Can everything run on renewable energy?

                                                                   An outline of the reasons for doubt.


                                                                                 Ted Trainer.
                                                                                   14.7.2022

The potential and limits to renewable energy are hotly debated, and far from settled. Many people take it for granted that it can meet all our energy needs, and numerous impressive agencies and technical reports say this.  However until the last few years when a few simulations based on detailed weather data have become available nearly all pronouncements have been little more than speculation and most have simply selected bits of evidence to confirm preferred beliefs. I have examined the about ten simulation studies for the Australian situation and have published various analyses showing how inconclusive they are. There are now several analysts and studies casting doubt on the 100% renewable claim. (E.g., Moriarty and Honnery 2010, Clack et al., 2017, Heinberg and Fridley 2016, Heard et al. 2017, Friedmann, 2016, de Decker, 2017, Floyd and Palmer, De Castro and Capellan-perez.) Heard et al., (2017), recently published a scathing review of claims.) For a list of 84 papers see RE100%Doubters.html

Just as you can run your house on torch batteries, it is technically possible to run everything on renewables … but that doesn’t mean you could afford to do it. The crucial question is what would it cost to have enough generating capacity to meet demand at any time despite the intermittency of renewable energy? The simulations we now have generally find that to meet an average electricity demand of one GW you would need renewable generating plant capable of generating four to seven GW in ideal conditions, and with plausible assumptions it would be much higher; de Decker says in some situations it is 10. Whether we could afford that is not settled, but below I indicate why it is very unlikely that we could.
What about the claim that wind and PV can produce a kWh more cheaply than coal now?  That could be true now, but it is quite misleading.  It doesn’t tell us much about what a kWh would cost if it came from a system with so much redundant renewable capacity to be able to supply that kWh at any time.  Again, that system might have to contain 4 to 7 times as much wind and/or PV capacity as we would need in the form of coal-fired generators, and it would have to contain a great deal of storage capacity.

Won’t batteries solve the storage problem? Not unless costs fall enormously. Grid level systems that have been built have cost around $1000 of more for the capacity to store 1 kWh. The “Big Battery” Elon Musk built in South Australia cost $1,550/kWh. A recent installation in Victoria cost  $3,500/kWh. ( … see my examination of the storage problem for renewables, Trainer 2017a.) If you want to store the output from one power station for one day you would need capacity to store 1 million x 24 kWh = 24 million kWh, and even  if the storage cost fell to $100 per kWh that would cost you $2.4 billion…which is more than it would cost to build another coal-fired power station. A national system would need the capacity to store enough to meet total demand for many days in a row, in European winters probably for weeks. And electricity is only 20% of energy demand. And several studies find that there are far too few reserves of scarce battery materials to enable all the world’s people to rely on them.
Pumped hydro storage?  Enthusiasts do not deal with the difficulties satisfactorily, especially the lack of affordable sites stated by two major studies. (Again see Trainer 2017a.)

Claims about renewable potential are of little or no value unless they are derived via complex simulations based on detailed weather data for a region over a long period. Only these can tell how much redundant plant would be needed to meet demand in the worst weather conditions. Very few such studies have been carried out anywhere in the world. In 2012 Elliston, Diesendorf and Macgill (2012) published what I think was the first analysis of this kind for Australia, based on recently available detailed weather data for about 40 regions across the country. This valuable study concluded that a 100% renewable supply system could meet all electricity demand reliably, at a production cost of about 10-15c/kWh.  At that time it was costing about 3-5 cents to produce one kWh by a coal-fired generator. In 2015 Lenzen et al. (2016) published the second Australian simulation concluding that the production cost could be 20c, and possibly 30+c.

These simulation studies inevitably involve many assumptions and in my view those made by Lenzen et al. are more acceptable, (… although I have published a detailed case that its assumptions re solar thermal efficiency in winter are much too favourable, probably two times too high. The findings on getting through difficult periods in winter relied very heavily on solar thermal, so the assumptions that I think would be more defensible would significantly raise the cost conclusions; see Trainer 2017a.)

Elliston, Diesendorf and MacGill assume wind will be a major contributor, providing up to 58% of electricity, but Lenzen et al. assume that it would/should be limited it to 30% in view of the studies indicating that above this level problems in integrating wind into the supply system become difficult and costly. So differences in conclusions in the renewable field are typically due to differing assumptions, and as result the findings by the ten studies differ greatly. This means the field is far from settled.

