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. Worse than that, all the CO2 from PV production is in the atmosphere today, while burning coal to make electricity, the emissions would be spread over the 25 year period. The image shows the true green credentials of solar PV where industrial wastelands have been created in China so that Europeans can make believe they are reducing CO2 emissions (image credit Business Insider).

I have been asked to write a post reviewing the concept of energy return on energy invested (ER0EI) and as a first step in that direction I sent an email to my State-side friends Charlie Hall, Nate Hagens and David Murphy asking that they send me recent literature. The first paper I read was by Ferruccio Ferroni and Robert J. Hopkirk titled Energy Return on Energy Invested (ERoEI) for photovoltaic solar systems in regions of moderate insolation [1] and the findings are so stunning that I felt compelled to write this post immediately.

So what is ERoEI? It is simply the ratio of energy gathered to the amount of energy used to gather the energy (the energy invested):

ERoEI = energy gathered / energy invested

Simple, isn’t it? Well it’s not quite so simple as it appears at first sight. For example, using PV to illustrate the point, the energy gathered will depend on latitude, the amount of sunshine, the orientation of the panels and also on the lifetime of the panels themselves. And how do you record or measure the energy invested? Do you simply measure the electricity used at the PV factory, or do you include the energy consumed by the workers and the miners who mined the silicon and the coal that is used to make the electricity? Ferroni and Hopkirk go into all of these details and come up with an ERoEI for temperate latitude solar PV of 0.83. At this level, solar PV is not an energy source but is an energy sink. That is for Switzerland and Germany. It will be much worse in Aberdeen!

Why is ERoEI important? It is a concept that is alien to most individuals, including many engineers, energy sector employees, academics and policy makers. The related concept of net energy is defined as:

Net Energy = ERoEI – 1 (where 1 is the energy invested)

Net energy is the surplus energy left over from our energy gathering activities that is used to power society – build hospitals, schools, aircraft carriers and to grow food. In the past the ERoEI of our primary energy sources – oil, gas and coal – was so high, probably over 50, that there was bucket loads of cheap energy left over to build all the infrastructure and to feed all the people that now inhabit The Earth. But with the net energy equation for solar PV looking like this:

0.83-1 = -0.17

….. Brussels we have a problem!

So how can it be possible that we are managing to deploy devices that evidently consume rather than produce energy? The simple answer is that our finance system, laws and subsidies are able to bend the laws of physics and thermodynamics for so long as we have enough high ERoEI energy available to maintain the whole system and to subsidise parasitic renewables. Try mining and purifying silicon using an electric mining machine powered by The Sun and the laws of physics will re-establish themselves quite quickly.

In very simple terms, solar PV deployed in northern Europe can be viewed as coal burned in China used to generate electricity over here. All of the CO2 emissions, that underpin the motive for PV, are made in China. Only in the event of high energy gain in the PV device would solar PV reduce CO2 emissions. More on that later.

Energy Return

The calculations are all based on the energy produced by 1 m^2 of PV.

Theoretical calculations of what PV modules should generate made by manufacturers do not take into account operational degradation due to surface dirt. Nor do they take into account poor orientation, unit failure or breakage, all of which are quite common.

The actual energy produced using Swiss statistics works out at 106kWe/m^2 yr

We then also need to know how long the panels last. Manufacturers claim 30 years while empirical evidence suggests a mean scrapage age of only 17 years in Germany. Ferroni and Hopkirk use a generous 25 year unit life.

Combining all these factors leads to a number of 2203kWe/m^2 for the life of a unit.

Energy Invested

The energy invested calculation is also based on 1 m^2 of panel and uses mass of materials as a proxy for energy consumed and GDP energy intensity as a proxy for the labour part of the equation.

Two different methods for measuring energy invested are described:

  • ERoEI(IEA)
  • ERoEI(Ext)

Where IEA = methodology employed by the International Energy Agency and Ext = extended boundary as described by Murphy and Hall, 2010 [2,3]. The difference between the two is that the IEA is tending to focus on the energy used in the factory process while the extended methodology of Murphy and Hall, 2010 includes activities such as mining, purifying and transporting the silicon raw material.

In my opinion, Ferroni and Hopkirk correctly follow the extended ERoEI methodology of Murphy and Hall and include the following in their calculations:

  • Materials to make panels but also to erect and install panels
  • Labour at every stage of the process from mining manufacture and disposal
  • Manufacturing process i.e. the energy used in the various factories
  • Faulty panels that are discarded
  • Capital which is viewed as the utilisation of pre-existing infrastructure and energy investment
  • Integration of intermittent PV onto the grid

And that gives us the result of ERoEI:

2203 / 2664 kW he/m^2 = 0.83

The only point I would question is the inclusion of the energy cost of capital. All energy produced can be divided into energy used to gather energy and energy for society and I would question whether the cost of capital does not fall into the latter category?

But there appears to be one major omission and that is the energy cost of distribution. In Europe, about 50% of the cost of electricity (excluding taxes) falls to the grid construction and maintenance. If that was to be included it would make another serious dent in the ERoEI.

This value for ERoEI is lower than the value of 2 reported by Prieto and Hall [4] and substantially lower that the values of 5 to 6 reported by the IEA [5]. One reason for this is that the current paper [1] is specifically for temperate latitude solar. But Ferroni and Hopkirk also detail omissions by the IEA as summarised below.

IEA energy input omissions and errors

a) The energy flux across the system boundaries and invested for the labour is not included.
b) The energy flux across the system boundaries and invested for the capital is not included.
c) The energy invested for integration of the PV-generated electricity into a complex and flexible electricity supply and distribution system is not included (energy production does not follow the needs of the customer).
d) The IEA guidelines specify the use of “primary energy equivalent” as a basis. However, since the energy returned is measured as secondary electrical energy, the energy carrier itself, and since some 64% to 67% of the energy invested for the production of solar-silicon and PV modules is also in the form of electricity (Weissbach et al., 2013) and since moreover, the rules for the conversion from carrier or secondary energy back to primary energy are not scientifically perfect (Giampietro and Sorman, 2013), it is both easier and more appropriate to express the energy invested as electrical energy. The direct contribution of fossil fuel, for instance in providing energy for process heating, also has to be converted into secondary energy. The conversion from a fossil fuel’s internal chemical energy to electricity is achieved in modern power plants with an efficiency of 38% according to the BP statistic protocol (BP Statistical Review of World Energy, June 2015). In the present paper, in order to avoid conversion errors, we shall continue to use electrical (i.e. secondary) energy in kW he/m2 as our basic energy unit.
e) The recommended plant lifetime of 30 years, based on the experiences to date, must be regarded as unrealistic.
f) The energy returned can and should be based on actual experimental data measured in the field. Use of this procedure will yield values in general much lower than the electricity production expected by investors and politicians.

Of those I’d agree straight off with “a”, “c” and “f”. I’m not sure about “b” and “e” I’m sure this will be subject to debate. “d” is a complex issue and is in fact the same one described in my recent post EU and BP Renewable Electricity Accounting Methodologies. I agree with Ferroni and Hopkirk that units of electricity should be used throughout but if the IEA have grossed up the electricity used to account for thermal losses in power stations then this would increase their energy invested and suppress not inflate their estimates of ERoEI. Hence this is a point that needs to be clarified.

Environmental impacts

The main reason for deploying solar PV in Europe is to lower CO2 emissions. The European Commission and most European governments have been living in cloud cuckoo land allowing CO2 intensive industries to move to China, lowering emissions in Europe while raising emissions in China and making believe that importing steel from China somehow is emissions free.

The example of solar PV brings this into sharp focus. Assuming the main energy input is from coal (and low efficiency dirty coal at that) and with ERoEI <1, making electricity from solar PV will actually create higher emissions than had coal been used directly to make electricity for consumption in the first place. But it’s a lot worse than that. All of the emissions associated with 25 years of electricity production are in the atmosphere now making global warming much worse than it would otherwise have been without the PV.

And it gets even worse than that! The manufacture of PV panels involves lots of nasty chemicals too:

Many potentially hazardous chemicals are used during the production of solar modules. To be mentioned here is, for instance, nitrogen trifluoride (NF3), (Arnold et al., 2013), a gas used for the cleaning of the remaining silicon-containing contaminants in process chambers. According to the IPCC (Intergovernmental Panel on Climate Change) this gas has a global warming potential of approximately 16600 times that of CO2. Two other similarly undesirable “greenhouse” gases appearing are hexafluoroethane (C2F6) and sulphur hexafluoride (SF6).


The average weight of a photovoltaic module is 16 kg/m2 and the weight of the support system, inverter and the balance of the system is at least 25 kg/m2 (Myrans, 2009), whereby the weight of concrete is not included. Also, most chemicals used, such as acids/ bases, etchants, elemental gases, dopants, photolithographic chemicals etc. are not included, since quantities are small. But, we must add hydrochloric acid (HCl): the production of the solar- grade silicon for one square meter of panel area requires 3.5 kg of concentrated hydrochloric acid.

Comparison with nuclear

The paper offers some interesting comparisons with nuclear power. Looking first at materials used per unit of electricity produced:

  • PV uses 20.2 g per kW he (mainly steel aluminium and copper)
  • A nuclear power station uses 0.31 g per kW he (mainly steel) for a load factor of 85%

kW he = kilowatt hours electrical

Looking at labour, the authors observe:

The suppliers involved in the renewable energies industry advertise their capability to create many new jobs.

While of course the best forms of energy use as little labour as possible. At the point where ERoEI reaches 1, everyone is engaged in gathering energy and society as we know it collapses!

  • Solar PV creates 94.4 jobs per MW installed, adjusted for capacity factor.
  • Nuclear creates 13 jobs per MW installed covering construction, operation and decommissioning.

This may seem great to the politicians but it’s this inefficiency that makes solar PV expensive and kills the ERoEI. And looking at capital costs:

  • Solar PV needs CHF 6000 per kW installed (CHF = Swiss Franc)
  • Nuclear power CHF 5500 per kW installed

But normalising for capacity factors of 9% for solar and 85% for nuclear we get for effective capacity:

66,667 / 6471 = 10.3

Solar PV is 10 times more capital intensive than nuclear.

Energy transformation

When ERoEI approaches or goes below 1 we enter the realm of energy transformation which is quite common in our energy system. For example, converting coal to electricity we lose approximately 62% of the thermal energy. Converting coal and other raw materials into a PV panel may in certain circumstances make some sense. For example PV and a battery system may provide African villages with some electricity where there is little hope of ever getting a grid connection. Likewise for a mountain cabin. Individuals concerned about blackouts may also consider a PV battery system as a backup contingency.

But as a means of reducing CO2 emissions PV fails the test badly at temperate latitudes. It simply adds cost and noise to the system. In sunnier climates the situation will improve.

Concluding comments

The findings of this single study suggest that deploying solar PV at high latitudes in countries like Germany and the UK is a total waste of time, energy and money. All that is achieved is to raise the price of electricity and destabilise the grid. Defenders of RE and solar will point out that this is a single paper and there are certainly some of the inputs to Ferroni and Hopkirk that are open to debate. But there are reasons to believe that the findings are zeroing in on reality. For example Prieto and Hall found ERoEI for solar PV = 2. Looking only at cloudy, high temperate latitudes will substantially degrade that number.

And you just need to look at the outputs as shown below. Solar PV produces a dribble in winter and absolutely nothing at the 18:00 peak demand. There is a large financial cost and energy cost to compensate for this that RE enthusiasts dismiss with a wave of the arm.

Figure 1 From UK Grid Graphed. The distribution of solar production in the UK has grown 7 fold in 4 years. But 7 times a dribble in winter is still a dribble.  The large amount of embodied energy in these expensive devices does no work for us at all when we need it most.

Energy Matters has a good search facility top right. Insert solar pv and I was surprised to find how many articles Roger and I have written and they all more or less reach the same conclusions. I have added these links at the end of the post.

Figure 2 A typical solar installation in Aberdeen where the panels are on an east facing roof leaving the ideal south facing roof empty. This is a symbol of ignorance and stupidity that also pervades academia. Has anyone seen a University that does not have solar PV deployed? I’ve heard academics argue that orientation does not matter in Scotland, and they could be right. I dare say leaving the panels in their box would make little difference to their output. Academics, of course, are increasingly keen to support government policies. Note that sunny days like this one are extremely rare in Aberdeen. And in winter time, the sun rises about 10:00 and sets around 15:00.

Two years ago I fulminated about the random orientation of solar panels in Aberdeen in a post called Solar Scotland. And this random orientation will undoubtedly lead to serious degradation of the ERoEI. PV enthusiasts will no doubt assume that all solar PV panels are optimally orientated in their net energy analysis while in the real world of Ferroni and Hopkirk, they are not. A good remedy here would be to remove the feed in tariffs of systems not optimally deployed while ending future solar PV feed in tariffs all together.

But how to get this message heard at the political level? David MacKay’s final interview was very revealing:

The only reason solar got on the table was democracy. The MPs wanted to have a solar feed-in-tariff. So in spite of the civil servants advising ministers, ‘no, we shouldn’t subsidise solar’, we ended up having this policy. There was very successful lobbying by the solar lobbyists as well. So now there’s this widespread belief that solar is a wonderful thing, even though … Britain is one of the darkest countries in the world.

If the politicians do not now listen to the advice of one of the World’s most famous and respected energy analysts then I guess they will not listen to anyone. But they will with time become increasingly aware of the consequences of leading their electorate off the net energy cliff.


[1] 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

[2] Murphy, D.J.R., Hall, C.A.S., 2010. Year in review-EROI or energy return on (energy) invested. Ann. N. Y. Acad. Sci. Spec. Issue Ecol. Econ. Rev. 1185, 102–118.

[3] Murphy, D.J.R., Hall, C.A.S., 2011. Energy return on investment, peak oil and the end of economic growth. Ann. N.Y. Acad. Sci. Spec. Issue Ecol. Econ. 1219, 52–72.

