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EROEI estimates show PV to be a fully mature technology

Alternative Energy

“The EROEI of Photo-Voltaics can be whatever you like these days” a friend of mine said once after attending a bio-physical economics conference. It epitomises a growing problem in this field, while the broad concept of net energy or Energy Return on Energy Invested (EROEI) is broadly accepted there is no unified methodology for its calculation. Different researchers apply different methods producing markedly different results.

Photo-Voltaics (PV) is an energy source where this problem has been more acute. Equipment and installation prices collapsed four or five fold since 2010, but published EROEI studies have not converged; in fact it appears they dispersed even further.

Fortunately, another friend, Rembrandt Koppelaar, has recently finished a study assessing these assorted EROEI estimates, entitled Solar-PV energy payback and net energy: Meta-assessment of study quality, reproducibility, and results harmonization. As it turns out, low EROEI figures are largely an artefact of outdated data and double accounting. A message by Rembrandt summarising the results of his study is reproduced below.

  • I looked at 29 existing studies, and attempted to reproduce all of their results (I managed to do so on the information provided in about 50% of the studies), after this I harmonized the data by making the boundaries equal.
  • The Boundaries I took for the harmonization include from quartz mining to end-of-life, including inverters and other components, disposal, transport. Excluded are grid connections and balancing, and excluded are labour wages (not an energy input) and financial capital values (as this is double-counting the material costs) (including embodied). The solar radiation value taken for the harmonization is 1700 kWh/m2/year

I also looked at several study methodology aspects, of which the most important are 1) The old age of the used data (Science is lagging on average 7 years behind reality). 2) The impact of (not incorporating) technological change.

The study also includes a sensitivity analysis that looks at the impacts of different solar radiation in kWh/m2/year and its effects on Net Energy.

The key conclusions:

  1. The study harmonization yielded a mean Energy payback time for mono- and polysilicon solar-PV of 3.9 and 2.9 years, and a mean Net Energy Ratio (EROI) of 8.6 and 9.2 times, as expressed in solar energy output gain per unit of energy input, respectively.
  2. The average time between study publication and sourced data was established at 7 years within a 2–18 year range, due to which energy input costs are typically overestimated as recent technological improvements are not captured. When filtering for studies with manufacturing data collected after 2008, the harmonized average EPT for mono- and polysilicon was found to be approximately half (e.g. 2.0 instead of 3.9) and NER (EROI) double (e.g. 14.4 instead of 7).
  3. An input correction with recent technological improvements for all studies resulted for mono- and polysilicon solar-PV in an adjusted mean harmonized EPT of 3.5 and 2.4 years and NER (EROI) of 9.7 and 11.4 times, respectively.

EROEI studies are yet to fully capture the collapse in PV technology costs of recent years. But even then, with the methodological harmonisation introduced by Rembrandt this energy technology can be easily classified as fully mature. The fact that it provides electricity in various parts of Europe for prices lower than fossil fuels is not merely conjectural.

Rembrandt is now working on a follow up study where he will investigate the impact of intermittency on these EROEI estimates. This aspect was seldom considered in previous studies and shall be tackled from a systems perspective using simulation software.

27 Comments on "EROEI estimates show PV to be a fully mature technology"

  1. Cloggie on Fri, 23rd Dec 2016 11:00 am 

    How are we going to bring this to Charles Hall, Pedro Pietro and sunweb?

    Seriously, we have many decades worth of optimization ahead of us. A lot of effort is put in the development of thin film solar cells, where the active layers are merely microns thick. Expect vast increases in EROEI here.

    The collapse of the doomer.

    Those darned techie dreamers.

  2. sunweb on Fri, 23rd Dec 2016 1:54 pm
    How am going to bring this to Cloggie
    In addition Cloggie sends me Youtubes of multiple ships installing wind turbines and then says he the future it will be all electrical. I hear this all the time. Tomorrow.

  3. IPissOnCanada on Fri, 23rd Dec 2016 2:05 pm 

    This is a more serious written post then the garbage that Gail is writing. Net energy has nothing to do with money and everything to do with the manufacturing process and solar input.

    Only Gail see a relation between energy, cost or money.

    Money is an old concept and should not be used in making decision for important stuff such as build energy plant or extracting tar sand or not.

    Tar sand are net energy negative (look at Venezuela) and for that reason alone should not be extracted. Does not matter if tar sand operation are making a profit. On a net energy calculation, they drain energy needed to generate economical activities or move locally before the big net energy drop.

