You can follow John on twitter at @JohnDPMorganFirst published in Chemistry in Australia.


Several recent analyses of the inputs to our energy systems indicate that, against expectations, energy storage cannot solve the problem of intermittency of wind or solar power.  Not for reasons of technical performance, cost, or storage capacity, but for something more intractable: there is not enough surplus energy left over after construction of the generators and the storage system to power our present civilization.

The problem is analysed in an important paper by Weißbach et al.1 in terms of energy returned on energy invested, or EROEI – the ratio of the energy produced over the life of a power plant to the energy that was required to build it.  It takes energy to make a power plant – to manufacture its components, mine the fuel, and so on.  The power plant needs to make at least this much energy to break even.  A break-even powerplant has an EROEI of 1.  But such a plant would pointless, as there is no energy surplus to do the useful things we use energy for.

There is a minimum EROEI, greater than 1, that is required for an energy source to be able to run society.  An energy system must produce a surplus large enough to sustain things like food production, hospitals, and universities to train the engineers to build the plant, transport, construction, and all the elements of the civilization in which it is embedded.

For countries like the US and Germany, Weißbach et al. estimate this minimum viable EROEI to be about 7.  An energy source with lower EROEI cannot sustain a society at those levels of complexity, structured along similar lines.  If we are to transform our energy system, in particular to one without climate impacts, we need to pay close attention to the EROEI of the end result.

The EROEI values for various electrical power plants are summarized in the figure.  The fossil fuel power sources we’re most accustomed to have a high EROEI of about 30, well above the minimum requirement.  Wind power at 16, and concentrating solar power (CSP, or solar thermal power) at 19, are lower, but the energy surplus is still sufficient, in principle, to sustain a developed industrial society.  Biomass, and solar photovoltaic (at least in Germany), however, cannot.  With an EROEI of only 3.9 and 3.5 respectively, these power sources cannot support with their energy alone both their own fabrication and the societal services we use energy for in a first world country.

Energy Returned on Invested, from Weißbach et al.,1 with and without energy storage (buffering).  CCGT is closed-cycle gas turbine.  PWR is a Pressurized Water (conventional nuclear) Reactor.  Energy sources must exceed the “economic threshold”, of about 7, to yield the surplus energy required to support an OECD level society.
Energy Returned on Invested, from Weißbach et al.,1 with and without energy storage (buffering).  CCGT is closed-cycle gas turbine.  PWR is a Pressurized Water (conventional nuclear) Reactor.  Energy sources must exceed the “economic threshold”, of about 7, to yield the surplus energy required to support an OECD level society.

These EROEI values are for energy directly delivered (the “unbuffered” values in the figure).  But things change if we need to store energy.  If we were to store energy in, say, batteries, we must invest energy in mining the materials and manufacturing those batteries.  So a larger energy investment is required, and the EROEI consequently drops.

Weißbach et al. calculated the EROEIs assuming pumped hydroelectric energy storage.  This is the least energy intensive storage technology.  The energy input is mostly earthmoving and construction.  It’s a conservative basis for the calculation; chemical storage systems requiring large quantities of refined specialty materials would be much more energy intensive.  Carbajales-Dale et al.2 cite data asserting batteries are about ten times more energy intensive than pumped hydro storage.

Adding storage greatly reduces the EROEI (the “buffered” values in the figure).  Wind “firmed” with storage, with an EROEI of 3.9, joins solar PV and biomass as an unviable energy source.  CSP becomes marginal (EROEI ~9) with pumped storage, so is probably not viable with molten salt thermal storage.  The EROEI of solar PV with pumped hydro storage drops to 1.6, barely above breakeven, and with battery storage is likely in energy deficit.

This is a rather unsettling conclusion if we are looking to renewable energy for a transition to a low carbon energy system: we cannot use energy storage to overcome the variability of solar and wind power.

In particular, we can’t use batteries or chemical energy storage systems, as they would lead to much worse figures than those presented by Weißbach et al.  Hydroelectricity is the only renewable power source that is unambiguously viable.  However, hydroelectric capacity is not readily scaled up as it is restricted by suitable geography, a constraint that also applies to pumped hydro storage.

This particular study does not stand alone.  Closer to home, Springer have just published a monograph, Energy in Australia,3 which contains an extended discussion of energy systems with a particular focus on EROEI analysis, and draws similar conclusions to Weißbach.  Another study by a group at Stanford2 is more optimistic, ruling out storage for most forms of solar, but suggesting it is viable for wind.  However, this viability is judged only on achieving an energy surplus (EROEI>1), not sustaining society (EROEI~7), and excludes the round trip energy losses in storage, finite cycle life, and the energetic cost of replacement of storage.  Were these included, wind would certainly fall below the sustainability threshold.

It’s important to understand the nature of this EROEI limit.  This is not a question of inadequate storage capacity – we can’t just buy or make more storage to make it work.  It’s not a question of energy losses during charge and discharge, or the number of cycles a battery can deliver.  We can’t look to new materials or technological advances, because the limits at the leading edge are those of earthmoving and civil engineering.  The problem can’t be addressed through market support mechanisms, carbon pricing, or cost reductions.  This is a fundamental energetic limit that will likely only shift if we find less materially intensive methods for dam construction.

This is not to say wind and solar have no role to play.  They can expand within a fossil fuel system, reducing overall emissions.  But without storage the amount we can integrate in the grid is greatly limited by the stochastically variable output.  We could, perhaps, build out a generation of solar and wind and storage at high penetration.  But we would be doing so on an endowment of fossil fuel net energy, which is not sustainable.  Without storage, we could smooth out variability by building redundant generator capacity over large distances.  But the additional infrastructure also forces the EROEI down to unviable levels.  The best way to think about wind and solar is that they can reduce the emissions of fossil fuels, but they cannot eliminate them.  They offer mitigation, but not replacement.

Nor is this to say there is no value in energy storage.  Battery systems in electric vehicles clearly offer potential to reduce dependency on, and emissions from, oil (provided the energy is sourced from clean power).  Rooftop solar power combined with four hours of battery storage can usefully timeshift peak electricity demand,3 reducing the need for peaking power plants and grid expansion.  And battery technology advances make possible many of our recently indispensable consumer electronics.  But what storage can’t do is enable significant replacement of fossil fuels by renewable energy.