[4] Prieto, P.A., Hall, C.A.S., 2013. Spain’s Photovoltaic Revolution – The Energy Return on Investment. By Pedro A. Prieto and Charles A.S. Hall, Springer.

[5] IEA-PVPS T12, Methodology Guidelines on the Life Cycle Assessment of Photovoltaic Electricity – Report IEA-PVPS T12-03:2011.

Energy Matters solar posts

Solar PV – an irresistible disruptive technology?

Net metering and the death of US rooftop solar

Hinkley Point C or solar; which is cheaper?

A review of concentrated solar power (CSP) in Spain

Rooftop PV Panels Point Where the Roof Points

A Potential Solution to the Problem of Storing Solar Energy – Don’t Store It.

The German Grid and the Recent Solar Eclipse

Large scale grid integration of solar power – many problems, few solutions

Solar Scotland

The efficiency of solar photovoltaics

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302 Responses to The Energy Return of Solar PV

  1. Joe Public says:

    Illuminating, thanks Euan.

    • Knut says:

      No it is not. It is the opposite of illuminating, whatever that is. Obfuscating, perhaps. The two authors are not reputable scientists, and “Energy Policy” is at best a borderline reputable journal. And the article is so littered with tendentious assumptions that it is hard to even know where to begin.

      For one thing, though this article is new, the data it builds on is old (e.g. “Myrans (2009)” to document the materials usage of PV panels). If you think PV panels production has not improved is materials efficiency since 2009 (and god knows when the data in the 2009 paper, in turn, is from) please raise your hand.

      Second, it is absurd to include labour and capital in the calculation of energy invested. Use a simple counterfactual test: if the people working in PV factories had not been employed there, would they insted have been sitting in a dark room, not consuming any energy? Of course not. Or capital: if not invested in PV production, would that capital have been invested in something energy neutral? Right. The only honest way to calculate ERoEI is to calculate the energy something produces divided by the energy consumed in actually producing it (including, of course, the production of input materials, facilities, transport, etc.).

      In any case, it is a waste of time to engage in the details of an argument that issues in a patently false conclusion. If photovoltaic panels had a low or even negative ERoEI, it is a physical and economic impossibility (what’s a good word for that? econophysical?) that PV power could be so cheap. The recent low of 2.99cents/KWh (unsubsidized)

      would quite simply be economically impossible if it took more energy (from other, more expensive sources) to produce the hardware that in turn will produce that energy. I know, or course, that Dubai has greater insolation Switzerland, but the difference would have to be orders of magnitude, which it is not.

      So, Euan, why write a single-sourced post based on an unreputable article from two unreputable authors in an unreputable journal to a patently false conclusion?

      • Knut says:

        Actually, I was so annoyed by this post that I took the time to track down “Myrans (2009)”. That is not a peer-reviewed article at all, but a “thesis submitted in conformity with the requirements for the degree of Master of Science, Graduate Department of Geography and Centre for Environment, University of Toronto”. The sources in therein, in turn, are of course older still.

        And google searches for the two authors of the article Euan bases this post on produces very little. There are very few hits, and the few there are suggest that they are either crackpots or charlatans.

        • mark4asp says:

          Why aren’t you posting your alternative ERoEI(ext) study to contradict this, because no such studies were ever done? Europe invested over €1 trillion in RE, much of it solar. All without any substantial studies to justify the expenditure. All done on the back of green bullying, blackmail, and political diktat.

          I’m not likely to take much you say seriously until you’ve written your counter ERoEI(ext), with properly sourced data. I expect I’ll wait my entire life for that.

          • Ajay Gupta says:

            There is plenty of work on EROI and PV EROI out there which can put this paper in context. Please see works of Charles Hall and David Murphy to start. You don’t have to wait for the commentor if you’re serious about your claim.

          • A.D. says:

            Here are the results of a literature study. A mr Bhandari looked at 232 papers on solar EROI from 2000-2013.

            Average EROI: 11.6

            …based upon relatively old solar cells/panels. Modern thin film cells have much higher EROI.


            Meanwhile the advance achieved in the field is substantial. Stress is no longer put so much on further enhancement of conversion efficiency, however spectacular that may be, but instead of cost cutting and improving production methods.
            Furthermore, standard calculation practice is to assume an economic lifetime of 25 year. Although not much data is available, anecdotal evidence suggests that panels can keep producing at 80% of the original output after 40 years:


            That significantly adds to EROI.
            Flexible thin film solar:


            Needs only 10% of the matter of conventional solid panels. It is obvious that embodied energy is far less per m2.

      • Alex says:

        “Second, it is absurd to include labour and capital in the calculation of energy invested. Use a simple counterfactual test: if the people working in PV factories had not been employed there, would they insted have been sitting in a dark room, not consuming any energy? Of course not.”

        No, the people and capital would have been doing something else – perhaps more productive, like building nuclear plants, perhaps less productive, like digging up and burning coal.

        Where we want to compare strategies, it’s perfectly acceptable to assign energy costs to people and capital.

        “The recent low of 2.99cents/KWh (unsubsidized)”

        Sounds like “too cheap to meter”. I wouldn’t pay too much attention to outlier auction bids. If someone has nothing to do with some cash, and wants 0% return, then 3 cents could be possible.

        In Europe, that’s still above the wholesale price when the sun shines.

        • Thinkstoomuch says:

          Ever been to Dubai? The sun is a nasty and only 24.5 degrees from the equator.

          According to PVWATTS (using the international data set) it is about the same as Arizona. A ~1,000 meter squared system yields 262,475 kWh per Year. (PVWATTS has that neat draw your system tool on the second page).

          Labor was extremely cheap last time I was there, 15 years ago.


        • Knut says:

          “No, the people and capital would have been doing something else – perhaps more productive, like building nuclear plants, perhaps less productive, like digging up and burning coal.

          Where we want to compare strategies, it’s perfectly acceptable to assign energy costs to people and capital.”

          Right, they could have done something with a higher ERoEI, or a lower ERoEI, or zero ERoEI because it doesn’t produce energy at all. But it is foolish to try to build that into the ERoEI in the first place.

        • gweberbv says:


          be aware that the planned plant in Dubai is 800 MW. For sure it is an outliner in terms of the combination of high insolation, cheap labour (compared to Europe) and its sheer size. But I doubt that the investors, developers and suppliers behind it are not seeking profit. EDF, Enel, Total and RWE are trying to enter the large-scale PV market on the arabiian peninsula.

          • singletonengineer says:

            How do we know that the low 3.99 price applies to all or only part of the 800MW plant you mention? Do we know that it applies to every one of those 800MW? Does Gweberbv? I very much doubt it, because he hasn’t provided a reference.

            Until I hear the true facts, I will pretend that the silly figure of 3.99 applies only to a silly percentage of the capacity of the PV, perhaps the first 5% or 40MW. Above that, the rate could be anything.

            One thing is certain – the actual figures are still confidential, so we can safely ignore the 3.99 figure.

          • gweberbv says:


            the link was given above by Knut. But it should not be too hard to find it on the web just typing “800 MW PV Dubai” in a search engine of your choice. As this acution sets a new record low for PV prices AND is one of the biggest PV projects worldwide, it enjoyed a decent media coverage.
            By the way: It is 2.99 US cents/kWh, not 3.99.

            If you manage to get the same price per kWh for a project of 1/20 the afromentioned size (your “5%”), you should enter the PV developer business right away!

          • singletonengineer says:


            Gweberv; you have avoided the topic. Again.

            I followed the link that you refer to. The details of the Dubai offer, admittedly $2.99US/MWh, have not been disclosed. It is conjecture as to what portions of the possible 800MW have been offered at that or any higher rates.

            To put it briefly: Until the terms of the proposed contract are known, if ever, discussion about a single line of the offer is meaningless.

            Indeed, the reason for disclosing one juicy line of the proposed contract must be political spin, because as the article stated, it is not yet contractual reality.

            If you have information to the contrary, please cite it. Otherwise, simply state that you are interested in the reports of a low bulk power price and that you await clarification of details of the contract, when they become available.

          • robertok06 says:


            The bid of 2.99 c$/kWh apply to a given amount of electricity/year. If the bidder doesn’t deliver there are penalties.
            This form of “creative” energy generation is nothing else than a ponzi scheme of a new kind. It has been applied already in other places recently, Chile, USA (Hawaii), and others.
            The bidders (I’ve read an interview with a ENEL Greenpower extecutive somewhere recently) bid low now for electricity to be delivered years from now, and do so because they project to the near future the cost decrease of PV which is well documented (learning curve). It is not at all guaranteed that this ponzi scheme will work at all… in fact none of the projects similar to this have already produced a single Wh of electricity.
            Only time will tell… but the record says, and this is not hypothesis it is history, that a very aggressive company which 1-2 years ago was on the rafters, SunEdison, for similar stories is bankrupt… a financial black hole of 16.7 BILLION dollars.

            Photovoltaics are a non-started to power mankind, not even at 0 dollars/kWh they would be capable of doing that, it is physically impossible, plain and simple.

      • Euan Mearns says:

        Dear Knut, It seems you do not like this post. Let me begin with your concluding statement:

        So, Euan, why write a single-sourced post based on an unreputable article from two unreputable authors in an unreputable journal to a patently false conclusion?

        You appear to have wisdom beyond most to already have concluded that the authors and the journal are unreputable. Else where on the thread someone points out that the lead author is the Health and Safety Manager at a Swiss nuclear power station. And we have had the merits of peer review rammed down our throats by certain sectors for years. But now it seems peer review is great so long as one agrees with the peers.

        The one point where you are correct is that I wrote a post relating the findings of a single article, and I say:

        If correct, that means more

        I thought about adding a more extensive disclaimer but didn't find it necessary since my American friends were more or less backing what the authors had to say…..

        Second, it is absurd to include labour and capital in the calculation of energy invested.

        Well in the post I question the inclusion of capital but it turns out I have not fully understood what capital means. But to claim it is absurd to include labour in an ERoEI calculation in my book you loose all credibility.

        And there are a couple of very important points in my post:

        1) OECD economies are exporting CO2 emissions (along with jobs and prosperity) to China, and

        2) All of the CO2 emissions associated with creating renewable devices are in the atmosphere today.

        Do you also disagree with these points?


        • Knut says:

          I don’t claim wisdom beyond most, no. I called it “unreputable” after looking at the bibliography at the end of the article, which gives the clear impression of being cherry-picked to reach a particular conclusion (e.g., again, “Myrans (2009)”. Whoever uses a seven year old masters’ thesis as their source for the materials usage of solar panels is either not motivated to find the truth, or not competent enough to find a better source). And I quickly looked at some journal rankings in the area. It ranks sufficiently far down to be at a level where, at least in the fields I know first hand, not everything that is published is of sterling quality, shall we say. The fact that it is published by Elsevier means nothing; those guys will print anything so long as they make a profit.

          I didn’t know when I wrote the comment that one of the two authors is employed in the nuclear industry. In the article, they are presented as: “Energy Consultant, Zurich, Switzerland” and “Engineering Research & Development, Maennedorf, Switzerland”. I should think it a basic question of academic integrity to disclose one’s employment in a competing industry when publishing a paper with such an obvious edge against the PV industry.

          So yes, I honestly think you shouldn’t participate in the spread of this kind of misinformation. A google search of the article’s title now gives the following top his:
          1. The paper itself, which is behind a paywall.
          2. This blog post.

          So it matters how things are presented. Prefacing it all with “If correct…” doesn’t discharge that responsibility.

          As for including labour in ERoEI, I see how that can be reasonable for certain purposes, e.g. economic policy, but the clear focus of the post was carbon emissions. And it is a simple fact that if those people had not been working at the PV plant, they would have been consuming energy regardless. Unlike raw materials, which reduced demand may cause to be left in the ground, reduced demand for labour will not cause people to not have been born.

          As for your questions,

          1) Yes. Though in order to properly think about that we ought to start with the most accurate numbers we can find, not obviously faulty ones. And I should confess that I hold the view that exporting prosperity from rich countries to poor countries is a good thing.

          2) Of course.

          • Euan Mearns says:

            Knut, to include labour or not is a controversial issue but I get the feeling that balance of opinion is to include it. This is what I wrote in an email this morning:

            The money paid to workers gets converted to energy apart from the part that is saved. So it would seem logical to use (savings/gross earnings)*energy intensity per capita per year. The part that goes to tax, leisure etc is that part of society that supports the energy industry. Net energy is that part of the energy industry that supports society.

            If you don’t want to include labour in your costs, it then becomes disingenuous to claim that solar PV is cheap. Every part of the energy chain that has a financial transaction has an energy transaction.

            It is in my opinion a mistake for you to try and undermine this work by making claims that the authors and journal are unreputable. That is standard operating procedure for Green Trolls.

            Whether or not the authors have been objective in their analysis and used good procedures and data is open to debate. That is the debate we are trying to have. But lets say they are not too wide of the mark. then it follows that many studies that find high ERoEI for solar may lack objectivity.

            Take the Prieto and Hall number of 2.4 for Spain and normalise that to capacity factor of 0.09 for northern latitudes and you get a number approaching that of Ferroni. You may not like me publicising this kind of information, but IF Ferroni is correct, then our policies are leading us off the Net Energy Cliff. I feel perfectly justified having a debate about this. Of course there is a part of society that relishes the prospect of collapse.

          • Knut says:

            Euan, you are right, of course, that questioning motive is very problematic and should only be done if it is absolutely impossible to avoid it. But I really cannot see how one could think Ferroni and Hopkirk are engaged in a dispassionate search for truth given the following:

            a) One of them fails to disclose (on the place in the article where you identify your institutional affiliation) that he works for a nuclear power company.

            b) Their numbers for material usage for PV comes from a 2009 masters thesis entitled: “COMPARATIVE ENERGY AND CARBON ASSESSMENT OF
            THREE GREEN TECHNOLOGIES FOR A TORONTO ROOF”. It is truly hard to believe that two authors in this field either wouldn’t know that a lot has happened in the PV industry since 2009, or would be unable to find more recent data.

            c) Hasn’t it become clear in the comments below that their numbers for energy yield in Swiss PV systems has been severely lowballed, and is not to be found in the source they list?

            d) Hasn’t it become clear in the comments below that they conveniently neglected to include concrete in the materials calculation for nuclear?