In my attempt to derive a possible retail price from the production cost conclusions Lenzen et al. come to I list 13 factors they didn’t and/or couldn’t consider but which would be likely to increase the production cost. (Trainer, 2017b.) Examples are, the fact that the capital cost assumptions used were for a time when the $A dollar was about much higher than it is now, meaning the turbines and panels etc. that would have to be imported would now cost more, the high probability that the year studied, 2010, was not the most one with t he most adverse weather ever likely to occur, and the fact that construction in remote areas has been estimated to increase construction costs 10%. The four factors I could quantify multiplied the Lenzen et al. production cost from 20 c/kWh to about 46 c/kWh. One important factor I could not include is the energy embodied in the construction of the huge amount of turbines, PV farms, transmission lines etc. that would be required. (I have since derived the uncertain estimate that this would add 17% to the amount of electricity that has to be generated, and therefore to the plant needed to do it; see Trainer 2017c.)The next important question is, given this production cost of electricity, what might the retail price be? For coal-fired power at the time of the study the retail price was about 5 times the production cost; i.e., it added about 22 cents to the maybe 3-5 cent production cost, mostly for distribution of electricity to consumers. So it seemed to me that the retail price from the pattern of renewable supply which Lenzen et al. found to minimise cost would probably be 46 + 22 = 68 c/kWh, and it could be higher. In my view this might be “affordable” but it would be very economically disruptive. Protest over electricity prices in Australia is a major political issue already.

I should note that I am not confident about these conclusions; they are possibilities I have come to given the information I have come across.

Keep in mind that this has been about Australia which has probably the best renewable energy sources of any rich country.  My attempt to assess the prospects for Europeans (Trainer, 2013) concluded that they would be most unlikely to meet all electricity demand from renewable sources. In winter Europeans frequently endure weeks of continually very cold, stable and cloudy conditions, and have little biomass for back up.
But all that is only about providing electricity. Over 80% of our energy use is not electrical; much of it is in the form of liquid fuels. Meeting this demand is far more problematic. Following is an indication of my recent attempt to clarify the task of meeting total Australia’s energy demand via renewables. (The easily followed derivation is detailed in Trainer, 2017d.)

I assumed, among other things, all light vehicles converted to electricity, use of the 96 million tonnes/y of biomass Crawford et al. (2012) think could be taken for energy, most of it producing ethanol, use of hydrogen thereby providing for all storage required, and conversion of as many functions as possible to electricity. (All the assumptions, derivations and arithmetic are in the paper.)

I found that the total amount of electricity that would needed to meet estimated 2050 total energy demand came to 5,867 PJ, in addition to use of all available biomass. This is over 8 times present electrical output. If the retail price of electricity was 50c kWh (and the argument above was that it could be higher) the cost of energy would be $814 billion p.a., which is around 54% of 2015 GDP, or 27% of 2050 GDP assuming 2% economic growth. Note that this does not include the cost of the biomass, converting it to ethanol, the transmission lines, the hydrogen production equipment, piping and storage system, or any of the embodied energy costs built into the wind, turbines, PV farms transmission lines, storage tanks etc. Energy expenditure now is only about 9% of GDP. For the US it has been found that if the percentage goes above about 6% for any period of time there is recession. (Hall and KIitgaard, 2014.)

If this (not confident) analysis is at all valid then100% renewable supply to meet all energy demand would be utterly impossible to afford. 
As noted, I have more recently attempted to estimate the Energy Return on Energy Invested (EROI) for a 100% renewable electricity (not total energy) generating system (Trainer, 2017d), bearing in mind that such a system must have a lot of generating capacity sitting idle much of the time, maybe five or more times as much equipment as would do the job in the form of coal-fired plant. The present energy system’s EROI is probably around 18, but I estimated that for the 100% renewable electricity supply system Lenzen et al. analyse, it would be 5.9, and there are reasons for thinking it would be considerably lower. (Capellan-Perez et al. 2019, arrived at a similar figure.) For a 100% renewable system to meet all energy demand (again electricity is only 20% of that), the figure would probably be much lower.

This has been an indication of the kind of detailed analysis on which agreement must be reached before we are in a position to make confident assertions about whether renewables can save us. The fact is that we are a long way from clear and confident conclusions in this area, but there is a strong case that we could not afford the amount of capacity needed to be 100% dependent on renewables.
Note if renewables could sustain energy affluent societies that would enable them to plunge right on gobbling up more resources, wrecking more ecosystems and accelerating limits to growth problems.

In my view renewable energy is not a very important issue in the quest for sustainability. I think it’s too late to fix the climate problem and at the very best renewable energy will be quite costly and this will add to the mounting and terminal difficulties consumer-capitalist society is running into. Many other factors will be more powerful determinants of our fate, most obviously oil depletion, the debt mountain, financial collapse, and the discontent brewing among the perhaps 80% in rich countries for whom this society is increasingly failing to provide.

What then should we do? The answer is, emphatically, move to 100% renewable energy supply as fast as possible! But we cannot function well on them unless we undertake an astronomically big De-growth transition to The Simpler Way. That means scrapping capitalism, and the obsession with wealth and affluence, individualism and competition, and instead being content to live frugally and cooperatively mostly in highly self-sufficient local communities. The many people living in Eco-villages today know that these ways can provide all with a high quality of life on extremely low per capita resource use rates. (See Lockyer’s evidence, 2017.) No other way can defuse the big global problems, because they are basically due to the quest for affluence and growth and the resulting unsustainable over-consumption.  We could make this transition easily and quickly…if enough of us wanted to do it. (For the detailed case see thesimplerway.info/.)  I think the chances of this path being taken are very poor, but it is the only sensible option, and lots of people are working for it, including the Simplicity Institute (2017.)