If we want to cut emissions and replace fossil fuels, it can be done, and the solution is to be found in the upper right of the figure.  France and Ontario, two modern, advanced societies, have all but eliminated fossil fuels from their electricity grids, which they have built from the high EROEI sources of hydroelectricity and nuclear power.  Ontario in particular recently burnt its last tonne of coal, and each jurisdiction uses just a few percent of gas fired power.  This is a proven path to a decarbonized electricity grid.

But the idea that advances in energy storage will enable renewable energy is a chimera – the Catch-22 is that in overcoming intermittency by adding storage, the net energy is reduced below the level required to sustain our present civilization.

BNC Postscript

When this article was published in CiA some readers had difficulty with the idea of a minimum societal EROI.  Why can’t we make do with any positive energy surplus, if we just build more plant?  Hall4 breaks it down with the example of oil:

Think of a society dependent upon one resource: its domestic oil. If the EROI for this oil was 1.1:1 then one could pump the oil out of the ground and look at it. If it were 1.2:1 you could also refine it and look at it, 1.3:1 also distribute it to where you want to use it but all you could do is look at it. Hall et al. 2008 examined the EROI required to actually run a truck and found that if the energy included was enough to build and maintain the truck and the roads and bridges required to use it, one would need at least a 3:1 EROI at the wellhead.

Now if you wanted to put something in the truck, say some grain, and deliver it, that would require an EROI of, say, 5:1 to grow the grain. If you wanted to include depreciation on the oil field worker, the refinery worker, the truck driver and the farmer you would need an EROI of say 7 or 8:1 to support their families. If the children were to be educated you would need perhaps 9 or 10:1, have health care 12:1, have arts in their life maybe 14:1, and so on. Obviously to have a modern civilization one needs not simply surplus energy but lots of it, and that requires either a high EROI or a massive source of moderate EROI fuels.

The point is illustrated in the EROI pyramid.4 (The blue values are published values: the yellow values are increasingly speculative.)

Finally, if you are interested in pumped hydro storage, a previous Brave New Climate article by Peter Lang covers the topic in detail, and the comment stream is an amazing resource on the operational characteristics and limits of this means of energy storage.

References

  1. Weißbach et al., Energy 52 (2013) 210. Preprint available here.
  2. Carbajales-Dale et al., Energy Environ. Sci. DOI: 10.1039/c3ee42125b
  3. Graham Palmer, Energy in Australia: Peak Oil, Solar Power, and Asia’s Economic Growth; Springer 2014.
  4. Pedro Prieto and Charles Hall, Spain’s Photovoltaic Revolution, Springer 2013.

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

642 replies on “The Catch-22 of Energy Storage”

Ppp251s 15 TWh figure is a little out of date

https://yearbook.enerdata.net/world-electricity-production-map-graph-and-data.html

…but that is electricity. Global energy consumption is 6 times that electricity figure at 150 TWh’s. I hasten to add that shippings energy consumption is something like 13.5 TWh’s with a massive over supply capacity from the world’s installed marine diesel engine stock. Turning that to Nuclear is perhaps the correct move.

Land based nuclear may become fussion powered if the ITER reactor proves viability for this stage.

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@Noel Kinnear: I thank you. After a few more iterations, we will come to the truth. Having made a hash of my attempt, I will observe for a while.

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Because ppp251 did not identify where he got his numbers from, this is just a guess on my part.

I didn’t provide sources because world energy consumption should be common knowledge for those who are interested in the energy debate.

I could have made a clearer distinction between power and energy though. 15TW is continuous power consumption, while annual energy consumption would be 1524365=131000TWh.

Power density for PV can be derived from basic physics. Solar irradiance is about 1350W/m2 as measured by satellites, but some of it is absorbed by the atmosphere and only 1000W/m2 gets it through. Surface of Earth is curved and on average it receives only 1/4 (ratio of sphere by circle area). So it’s about 250W/m2 on average without clouds. Make it 150-200W/m2 because of cloud albedo and at 20% (efficiency of panels) you get 30-40W/m. Accounting for some extra space between modules gives you to about 20W/m2, which is common number that can be found in many sources, such as here:

Click to access smil-article-power-density-primer.pdf

Of course 20W/m2 is an approximation and an average. It’s higher in tropics and subtropics, and lower in northern latitudes.

Of course, the same calculation can be done with annual energy consumption (approx. 131000TWh), and the result is the same. Less than a tenth of Sahara desert is needed to meet this demand with PV.

In comparison: we use 10x (!) more land for urban and rural areas, 20x (!) more for cultivated crops and 40x (!) more for meadows and uncultivated pastures.

Click to access i1052-5173-22-12-4.pdf

Land use for PV is miniscule and using deserts isn’t destroying any habitats anyway. It’s a non-problem. Contrast that to urban areas and agriculture, which are vastly greater and actually destroying wildlife habitats.

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My bad – I excluded the Sahara ;)
Now, I want to change the subject back to Eroei.
I believe we all know which fossil free source has the highest Capacity Factor. We all should know (by now) that the higher the CF, the more that source can energy afford the ESOI of storage. We should also know that batteries are about an order of magnitude better than liquid fuels made from air and water, and that pumped storage (where the lower reservoir can be a river). However, nuclear has an high enough Eroei and a high enough CF to afford the negative ESOI of liquid fuels.
It will be physics which intrinsically dictate how we implement the low carbon economy.
I also want to say that I have already spent much time re-reading the comments, too. I have learned much from this page!

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Some energy sources are improving their EROI, while others aren’t. This should be taken into consideration. PV has already improved a lot, but further improvements are in the pipeline. Manufacturers are switching from established, but energy intensive, Siemens process, to high pressure fluidized bed reactor, for producing high grade polysilicon. This cuts energy use by 90%.

http://www.pv-magazine.com/news/details/beitrag/sunedison-begins-production-of-electronic-grade-polysilicon-using-fluidized-bed-reactor-technology_100016659/#axzz3TSIHgplE

These are substantial changes. When discussing EROI of rapidly changing technologies, only the most recent data should be used. Weissbach et al used 10 years old data for PV which is a mistake (and 20 years for wind, which is another mistake).