            (Regarding c) and d), haven’t had time to re-check, a bit busy, sorry.)

            I would never object to you publicizing any kind of information and having a debate about it. I do object to publicizing deliberate misinformation in a way that lends credence to it.

            You can try to say you just want to put different arguments on the table and have an open debate. But the picture on the top of the post, and this sentence, for example:

            “The image shows the true green credentials of solar PV where industrial wastelands have been created in China so that Europeans can make believe they are reducing CO2 emissions”

            Well they are on you.

          • robertok06 says:


            “(e.g., again, “Myrans (2009)”. Whoever uses a seven year old masters’ thesis as their source for the materials usage of solar panels is either not motivated to find the truth, or not competent enough to find a better source).”

            Well… it is clear (to me, clearly, Ispeak for myself) that you are on eof the many PV/renewables agit-props that come visit this excellent blog, so I am sure that you know who Mark Z Jacobson is, and what he has published (incidentally, often published on Energy Policy, the journal that here above you’ve called unreliable or something like that!)… well, Jacobson has puplished a peer-reviewed paper with as co-authors two of his sons, at least one of which was still in high-school at time of writing)… how about that?… this Myrans guy at least has written a master thesis.

            Nice try, though.

            P.S.: did you read the Myrans thesis, at least? If not, why not?
            I did it, and it is a very well written document.

          • robertok06 says:


            “d) Hasn’t it become clear in the comments below that they conveniently neglected to include concrete in the materials calculation for nuclear?”

            The amount of concrete used for nuclear installations is very small, once normalized to the amount of energy generated… so even if they did omit it (which I would need to check) they didn’t do a big mistake.
            On Vattenfall’s Environmental Product Declaration for Forsmark’s reactors they quote 4.1 grams per kWh, just consider that a 3 MW turbine can use in excess of 1000 tons of concrete, if you divide 1billion grams by the amount of kWh produced by the 3 MW turbine in 20 years, 5.3E+8 kWh (25% capacity factor), you get 7.6 g of concrete per kWh… much more than for nuclear reactors.
            “another one bites the dust”… I’m talking about one of the many myths around nuclear… “it needs huge amounts of concrete”.

            Nice try, again.

          • Knut says:

            Dear robertok06,

            Sorry, I don’t know who Mark Z Jacobson is.

            I did read some of Myrans 2009. It struck me as a very good master’s thesis. Impressive, in fact.

            I doubt that Kathatrine Myrans is a “guy”, though.

            My point has nothing to do with the quality of the 2009 paper. My point is that the price of PV panels has dropped manyfold between 2009 and 2016. It strains credulity that this could happen without a radical reduction in the materials usage.

            And it strains credulity that Ferroni and Hopkirk would be unaware of this. Yet they went ahead and used numbers from 2009 (actually, 2008, the year of the sources in Myrans’ excellent thesis) anyway.

            There is simply no scenario in which this happens in which Ferroni and Hopkirk are both a) competent, and b) motivated to find the truth.


          • robertok06 says:


            “There is simply no scenario in which this happens in which Ferroni and Hopkirk are both a) competent, and b) motivated to find the truth.”

            a) The authors are certainly, and without any doubt competent people, don’t be sillier than you already are, please!
            b) Notwithstanding the choice of the latest, fresh-of-the-mill data about costs of PV materials, the “truth” behind the paper stays the same: if you don’t like the 2 authors and think you are good enough to do it, then take YOUR OWN data and re-do the analysis they have done… it is very simple, a bit time consuming but doable. The results and conclusions will not be far off of those reached by the two authors. PV is and always will be a marginal, money-sucking technology, that due to its inherent intermittency and highly seasonal production (non-production during 4 entire months, that is, in non-southern european countries).
            That’s a fact, as much as you would love to see it differently there is nothing you or anybody else can do, it’s Mother Nature, baby!


          • It doesn't add up... says:

            You may find an exploration of Leontief analysis useful in helping to clarify your mind. It represents an economy using a set of technical co-efficients for direct inputs to each industry from the other industries where appropriate. Indirect inputs can be derived by inverting the matrix and applying it to a vector of final demand. Marginal effects are easily explored by varying the demand vector. Implied pricing is derived from the principal eigenvector (which by construction has a unit eigennumber). In most such systems, indirectly every industry contributes to every other one. Exceptions would require whole sections of the economy to be isolated from each other (as might happen with two islands with no trade between them). This kind of analysis was originally proposed by Karl Marx, although he lacked the mathematics to solve it (and indeed the full solution awaited Paul Debreu, for which he won an economics “Nobel”) – and his objective was to assess the extent of “embedded labour” in economic outputs. You can equally assess the extent of embedded energy and other factors of production.

        • mark4asp says:

          Knut has so much genius, he posts anonymously. I guess he is too modest to take credit, in his professional sphere, for the pearls of wisdom deposited upon us.

          • Knut says:

            Dear Mark,

            I’m Knut Skarsaune, Postdoctoral Research Fellow in Philosophy at the University of Oslo.

            I come to this site to learn more about energy and the climate challenge.


      • Knut,

        If photovoltaic panels had a low or even negative ERoEI, it is a physical and economic impossibility (what’s a good word for that? econophysical?) that PV power could be so cheap. The recent low of 2.99cents/KWh (unsubsidized)

        It is not true that is unsubsidized, It was signed a 15 year contract for the 2.99c/kWh and a 20 year contract to exploit the green energy certificates, that US-EPA is strongly advocating, the REC price forecast is growing, heading the $8c/kWh.

        • Knut says:

          Do you mean there are green energy certificates in Dubai? Source for this? Or are you talking about a different project?

          More broadly, I have no doubt the Dubai project is an extreme case. And it may not be profitable. But there are other examples not much higher. Read the linked article.

          The main point is just that any argument, with many doubtful and speculative assumptions, which issues in the conclusion that PV has a very low ERoEI can thereby be considered a reductio ad absurdum of its own assumptions. Because if that conclusion were true then it would be econophysically (I say, if that isn’t a word, then it should be) impossible for PV power to be as cheap as it demonstrably is. Whether the true cost of the cheapest unsubsidized PV plant is 2,99c/KWh, or 4, or even 6 or 7 does not affect the point.

          (None of that is meant as an argument that we should be rushing to put solar panels in Scotland.)

          • gweberbv says:


            this is the most detailed analysis on the recent Dubai auction that I found:
            No certificates, no tax credits (but probably very low financing costs by the sheikhs). What is really important is not the 2.99 US cents/kWh winner, but the fact that several major players offered prices below 4 US cents/kWh.

          • Alex says:

            The cost of solar depends very heavily on the discount rate. Here’s a copy of an analysis I did recently – which I think is on the optimistic side, and doesn’t cover network costs (not an issue for solar producers).
            If you take a cost of 3p at close to zero %, and treble that for UK sunlight, you are at the 9p in the chart. Add in a cost of capital, and it’s 15p. Add in network and indeterminacy costs ……

            This posting is not about solar in Chile or Dubai, where I think it has a bright future, but North of the Alps, where the future is as dark as the weather.

          • Knut says:


            absolutely. Uneconomical north of the Alps at present.

            To infer a dark future, though, we need three assumptions.
            1. PV costs will not continue to come down.
            2. Storage costs will not continue to come down.
            3. Interests rates will not continue to be low.

            My crystal ball seems to be saying that all these are false. Depending on *how* false they are, and especially 2, I say the line below which solar can pay its way will creep further north than many people on this forum believe.

            I should mention that my crystal ball is a techno-optimist.

      • robertok06 says:

        “in an unreputable journal”

        You’ve got to be kidding!… Energy Policy is one of the major publications in the field! C’mon!

        You may have a point in some exaggerations made by the authors, but you can’t call Energy Policy “unreputable”, it is nonsense.

        Also, you counter-example of the recent contracts for very low PV electricity in Dubai doesn’t prove anything against the paper being discussed here: the authors of the paper talk about Germany and Switzerland, I don’t recall Dubai being a neighbour of any of the two, do you? 🙂

        Also, the 2,99 cents/kWh do not take into account the intermittency and seasonality (which is, to tell the truth, in Dubai rather small)… which is exactly one of the points of the paper being discussed here… i.e. that IF one correctly includes ALL costs so that intermittent sources can really take the place of baseload ones, then the real cost (energy and capital) of the intermittent ones goes to the roof, and their EROI collapses.
        See, what a coincidence, another paper in Energy Policy by Weissbach et al… you can find it without need to pay on the internet.

        Nice try, though.

      • mark4asp says:

        According Charles Hall the minimum ERoEI for sustainability = 5, according to others it is 12. The study indicates solar PV needs to be either 6 times, or 14½ time better than it is in this respect (ERoEI). Even were they out by a, very unlikely, factor of 4 solar would still not be good enough. According to some they could be out by an order of magnitude but solar would still not be good enough.

        Have you even read the study, or attempted to validate their numbers?

      • mark4asp says:

        Your second sentence is an argument from authority. Do you not know how to properly argue or do you deliberately do fallacies? If the former, you should go back to college.

        • Knut says:

          Dear Mark,

          I have a PhD and teach in college for a living. When people follow the norms of academic debate, you engage with their arguments. When they deliberately cherry-pick and massage their “data” in order to reach a desired conclusion, it’s another matter.

          I actually agree that PV in Northern Europe does not make sense with current technology. But I absolutely hate it when academic journals print partisan piffle, one way or the other. That’s why I got worked up about this.


      • It doesn't add up... says:

        There is no guarantee that solar panel prices will carry on falling. The present low costs are the consequence of massive overcapacity in the industry, which results in panels being sold for any cash they might raise in a firesale. This was over two years ago:

        The solar industry seems to be full of financial frauds, many of them preying on the naïveté of governments wedded to green agendas. SunEdison, Solyndra, Iberdrola, Solar CIty…

        MEED reported that it’s a group including Masdar Abu Dhabi Future Energy Co., Spain’s Fotowatio Renewable Ventures BV and Saudi Arabia’s Abdul Latif Jameel.

        Who? A real confidence inspiring bunch.

        • @It doesn’t add up…

          Indeed. If you take the costs for solar in Germany from the AGEE stat reports*, you can see the curve leveling out. We are in the corner of the curve so not clear how low it can go.

          Development of renewable energy sources in Germany 2014
          Charts and figures based on statistical data from the Working Group on Renewable Energy-Statistics (AGEE-Stat),
          as at February 2015

          • singletonengineer says:

            The curve cannot continue to fall for ever.

            Eventually the Law of Diminishing Returns always wins over the Learning Curve.

        • sod says:

          It does not add up, indeed.

          The article you quoted is from 2013. That was 2.5 years ago and the chinese solar PV production has not collapsed.

          The article says:

          “According to Bloomberg, if all of China’s solar producers were to run their factories at full speed, they could produce 49 gigawatts of panels annually – a ten-fold increase from 2008 and 61% more than global installed capacity last year. ”

          But the PV market did actually install 51 GW in 2015.

          So this was not overcapacity, but pretty good planning.

          • Jan Steinman says:

            if all of China’s solar producers were to run their factories at full speed

            Ah yes. The infamous “if only” argument.

            I suppose next you’ll tell us that “if only we covered ‘useless’ desert land with solar panels,” or “if only we had giant solar panels in space, beaming energy to microwave rectennas back on Earth,” or “if only roads and parking lots were made out of PV material that will come out of the labs Any Day Now™”

            Don’t tell me what’s gonna happen. Or you’ll have to put up with an earful of my ideas about what’s gonna happen. And they’re just as valid as yours.

        • gabs says:

          You may follow the development op prices of solar modules here: . And be aware that different from the situation two or three years ago, module manufacturers earn moeny today. And you might think about what a price drop of 0,3-0,5% per week means for competing technologies.

          • Jan Steinman says:

            you might think about what a price drop of 0,3-0,5% per week means

            Uhm… bankruptcy?

            Oil has fallen at over double that rate in the same period. What would that mean for “competing technologies,” and if different than what you claim it means for PV solar, why?

            You have to be very careful about discriminating between price drops because of economy of scale and improved manufacturing efficiency, and price drops due to demand destruction and deflation.

            There are empty, abandoned factories in China. There are thousands of empty container and tanker ships, tied up idle outside Chinese ports. The Baltic Dry Index (a measure of global demand based on shipping statistics) is at 30-year lows.

            In a global recession, price drops don’t count. Indeed, they can be seen as an indicator of an ailing industry. If demand for solar is so hot, prices should be rising, says Adam Smith!

  2. mike h says:

    And looking at capital costs:

    Solar PV needs CHF 6000 per kW installed (CHF = Swiss Franc)
    Nuclear power CHF 5500 per kW installed

    Given that hinkley has a reported build cost of 18bn, delivering 3.2GW that would seem to calculate closer to CHF 8,000

    Solar PV does not cost CHF 6,000/KWp installed. Roof top and Utility solar have significant difference, so it is strange to consider all solar as equal.

    Utility scale is cheaper, but then you could associate grid costs for distribution.
    Residential is more expensive, but has very few losses.

    Rough estimates for these 2 in the UK are; (CHF/GBP 0.71)
    Residential CHF 2,800
    Utility CHF 1,800

    Residential costs again vary significantly by country, principally around Balance of Plant where the US is the most expensive and Germany the cheapest.

    • Alex says:

      I know Switzerland is very expensive, but CHF 6,000 / KW is way out. €2,000/KW is more likely – certainly over the border.

      • robertok06 says:

        I work in Switzerland, and you wouldn’t imagine how expensive this place can be… for everything.
        I have posted a few weeks ago on this very same subject a link to a Swiss PV web site, where they cited 2800 CHF/kWh.

