Wind and carbon emissions – Peter Lang responds

The following is a response from Peter Lang to various comments made in the post “Does wind power reduce carbon emissions?

Energy Storage

Energy storage, at the scale required to make wind power a reliable source of dispatchable power, is uneconomic. This link provides comparative costs of energy storage technologies.

Even without energy storage wind generation is uneconomic. Wind must be mandated by governments and subsidised, otherwise it would not be built. Wind power is high cost for low value energy. It has low value because it cannot be controlled and called up on demand. It requires high cost upgrading to the grid in remote areas and requires costly systems to maintain power and frequency stability on the grid. Wind generators need $90/MWh to $140/MWh to be viable. As well, the electricity distributors and the national grid operator all incur substantial additional costs as a result of being forced (by government regulation) to buy wind energy. For comparison, the cost of new entrant baseload power is about $40/MWh.

Barry Brook will soon be posting another paper which provides insight into the amount of energy storage that would be required and just how far from being economic are intermittent, not dispatchable renewable energy generation technologies with energy storage. These technologies are not just 10% or 20%, or even 50% from being economic. Solar PV with energy storage, for example, would be some 20 times more costly than nuclear power to provide the electricity we demand. We have been researching and developing solar PV for the same time as nuclear power, and wind power for three times as long. Yet these renewables are still totally uneconomic. The advocates are making the same sorts of statements now as they were making in the early 1990s about the economics of these generation systems – “they are economic now if the government would just subsidise them and mandate them more”.

Regarding plug-in hybrid electric vehicles (PHEV’s), there are many technical and cost issues to be solved before these become economic and widely used. However, together with substantial nuclear power generation, some energy storage with PHEV’s may make sense in the future. With some 80% of electricity generated by nuclear (as in France), and the remainder from gas and renewables (mainly hydro), then PHEV’s may make sense. They could allow wind and solar to make a genuine, economic contribution to electricity generation.

The fallacy of Dr Mark Diesendorf’s “The Baseload Fallacy”

Dr Mark Diesendorf claims that “the wind is always blowing somewhere”, so, with sufficiently wide spread wind farms, wind power is dependable. Figure 1 demonstrates that this claim is wrong. Figure 1 shows the total output for wind farms in NSW, Victoria, Tasmania and South Australia for June 2009. The conclusion: wind power is unreliable, not dispatchable, and often zero when needed, no matter how large the area over which the wind farms are distributed.

langfig0

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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.

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Critique of the proposal for 100% renewable energy electricity supply in Australia

Below is a new, detailed critique by Dr Ted Trainer of the simulation studies by Elliston, Diesendorf and MacGill on how eastern Australia might be run off 100% renewable energy. The summary:

Three recent papers by Elliston, Diesdendorf and MacGill (2012, 2013a, 2013b) elaborate on a proposal whereby it is claimed that 100% of present Australian electricity demand could be provided by renewable energy. The following notes add considerations arising from the last two papers to those discussed in my initial assessment of the first paper. My general view is that it would be technically possible to meet total Australian electricity demand from renewables but this would be very costly and probably unaffordable, mainly due to the amount of redundant plant needed to cope with intermittency. This draft analysis attempts to show why the cost conclusions EDM arrive at are probably much too low.

Ted has also updated his critique of the Zero Carbon Australia’s report on 100% renewable energy by 2020. The original BNC post is here, and the updated PDF here.

Ted notes the following:

These efforts have taken a huge amount  of time and I am still not clear and confident about my take, mainly because neither party will cooperate or correspond.  Thus I have not been able to deal with any misunderstandings etc. I have made.  Both critiques are strengthened by information I have come across since circulating previous commentaries, but they are essentially elaborations on the general line of argument taken in earlier attempts.

I find this unwillingness to engage on these criticisms by the primary authors disappointing, but typical.


Introduction

I think these three papers are valuable contributions to the considerable advance that has occurred in the discussion of the potential of renewables in the last few years. My understanding of the situation is much improved on what it was three or four years ago and I now think some of my earlier conclusions were unsatisfactory. EDM take the appropriate general approach, which is to look at how renewable technologies might be combined at each point in time to meet demand, or more accurately, to estimate how much capacity of each technology would be required, especially to get through the times when solar and wind input is minimal. EDM put forward a potentially effective way of coping with the problem of gaps in their availability via biomass derived gas for use in gas turbines. My earlier analyses did not consider this.