There is a discussion that they also made other mistakes. This was the first published comment:
http://www.sciencedirect.com/science/article/pii/S0360544213006373

To which Weissbach responded:
http://www.sciencedirect.com/science/article/pii/S0360544214001601

Which was followed by another rebuttal: http://www.sciencedirect.com/science/article/pii/S0360544214014327

The discussion about EROI is obviously far from settled.

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Agreed, Aidan, but longer/higher legs demand much more material.

The last solar thermal station I was involved with was designed to hug the ground on tiny legs which sit on even tinier screws, called “earth nails”. Anything taller than a medium dog would be on its knees to pass beneath.

PPP’s Third Law as proposed by Aidan would stipulate a minimum height beneath collectors of at least a few metres, combined with the ability to resist the amorous intentions of a pachyderm, or whatever the largest local feral animal might be (remember: including humans).

To ensure that the earth nails functioned properly, the upper 800mm or so of soil was dug out, inspected, rejected, replaced, recompacted, watered, tested and retested, surveyed, graded, trimmed and generally shaved clean. Plus drainage systems, roads, pits, drainage pipes, silt traps and steam pipes and control room. Because it feeds steam to an existing power station it does not have boilers or turbines, transformer yards or switchyard. Are all of these things to be mounted above an unlevelled natural surface and not fenced?

PPP will meet a huge amount of resistance to his 2, now 3, laws but ultimately I agree with his sentiments which are that nuclear options have much smaller and thus more acceptable footprints than commercial PV or solar thermal, all other considerations being equal.

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Picture a grid-scale battery or pumped hydro storage system mounted on legs in accordance with PPP’s “don’t fence, don’t grade” philosophy.

Easier said than done, I would think.

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What is the relevance of the 15 or 25 TWh figures?

The world’s total annual energy consumption is half a dozen times larger. Figures of 150 and 170TWh appear upthread.

It makes little sense to focus only on electricity when the majority of total energy consumption is still derived from FF, and industrial use of FF feedstocks, eg for fertilisers and plastics, continues to rise.

We cannot ignore energy for transport. Presuming that electricity-to-liquids, batteries and electrical railways must eventually replace FF for land and air transport, then increasing global industrial electricity demand will on the same timescale dwarf current electricity consumption, Discussions based on 15 or 25 TWh are thus irrelevant.

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EROEI is understated for solar power, the fact is over 30 years solar stomps oil’s EROEI. Storing solar is easy, you just use solar electricity to create hydrogen, than use the hydrogen to run a power plant. Or you can store heat using molten salt. Storing it should not be a problem.

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Adrian,

Can you provide any authoritative references to demonstrate that John Morgan’s post is wrong on the substantial points?

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Adrian, your unsubstantiated affirmation does not align with data that appears elsewhere on this site.

Regarding hydrogen generation, the efficiency of a cycle through electrolytic generation and back to AC again returns only a minor fraction of the energy that came from the inverters on the solar panels. The energy maths don’t work and neither do the economics.

I suggest http://en.wikipedia.org/wiki/Grid_energy_storage as a general short introduction to energy storage. Hydrogen’s round trip efficiency is quoted at 20% to 45%. Adopting the mid-point indicates that 2/3rds of the energy is not stored – it is lost, and that is before any transmission losses and repayment of capital and operating costs.

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Hi John Morgan

A 6MW Siemens turbine typically runs at 50% capacity for a projected design life of 25 years during which it will produce 365 x 24 x 25 x 50% MW = 109500 MW, which begs the question, do you assume that 6800 MW is consumed during the lifetime.

AWEA has tried to put things straight in this post http://www.aweablog.org/setting-the-record-straight-about-winds-lifecycle-emissions-and-return-on-energy-invested/

Materials use is in rapid decline per produced MW and the capacity factor is in steady growth as is the design lifetime, which increase EROI on a steady basis.

The EROI figure you chose for wind is based upon an old German 1,5 MW Enercon wind turbine on a bad onshore location with only 2000 full load hours (22% capacity factor) and with an assumed lifetime of 20 years. Enercon tend to use concrete towers and their generator is significantly heavier than all other leading turbine makers. http://festkoerper-kernphysik.de/Weissbach_EROI_preprint.pdf

For a blog about the prospect of future storage build out you have carefully chosen an outdated worst case EROI study based on a turbine from an insignificant producer of wind turbines, which to top it off does not include reuse and recycling.

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Hi Jens Stubbe,

A 6MW Siemens turbine typically runs at 50% capacity for a projected design life of 25 years

Do you have evidence of a fleet of grid connected wind turbines achieving 50% capacity factor over a period of years. And do you have evidence that the average life expectancy of a fleet of wind turbines (where a ‘fleet’ means for a whole country or whole grid) is 25 years?

A new report, just released, for the NEM gives a great deal of very interesting information about the emissions avoided by wind generation in the NEM in 2014. This includes the the average capacity factors of wind turbines by state.

Wind provided 8.7TWh in 2014 or 4.5% of total energy generated. [Power output ‘as’generated’ at 5 minute intervals] data is available for 34 wind farms with total installed capacity of 3394MW. These generated 970MW on average, which corresponds to a capacity factor of just under 29%. Capacity factors at regional level were 19%(NSW), 35% (TAS), 31%(SA) and 28%(VIC).

Click to access report.pdf

Other studies of emissions avoided by wind can be accessed here: http://joewheatley.net/category/wind-energy/

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Jens Stubbe, as my post is about the prospects of storage, I have “carefully chosen” the most current peer reviewed studies on storage. You’re welcome to commend other studies on storage EROI I may have missed.

The paper you object to in fact affirms a wind EROI in excess of the minimum required for viability. So I’m not sure what you’re objecting to, and I’m not sure you are either.

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John Morgan,

Audi claims to be making 160 L of diesel per day from seawater in a pilot plant (using renewable energy) http://www.sciencealert.com/audi-have-successfully-made-diesel-fuel-from-air-and-water . The article says they expect to be able to sell to the public at 1.50 euro /L when they ramp up to production scale.