        Few exemples (OT):
        Do you want to see pizza at 50 CHF/each? Come to Geneva…. 🙁
        A badly parked car iin the middle of nowhere? 150 CHF and a threat to be taken to jail for one day if you don’t pay. 🙁 🙁

    • Euan Mearns says:

      Roger queried the CHF 6000 figure. If it is so wildly out it raises the question why the authors used it and why it got through peer review.

      But the prices you quote still need to be normalised for capacity factors:

      CHF 1800 / 0.09 (capacity factor) = CHF 20,000 for effective kW installed
      CHF 8000 / 0.85 (capacity factor) = CHF 9,412 for effective kW installed

      And normalising for plant life 30y for solar and 60 y for nuclear halves the relative capital cost of nuclear again.

      But the post is really about energy invested and not about $ invested. Would you be confident going out to mine and purify silicon and aluminium using only electricity from high latitude solar PV. And powering the factory and growing all the food for the workers?

      • Alex says:

        “But the prices you quote still need to be normalised for capacity factors”

        If you want to compare with nuclear, yes. In the referenced paper, it’s accounted for, but seemingly a pessimistic view.

        “Would you be confident going out to mine and purify silicon and aluminium using only electricity from high latitude solar PV.”

        You’d have to shut down operations in the winter. But this will be needed on Mars at some point.

        • mark4asp says:

          Seems a silly idea to manufacture solar power on Mars!, given the difficulty of energy storing. Much easier to extract uranium and/or thorium to run Mars on 24/7/687 nuclear power. Nor do I understand how you managed to put “prices” and “Mars” in the same post!

      • Auss says:

        Be aware that Mr. Ferroni calculates the energy investet directly from the capital invested, you cited this in your text.

      • robertok06 says:

        “Roger queried the CHF 6000 figure. If it is so wildly out it raises the question why the authors used it and why it got through peer review.”

        Unfortunately the much touted “peer review” process is not what it used to be back then… the good ‘ol times… I have a very good opinion of Energy Policy, as a journal, and I am a fervent pro-nuclear and PV-skeptic guy (as you’ve probably noticed… ) but in this case I’m afraid the authors have exaggerated with the CHF/Wp value… not that it changes much, in fact PV keeps on being a looser technology if nothing because of its intermittency and seasonality.
        Also, to those who object to the authors’ choice of 6 CHF/Wp, one should also point out that it is not that all nuclear reactors cost those proposed for like Hinkley Point, the (in)famous EPRs… and on that there is a very recent paper, again in Energy Policy, which deals with the cost and cost overruns trends of several nuclear program in different countries, which basically shows that only the USA have a disfunctional way of dealing with nuclear… mainly because of their anti-nuclear lobbying based on law suits… just see what’s happened recently in California, NY, Vermont,… they have shut down reactors “for the sake of the environment” just to see GHG emission skyrocket because nuclear electricity has not been substituted by renewables (it’s physically impossible to do it), but by gas.

    • Euan Mearns says:

      And Roger went into greater detail here

      My (your) numbers above make solar 4 times the capital cost and adding in the cost of storage, I have no problem getting to a figure a factor of 10 albeit that Ferroni maybe got there by the wrong route.

      • mike h says:

        I’m not at all disputing that implementing Solar in northern latitude countries is a poor use of a valuable asset. I’m absolutely certain that several installations are, in effect, worthless. It’s also important to point out that this wanton waste of resources is not limited to the solar sector.

        The 10gw solar in the UK would be far more sensible if located in Morocco.

        What is concerning is that in supportive arguments for what may be a very valid case, basic cost estimates for installation of solar (no mention if rooftop or utility) are so far out as to raise valid questions on other assumptions used.

    • robertok06 says:

      “Given that hinkley has a reported build cost of 18bn, delivering 3.2GW that would seem to calculate closer to CHF 8,000”

      As far as I know, the much mentioned high cost of Hinkley Point C includes the decommissioning of the reactors, and the storage of the spent fuel/waste.

  3. singletonengineer says:

    It is sad how many times some messages need to be repeated before they are heard.

    I live in sunny Australia, where the return is significantly better but still inadequate, even after including government subsidy in the form of REC’s, Renewable Enerrgy Certificates.. This is, unless as stated above, myhome was a yacht, a mountain cabin or an island, in which case a battery plus lights at night would be handy – but the battery reduces the ERoEI significantly and will end up as poisonous waste every 5 or 6 years.

    • SP says:

      Lead can be recycled and you are supposed to take your lead acid batteries to the battery collection point at your local tip.
      Li is not “toxic” in the same sense that lead is toxic and can also (ie should) be recycled.

  4. Alex says:

    Interesting. Without access to the core data – which probably exists only in the Chinese factory (or not even there, in the case of non-accounting state owned enterprises) – it’s hard to evaluate.

    However, in their first four years, my panels, about 10km North of Switzerland, have been delivering 155 KWh/m2 (based on the external dimensions – add a few if it’s just the PV surface). That compares to the figure given of 106 KWh/m2.

    I get about 1,143KWh/KWp/year, which is slightly better than “advertised”, but most people seem to get better than advertised.

    As for time – hard to say. There’s no reason why panels shouldn’t last 60 years, but it’s quite likely that people are scrapping 15 year old panels because the replacement costs are so low.

    For energy in production, the critical dimension is time. Regardless of the arguments in a to f above, it is likely that there is a strong correlation between cost and energy input. Given that solar panel prices are halving every few years, it seems likely energy input is doing the same – apart from the costs of integration which will increase for anywhere without a significant hydro potential and a sun-demand correlation. (i.e most of Northern Europe).

    On what year is the analysis predicated? Regardless, it’s likely that 10 year old panels in Switzerland won’t make an energy payback, but current ones will. And of course, move them to Aberdeen…..that would be silly.

    Grid integration costs …. Germany is planning to spend several 10s of billions of Euros on North – South grid links. This is needed to link wind in the North with solar in the South. Clearly, a cost of solar and wind, but paid for by all users. Classic grid cost of solar.

    However, if we move somewhere hotter, with air-con load, and more reliable sun, then the amount of electricity being shifted round the grid could fall. Households with solar and storage could get by with a 13A (3KW) connection to the grid.

    • Alex says:

      Looking at the supply side, panels cost about €2,000/KW, for a fully installed system. That includes VAT. Ex VAT, that comes to about €225/square metre.

      The study claims that this square metre requires 2,664 KWh to make, all in.

      So if ALL the cost of the panels were to be spent on energy, then the energy could cost no more than 8.5 cents / KWh.

      The point (d) above states:
      “since some 64% to 67% of the energy invested for the production of solar-silicon and PV modules is also in the form of electricity”

      So it would seem that either the manufacturers, distributors and installers have access to very cheap energy, or the figure is an exaggeration.

      Another way of looking at it, Chinese energy intensity is quite high, 231 toe/million$. That comes to 2.68KWh/$ of GDP.

      So at average Chinese energy intensity, the €225.68, call it $300 square metre of cell, implies an input of 805 KWh.

      Whilst solar cell manufacturing is more energy intensive than most industries, a lot of that cost (perhaps over 50%) is spent in the west, at a much lower energy intensity.

      The 805KWh figure, coupled with 155 KWh/m2/year from above, and a 25 year life, would give a ERoEI of about 6.

      This rather reminds me of my early years calculating Net Present Values. “How is the NPV looking?” my boss would ask. “How do you want it to look?” I’d reply.

    • Euan Mearns says:

      However, measurements with a pyranometer, from which these values are derived do not take into consideration the reduction of irradiation and hence of solar cell performance due to the pre- sence, in the course of real operation, of accumulations of dust, fungus and bird droppings, due to surface damage, ageing and wear and finally due to atmospheric phenomena like snow, frost and condensing humidity.

      And to that I’d add poor orientation. And…..

      An alternative route to obtaining the energy return starts with the published statistical data of the PV installations themselves. The values measured are the electrical energy flow after conver- sion in the inverter from direct to alternating low voltage current and the indication of the kWp peak rating of the installed PV system. In this case, applying the module surface per installed peak kWp, it is possible to calculate the electricity production per square meter of the module. According to the official Swiss energy statistics (Swiss Federal Office of Energy, 2015), an average for the last 10 years of 106 kW he/m2 yr is obtained for relatively new modules.

      The authors have either faithfully reported the official statistics or not.

    • gweberbv says:


      we have a lot of data – at least for Germany – for kWh/KWp. The result is a capacity factor slightly above 10%.
      kWh/m2 is a different story as module efficiencies have improved over time.

      If you installed high-efficiency modules with a perfect orientation and in addition you are sitting at a sweet spot with respect to sun hours, your PV yield will be significantly better than the average value (be it in Germany or Switzerland).

      • Alex says:

        It seems then I’m getting 13% CF. I was promised 11.4% according to the official prescribed estimates, which tend to be cautious. That is about as far south as you can get in Germany, though we get some fog and shadow in mid winter, but what happens in mid winter is irrelevant for panels.

        • Maury Markowitz says:

          “It seems then I’m getting 13% CF. I was promised 11.4% according ”

          Yes, my array in Toronto is outperforming PVWatts as well.

          From what I can see PVWatt’s 14% derate is likely the problem. Tweaking that slightly to 12% makes my numbers match. Try that on your own system and see what happens.

          PVWatts used to have 18% in that field, but lowered it to 14% to match improve inverters. However, it seems micros like mine squeeze out that little extra?

          For comparison, Apple’s new array in Princeville has a derate of something like 5%.

    • robertok06 says:

      “There’s no reason why panels shouldn’t last 60 years, ”

      your are COMPLETELY wrong on this: there is plenty of reasons for them not to last one day more than the “guaranteed” time, i.e. 20-25 years.
      A PV system can “fail” in tens and tens of different ways. There’s plenty of literature on that.

    • mark4asp says:

      Alex, I see your panels are doing way better than average. Good for you. Ferroni + Hopkirk use published data to draw conclusions on long-term energy costs of solar PV. They conclude solar PV ERoEI(ext) = 5 to be sustainable. According to others, the minimum ERoEI must be 12 for sustainability! Even admitting slight inaccuracies in their interpretation of the data, it’s hard for me to see how solar PV is sustainable in Northern Europe.

    • Graeme No.3 says:

      My neighbours replaced their panels because of complete failure after 9 years.
      You are told to expect the inverter to need replacing after 10 years (on average).
      PV panels deteriorate as they age. You might leave them in place for 60 years but you won’t be getting much, if any, electricity.
      In Australia you get by on a 2.3KW (10A) system. Current costs of storage mean that only multi-millionaires or people who can’t do arithmetic would add it to a grid supplied home.

      • Alex says:

        The official figures assume a 1% degradation of solar panels per year, but this is reckoned to be pessimistic. This figure is hard to measure – I certainly can’t see it on my panels from the “background” yearly variability.

        Yes, inverters about 10 years – that figure has improved recently.

      • Enphase inverters are now warranted for 25 years. I have had a system with 25, M-215 inverters for the last two years, and not a single failure. Their old M-190 inverters had a high failure rate, but not these new ones.

  5. Neil says:

    Is there a similar analysis for the proposed Swansea Bay lagoon?

    • Euan Mearns says:

      Not that I’m aware of. But there should be. For so long as I’ve know him, Charlie Hall has bemoaned the fact that no one seems willing or interested to support net energy analysis.

      • Greg Kaan says:

        The “over” 17.8% capacity factor that you can calculate from the figures on the proposal’s web site should be a good place to start.

      • Ajay Gupta says:

        My company EROI Energy Advisors Inc. can help provide EROI information, research, and resources if anyone wants to work towards generating EROI information. Based in Toronto area in Canada. Feel free to contact me personally through LinkedIn.

  6. clivebest says:

    There is another myth that needs addressing concerning renewable energy – battery storage. If we assume that transport, heating & industry have all need to be electrified then each of us on average will need 125 kwh/day (MacKay).

    For energy storage from excess renewables to run all UK energy needs for 24 hours without wind would require a capacity of 2.6 x 10^16 joules. That is ~6 Mtonnes of TNT or 6 trident nuclear warheads. Perhaps this could be reduced to 4 nuclear warheads with efficiency savings. Batteries are a pipe dream if you imagine they could power a nation. Solar/battery installations are only a good idea for small isolated communities in deserts or on islands.

    Therefore if we must provide reliable zero-carbon (nuclear) energy to cover the highest demand for UK in winter , then we may as well use it the whole year round. It makes no sense to invest in renewables as well. If we have excess nuclear energy at night then we can use it to make hydrogen for fuel cells or synthetic hydrocarbons for plastics, fertilizers, and aviation fuel instead.

    Germany’s Energiewende is the worst possible solution, because for ideological reasons they are phasing out nuclear. This means that they are building two separate energy infrastructures at vast expense.

    1) Renewable Energy
    2) Fossil Fuel Energy as backup for 1) when it doesn’t work

    Germany recently built 19 new modern coal stations and CO2 emissions are not reducing. A zero carbon energy system is impossible without nuclear.

    • Alex says:

      The figure you cite makes no account of the efficiency of electricity for heating and locomotion, nor for future improvements in building efficiency. 36KWh/day (of electricity) on the coldest days, and 25KWh/day in the summer would be more reasonable.

      The rest of your argument holds – but perhaps not to the same level.

    • robertok06 says:

      “Germany recently built 19 new modern coal stations and CO2 emissions are not reducing.”

      In fact, it is recent news (two days ago I think)… European emissions have gone UP in 2015, in spite of a lower demand (mainly due to economic stagnation and the warmer weather conditions) and in spite of the increased installation of intermittent renewables, PV and wind.

      “A zero carbon energy system is impossible without nuclear.”

      Bingo!… in fact there is that large country, called France, which exemplifies this statement of yours, Clive. 🙂

      … 415 TWh/year with less than 10 gCO2/kWh and low costs… how about that?