It is not difficult for an approach of this kind to show that electricity demand can be met, and many impressive 100% renewable energy proposals have been published. (For critical analyses of about a dozen of these see Trainer, 2014), but a great deal of redundant capacity would be needed, and the key questions are, how much, and what would it cost? My present uncertain impression is that Australia might be able to afford to do it, but if it could it would be with significant difficulty, i.e., with major impacts on lifestyles, national systems and priorities, and on society in general.

A major disappointment with the EDM analyses is that for some crucial elements no data, evidence or derivations are given and as a result the proposal can only be taken as a statement of claims. We need to be able to work through the derivations in proposals such as this to see if they are sound or what questionable assumptions might have been made etc. Consequently I have had to spend a lot of time trying to guestimate my way to an assessment of the cost conclusions and it is not possible to confident about the results.

Required capacity?

A merit of the EDM approach is to take as the target the present demand. This avoids the uncertainty introduced when attempting to estimate both future demand and the reduction in demand that conservation effort etc. might make.

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Further critique of ‘100% renewable electricity in Australia’ – winter demand and other problems

Recently on BNC, I ran two guest posts on the economic and technical challenges of supplying an energy-intensive, developed-world market using 100% renewable sources (under a situation where large hydro and/or conventional geothermal can provide little or no contribution). The case study was the national electricity market of Australia, with an average demand of 25-30 GWe.

100% renewable electricity for Australia – the cost

and the response, from one of the authors of the original simulation study:

100% Renewable Electricity for Australia: Response to Lang

Below is a further commentary, by Ted Trainer of UNSW, which focuses particularly on the issues of supplying winter demand, the feasibility of the biomass option for the gas backup, and the “big gaps” problem (i.e., long-run gambler’s ruin). Ted asked me to post it here on BNC to solicit constructive feedback (and has promised me he will be responding to comments!).

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Comments on

Simulations of scenarios with 100% renewable electricity in the Australian National Electricity Market”  Solar 12011, 49th AuSES Annual Conference,  30 Nov – 2 Dec., By Ben Elliston, Mark Diesendorf and Iain Macgill, UNSW.

Ted Trainer; 21.3.2012

The paper outlines a supply pattern whereby it is claimed that 100% of present Australian electricity demand could be provided by renewable energy.

The following notes indicate why I think that although technically this could be done, we could not afford the capital cost.  This is mainly because the analysis seems to significantly underestimate the amount of plant that would be required.

I think this is a valuable contribution to the discussion of the potential and limits of renewable energy.  It takes the kind of approach needed, focusing on the combination of renewable sources that might meet daily demand.  However it is not difficult to set out a scenario whereby this might be done technically; the problems are what quantity of redundant plant would be needed to deal with fluctuations in renewable energy sources, and what might the capital cost of this amount to?

Two of the plots given set out the contributions that might be combined to meet daily demand over about 8 days in 2010, in summer and winter.  It seems to me that when these contributions are added the total capacity needed is much more than the paper states.

Australia's recent history of energy use by source

The task is to supply 31 GW.  The plots given show that at one point in time wind is contributing a maximum of 13.5 GW, but at other times its contribution is close to zero, meaning that other sources are backing up for it.  The corresponding peak inputs from the other sources are, PV 9 GW, solar thermal 27, hydro 5 GW and gas from biomass 24 GW.  Thus the total amount of plant required would be 75.5 GW of peak capacity… to supply an average 31 GW.  (in his response to Peter Lang, Mark Diesendorf says their total requirement is 84.9 GW.) That’s the magnitude of the redundancy problem and this is the major limiting factor for renewables; the need for a lot of back up plant, which will sit idle much of the time.

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100% renewable electricity for Australia – the cost

Download the printable 33-page PDF (includes two appendices, on scenario assumptions and transmission cost estimates) HERE.

For an Excel workbook that includes all calculations (and can be used for sensitivity analysis), click HERE.