I doubt the cost estimates, but if even close to correct, it would mean the cost could be greatly reduced if their production plant could run 24 h per day using reliable, much cheaper, nuclear power.

Do you have any comment on this, especially on the costs competitiveness, now and int the medium term future?

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sodacup,

Thank you. That’s a very interesting article.

Key points for the estimate of cost per tonne of diesel:
• Hydrogen: $1,176 (but 50% higher for the process they assumed)
• Electricity = $55.20
• Thermal energy: $90.35
• Total: $1,322 (to $2,000)
• 1 tonne diesel – 352 gallons
• Cost per gallon: $3.76 (to $5.43)

These are within the range estimated by the US Navy for producing jet fuel from seawater and nuclear power on board their aircraft carriers (i.e. $3-$6 gallon). However this is the cost of the feedstocks only. Need to add “several more dollars per gallon” for the capital cost and O&M costs of the processing plant and more for distribution costs.

For comparison, “the current spot price of diesel in the U.S. is under $2/gal.”

Points I noted and questions:

The article says:

This is also $17.25 per ton of carbon dioxide captured, which is much lower than other numbers I have seen — especially considering they are proposing to extract the carbon dioxide from air.

The $17.25/t cost of extracting CO2 from air is much less than the $1000/t estimate a friend sent me a couple of years ago for my critique of this post on “CO2 sequestration in Antarctica”: http://judithcurry.com/2012/08/24/a-modest-proposal-for-sequestration-of-co2-in-the-antarctic/#comment-233330 . (Unless I’ve misunderstood something). The friend said:

* A paper came out in December last year on thermodynamic limits to the energetics and the cost of direct air capture of CO2, and operational experience with industrial separation processes. While the thermodynamic limit is about 20 kJ/mol CO2 for air extraction, actual processes use around 400 kJ/mol. A cost of ~$1000 per tonne was estimated. […] The paper is here (free): http://www.pnas.org/content/108/51/20428.full . A summary is here: http://arstechnica.com/science/2011/12/carbon-capture-and-storage-too-expensive-for-all-but-powerplants/

Natural gas is used to produce steam. That makes it not sustainable over the long term and also a CO2 emitting process.
They assume hydrogen at $4/kg ($4,000/tonne). I understand high temperature reactors can be designed to produce hydrogen. Do you have a source for the estimated cost per tonne of hydrogen and could this be a less expensive way to produce it?

His point near the end of the article provides a reality reality check

If everything works as hoped, they will then need to scale up again to something in the 100 to 1,000 barrel per day range. These scale-up steps are like gates that must be successfully passed, and historically most seemingly promising processes fail to pass through those gates for various reasons. As a result, one should never take too seriously a cost estimate for fuel production from a commercial plant when the data is derived from experiments at a much smaller scale.

I am surprised the author didn’t mention the option of using high temperature reactors to produce the hydrogen. Any thoughst on why that might be, anyone?

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sodacup,

Wow. If that figure is correct, it would halve the estimated cost of the inputs. Its a DOE report from 2003. I wonder if there is anything more recent. Are you aware if the Chinese HTR is intending it to be capable of producing hydrogen economically and if so at what cost.

It does seem there is potentially a viable way forward for unlimited hydrocarbon transport fuels. This has to be good news and worth exploring further and discussing more widely.

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This ( http://www.lightsail.com/ ) is an interesting energy storage technology. They have a way to make compressed air storage efficient that looks like it should work.

I expect it would be much better than any chemical battery for energy storage per energy invested, but I don’t expect it to be so much better than pumped hydro that we would get around the ‘Catch 22’ of the original post.

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A friend just emailed this reply to Weissbach, and for the next week or so I seriously just don’t have the time to reply. Has anyone read Raugei before? He sounds like the expert on LCA, not Weissbach.

Unfortunately, the paper is much as I expected. There is a vast body of peer-reviewed literature on geographic dispersion that is entirely ignored, so that the only alternative to storage is “over-capacity”, taken from something by a retired engineer on the blog of a nuclear energy advocate, which also ignores the science. If I could get papers accepted with dodgy references like that backing even minor points (let alone central ones), life would be so much easier.

The issue with ignoring this very straightforward answer is that it is plainly demonstrated. Wind speeds are less correlated the further they are separated; so just as we can easily say that the sun doesn’t shine at night, we can also say that while there may be no wind in one place there will be somewhere else. Whether or not a country has solved 100% of its energy issues by acting on this reality sufficiently does not make it less real, rather it highlights the difficulty in getting good clean energy off the ground when one industry after another wants to undermine the efforts. To tell people that an energy source like nuclear is now safe because of non-existent technology like the Integral Fast Reactor asks for a lot of faith; this doesn’t.

That’s my main gripe with the paper; others have other problems. It’s a paper on EROI that calculated EROI incorrectly, as pointed out in the reply paper (Raugei 2013). Dr Marco Raugei is a world-leading expert on the subject; life cycle studies are his expertise and his interest. Daniel Weißbach is a student working on nuclear physics – nuclear power is his expertise and his interest. Rather than learning from the expert and correcting his paper however, he published a sarcastic reply (Weißbach et al. 2014) characterising the call to use standard practice and published definitions as “allegations”, “sophistry” and “deception” without providing the necessary precedents. The rebuttal to that was remarkably gracious (Raugei et al. 2015), however Raugei et al did point out some further assertions that defied basic thermodynamics, and concluded quite pointedly: “Weißbach et al.’s defence of their untenable assertions by setting up straw man arguments and misinterpreting and misquoting Raugei’s comments comes across as a worrying indication of their seeming lack of familiarity with scientific standards and widely accepted methodological conventions.” In my view it all reads as the debate between a scientist and a market advocate.

Unfortunately, this is all too familiar territory for me. Occasionally some journal lets slip in a terrible paper by a denialist from one camp or another and to do it justice, I spend hours following the leads. This looks very much like the same thing happening, so given my exploration of your argument so far, I’m going to leave it here. Please, try to be less adamant in shooting down people coming from a renewable energy perspective.

REFERENCES
Raugei, M. (2013) Comments on “Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants” – Making clear of quite some confusion. Energy, 59, 781–782.