            Appendix:


Following is a much simplified but transparent derivation indicating the magnitude of the task.
Let us assume that electricity demand is X GW, and therefore the amount of energy needed in non-electrical form at present is 4X GW. If we assume that 75% of present non-electrical demand, i.e., 3X GW, can be shifted to electrical drives then X GW of energy would be needed in non-electrical form. If this is to be delivered to wheels etc. as hydrogen produced from electricity at an efficiency of 25% as indicated above then 4 GW of electricity would have to be produced for this purpose, bringing the total amount of electricity to be generated to 8X GW. If this amount is produced from renewable sources by a system which has an overall capacity factor of 25%, then the total generating capacity needed would be 32X GW.
In Australia X is now around 25 GW, so the peak capacity needing to be built would be 800 GW. If the average capital cost of the system’s renewable technologies was $2,000/kW, then the total capital cost of the generating system needed would be $1.6 trillion. If plant lasted 20 years the annualised capital cost would be $80 billion.    This is around 15 times the annualised capital cost of sufficient coal-fired generators to provide 8 times the present amount of electricity consumed (assuming 40 year life time and 0.8 capacity factor for coal-fired generators.)

However, this exercise has been based on a system average capacity factor assumption of 25%. (The renewable system arrived at by Lenzen et al. had a capacity factor of around 14%.) But the Aneroid data (2022) shows that system capacity can fall to 5% for 2 or 3 days in bad weather conditions meaning that the amount of capacity needed and the associated cost figures would be 5 times as high as indicated above. Note that this exercise does not include a storage cost nor embodied energy costs, and that the total production cost of electricity is many times  the capital cost of the plant, and that the present Australian retail price is over three times the production cost. The exercise suggests that the retail price resulting from the system assumed would be very high.

Aneroid, (2022), Wind energy. https://anero.id/energy/wind-energy/2022/january
Aneroid, (2022), Solar energy.  https://anero.id/energy/solar-energy
Capellan-Perez, I., C Castro and L. Gonzlez, (2019), “Dynamic Energy Return on Energy Investment (EROI) and material requirements in scenarios of global transition to renewable energies’ Energy Strategy Reviews, Volume 26, November. 100399 https://doi.org/10.1016/j.esr.2019.100399
Clack, C. et al., (2017), “Evaluation of a proposal for reliable low cost grid power with 100% wind, water and solar”, PNAS, June 27, 114, 26, 6722 – 6727.
Crawford, D., T. Janovic, M. O”Connor, A. Herr, J. Raison and T. Baynes, (2012), Potential for electricity generation in Australia from Biomass in 2010, 2030, and 2050,  AEMO 100% Renewable Energy Study, 4 Sept. CSIRO Report EP – 126969.
Elliston B., Diesendorf, M.,and I. MacGill, (2012). “Simulations of scenarios with 100% renewable electricity in the Australian National Electricity Market”, Energy Policy, 45, 606 – 613.
Friedmann, A., (2016), When Trucks Stop Running, Dordrecht, Springer.
Hall, C. A. S and K. A. Klitgaard, (2014), Energy and the Wealth of Nations, Dordrecht, Springer.
Hart, E. K., and M. Z. Jacobson, 2011.  A Monte Carlo approach to generator portfolio planning and carbon emissions assessments of systems with large penetrations of variable renewable, Renewable Energy, 36, 2278 – 2286.
Heard, B., et al, (2017), “Burdon of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems”, Renewable and Sustainable Energy Reviews,  76, 1122-1133.
Heinberg, R., and D. Fridley, (2016) Our Renewable Future, Santa Rosa, California, Post Carbon Institute.
Lenzen, M., B. McBain, T. Trainer, S. Jutte, O. Rey-Lescure, and J. Huang, (2016), Simulating low-carbon electricity supply for Australia, Applied Energy, 179, Oct., 553 – 564.
Lockyer, J., (2017),  “Community, commons, and De-growth at Dancing Rabbit Eco-village”, Political Ecology, 24, 519-542.

Moriarty, P., and D. Honnery, (2010), The Rise and Fall of Carbon Civilization, Springer, Dordrecht.
The Simplicity Institute, 2017. simplicityinstitute.org/
Trainer, T., (2013), "Can Europe run on renewable energy? A negative case", Energy Policy, (63) 845 – 850.
Trainer, T., (2017a), “Some problems in storing renewable energy”. Energy Policy, (in press.) thesimplerway.info/REstorage.htm
Trainer, T., (2017b), “Can renewables meet total Australian energy demand: A “disaggregated” approach.”  Energy Policy, (in press.) thesimplerway.info/CanRE.htm
Trainer, T., (2017c), “Estimating the retail price for 100% Australian renewable electricity.” (In press, Energy Policy.) thesimplerway.info/REretailprice.htm
Trainer,T., (2017d), “The overlooked significance of the EROI for renewable energy supply systems.” (In press, Energy Policy.) thesimplerway.info/REsystemEROI.htm