  4. sunweb on Fri, 23rd Dec 2016 2:12 pm 

    This is sustainable:
    Dutch windmill
    How A Wind Powered Sawmill Works- AMAZING

  5. Cloggie on Fri, 23rd Dec 2016 3:07 pm 

    Sunweb, please let the following sink in:

    under the North Sea alone there is some 30 times more coal present than the total amount of fossil fuel burned in the entire planetary history:

    That coal doesn’t need to be mined, but can be burned “on location” and harvested as H2, CH4, CO, etc. The God-Emperor is right, we do have for centuries worth of coal. Where he is wrong is that we should actually consume that coal. We do not have a fossil fuel depletion problem. We do have a atmospheric capacity problem; we can’t burn all that fuel without causing major damage to the environment.

    The point is: we will always have enough fossil fuel to build solar panels and wind turbines or perhaps power ships or agricultural machines if we can’t power them with electricity (a big if) or with other methods.

    So the sport is to replace as much as possible fossil fuel with renewable energy and, if necessary, keep using fossil fuel for niche applications.

    There is no long term energy problem.

    I know it is hard to let go of a long cherished opinion, it feels almost like an amputation and requires revision of a world view. Not to mention that you have to update your friends about your new insights (loss of face).

    Or if you have been running a consultancy bureau for years and made money instructing your clients for $100/hour that “we are all f*” (hi shortonoil!), then I can imagine that you will fight tooth and nail against a**holes torpedoing your business model.

    Homo sum, humani nil a me alienum puto

  6. Apneaman on Fri, 23rd Dec 2016 3:20 pm 

    Rain Bombs keep falling on their heads

    Broome swamped in wettest December on record

    The humans are at least 20 years too late for their little band aid solar. The planetary natural cycles have already been radically altered with much more to come due to inertia (and they still forcing). It’s going to get much worse and will not go back to the way it was for thousands to tens of thousands of years.

  7. sunweb on Fri, 23rd Dec 2016 3:35 pm 

    Please let THIS sink in – you continue to promote business as usual. Who will constrain their energy use or procreation with all this energy available. Sir, you are the doomer. You with your technophilia are dooming the next generations. We will never agree.
    My position has never really been about EROEI. It has been as your starting to grasp about the underlying support of the various devices. What could possibly go wrong with burning all that coal. Humanity has such a great track record.
    You have a good life, I know you will never understand.

  8. onlooker on Fri, 23rd Dec 2016 6:25 pm 

    Sun, your right Clog, will not understand as others of his ilk will not either. It is about the underlying natural systems and our profligate abuse which individually we have shown no sign of restraint and together we do not either in our consumption patterns or procreation patterns. So you can say tomorrow we can avail ourselves of infinite energy sources and the only thing in the final analysis that would mean is we would end up ravaging and destroying our natural environmental life support systems that much faster. I am on this site because of energy and how its use ties inextricably into our fate. However, I also find it so fascinating to see the optimists and technotopians be completely oblivious to the Limits to Growth. One would think that at least here people would have had the time to peruse the logical and compelling arguments that the LTG study back in the 70’s bequeathed the planet so that we would show some restraint ,humility and wisdom in our path of earnest “progress”. Sorry to say humanity as a whole did not learn the lesson and so some here also.

  9. makati1 on Fri, 23rd Dec 2016 6:40 pm 

    If the deniers would just take a minute and look in their pantry, maybe they would understand limits. If their pantry was the earth and what is in it, at this moment, is ALL there was, they would see the LIMITED amount of meals they had left before they starved.

    The Earth has a LIMITED amount of resources in her pantry. We are consuming them at ever faster rates. Soon the pantry will be empty with the resulting consequence … we die.

    No only are we consuming faster and faster, but the ‘garbage’ is piling up in our living room, bringing disease and pestilence into our lives in the form of climate change.

    Ah, but the techies want to hug unicorns and hope someone will make the ‘garbage’ and its consequences go away so they can have their dream future. Flying cars and vacation trips to the moon. LMAO

  10. Anonymous on Fri, 23rd Dec 2016 6:55 pm 

    Ah, I bit more nuance is called for mak, there will always be resources lying around. The key point is, what is left will be so diffuse, low-grade, or at least compared to what we are digging up now, and marginal, that any exploitation of such resources will be severely constrained. Localized if you prefer.

    The cupboard won’t be bare as you suggest, but what is left will be pretty meager. Scraps basically.

  11. makati1 on Fri, 23rd Dec 2016 7:10 pm 

    Anon, yep, you are correct, but I didn’t want to overload the small brains that like to think all is well and tech will make their future beautiful and pain free.

    The idea of recycling the junk in landfills, or the metals laying around, will prevent the end of humanity. They don’t even consider the huge amount of energy needed to ‘recycle’ that junk. Metals melt at temperatures of 1,000C. Glass, at about the same temp. Tools to cut and shape existing parts will also be gone. You do not cut even aluminum plate with a kitchen knife. Yes, there will be a lot of ‘scraps’ but most will not be usable, as you said.