Raugei, M., Carbajales-Dale, M., Barnhart, C.J. & Fthenakis, V. (2015) Rebuttal: “Comments on ‘Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants’ – Making clear of quite some confusion.” Energy, 82, 1088–1091.

Weißbach, D., Ruprecht, G., Huke, A., Czerski, K., Gottlieb, S. & Hussein, A. (2014) Reply on “Comments on ‘Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants’ – Making clear of quite some confusion.” Energy, 68, 1004–1006.

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@Eclipse Now

The study doesn’t cover every possible use of renewable energy, but it does cover one and shows that there are EROEI problems for solar pv. Rather than get mad that the study isn’t all inclusive why don’t the people who do studies for 100% renewable energy estimate the energy needs for the systems they are proposing and give an EROEI for the system as a whole. It is very difficult to prove a negative. It would take many studies for an almost limitless number of possible uses. Even if you did 100 studies that came up with EROEI problems there would likely still be people who are unsatisfied. Proving a positive is much easier. It would be nice if the supporter of 100% renewable energy made the effort to do so.

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[…] If we take recent LCA data for lithium-ion traction batteries of 586 MJ/kWh, and apply this to a nearly-off-grid system that will power the average Victorian household for 95% of annual hours, the EROI calculates to less than 2:1 after 30 years – the system takes around 15 years to pay back its embodied energy debt. The use of such a system to power a regularly driven EV during winter would be even more demanding. Such as system can work in isolated cases when supported with external energy, but adopted universally, couldn’t support an advanced society. Morgan describes this as the Catch-22 of energy storage. […]

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John,

I don’t understand something about this result.

Most studies show that the lifecycle carbon emissions of nuclear power per TW/h are comparable to those of wind power, e.g. this study by the World Nuclear Association.

Click to access comparison_of_lifecycle.pdf

Shouldn’t that mean that the EROI of nuclear and unbuffered wind should be similar too?

Why the massive difference?

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“The range of results is influenced by the primary assumptions made in the lifecycle analysis. For instance, assuming either gaseous diffusion or gas centrifuge enrichment has a bearing on the life cycle results for nuclear.”
– From the WNA paper

I don’t believe diffusion enrichment is used anywhere in the world now. Therefore the studies including any diffusion enrichment are too high in their estimates. In other words the nuclear CO2 calculation is too high in this paper.

Question – Since Russia does most of the centrifuge enrichment, what is the electric generation mix for the Russian district where the enrichment takes place. If it is all nuclear, then enrichment produces very, very little CO2.

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Alex, Martin has the key point, I think. Gaseous diffusion is much more energy intensive than centrifuge enrichment, but is no longer used. From the Wikipedia entry:

Throughout the Cold War, gaseous diffusion played a major role as a uranium enrichment technique, and as of 2008 accounted for about 33% of enriched uranium production, but in 2011 was deemed an obsolete technology that is steadily being replaced by the later generations of technology as the diffusion plants reach their ends-of-life. In 2013, the Paducah facility in the US ceased operating, it was the last commercial 235U gaseous diffusion plant in the world.

The source studies in the WNA review of your example range from 1997-2010. The data in those studies will have in turn been acquired over years prior, so will have accounted a fair amount of gaseous diffusion enrichment in the energy input. I would expect any study of nuclear emissions which considered enrichment as being entirely centrifuge derived would show a markedly lower emission intensity than earlier studies.

Another consideration is the lifetime of the assets. Nuclear plants are turning out to be very long-lived infrastructure, with initial nominal plant lifetimes of 40 years turning into 60 years, maybe 80 years and beyond as the infrastructure proves out and plant life extensions are granted. This will also weigh more heavily in the later studies. While wind is advancing on many fronts, I don’t think major plant life extension is one of them.

Aside from that, simply a simple metareview, like the WNA summary, is problematic, because these calculations need to be done on the basis of a common methodology. For instance, the mean emissions intensity of studies reviewed by WNA for wind and nuclear are very close, at 26 and 29 tCO2/GWh. But the ranges are huge: wind spans 6-124 tCO2/GWh, and nuclear spans 2-130 tCO2/GWh. It should be clear that the approach of just taking the average of the values in these reports will produce meaningless results. Discrimination on the basis of the content of the reports is required.

Why such a large range in emissions intensities? I’d refer you to section 8 of the Weißbach paper, “Comparison with other results”, to get a flavour of the issues. How one draws the system boundaries, and the plant lifetime, have a big influence on the results, and a good accounting of both emissions intensity and EROI within a single consistent methodology is yet to be done.

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John, thanks for your response.

So, on the one hand we have papers in the literature from anti-nuclear people (e.g. Deisendorf) that show lifecycle emissions from nuclear to be up to 10 times higher than wind, and then we have the IPCC “consensus” which holds that they’re about equal, and then this study shows that wind is about 5 times higher than nuclear.

I suspect that a weakness of this study is that it tries to present two controversial conclusions in the same paper: that nuclear’s EROI is much higher than thought; and that storage can’t be used to buffer renewables as a result of very low EROI.

I suspect this makes it too easy to ignore an incredibly important result – assuming it’s true.

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” CCGT is closed-cycle gas turbine.” – from the caption of the EROEI chart.

I am familiar with the acronym CCGT meaning Combined Cycle GT’s. These typically use natural gas as fuel.

I was not aware of Brayton cycle turbines being referred to as Closed Cycle GT’s, until I checked Wikipedia. So, we have a turbine but what is the fuel?

I suspect that the CCGT bars in the EROEI chart actually refer to Combined Cycle Gas Turbines.

.

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If the reader is puzzled by the change of word, a CCGT usually refers to a combined two-stage engine, with the first turbine being driven by burning “natural” gas, with its exhaust fed through a boiler whose steam drives a second turbine stage. It is called a cycle because some of the energy generated is used to compress the incoming air, but unless you have studied thermodynamics, you can ignore the word “cycle” when used here.

On the other hand, in a closed cycle gas engine, the gas really is recycled, being helium, CO2 or even air. Heated externally, the gas drives the turbine, is cooled, compressed and then completes the cycle by returning to be heated again. Compression costs some of the energy generated at the turbine. Efficiency is increased if cycled near the critical temperature and pressure.