      Of course, in France too incompetent politicians are doing their best to spoil the system, trying to convince electors that shutting down 25% of the nuclear fleet by 2025 will be a good deal if done using intermittent wind and PV…. how crazy is that?
      Luckily next year’s election may bring back some sanity…

  7. Roy Ramage says:

    “to feed all the people that now inhabit the earth.” That comment is a little wide of the mark Euan. There are still hundreds of thousands dying of starvation and their numbers are increasing regardless of energy sources. The reason most Australians buy solar panels is economic – nothing else. Australians hate being financially raped by traditional energy companies still enjoying massive government subsidies. The Australian Energy Market Operator (AEMO) in their 2012 report identified $2.2billion in unnecessary energy costs borne by Australians. They have not lowered that figure to date. The human race continues to damage the planet regardless of what enrgy source is in use. Pollution, ocean acidification, land degradation,species extinction etc. It seems our turn at extinction will come regardless of energy source.

    • Greg Kaan says:

      That the reason that Australians buy PV arrays is economic is true but that is because the energy markets are distorted by renewables via subsidies like Renewable Energy Certificates, Feed In Tarriffs (thankfully greatly reduced now), rooftop PV installation rebates and Power Purchase Agreements forced on the market ostensibly for carbon abatement.

      In the case of grid connected rooftop PV, the real effect is a transfer of wealth from those who cannot afford rooftop PV (or whose situation does not allow it) to those who can because they also get the Small-scale Technology Certificates as a subsidy. Plus they pay for less power so they are subsidised on the maintenance of the grid on which they still depend on at night and cloudy days – Queensland utilities are trying to address this situation by altering the fee structure to weight the connection fee to a higher degree which, of course, has been met with protests by the solar companies and lobby groups.

      I knew all this when I had my system installed but not taking advantage of the situation would just be a case of missing out on subsidies I would otherwise fully fund.

      • Graeme No.3 says:

        I did the same after working out the costings using 4 year old figures from my neighbour (whose system packed up in 9 years). I estimate the return on capital at 1.1-1.2% without feed-in tariff as subsidy, but it worked out much better and should pay for itself in about 12 months (5.5 years).
        Curiously the Feed in Tariff is good for 17 years or until I move.

        I could have done without one of the local Greenies congratulating me on “making the moral decision”.

    • mark4asp says:

      Roy Ramage says: “There are still hundreds of thousands dying of starvation and their numbers are increasing regardless of energy sources”

      The number of people suffering starvation and/or malnutrition decreases year on year, despite the best efforts of the green movement. See: Max Roser (Oxford), “Our World in Data”: , and Hans Rosling (Karolinska Institutet).

  8. gweberbv says:

    The estimation of the mean scrapage lifetime in the cited publication must – based on sanity and reason – be regarded as meaningless. Just read the paragraph that is explaining their method. It is plain obvious that it does not make sense at all.

    Also the idea that it is necessary to couple PV installations to installations of hydro storage plants is not appropiate unless PV installations reach a penetration where PV yield exceeds demand on a regular basis. Even Germany is roughly a factor of 2 away from such a penetration. Just think about it: The study assumes that every kWh that is produced by PV solar has to be stored in a hydro storage plant before it is consumed! Thus, the study is adressing exlusively the ERoEI of excess PV production. The global energy market is several TWs (!!!) of installed PV capacity away from generating significant excess PV production.
    It would be much more appropiate (and also easily doable as data real world data existis) to take into account the decrease of FF plant efficiency due to the necessity of ramping to accomodate the PV peak (this will of course depend on the PV penetration level of the system).

    To include energy invested for labour and capital is also nonsense. If capital is not invested in a PV project, it will be invested into something else that most probably will also consume energy. The same is true for the workface. To bring matters to a head: A PV plant installed by a vegetarian who goes hiking in his holidays would have a higher ERoEI than one installed by a 5-oz-steak aficionado who spends his holidays on the Maldives. Does this make sense to you? Without the PV plant, both guys will do something else to earn money and keep their lifestyle habits as they are.
    This way of counting is also in contradiction to the idea of ERoEI that is that the whole society has to be feeded from the return on energy, right? But the authors include the energy that is consumed by workforce and capital in the ‘energy invested’ part.

    That the authors on the one hand discuss issue that only arise when installing something like 1 TW of PV capacity in Europe and on the other hand state costs of small-scale residential rooftop PV installations (and even these costs are a at least a factor 2 too high – as even my very best friend Roberto admitted) shows an inpleasing degree of ignorance by the authors towards their subject of study.

    • Euan Mearns says:

      The same is true for the workface. To bring matters to a head: A PV plant installed by a vegetarian who goes hiking in his holidays would have a higher ERoEI than one installed by a 5-oz-steak aficionado who spends his holidays on the Maldives. Does this make sense to you?

      Yes, that’s exactly correct. If the human labour used to create an object consumes different amounts of energy in different countries then that needs to be factored into the analysis. It used to be the case that Chinese used a lot less energy per capita than OECD, but not any more.

      If slaves were used to construct PV then the energy cost of labour would be next to zero. But if they are constructed by truck driving, steak eating, beer guzzling texans, then the energy cost of labour would be much higher. But we can have a discussion about where the labour boundary gets drawn.

      This way of counting is also in contradiction to the idea of ERoEI that is that the whole society has to be feeded from the return on energy, right? But the authors include the energy that is consumed by workforce and capital in the ‘energy invested’ part.

      All energy we produce can be divided into energy used to produce energy and energy for society. And the population can be divided into energy workers and everyone else. The energy consumed by energy workers has to be counted in the energy invested part. Everyone else gets a free ride on the back of the energy workers. And the problem with low ERoEI systems is that they involve vast numbers of energy workers meaning lesser numbers of everyone else.

      • gweberbv says:


        if you accept to include the energy for supporting the lifestyle of workers and investors in the invested energy then you should also subtract this energy from the necessary output energy. This might look picky in the first place, but as you say some of the renewable technologies are rather labour intensive. Thus, the number of heads that must be feeded from the output energy shrinks when all the needs of the workers (and their families) in the energy sector were already included in the invested energy. (As we have more than 10 million unemployed people in Europe, we will for sure not run out of workforece for labour-intensive energy production).

        But I think, to include the needs of energy investors and energy workers into the invested energy makes the ERoEI business much more complicated than it already is. Without gaining a deeper insight.

    • robertok06 says:

      “If capital is not invested in a PV project, it will be invested into something else that most probably will also consume energy. ”

      Bogus argument, Guenter!… (not the only one)… nobody says that other alternatives wouldn’t consume energy, but since it is PV that consumes it, it is absolutely normal that the authors charge the energy to PV.
      Any life-cycle analysis would do that.
      Installing PV, produced overwhelmingly more and more in China and Taiwan, burning coal to do it, doesn’t make any sense at all when the said PV is supposed to take the place of CO2-free, low-cost sources, like hydro and nuclear in CH and FR… the emission costs and effects will NEVER be recovered, plain and simple… while the whole rationale to move to the renewable heaven is to reduce emissions and save the planet from the terrible effects of the poisonous CO2… how silly is that?

    • robertok06 says:

      “Even Germany is roughly a factor of 2 away from such a penetration.”

      no way!… you are completely off the mark, Guenter!… it has happened no later than YESTERDAY!

      Look at this, German data:

      8.5.2016… lots of sunshine and a reasonable amount of wind at the same time (rather uncommon though)… result?… the sum of PV and wind have been bigger than the consumption (remove the export, “healthy” lignite/coal… cough!… cough!…).
      And this is May 8th, just wait for the many low-electricity demand weekends and holiday season in summer, with many large power-hungry factories shut down.
      Germany desperately needs large scale storagen NOW, not tomorrow or next week.

      • gweberbv says:


        you seem to have a high regard for PV and wind production when you seriously demand large scale storage *NOW* to save a few percent of annual production. At the moment and also for the upcoming years it would be enough to increase transmission capacities to Scandinavia – if the goal is realy not to waste a single electron. But I think there is no need to worry as long as curtailment (which was also used yesterday to reduce wind production, I guess) is less than roughly 10% of annual production.
        And if – one day – we will see negative power prices for all weekends throughout summer, some energy-intensive companies (paying more or less zero renewables surcharge) will be happy to introduce weekend shifts. Moreover, it is easily possible and requires o large investments to dump electricity into the low grade heat market if one reduces the fixed part of the electricitiy price at times of excess demand. But nobody will act here as long as these excess events happen only a few times per year.
        At the moment it is merely an aesthetics problem (negative power prices – than cannot be!). It would be a real problem at 80 GWp of PV, I agree.

        • robertok06 says:

          “you seem to have a high regard for PV and wind production when you seriously demand large scale storage *NOW* to save a few percent of annual production. ”

          Guenter: the few percent of annual production costs as 15-20%, since each kWh of wind or PV costs 4-8 times as much as a kWh on the market.
          But if it is fine for you and you like to throw money away it’s your call, fine with me.

          • Roberto

            “the sum of PV and wind have been bigger than the consumption (remove the export, “healthy” lignite/coal… cough!… cough!…).”

            The healthy export of course is a total sham. We need a breakdown of the day but over 2014, Austria is the biggest export market for electricity. There are few coal plants along the border of Austria but lots of renewables. So you can safely say most of the exported electricity will be renewable.

            It seems that coal for export is simply an assumption based on the merit order without considering the physical realities of the grid and that electricity is used close to point of source.

            But not to worry. Even if it is coal electricity, it is still good.

          • robertok06 says:

            “The healthy export of course is a total sham. We need a breakdown of the day but over 2014, Austria is the biggest export market for electricity. There are few coal plants along the border of Austria but lots of renewables. So you can safely say most of the exported electricity will be renewable.”

            Absolutely incorrect. The electricity which is exported has to be taken as the mix of the exporting country.
            Residential PV is on a low-voltage network, which is very likely going to be used locally, on the other hand large thermal units are always on a high-voltage network and they are more naturally exported (you can skip the down- or up-voltage transformers).

            Whatever the origin/source of the electricity is, it is funny that the Germans try to tout and defend their oximoronic Energiewende as the way forward to a…

            1) low-cost

            …. and…

            2) CO2-free

            … electricity future!… when the data that y9ou and Iare discussing are crystal clear: when there is a lot of wind and/or PV they export a lot, the export curve mirrors almost perfectly the sum of the production of wind and PV… which can be explained only by one of these cases:

            1) the use their own clean wind and PV production and they export coal/lignite (which means they are so smart they they take the heavy 30-50 deaths/TWh linked to this form of energy production), and they do this for a penny… asking 20-30 Euro/MWh while the social/health costs of these sources are at least ten times higher!

            …. or

            2) they use the electricity made by lignite/coal an export clean energy that costs TO THEM on average 200 Euro/MWh (300 for PVand 10 for wind, and I’m probably on the low side here)… while still retaining the social/health costs!… and all this for the 20-30 Euro/MWh that they get when they export the electricity.

            Third possibility (which is the correct one) is that they export a mix of clean and not-so-clean electricity, but the conclusion is the same… they spend a lot of money to subsidize the ridiculous intermittent sources while keeping lignite/coal at high production rate, they get a little money from exports and get all of the social/health losses at home!… and I even left out the nefarious effects of the negative prices on the market at peak time.

            It is a mission impossible kind of entrerprise.


          • “Absolutely incorrect. The electricity which is exported has to be taken as the mix of the exporting country.”

            So what you are saying thus is coal electricity generated on the other side of the country somehow bypasses electricity coming onto the grid between the coal power station and the border and somehow gets to the export instead? That is Fraunhofer lines.

            “Residential PV ”
            Please read my post. I did say that there would be a good chance of it being largely renewable…

            Otherwise I agree.

    • robertok06 says:

      “shows an inpleasing degree of ignorance by the authors towards their subject of study.”

      Well, takning not up to date data doesn’t mean that the paper is not good or the authors are ignorant… just look at your side, Guenter!… every time you guys rant against nuclear you always use the capital cost of Hinkley Point, which is admittedly very high, and never, ever, not a single time use the data for countries where the nuclear installation rate is the highest now… China, Russia, India… in the last 2 weeks there have been 4 nuclear reactors which has gone critical or have been connected to the network… all stuff which will produce electricity 24h/24, on-demand, at costs which are a fraction of the costs that PV will ever be able to reach, even a century from now.

  9. singletonengineer says:

    gweberby’s approach to scheduling renewable energy in the electricity market is similar to assuming that his vehicle has right of way under all conditions on the roads – which is complete rubbish.

    Sooner or later unreliable solar and wind will need to learn some manners and to cease behaving like the spoiled, selfish brats that of the energy industry, stop throwing tantrums and start playing according to the rules of the road. This,of course, includes paying their fair share of the costs of providing the “roads” ie excess transmission systems and backup supplies and system services such as frequency control and spinning reserve that they currently treat as OPP – Other People’s Problems.

    The sooner, the better.

    • mike h says:

      It’s patently not rubbish, it’s a fact and every liberalised power system in the world schedules zero marginal cost power in this way.

      Power systems are changing fast and will never revert to centralised command and control that many see as an ideal solution.

    • gweberbv says:


      paying for the costs of MWh of generated electricity and paying for the MW of generating capacity to be in place when it is needed will be more and more decoupled int he future.

      What existis today is mainly stemming from the times of regional monopolies/oligopolies, where a small number of power companies were responsible for generating electricity, grid stabilization and grid infrastructure all in one. Also at that the few power plants that are necessary for providing peak demand for a few days of the year were not profitable by itself. But they were simply necessary parts of a larger system that was generating the profits (also the IT security system of a bank does not generate profits, but it would generate huge losses if it was not in place).

      • A C Osborn says:

        Not in the real world it won’t, the world is beginning to wake up to the utter stupidity of renewables.
        Once the subsidies disappear, so will the Solar and Wind projects, the cash is already starting to dry up for investment.
        You have Solar manufacturers all over the world going bankrupt, it is just a matter of time.