  12. John Kintree on Fri, 23rd Dec 2016 8:08 pm 

    If the EROI of PV solar energy based on manufacturing costs after 2008 is 14.4, then the EROI based on manufacturing costs after 2012 might be even higher. That’s good.

    Yes, considering the concentration of greenhouse gases that are currently in the atmosphere, we may already be toast. How badly burnt the toast is may still be an open question.

    One thing that might help in addition to improving EROI for renewables would be a significant carbon fee and dividend as proposed by the Citizens’ Carbon Lobby.

  13. makati1 on Fri, 23rd Dec 2016 8:56 pm 

    John, a “FEE” never works. It only enriches the fee imposer. More dreams of a “fix” that will never come. I hope you are old like me and will not live to seethe end of humanity. but…

  14. Kenz300 on Sat, 24th Dec 2016 6:06 am 

    Wind And Solar Now Cheapest Unsubsidized Electricity Sources In The U.S. – First Solar, Inc. (NASDAQ:FSLR) | Seeking Alpha

    World Energy Hits a Turning Point: Solar That’s Cheaper Than Wind – Bloomberg

    Solar cheaper than natural gas and coal. Climate Change will be the defining issue of our lives.

  15. Boat on Sat, 24th Dec 2016 10:46 am 

    Solar and wind will get cheaper. For those having this competive energy will have an advantage in the market. In turn this will force FF supplied industry to switch to renewables or die. The future is here.

  16. Cloggie on Sat, 24th Dec 2016 12:02 pm 

    Merry Christmas everybody!

  17. GregT on Sat, 24th Dec 2016 12:36 pm 

    “In turn this will force FF supplied industry to switch to renewables or die. The future is here.”

    Alternates are adding to our global energy mix, they aren’t replacing fossil fuels. Oil, coal, and natural gas consumption are at all time highs, and continue to grow.

  18. Boat on Sat, 24th Dec 2016 6:20 pm 


    That is correct mr greggiet. But the tipping point has been reached when it comes to cost per btu. Getting to scale is happening and prices are still dropping.

  19. Boat on Sat, 24th Dec 2016 6:24 pm 

    On the nat gas front a local gas station just started selling CNG. It will be interesting to see how many semi’s switch over the next decade.

  20. makati1 on Sat, 24th Dec 2016 7:16 pm 

    Ah, I wish I were a small sparrow watching some of the techie dreamers here, when the SHTF and all these techie fantasies go POOF!

    They don’t seem to understand three words: Globalization and Total Systems. The only thing they see are a few propaganda headlines that basically say: “Go back to sleep, we have you covered”.

  21. GregT on Sat, 24th Dec 2016 7:20 pm 

    A BTU is a measurement of thermal energy Boat. One BTU is the amount of energy required to heat one pound of water by one degree Fahrenheit.

  22. GregT on Sat, 24th Dec 2016 7:38 pm 

    “On the nat gas front a local gas station just started selling CNG.”

    We’ve had CNG filling stations here for decades Boat. At one time, my former company had an entire fleet of vehicles running on CNG. Too many problems. They were all switched back to gasoline.

  23. Apneaman on Sat, 24th Dec 2016 10:24 pm 

    Y’all will be replaced – obsolete. Don’t cha love that technology?

    World’s largest hedge fund to replace managers with artificial intelligence

    Bridgewater Associates has a team of engineers working on a project to automate decision-making to save time and eliminate human emotional volatility

    “Automated decision-making is appealing to businesses as it can save time and eliminate human emotional volatility.”

    “…save time and eliminate human emotional volatility.”

    “…eliminate human …”

    “…eliminate human …”

    “…eliminate human …”

    That is the conclusion AI will come to – eliminate human.

  24. Apneaman on Sat, 24th Dec 2016 10:25 pm 


  25. John Kintree on Sun, 25th Dec 2016 11:05 am 

    The carbon fee proposed by the Citizens’ Climate Lobby would be refunded through monthly payments to U.S. households. So, the price of fossil fuels would rise, but it would be revenue neutral.

    I’m just saying this looks like a good proposal to me, not that the political will exists in the United States right now to make it happen.

  26. Davy on Sun, 25th Dec 2016 12:04 pm 

    Revenue neutral is like saying free lunch. There are no free lunches. Why not just do less? Everyone from A-Z included. WTF, why does there always have to be a rebate. Let’s face this like adults and do less with less. We are not going to solve this problem with gimmicks. The reality is it is over so we should just face that music.

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