By Peter Lang. Peter is a retired geologist and engineer with 40 years experience on a wide range of energy projects throughout the world, including managing energy R&D and providing policy advice for government and opposition. His experience includes: hydro, geothermal, nuclear, coal, oil, and gas plants and a wide range of energy end use management projects.

Summary

Here I review the paper “Simulations of Scenarios with 100% Renewable Electricity in the Australian National Electricity Market” by Elliston et al. (2011a) (henceforth EDM-2011).  That paper does not analyse costs, so I have also made a crude estimate of the cost of the scenario simulated and three variants of it.

For the EDM-2011 baseline simulation, and using costs derived for the Federal Department of Resources, Energy and Tourism (DRET, 2011b), the costs are estimated to be: $568 billion capital cost, $336/MWh cost of electricity and $290/tonne CO2 abatement cost.

That is, the wholesale cost of electricity for the simulated system would be seven times more than now, with an abatement cost that is 13 times the starting price of the Australian carbon tax and 30 times the European carbon price.  (This cost of electricity does not include costs for the existing electricity network).

Although it ignores costings, the EDM-2011 study is a useful contribution.  It demonstrates that, even with highly optimistic assumptions, renewable energy cannot realistically provide 100% ofAustralia’s electricity generation.  Their scenario does not have sufficient capacity to meet peak winter demand, has no capacity reserve and is dependent on a technology – ‘gas turbines running on biofuels’ – that exist only at small scale and at high cost.

Map of Australia's transmission lines. There are no transmissions lines to any of the proposed CSP sites, and the best solar areas are far removed from the existing transmissions infrastructure.Source: Grattan Institute, Figure 10.1 (attributed to DRET (2010), Grattan Institute)

Introduction

I have reviewed and critiqued the paper “Simulations of Scenarios with 100% Renewable Electricity in the Australian National Electricity Market” by Elliston et al. (2011a) (henceforth EDM-2011).

This paper comments on the key assumptions in the EDM-2011 study.  It then goes beyond that work to estimate the cost for the baseline scenario and three variants of it and compares these four scenarios on the basis of CO2 emissions intensity, capital cost, cost of electricity and CO2 abatement cost.

Comments on the EDM-2011 study

The objective of the desktop study by EDM-2011 was to investigate whether renewable energy generation alone could meet the year 2010 electricity demand of the National Electricity Market (NEM).  Costs were not considered.  The study used computer simulation to match estimated energy generation by various renewable sources to the known hourly average demand in 2010.  This simulation, referred to here as the “baseline simulation” proposed a system comprising:

  • 15.6 GW (nameplate generation capacity) of parabolic trough concentrating solar thermal (CST) plants with 15 hours thermal storage, located at six remote sites far from the major demand centres;
  • 23.2 GW of wind farms at the existingNEMwind farm locations – scaled up in capacity from 1.5 GW existing in 2010;
  • 14.6 GW of roof-top solar photovoltaic (PV) inBrisbane,Sydney,Canberra,MelbourneandAdelaide;
  • 7.1 GW of existing hydro and pumped hydro;
  • 24 GW of gas turbines running on biofuels;
  • A transmission system where “power can flow unconstrained from any generation site to any demand site” – this theoretical construct is termed a “copperplate” transmission system.

The accompanying slide presentation by Elliston et al. (2011b), particularly slides 5 to 12, provides a succinct summary of the objective, scope for their simulation study, the exclusions from the scope, the assumptions and the results.

The results of the baseline simulation show that there are six hours during the year 2010 when demand is not met, with a maximum power supply shortfall of 1.33 GW.  It should be noted that the supply shortfall would be significantly greater with higher time resolutions, e.g. 5 minute data rather than the 1 hour increments used, but this limitation is not addressed by EDM-2011.

The EDM-2011 approach is more realistic than Beyond Zero Emissions (2010)Zero Carbon Australia – Stationary Energy Plan” (critiqued by Nicholson and Lang (2010), Diesendorf (2010), Trainer (2010) and others), especially because EDM-2011’s approach, as they say, “is limited to the electricity sector in a recent year, providing a more straight forward basis for exploring this question of matching variable renewable energy sources to demand.”  As the authors say, “this approach minimises the number of working assumptions”.

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