        • gweberbv says:

          A C Osborn,

          I agree that probably 80 to 90% of demand for wind and PV is due to incentives by governments. But recent numbers do not show a decline in global installations.

          A large portion of companies going bankrupt is typical for the evolution of relatively young markets. Just remember how many dotcoms went belly up when the internet became a mature technology. This does not contradict the fact that the ones that survive do more business than ever.

          • singletonengineer says:

            Geunter,(, there might not be “a decline in global installations” of PV, but where the subsidies have been removed, the industry is winding right back.

            Case in point: Nevada’s recent removal of net metering. The subject is discussed in detail at

            Queensland reduced the feed-in-tariff and increased connection charges for small scale PV several months back, again in an attempt to distribute payments and costs equitably. Industry mouthpieces complained loudly, as expected.

            I’m sure that there will be many more examples around the globe during the coming year, including in Germany, as electricity businesses and governments try to reduce uneconomic subsidies.

          • robertok06 says:

            “But recent numbers do not show a decline in global installations.”

            Are you kidding me? The invesment in wind and PVin Europe is going down, it is news of two days ago that the German wind and PV (and other REN technologies) are objecting to the leaked government ideas of reducing largely the feed-in incentives, and going only for lowest-bidder forms of auctions… and this, even they admit, will cut down on the number of new installations.
            Like all Ponzi schemes, this too wil crush under its own greedy and weight… welcome to the Energiewende. 🙂

          • Thinkstoomuch says:


            Robertoko6 was referring to incentives and economics. As I understood it. Feel free to correct my misunderstanding.

            By the way just did a quick sum of what the EIA is projecting through the end of the year. From last month’s report so it discounts what was installed in January and February. Just March 2016 to December 2016.

            Comes out to a tidy 8,710.6 “Nameplate Capacity (MW)”
            for just the US . Which I showed the company presentation where federal, state and local incentives were required to get it to be even close. And the reason that they did it this year.

            So I would take that PV forecast of 8.9 GW to demonstrate the uneconomic aspects for robertoko6.

            If you want to check table 6.5.

            Easy spreadsheet to sort and sum.


  10. singletonengineer says:


    “…spoiled, selfish brats of the energy industry…”

  11. Thinkstoomuch says:

    Thank you again Euan for an informative and thought provoking post. Especially the links to past posts. Wish I had found those a few months ago. But then I didn’t even know the questions to ask. Thank you again for teaching me.

    Couple of things I did want to mention.

    PVWATTS offers a annual excel sheet on everything. Including estimates on PV module temperature, Another huge file broken out by hour. Which is why reading the spec sheet on new solar panels is important. Before I noticed that I didn’t think about it. I live in FL where it rarely gets over 40 C. Except the panels get up to 55 C in the spreadsheet. When I built my campsite solar charger laid it on the roof to verify it was showing over 150 F on my roof. Still generating 10 watts out of “20 watts” of panels but small panels not optimal for generating power(after giving them an under airspace to lower it some). Just power for when I am at a campsite.

    Just noticed this last night while watching the presentation by Pedro A. Prieto (link elsewhere on energy matters) that he didn’t really address it correctly, I think.

    Second for real world examples. Solaredge has a public monitoring website.

    Which leads to this.

    Shows the layout (click on layout to look at it) and output for a 2 year old system in Scotland (I think). Panels are not what I would call optimum but gives real world data at the panel and system level.

    It also leads to this site in Bobenheim-Roxheim, Germany. A 9.72 kWp system composed of Yingli Panda 270 watt panels. If you hover over the panels in layout gives info on the panel, tilt and orientation. If the information is correct it 8.266 MWh in 2015.

    Wonderful thought fodder everywhere,

  12. Auss says:

    Sorry too many too basic errors in the numbers to make it worth a comment. Some of the basic errors have been shown up already.
    Wel the phantasyful calculations of Mr. Ferroni are legendary, I wouldn’t have expected anyone would reference them here.
    But maybe Euan can provide the calculation instead of citing a anonymous text which is not public available for everyone. To hunt down the errors included in more details.
    To show one point a bit more in detail:
    20,2g Aluminium and Iron and copper per kWh produced with a production of roughly 1000kWh/kWp per year in low insolation areas, means with 30 years lifetime 606kg Aluminium and Iron per kWp of solar System as a whole. Modern solar sytems have about 180W/m² so 5,5m²/kWp. Which would mean 110kg Aluminium, Steel, Copper per m² solar system.
    A typical solar Module (1,6m²) has a weight of 17kg, of which 13kg vcan be directed to the Glas plane (3,2mm). So 4kg of silicon, aluminium, copper, silver, foil, glue, etc. per 1,6m² or 2,5kg of all non-glass materials per m²
    Naturally there are other parts which need material as well, as sometimes (not always) subconstruction, inverter, ground cables etc.
    But it will still be interesting how these 110-2,5=107,5kg/m² of Aluminium, Iron, COpper etc shall be distributed on the other components.
    E.G. this subconsruction brings another 3kg/m³ Aluminium, leaving 104,5kg/m² to explain: Leaving so far space for a error margin of up to Factor 10.

    • Euan Mearns says:

      I took the numbers at face value in good faith, which I guess I don’t always do. But I did so for the following reasons 1) the reported ERoEI is not so different to Prieto and Hall and it seemed reasonable that a further reduction in ERoEI is to be expected at high latitudes, 2) the authors cite omissions with the IEA analysis (I haven’t checked to see if these are correct) which if true most certainly need to be included in the analysis and 3) I look around in Scotland and see panels facing north, covered in moss, and in near darkness for 4 months of the year.

      Unfortunately your comment starts with an ad Hom and I don’t easily follow the remainder of your argument.

      But I have a question. If I know the MW of deployed solar panels in the UK how do I convert that to m^2. i.e., what is the typical power rating per m^2? I’d like to check the mean output per m^2 for the UK.

      • Thinkstoomuch says:

        Euan generally from what I have seen for MWp.

        PVWATTS figures about 150 watts per meter squared of array. Which Is fairly conservative but would probably get you a good swag..

        For that system I linked to in Scotland before. Those Yingli Panda 270W mono solar panel above and use 1.63 m^2.

        Yields about 165 wp/m^2.

        System produced 3,401 kwh in 2015(first full year) using 13 panels. ~160 wh/m^2.

        In the ball park for a standard 60 cell module. They go down to 220 watts and up to 290 or so.

        As with everything, more watts(efficiency), more cost for the module but less cost to mount less panels for the same power.

        A real world example of what is a fair layout. Not going to get that information on a utility scale project.


        • Alex says:

          Those numbers seem a tad optimistic for Scotland. My panels might be a bit older – and are rated at 235W/m2 – though the test results were all a bit above.

          Tilting the panels a bit more might help. Over tilting reduces total output but increases winter output, which would make the panels more useful, but less financially viable.

        • Auss says:

          The upper end are at 340-350W/Module, and Modules below 250W are hard to get today, because nobody produces such Modules any more.

      • Alex says:

        Regarding energy density, see my comment above:
        – My panels cover 40m2 for a 5.4KW system, with an annual yield (first 4 years) of 6167KWh.
        – This is near North Switzerland. I think the benchmark here is 1100KWh/KWp, compared to 1,000 in Devon and probably 700 in Aberdeen, but check the maps.

        Incidentally, if you want to see the real problem in Northern Latitudes, see here:
        And that is North Switzerland. It will be a lot more extreme in Scotland and other Arctic 🙂 regions.

        • Thinkstoomuch says:

          That site is in Troon 55.5N the tilt is set @40 degrees 4 panels oriented at 225 degrees and 9 panels at 135 degrees. Assuming they entered the data correctly. I have to make assumptions someplace.


          Layout with lifetime output displayed.

          Also thank you for showing me lightshot. Now I can post a links to my graphics.

          Have fun,

      • Auss says:

        Euan, sorry for ranting at first place, but the nubers were so far out of todays numbers in so many places, that it was simply too much for me.

        The rest is the big questionmark one should have when reading the numbers stated in your text. It’s a simple control calculation if there is a basic plausibility for the numbers. It did not end up in favor of the numbers in the texts, so they need some deeper explanation.

        The Text of Prieto and Hall is a much better document, from what I could find but also not publicly available, or I didn’t find a link yet.

        The discussion you liknked in the text you linked above came to the question why tthere are so big differences in calculations done also or only based on money, and in those calculations done based on the material streams.
        One big answer is productivity.
        The EROI of a manually manufactured module, as used in the systems checked by Prieto &Hall includes e.g. 90% labour costs and 10% material costs. With the next generation of multi GW production lines, this will go down to 50% labour costs and 50% material costs. (and material costs also usually much lower due to economy of scale) Which leaves – beside some improvements we can skip here to make the thought more understandable, the EROI based on the MAterial streams constant, while the EROI based on the system costs falls sharply.
        The same happens to many other parts of the whole system costs Prieto&Hall list – today nobody uses conrete any more for foundations, the Steel foot itself is formed in a way that it is it’s own foundation. Nobody spends money any more on security for a solar park. Modules are to cheap, so remote monitoring is enough. Insurance costs drop with price or are skipped at all.
        A todays PV-Park selling in a PPA at 5ct/kWh at a similar climate than spain could by far not afford the labour and material consumed by the parks Prieto&Hall analysed then, being economically based on 42 ct/kWh. If ROI would be the same (which is surely disputable) the EROI at the end of the same calculation should be roughly 8 times higher than the EROI they ccalculated then.
        Or the other way round: if you “enegrgize” all money involved in the system outside the material stream of the system, you can as well montetarize the material stream and the sold enegy, and look if the financial balance is positive and competitive with fossile fuels.
        To see this it will be interesting to see if such projects: (or less extreme priced projects) end up economical reaonable.
        And on the other hand, with the same calculation done on systems like Hinkley Point, the EROI of this kind of nuclear power station is likely to look worse than some PV-Systems, since obviously a lot of money needs to flow there beside the material streams.

        • robertok06 says:

          “And on the other hand, with the same calculation done on systems like Hinkley Point, the EROI of this kind of nuclear power station is likely to look worse than some PV-Systems, since obviously a lot of money needs to flow there beside the material streams.”

          No way… nuclear is cheaper than PV under ANY values for its Euro/W ratio… when the 2 technologies are compared on a reasonable basis, i.e. provide electricity 24h/24, 365dd/year.
          PV in Switzerland or Germany can’t simply make it, not even if it’d cost ZERO CHF/Wp… the cost of the mandatory installations needed to guarantee baseload coverage would make it more expensive than Hinkley Point nuclear costs.
          On the last issue of Energy Policy there is a nice paper on what Energiewende will accomplish, zero… none of its stated goals will be met.. other than over-installing panels and turbines… I’ll try to find it and post it here.

          • robertok06 says:

            Here it is:


            “We find that almost all targets of the German ‘Energiewende’ are not reached, for the case in which no further measures are undertaken. In particular reductions in GHG emissions fall short to the target value. Contrary to the negative results, e.g., regarding GHG-emissions as well as gross electricity consumption, generation from renewable energy sources will exceed the policy’s target value.”

      • robertok06 says:

        “If I know the MW of deployed solar panels in the UK how do I convert that to m^2. ”

        150-160 W/m2 for polysilicon, them most used technology.

        The 100 GWp which are installed at this very moment in Europe correspond to an area of 100E+9/160=0.625E+9 m2, or 625 km2.
        That’s only a 0.00…% of the surface of the continent… which is the good news often cited in green blogs, unfortunately the bad news is that even by increasing a 100-fold the installations (which won’t happen anytime in the future in Europe) PV would always be in the “also ran” column… a useless, extremely expensive technology uncapable of guaranteeing the working of modern industrialised countries “as we know them”… but maybe GreenPiss et al. have a different opionion on that… (sorry, couldn’t resist).

        • gweberbv says:


          let’s forget about 100 x 100 GW of PV for Europe and look to the facts. Here you find German PV production together with electricity demand for the last 31 days:

          Would you agree that the performance of PV production does not look to much different from that of peaker plants. And if we could rebuilt German PV fleet for todays utility-scale prices which are near 8 Cents/kWh according to the last auction, wouldn’t it make sense to build at last maybe 20 to 30 GW to cover a good portion of the (working day) peak demand? And so much more for a more southern location with higher insolation and more need of air conditioning (eben better correlation of demand and sunshine)?

          • Thinkstoomuch says:

            Again look at California. It meets all your specifications. Yet grid demand does not match solar. Highest peak is after solar has gone away for the day. Thus they import energy because of the mismatch.

            That is the reality of solar just like August is hotter than June and morning is cooler than evening. This is fundamental science.

            Look at a temperature graph average low temperature is when daily? About half an hour to an hour before sun rises through out the US allowing for when a front passes through to discombobulate things a bit.


          • Alex says:

            This week, Germany has been net exporting about 8GW during the day, and importing about 2GW at night. So it’s dumping much of the intermittency problem onto it’s neighbours, for a fee. It means copying Germany’s solar policy will be pointless for those neighbours.

          • Greg Kaan says:

            Would you agree that the performance of PV production does not look to much different from that of peaker plants.

            This is a statement that borders on delusion.

            Peaker plants run according to demand and the output profile is a consequence of the economics due to current market price vs fuel/maintenance cost. If required, a peaker plant could run with a flat output but the situations where this makes economic sense are rare.

            PV, on the other hand, is entirely inflexible in its output and prone to sags and spikes from clouds.

          • Greg Kaan says:

            Sorry, that should have been

            Would you agree that the performance of PV production does not look to much different from that of peaker plants.

            This is a statement that borders on delusion.

            Peaker plants run according to demand and the output profile is a consequence of the economics due to current market price vs fuel/maintenance cost. If required, a peaker plant could run with a flat output but the situations where this makes economic sense are rare.

            PV, on the other hand, is entirely inflexible in its output and prone to sags and spikes from clouds.