In most big power stations, the working gas is steam. Compression is achieved by condensing it to liquid water, so it is not referred to as a “gas” cycle. Because extra energy has been removed during the condensation as latent heat, there is a fundamental inefficiency in the steam cycle.

Heat removed during cooling and condensation can be used by other, lower temperature processes such as desalination, driven by electricity that has been generated excess to demand. To the extent that desalination etc can be peaked intermittently, it could provide the power station with the equivalent of intermittent storage of electricity.

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[…] Wind turbines also have a net energy gain, meaning that eventually, they produce more energy than was consumed during their construction.  In fact, during a turbine’s lifetime, it produces several times more energy than was required to build it, making turbines both economically and energetically efficient.  Furthermore, the energy return on investments, or the EROI is quite high.  For wind turbines, this number (calculated by dividing the total energy generated by the energy required to build the turbine), ranges from 5 to 35 according to a meta study.  This study examined data from 1997 to 2007.  So, the lower EROI can be attributed to older, out of date technology.  Now, the most common wind turbines have an EROI of 16.  This is important because in developed countries, 7 is considered the minimum EROI. […]

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Audi diesel from CO2 and electricity
http://www.energytrendsinsider.com/2015/04/30/is-audis-carbon-neutral-diesel-a-game-changer/

Key points for the estimate of cost per tonne of diesel:
• Hydrogen: $1,176 (but 50% higher for the process they assumed)
• Electricity = $55.20
• Thermal energy: $90.35
• Total: $1,322 (to $2,000)
• 1 tonne diesel – 352 gallons
• Cost per gallon: $3.76 (to $5.43)

These are within the range estimated by the US Navy for producing jet fuel from seawater and nuclear power on board nuclear powered aircraft carriers (i.e. $3-$6 gallon). However this is the cost of the feedstocks only. We need to add “several more dollars per gallon” for the capital cost and O&M costs of the processing plant and then distribution costs.

For comparison, “the current spot price of diesel in the U.S. is under $2/gal.

Points I noted and questions:

The article says:

This is also $17.25 per ton of carbon dioxide captured, which is much lower than other numbers I have seen — especially considering they are proposing to extract the carbon dioxide from air.

$17.25/t cost of extracting CO2 from air is about 2% of the $1000/t cost a friend sent me a couple of years ago for my critique of this post on “CO2 sequestration in Antarctica”: http://judithcurry.com/2012/08/24/a-modest-proposal-for-sequestration-of-co2-in-the-antarctic/#comment-233330 . (Unless I’ve misunderstood something). The email included this:

* A paper came out in December last year on thermodynamic limits to the energetics and the cost of direct air capture of CO2, and operational experience with industrial separation processes. While the thermodynamic limit is about 20 kJ/mol CO2 for air extraction, actual processes use around 400 kJ/mol. A cost of ~$1000 per tonne was estimated. […] The paper is here (free): http://www.pnas.org/content/108/51/20428.full . A summary is here: http://arstechnica.com/science/2011/12/carbon-capture-and-storage-too-expensive-for-all-but-powerplants/

Natural gas is used to heat the steam. That makes it not renewable and also a CO2 emitting process.
Hydrogen production comprises 90% of the total cost of synfuel production (i.e. $1,176 / $1,322). The cost estimates assume hydrogen at $4/kg ($4,000/tonne) based on an NREL report. However, estimates for the cost of hydrogen from high temperature nuclear reactors are around half the cost, e.g.:

The economics of hydrogen production depend on the efficiency of the method used. The IS cycle coupled to a modular high temperature reactor is expected to produce hydrogen at $1.50 to $2.00 per kg.

http://www.world-nuclear.org/info/Non-Power-Nuclear-Applications/Industry/Nuclear-Process-Heat-for-Industry/

Therefore, using hydrogen from high temperature nuclear reactors could halve the estimated $3-$6 per gallon estimated cost of diesel and jet fuel.

A point near the end of the article provides an important reality check”

If everything works as hoped, they will then need to scale up again to something in the 100 to 1,000 barrel per day range. These scale-up steps are like gates that must be successfully passed, and historically most seemingly promising processes fail to pass through those gates for various reasons. As a result, one should never take too seriously a cost estimate for fuel production from a commercial plant when the data is derived from experiments at a much smaller scale.

I am surprised the author didn’t consider the option of using high temperature reactors to produce the hydrogen.

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Most of the ERoEI literature cited in this article has mathematical or logical errors which invalidate its conclusions.

There are massive errors in the calculation of EROI which are found throughout sources various sources for EROI. When those errors are corrected, it can be shown that renewable sources of power have EROI ratios which are comparable to, or higher than, fossil fuel sources of generating electricity.

http://bountifulenergy.blogspot.com/2014/07/renewables-have-higher-eroei-than.html

http://bountifulenergy.blogspot.com/2015/05/six-errors-in-eroei-calculations.html

http://bountifulenergy.blogspot.com/2010/09/eroi-doesnt-matter.html

-Tom S

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Geoff Russel,

That bountiful energy site (which I wrote) clearly demonstrates why the numbers you guys are relying upon are totally wrong. You have not produced any substantive response, either here or there. If you have no response to me refutation, then your point is refuted.

If you have any serious repsonse, then you need to STATE WHAT IT IS. Otherwise, the point stands.

I think it is you who seriously understands very basic issues here. You need to crank up the critical thinking A LOT here if you can’t find any problems with Hall’s book or Weissbach’s paper.

-Tom S

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Hi eclipse now,

“yeah, we have to do it that way or the windies and sunnies get up in arms with all sorts of conspiracy theories.”

I am the author of that article. There are no conspiracy theories of any kind in the article you linked to. Also, when you say “windies and sunnies” then your argument has been reduced to name-calling and nothing more.

The EROI papers which indicate high EROI ratios for fossil fuels, certainly DO NOT do it that way. Your point is simply wrong. For example, almost all EROI studies of coal calculate the EROI of coal at the MINE MOUTH which obviously would not include massive waste heat losses.

I pointed out various mathematical and logical errors which you have not addressed. Unless you have some serious objection, the point stands.