          • Alex says:

            The “spikes” from clouds tend to iron themselves out, but it’s still an intermittent source, which is pretty much the opposite of a peaker plant.

            Germany recently “celebrated” 95% renewables or something like that – but the coal plants are still running, and exports have risen to 8GW during sunny periods, and -2GW at night. So the intermittency problem has been dumped on the neighbours – which will make it hard for them to copy Germany’s “success” in deploying panels, without a lot of very expensive battery storage.

          • robertok06 says:

            “Would you agree that the performance of PV production does not look to much different from that of peaker plants. ”

            I don’t agree.
            40 GW of peaker plants can deliver 40 GWe anytime you ask them to, 40 GWp of useless PV can deliver only 28-29 GW for a few hours —> IF and ONLY IF <– mother nature agrees, and it's not a date between end of October and beginning of March… how can you possibly say they have the same performance is beyond my sense, Guenter! C'mon.

          • gweberbv says:

            Alex and Greg,

            please look at this graphic:
            What is needed on an average working day in the summer are peaker plants that ramp up during daytime and ramp down during night time. This is exactly what PV does. It ramps up a little bit too late and goes down a little bit too early to perfectly match demand, but it does a quite good job in reducing the usage of conventional peaker plants.

            See here the comparison for January 2016 and the last days (April/May):
            In January there is basicly no PV production. Thus the 20 GW rise in electricity demand during daytime has to be covered by hard coal and gas. But in the last days, the ramping of coal and gas was reduced to roughly something between 5 and 10 GW because PV production is covering most of the demand peak.

            (One could argue that Germany has already too much PV for just covering the daytime electricity peak. But this is a different story.)

          • Alex says:

            Firstly, a peaker plant is needed more in mid winter. A peaker plant that is only available on some summer days is not much use.

            Germany certainly has too much solar, given the relative inflexibility of it’s despatchable output. If the rest of Germany’s electricity came from hydro, it wouldn’t be too much. As it is, over the last few days, Germany has gone from importing 2GW in the morning to exporting 8GW at the sunny time. So it’s shifting 10GW of the problem to its neighbours, whilst pushing down the cost of wholesale prices at certain times (a classic case of “dumpoing” and “predatory pricing”).

            Also the ramp up in demand may be caused by solar – which is a good thing, to an extent. Yesterday was sunny, so I got some loads of washing on.

          • Euan Mearns says:

            Now lets see same chart for December and July on same scale.

          • Greg Kaan says:

            Alex, as always, it’s horses for courses. A peaker plant is in greater need in summer for most of Australia due to cooling rather than heating requirements.

            That is why around this coming Christmas period, we should be watching both Scotland and South Australia to see which grid is the first to collapse due to their commitment to intermittent generation not being up to meeting their peak demand.

          • robertok06 says:

            Show me the production profile of PV in Germany for the 120 days between Nov 1st and Feb 28th, and then we can re-discuss the whole thing, OK? 🙂

        • Greg Kaan says:

          Guenter, you used the same hand waving argument at the ClimanRecon site so I will link your statement and our responses since it is getting repetitive responding to the “correlation” assertion.

    • gweberbv says:


      the authors include 25 kg/m2 of metal for balance of the plant (55% of the total weight). Maybe such numbers were correct 10 years ago when the costs of the mounting of the PV cells were negligable compared to the cells itself.

      Here you find the paper without the paywall:

      • Auss says:

        Thanks for the link I started reading – and on page 332 upper left corner, they mixed up the production of thermalsolar units in swizerland (400kWh/m²a) with the solar iradiation on one m² in swizerland, and tried to multiply this with the efficiency of solar cells. Well swizerland is not tooo sunny, but it gets a bit more than 400kWh/m²a in a squaremeter oriented to the sun, see PVGIS….

        At the end of page 338 they calculate that a module has a weight of 16kg/m² and subconstruction ahs a weight of 25kg. Well, look at the market to find modules with 25kg/Module. I couldn’t find one that heavy, and of the ones I find most of the weight is Glass, not Aluminium or Steel or Copper.
        And then the calculation with the nuclar power station, 60 years, and its weight is moslty steel. When I look at the data I find a nuclear power station, in tons mainy consists of concrete. The EPR roughly has a weight of 2 Million tons, exact data I could not find so fast. (Uranium production etc. excluded) So it would need to produce 6,7 PWh in 60 ywars to fit to the data in the text. Or 111TWh per year. Or if running 60 yeas with zero pause it would need to have a generating capacity of 12,7 GW. Maybe the data of the weight is not absolutely exact, but I guess it is not wrong by factor 10, because older systems with less thick structures are already much more heavy than 200.000t, giving data between 700.000t and higher for older reactors. The 0,3g/kWh would male complete sense for the steel, copper and aluminium part of the reactor.
        If I look at the referenced Document: I find completely different data. Is shows 4,35g gravel /kWh, 1,11g calcit/kWh, 0,405g Iron/kWh etc… nothing similar to 0,31g/kWh total. but my estimation that the number fits to the iron alon was nearly correct.

        • robertok06 says:

          “The EPR roughly has a weight of 2 Million tons, exact data I could not find so fast. ”

          The two million tons are in vast majority reinforced concrete. The steel part of the reactor is the pressure vessel (4-500 tons max) and the 3 steam generators (250 tons/each, if I remember correctly).
          All of the remainder steel is under the form of a maze of pipes, turbine, etc… which are EXACTLY the same as any thermal power station (gas, coal)… the only difference possibly being a larger quantity to account for the huge power to dissipate (5 GW thermal).
          Any Environmental Product Declaration certificate, which defines EXACTLY the requirement materials and effects on the environment for the production of 1 kWh show that nuclear is at the lower end of material consumption once normalized to the energy it generates.
          The typical energy pay-back time of a nuclear reactor is 4-6 months max, because each GWe produces 6-8.5 TWh/year, i.e. 21.6-3.1 PJ.
          EPD link for Vattenfall’s units to be found here:


  13. Greg Kaan says:

    That “liberalised power system in the world schedules zero marginal cost power in this way” does not make it the optimal use of resources. Rather, it is the result of legislators who have no idea of the consequences of unscheduled and sudden ramping up and down of thermal generators.

    Please outline your alternative to electrical supply under “centralised command and control”.

    • Greg Kaan says:

      Sorry, the above reply was to mike h’s statement

      It’s patently not rubbish, it’s a fact and every liberalised power system in the world schedules zero marginal cost power in this way.

      Power systems are changing fast and will never revert to centralised command and control that many see as an ideal solution.

    • mike h says:

      It may or may not be optimal, I guess we have a different view on that. What is indisputable is that it is a fact. ERCOT (that bastion of greenness), PJM, NYISO, California, Europe, Australia and Japan all work this way.

      As for system alternatives;
      Those being developed around New York that allow customers to transact directly and locally using the existing grid, which also provide grid stability in the event of large scale outages.
      Transparent prices to incentivise dynamic demand and storage.
      Use of a realistic carbon price to allow the market to choose EG solutions.
      Flexible thermal stationery generation sources.

      • singletonengineer says:

        Mike, nothing in your post disagrees with my contention that the rules that apply to all forms of electricity production are not being applied fairly and evenly. There is no logical, inescapable,overarching reason for some technologies to have to ramp down to let others charge in whenever they are able to supply and to depart the scene when the wind stops blowing or the sun stops shining.

        I am not aware of a single form of electricity production that is not disadvantaged commercially when it is forced to ramp up and down. You have entirely failed to address this, on the basis that it happens in a lot of places.

        Does that make it right? Or optimal? I say that this is not acceptable behaviour in a rational marketplace. You say nothing much.

        In closing, there are real, measureable and paid-for aspects of the services such as frequency control and spinning reserve and rapid response loading and unloading. They don’t come for free, unless you happen to be a producer of unreliable, weather-dependent wind and solar power in a politically distorted market such as the ones you listed. The poor consumer pays the bill for thoseless of whether he/she/it has PV on the roof or a wind turbine out the back.

        I stand by my analogy. The rules of the road should apply equally to all traffic. That’s the fair and reasonable and, ultimately, the most efficient way to operate the (road or electricity) system.

        • mike h says:

          The rules are clear for everyone, all these markets work using the final decider in this. Price.

          No-one forces you to build a power plant or to run it if you do. Should you decide the market doesn’t reward your service adequately (energy provision, ramping, frequency etc…) then stop delivering them.

          Electricity markets in Europe are oversupplied, there are too many generators chasing too few MWh and they are involved in a race to the bottom on price. (incidentally I think the price of wholesale power is ridiculously cheap)

          It’s worth nothing that Nuclear and run of river have low marginal costs and often offer into the DAM at rates well below values require to give a generator a return. Are these also parasites? Solar and wind are notable as they are delivering in such volume that they have a larger impact.

          Where I fully agree with you is that the residential customer foots the bill. This habit of piling costs onto them creates massive distortion (incentivising solar panels in Denmark)

          In the end, can you make thermal and 0 priced SRMC sources work together in this market design? It’s surely difficult, but once the genie is out of the bottle, I really don’t see how you put it back.

          • A C Osborn says:

            You have a very idealistic way of looking at the world.
            In Germany the Coal, Gas & Nuclear plants were all built before the “renewables” came along and you are wrong because they cannot “just turn them off” without being very heavily fined or put out of business.
            Germany has been building new Coal powered stations, but mothballing more efficient Gas ones.

            In the UK you cannot get anyone to build new power stations of ANY kind without massive subsidies, after all why would you build something that is totally unprofitable in the distorted markets that “Renewables Subsidies” & “Renewables first take” have brought about.
            For this reason the UK will soon be the subject of Blackouts because there will not be enough “Baseload” production.

            In your idealistic world you do know what “Baseload” production is, or do you?

            It is what the “Renewables” need to allow them to be the parasites that they are, because without it this and every other Industrialised country would grind to a halt if it relied on those renewables.

            The other thing that was also built before renewables came along is the Grid required to distribute the Electricity, that is the same grid, which renewables use but have never contributed to.
            In your idealistic world you don’t seem to need one of those either as you do not believe in “centralisation” which is exactly what the Grid is.

          • robertok06 says:

            “The rules are clear for everyone, all these markets work using the final decider in this. Price.”

            Not even close to reality!… intermittent renewables, wind included, on the basis of their REAL price would not be able to be ranked before any existing baseload technology.

  14. David Ellard says:

    All of these calculations are telling us that solar PV is not an economical way of generating electricity. Regardless of whether we do the calculation in units of energy, or simply money (which is the most logical and straightforward unit of account), it follows that there is an opportunity cost to generating a given amount of electricity from solar PV vis-a-vis an economical way of doing it i.e. there will be more surplus left to society by not using solar PV (not necessarily of energy, of whatever we want to spend that surplus on).

    But we knew all this anyway. Nuclear power and ‘renewables’ are subsidised by governments. The reason they are subsidised is because they are not economic. QED.

    The real reason why governments pursue these energy sources has nothing to do with economics and, we can assume, nothing to do with ‘CO2 emissions’ either (because using CO2 emissions as an accounting unit would also not change the result of our calculation because the economic surplus can also be spent on destroying CO2, if we were so inclined).

    So what is it to do with? The answer is: energy security. If China burns coal in order to make a solar PV cell which is then shipped to Europe, that source of energy – a sort of solar-operated battery if you want – cannot then be taken back or cut off by China. Whereas oil is expensive to store so the Middle East and other oil producers can much more easily and destructively cut off the supply should they wish.

    • A C Osborn says:

      No it is not energy security, Oil is hardly ever used for Electricity Generation, but gas is.
      However if you want energy security in the UK you would use North Sea Oil, natural Gas, Nuclear and Coal. The UK has a great deal of coal and depends on no other country to supply it. It can also be used for gassification as it used to be before Natural gas came along. For Germany it is Lignite & Coal and France it is Nuclear.
      Oil is used for Transportation and Chemistry (Plastics etc) not energy generation, Wind and Solar is not used for those purposes.
      The UK Government uses Wind & Solar due to ideological reasons, the worship of “The Great Climate Change Idol).
      There is no Logical Reason to use either of them all the time that you have Gas, Oil, Coal & Nuclear.

    • RDG says:

      Except that PV panel cannot make liquid fuels.

      Liquid fuels are everything. No access, and you have nothing except long lines of people waiting to be fed by the financial overlords.

    • Ajay Gupta says:

      I find that especially when it comes to renewable energy, the definition of “economic” is often dynamic. According to my math, PV is only uneconomic where society requires ~3% annual GDP growth. Often when discussing EROI this point is lost. We do not all assume a need for ~3% GDP growth (BAU) in our assumptions. Perhaps we could all be more explicit in our economic assumptions, especially where using energy intensities as energy inputs, as they are dynamic through time, geography and policy.

      • Alex says:

        “According to my math, PV is only uneconomic where society requires ~3% annual GDP growth. ”

        Society doesn’t require any GDP growth. It WANTS GDP growth as that is the main thing which allows people to progress. But that has nothing to do with the economics of solar.

        It might more accurate to say, PV is only economic where society requires a nice sunny climate and lots of air-conditioning.

        • Jan Steinman says:

          Society doesn’t require any GDP growth.

          I disagree.

          Gail Tverberg asserts that modern civilization requires growth, because the entire house of cards is built on debt. Debt assumes a level of growth high enough to pay interest plus return a profit.

          I think Joseph Tainter (Collapse of Complex Societies) would also agree that human civilization requires growth, which inevitably results in collapse.

          Finally, Panarchy Theory (“theory of everything”) describes a loop in three-dimensional space that includes a growth phase, followed by a collapse phase.

          • Alex says:

            Tverberg is wrong. Society has managed before without growth and could manage again.

            It would be very hard, but not for the reason Tverberg gives. The reason is that we as individuals want to live better than we did – or better than our parents did. With no growth, life is a zero-sum game. We can only do better if someone does worse. And given the losers shout louder than the winners …..

            Anyway, it’s not really an issue, as there’s plenty of scope for growth left. Especially once we’ve sorted out plentiful energy.