-Tom S

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Your EROI numbers are ones NO ONE ELSE AGREES ON.

the solar pv one is absurd. sole has an energy payback of a year to 3. and last 30 years.

Nuclear by some calculations has a negative EORI, unless you skip the mining and wastes.

Solar and wind don’t need storage, the need a single agile energy sources like hydro and fuels from waste in convention load following generators.

the same ones nuclear and coal needs.
Storage is a red herring.
BNC MODERATOR
I have approved your post as you are a newcomer to BNC. Please read the BNC Comments Policy before posting again. In particular please do not offer as fact something which is your opinion. Comments must be backed up by links, references etc preferably peer reviewed.

Storage is a red herring.

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This article nicely exposes what is called The Energy Trap. As ERoEI drops, more and more energy has to be diverted from society to get more energy.

This does not include decommissioning of plants. Wind turbines have to be replaced every 20-25 years. That ups the required ERoEI needed to run their entire lifecycles.

The article didnt touch on nukes, particularly Liquid Fluoride Thorium Reactors. My understanding is they have a very low ERoEI requirement of building and operation, leaving more energy for society.

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Wind turbines have to be replaced every 20-25 years.

Actually, the average life of wind turbines is much less than that and they needed a great deal of maintenance and replacements throughout their lives. Many in Europe are being replaced after just 15 years.

The article does deal with nuclear, ERoEI = 75 for current reactor types. However,eventually this could increase by approaching a factor of 100 (i.e. to say 7000) with future generations.

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John Morgan,

There are a number of presentations on ERoEI here you might find interesting.
Science for Energy Scenarios: 3rd Science and Energy Seminar at Ecole de Physique des Houches, March 6th-11th, 2016http://science-and-energy.org/slides-videos/

Jessica Lambert ‘Examining The Relation between Quality of Life and Biophysical vs Economic Conditionshttp://science-and-energy.org/wp-content/uploads/2016/03/EcoleDePhysiqueDesHouches_JGL_2016_03_08.pdf is interesting. However, it seems to me she, and many of the other presentations, are using energy intensity as a proxy for ERoEI and in fact are simply plotting energy intensity and calling it ERoEI. I’d welcome comments on what others think about this.

Daniel Weißbach, et al. ‘ The EROIs of Power Plants – why are they so different?http://science-and-energy.org/wp-content/uploads/2016/03/EROI_LesHouches2016.pdf is interesting too. I’d like to hear comments and discussion from others about the methodology, because it is differences in methodology and assumptions that are reason for the large differences in ERoEI estimated by different authors. The second last slide summarises the ERoEI for the different technologies:
Wind and solar: 1-4
Fossil fuels: 30
Hydro: 35
Nuclear (today’s LWRs): 75
Nuclear theoretical limit: 10,000

Weißbach includes his spreadsheet here: http://tinyurl.com/z7329lh

Also see other EROEI presentations linked in my first link above.

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[Repost]
Euan Mearns has a new post on Energy Matters: http://euanmearns.com/the-energy-return-of-solar-pv/

A new study by Ferroni and Hopkirk [1] estimates the ERoEI of temperate latitude solar photovoltaic (PV) systems to be 0.83. If correct, that means more energy is used to make the PV panels than will ever be recovered from them during their 25 year lifetime. A PV panel will produce more CO2 than if coal were simply used directly to make electricity.

Ferruccio Ferroni and Robert J. Hopkirk 2016: Energy Return on Energy Invested (ERoEI) for photovoltaic solar systems in regions of moderate insolation: Energy Policy 94 (2016) 336–344 http://www.sciencedirect.com/science/article/pii/S0301421516301379

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0.86 overall eroei? That’s hard to believe unless the batteries are old fashioned and the overall scheme is located within a small area (with hardly any sunlight).
Now, the true eroei has to be averaged over GLOBAL conditions, including with long powerlines necessary to offset crappy local RE conditions.
Eventually, with continued science research, there will be solid state batteries which require less energy input and which will charge/discharge in freezing and hotter temps. The solar will require a little less energy, and the powerlines, well, nothing wrong with them, either.
I’ve given up on nuclear for 3 reasons, nobody wants it, humans have been known to err, and we leave the wastes susceptible to missile attacks (as they are not heavily shielded while in the cooling down process). Therefore, we HAVE TO make the weak and intermittent sources of energy work for us until these problems are solved. Best bet is continued science research on battery, supercapacitor and miniature fusion technologies. The starshot idea from current billionaires would bolster science in these fields as well.

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No, what we HAVE to do is wait until the storage problems are solved BEFORE we make the weak and intermittent sources of energy work for us. Until then, they make no sense at all.

Billions are being invested into energy storage but what boils down to is that we need a fundamental breakthrough in physics before we can depend on weak and intermittent sources of energy.

Giving up on nuclear is silly. It works and would work better and more cheaply with sensible regulations that aren’t framed by scare mongerers armed solely with an agenda and or ignorance.

The paper specifically studies PV in areas of low insolation – temperate latitude. The low reported EROEI is to demonstrate the unsuitability of PV outside the tropics. Within the tropics, the EROEI is bound to be better – how much requires another study of this detail.

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I agree that in order to make RE work, we have to make the batteries with less energy input and for much cheaper. It seemed impossible that solar would cover as much as it does already. Just a thin layer of battery material laminated with the panels (once we have solid state batteries) would store a good percentage of their energy for a day. Even a thin layer of lifepo4 would work (until it freezes). I know that’s probably not the best way to do batteries but suggests that it should be within material constraints and will thus be possible with better tech.
So ya, all this solar will require BETTER storage technology and manufacture.

Meanwhile, I’m not for ditching the nukes we already have (and would like to see a way to fission that contains it all, and without need for water cooling). I know there is a way to do fission but it has to be cheap. Consider that when fusion gets developed, it’ll already be obsoleted by solar and batteries – until it gets miniaturized. I believe continued research in lasers and the desire to propel tiny devices with cameras to the Alpha Centauri will lead to “fusion on a chip”.

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As I suspected, the ultra low figure is arrived at by making dodgy assumptions and fudging the figures by pretending non energy inputs are energy inputs.

19% of the calculated “energy investment” is labour. But that’s a societal cost; it should not be counted because the people would (assuming a competently run economy) be working anyway.

16% of the calculated “energy investment” is the capital cost. This relies on the false assumption that money is the direct result of someone making a profit (hence they calculated the energy used to make that profit). In reality the money comes into existence by being borrowed from a bank, whether or not any previous profit has been made. So the correct figure should be zero.

Removing those two bogus inputs is enough to get the EROEI up to 1.25

I suspect the true figure is higher, as separately including the energy cost of faulty equipment is likely to be double counting.

The energy cost of integration of the intermittent PV electricity in the grid and buffering may also be exaggerated, as some of the equipment it relies on may already exist, and the estimated energy cost for operation of smart-grid infrastructure appears unrealistic; no reason is given to justify such a high figure.

So if the manufacturing and output numbers are right, the EROEI could still exceed 1.4

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I don’t believe even 3 to 1 is good enough. The economy now is still enjoying higher energy returns from fossil fuels – and at a much faster “turn around”.
Although I have hope for RE, the way we do it today is not good enough. We don’t have intercontinental HVDC lines, we don’t have a cheap and plentiful solid state battery and we have too many people thinking we can get by with not enough renewable energy coverage (we need more power than what fossil fuels provide at the moment).

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Aidan Stranger,

19% of the calculated “energy investment” is labour. But that’s a societal cost; it should not be counted because the people would (assuming a competently run economy) be working anyway.

Correct! if they were not incentivised by governments to work on solar (destroying wealth) they’d be working elsewhere producing wealth.

You have made it clear in comment on BNC and on many other blog sites you do not understand economics, and therefore your comment cannot be taken seriously. Certainly, the authors clearly know much more about the subject than you do. I’d urge you to read “Economics in One Lesson”.

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Although I have hope for RE, the way we do it today is not good enough. We don’t have intercontinental HVDC lines, we don’t have a cheap and plentiful solid state battery and we have too many people thinking we can get by with not enough renewable energy coverage (we need more power than what fossil fuels provide at the moment).

The obvious answer is nuclear power. Effectively unlimited fuel, requires much less resources than other technologies, can be rolled out to replaced other technologies faster than any alternative and could be much cheaper than the alternatives (https://judithcurry.com/2016/03/13/nuclear-power-learning-rates-policy-implications/ ). And it is demonstrably the safest way to generate electricity.

Unfortunately, it is blocked by the ignorance and denial of the anti-nukes.

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fireofenergy,

What’s good enough depends on cost of net energy. EROEI is not the deciding factor; it’s just one of many contributing factors.

Peter Lang,

Working on solar does not destroy wealth.
Coal (due to the environmental problems it causes) is a big destroyer of wealth.

I understand economics much better than you do. I understand it well enough to know that many of the assumptions that most of the population (including you) assume to be true are actually false. And it is only because you make those false assumptions that you conclude me to not understand economics.

As for Economics In One Lesson, ISTR I read and criticised it the first time you referred me to it.

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Aidan,

As for Economics In One Lesson, ISTR I read and criticised it the first time you referred me to it.

You criticise many papers, books, posts, facts that do not support your beliefs. But your criticisms are invariably baseless and/or wrong. In the case of ‘Economics in one lesson’, you clearly hadn’t read it, because your stated reason was the book didn’t address inflation. Chapter 22 ‘The Mirage of Inflation’.

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Peter, I’ve checked and my exact words were:
The “Economics in one lesson” site’s one basic point is good, but because it fails to understand how inflation is affected by savings and productivity improvements, many of its conclusions are wrong.

I stand by that comment. I’ve had another look at its The Mirage of Inflation chapter (23 not 24) and it only deals with the direct effects of money supply increase on inflation; it ignores how inflation is affected by savings and productivity improvements. Also the claim later on in the chapter that…

The government cannot keep piling up debt indefinitely; for if it tries, it will some day become bankrupt

…is blatantly false for countries borrowing in the currency that they print. To be fair to Hazlitt, when his book was first published the gold standard was almost ubiquitous, and running out of gold could be considered a form of bankruptcy. But now the gold standard is dead, it’s impossible for countries such as the USA, Japan and Australia to go bankrupt no matter how much debt they have.

Chapter 24 (The Assault on Saving) deals in an extremely limited way with the interactions between inflation, savings and technology, but seems wilfully blind to the disinflationary effects they have. It also fails to recognise that the amount of money the banks can lend does not depend on savings.

Just because you’re unwilling to seriously consider my criticisms doesn’t mean they’re baseless.

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“The government cannot keep piling up debt indefinitely; for if it tries, it will some day become bankrupt”

…is blatantly false for countries borrowing in the currency that they print.

The quoted statement is correct. It’s been demonstrated repeatedly. The fact you do not understand basic concepts is clear demonstration you have no idea what you are talking about.

No point discussing this any further.

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Peter Lang,

I suggest you have another look at the intellectual honesty page you’ve previously referred me to. For the last few posts you’ve been displaying the second sign of intellectual dishonesty and now, by claiming there’s no point discussing this any further, you’re displaying the third.

This is rather off topic here so I suggest we move the discussion to the Open Thread. But it’s certainly worth discussing. You claim that it’s been demonstrated repeatedly, yet you did not give even a single example.

I’m not assuming my claim to be true because I want it to be true. Nor was it something that I’ve always believed to be true and never bothered to question. Indeed I, like most of the population, originally believed it to be false. But all the evidence I’ve seen shows it to be true. So I’m going by the evidence. Are you willing to do likewise?

If you have a counterexample, I want to know. If you can find any examples of countries that issue freely floating currencies that have (because of debt in that currency) gone bankrupt, been forced to default or been forced into hyperinflation, tell me and I will cease (or at the very least, substantially revise*) my claims. But if, as I suspect, you find no examples, do you have the intellectual honesty to admit you’re wrong and reconsider what I’ve written?

*If you find an example but it’s an extremely obscure situation, such as the country devoting most of its economy to fighting a war, a complete cessation would not be justified.
BNC MODERATOR
This argument is becoming circular and as such, is not suited to this thread. Please move to the Open Thread where the comments policy is more relaxed. Further to-ing and fro-ing here will be deleted.

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