          • Jan Steinman says:

            it’s not really an issue, as there’s plenty of scope for growth left…

            … said one yeast cell to another, one doubling-period away from consuming all their resources and dying in their own excrement.

  15. Ajay Gupta says:

    Thanks for spreading the word! I would also add, that this EROI number you quote, like Preto and Halls, uses far out system boundaries and can Include energy inputs such as interest on bank loans. Such scope has never been done for oil or coal or nuclear especially. If you used the same boudaries here on say nuclear, it too would give a different picture. Add the impending law suits to Exxon and the embodied energy therein as an energy input to oil In order to remain consistent, for example.

    This is great work! But I hope it is used in the proper context and not sensationalized. Personally, I would love to see this scope of research on the fossil fuels and nuclear industry!

    Thanks again for spreading the word. EROI matters.

    • Euan Mearns says:

      Ajay, I’ve had emails from Dave Murphy making this point, i.e. using broad boundary will give numbers that shouldn’t be compared with other published narrow boundary figures. And with that I agree.

      I personally think ERoEI is vital, especially in low ERoEI systems (<10). There is ever present danger that politicians and policy makers (and many others) fool themselves into believing they are creating energy producing systems while they may simply be creating energy conversions or energy sinks.

      I think that message has sunk into EU regarding biofuels that I think they are going to abandon.

      • Ajay Gupta says:

        Very glad to hear that! Yes this paper seems to making waves in the energy circles around me. I’ve been discussing it now myself for about a week. Communication is important and unfortunately not all media outlets are as careful and informed as you.

        Let’s not forget, at least for me, your insights into EROI<10 are paramount to understanding how we use and account for energy in our respective economies, especially going forward from here.

        Thanks again for all the work you do! And the communication of data you provide!

  16. Euan Mearns says:

    This is in response to Alex and T2M up thread. Alex lives close to Swiss border and says his panels produce 155 kWh/m^2 per year. Ferroni and Hopkirk say the Swiss average is 106kWh/m^2 per year. Using BP stats for 2014 I get (and we have in earlier posts decided the BP stats on solar are not that good) and T2M’s value of 150W/m^2:

    And doing the sum 2 ways. The most correct way is to use the mean of capacity end 2013 and end 2014. The other way is to simply use the 2014 year end capacity figure:


    6.107^6 m^2 using mean 2013/14 capacities (best method)
    yields 131kWh/m^2 per year

    7.173^6 m^2 using the end 2014 capacity (not correct method)
    yields 112 kWh/m^2 per year

    The latter is close to Ferroni suggesting that they have perhaps not allowed for growth in capacity from 756 MW at the beginning of 2014 to 1076 MW at the end.

    The best method number of 131kWh/m^2 per year is lower than Alex consistent with average performance degraded by factors such as dirt and snow and poor orientation.

    I’ve done calc for UK also which gives similar numbers.

    • willem says:


      In Vermont, New England, 1253 kWh/y from 1 kW of roof-mounted, properly oriented, clean, new, 250 W panels, with an area of 6.54 m2/kW of panels, or 191 kWh/y/m2, or 21.84 W/m2.

      That is much better than a large array of similar, field-mounted panels, which have about 52.38 kWh/y/m2, or 5.98 W/m2, due to spaces between panels and access driveways, all enclosed by a fence.

      1 W/m2 = 8.766 kWh/y/m2

      • Willem Post says:

        Addition to above comment:

        On a real world basis, i.e., not properly oriented, aged, partially shadowed, dusty, snow or ice covered, for thousands of systems, as in Germany, US Southwest, etc., there is about a 17% deduct, so 191 less 15%, for roof mounted; a slightly lesser % for field mounted, as they usually are properly oriented.

    • Euan Mearns says:

      I have rarely had a post where there is so much disagreement over raw numbers. There must be a reason for that and I suspect the reason is advocacy trumping science.

      On the rating of panels I now have the following:

      Roger (via email) 100kWh/sqm/y (for the UK)
      Willem 191 100kWh/sqm/y
      Alex 235 W/sq m
      Aus 340-350 W / module

      Roger and Willem get brownie points for using correct units.

      Using Roger’s figures brings the Switzerland example from BP more into line with Ferroni.

      I also have via email someone claiming that the ERoEI for PV is 30 and heading for 120 🙂 So I suggested to him that subsidies should be axed without delay and PV owners taxed at 70% on their production.

      • Thinkstoomuch says:

        Well the 340-350 number would seem to come from a 72 cell module that is generally. 990 mm by 1971 mm, 1.95 M^2. Though I don’t see any of those for sale. Biggest I see is 335 watt modules. ~170 watts per meter squared.

        Though you can get an LG 60 cell module for 1.5 times the price that puts out about 315 watts. 1.64 meter by 1 m. 192 Wp/m^2.

        spec sheet.

        It is really a different language to sort out what all the stuff means on it. Or at least it was for me. With the understanding that it is company claims mostly verified…sort of.

        Good luck sorting it all out,

        • Thinkstoomuch says:

          Disregard that last I screwed up my thoughts and terms.

          Product of thinking too much.


      • Alex says:

        I said:
        “However, in their first four years, my panels, about 10km North of Switzerland, have been delivering 155 KWh/m2”

        Apologies for not putting in “/year” 🙂

        I think there’s a lot of discrepancy in the numbers because of how they’re installed (the local Aldi now has them on a 25 degrees North facing roof, as well as on the 25 degrees south facing roof!), maintained, and reporting.

        Most solar comes from amateurs – which is why it’s more dangerous than wind power (which is more dangerous than nuclear power).

        I think the Government mandated calculators are fairly accurate and they say typically say 1,000KWh/KWp for Cornwall and most of Germany for south facing panels. I get 1,143 KWh/KWp per year. That’s a more common measure than KWh/m2/year.

      • Thinkstoomuch says:

        Ok I am going to try again. Maybe this on topic.:-)

        In relation to your observation of solar opinions. Solar is inherently all over the sky.

        Somebody said PVWATTS is fairly good. Very much true. Especially for the US with gridded anywhere data. Change the location over a utility scale plant and will yield a result that will average out over the course of years to match its guess. It more or less breaks stuff down to the minutia in that annual output file. Cloud cover, air temp, module temperatures, global and planar angle of incidence …

        Just think of how much weather and climate can change just going through a pass. One side will be great, the other side will be good or maybe even poor, depending. Of course it also might be the same. 🙂

        Now once you get every contractor and homeowner involved the silliness really gets bad. Contractor is out to make a buck. The Homeowner if he does get a good contractor overrides him because he knows better.

        All of the above is going to influence opinions, rightly or wrongly. IMO better off looking at either the solaredge stuff if it has a layout and PVWATTS.

        Good luck on getting anything solid.

        Just to install solar panels here they have to stand up to that hurricane. It is a 170 MPH wind in case that requires a lot more structure. Which is going to be different in different places as well.

        It is an interesting topic and I like seeing all the info people post. Thank you all.


      • Dave Rutledge says:

        Hi Euan,

        I get 187kWh/m^2/y in New Mexico for 2013 through 2015. It is a 14.0% capacity factor.


        • Euan Mearns says:

          Hi Dave, thanks. If we normalise to 9% capacity factor then we get 120kWh/m^2/y. So I don’t think that Ferroni’s number of 106 is too far off the mark if we take into account sub-optimal operation.

          • Alex says:

            I think anyone getting 106KWh/m2/y in Switzerland should be excluded. They are not in the business of providing electricity, or even farming subsidies.

            Measuring the ERoEI for such panels is like measuring the ERoEI of Three Mile Island Unit 2, or some of the reactors finished but no commissioned.

      • robertok06 says:

        Euan, you can add this to the list of estimates:

        Italy, 23.8 TWh (2015) with 19 GWp, i.e. 1.19E+8 m2… for a specific production of 200 kWh/m2/y.

        Italy’s average capacity factor is 14.5% (2015)

    • Rob says:

      David MacKay seemed to have conflicting views on solar

      Manufacturing a solar panel consumes more energy than it
      will ever de-liver.

      False. The energy yield ratio (the ratio of energy delivered by a system
      over its lifetime, to the energy required to make it) of a roof-mounted,
      grid-connected solar system in Central Northern Europe is 4, for a system
      with a lifetime of 20 years (Richards and Watt, 2007);

      • Euan Mearns says:

        I’m not familiar with Richards and Watts, but I’b be quite confident that there number could be reconciled with those being discussed here if the boundaries of the analysis were changed. i.e. ensure that all labour costs are included and that allowance was made for panel failure etc.

        An analog for failure in the oil industry would be drilling a dry exploration well or having a blowout. Should the energy cost of those failures be included in the ERoEI of oil? – of course they should.

  17. I’ve tried several time to agree and obtain an installation of good quality panels at 2000 € per kWp but finally was impossible despite my 10000sqm factory roof. The installers always proposed me 14% or lower efficient modules with half life expectancy. The E21% modules were offered at €7000 per kWp or more.

    The huge utility scale projects better represent the true marginal cost.
    Topaz Solar Farm is a 550-megawatt (MW) photovoltaic power station in San Luis Obispo County, California.The $2.5 billion project includes 9 million CdTe photovoltaic modules based on thin-film technology, manufactured by U.S. company First Solar.

    In this case I think they had a strong argument to obtain a very good quotation, however the amount appear to be CHF = $ 4545/kW.
    note that CdTe are less expensive than mono-crystalline.
    According my experience the Ferroni figures are accurate.

    • Alex says:

      That is surprisingly expensive. I suppose consumers have the advantage of a sloped roof. whereas a lot of the industrial roofs are flat with frameworks to tilt the panels.

      One of the most expensive installations in the UK, in terms of cost per KW, is that at Blackfriars bridge. I seem to recall them talking about access problems and health and safety, but I think it’s also down to higher margins.

      In this area, bigger seems more expensive. Bigger jobs are done by bigger contractors with higher margins and overheads. But there aren’t really the economies of scale.

      I paid €2,750/KW, all in, including installation and cabling and VAT, and that was over 4 years ago. One guy.

      • robertok06 says:

        “I suppose consumers have the advantage of a sloped roof.”

        Yes, sloped, but not necessarily in the right direction and with the correct slope… which is very important.

    • Alex says:

      This has just come up:

      £2.05 million for 1.6MW on a large commercial roof in London. So less than €2,000/KWp.

      That’s pretty good for the UK.

  18. Chris says:

    Maybe a naive question, but, in the UK, how do we calculate how much energy is generated per hour or per year from the installed PV? We know the installed capacity, but we don’t know the average efficiency (orientation, dirtiness, shade etc.). Much (most?) isn’t directly metered in real time. So where do the output numbers come from?

    • Euan Mearns says:

      Hi Chris, The Renewable Energy Foundation have a data base of all installations based on the subsidy applications:

      Their website is a great resource, but you need to spend a bit of time finding your way around. And so I believe you can get installed capacity and production numbers from there. Roof top solar is not monitored by BM reports and appears as negative demand in their reporting format.

      One thing we learned with wind is that large wind farms on the HV grid are monitored by BM reports and those are what you see on Gridwatch. Small wind farms are like solar and appear as negative demand. But National Grid do publish stats for unmetered wind and solar too. If you look at UK Grid Graphed you’ll see that we have solar and unmetered wind on their.

      Some readers may be interested to know that my son Neil, who put together Grid Graphed got one call, was offered a job and today was his first day at work :-))))) Actually in a job that uses his qualifications :-)))))

      • Willem post says:

        Good for him and you.
        It must gladden your heart to see your son in a job he will like.

      • singletonengineer says:

        I don’t know about UK practice, but it seems that in Australia the output from small scale renewables is derived from the applications for REC’s and that actual performance is not monitored, even by sample – so it is statistically very unreliable.

        For example, some systems (most) shut down completely if one panel fails. Until that is repaired, any assumption regarding output will be 100% wrong. Since there often isn’t any kind of alarm or metering attached to the panels, apart from a little fault light, and of course everybody climbs onto his roof weekly to check the fault light, a single LED and to polish the glass. Faults aren’t noticed until the next billing cycle (three months, in my case).

        Even if the house burns to the ground or the inverter is kaput, the panels are assumed to be still functioning for the assumed life of the system. This, despite the life of an inverter being less than half of the life of a typical panel (say, 8 years Vs 25 years?).

        None of this would be knowable from the perspective of BM (UK), NEM (Australia) or any other entity.

        End result: The output from small scale PV is, at best, a guess and is accordingly not reliable, verifiable, auditable, etc. Is, thus, pretty much useless for statistical purposes.

      • robertok06 says:

        Best of luck to Neil in his new job, Euan! 🙂

      • Chris says:

        Thanks, I understand about the (unquantified) negative demand for small scale renewables. I guess as singletonengineer outlines below the actual real time PV generation is largely unknown as we don’t know the real time condition of the installed PV, let alone the real time local weather. I suspect we do have good quality quarterly data based on meters and FiT payments.

        • Grant says:

          I rather suspect that you have identified a significant and intentional anomaly of data availability that m akes it is almost or completely impossible to undertake correctly accurate comparisons of cost effectiveness.

          The subject will remain an ideological battle ground for generations.

  19. Bert van den Berg says:

    Another data point:
    Location: Ottawa Canada
    Latitude 45N, Tilt 29degrees, roof mounted, Azimuth ~35 degrees off south
    10KW system, 250W panels
    Annual production 170W/m^2

    PVwatt is generally quite reliable. PVwatt for Geneva Switzerland produces about 10% higher than the above (i.e., closer to 190W/m^2), leading me to doubt the paper.

    • robertok06 says:

      The paper may have exaggerated some data (in good faith, Ihope) but concerning this issue of yearly production from PV panels in any location there is a large variation of output which is easy to simulate using, for instance, this tool:

      … write “Satigny” (in the Geneva countryside, I spot it from my window… largest wineyard in Switzerland)… if you leave all parameters to default value, you click on “calculate” and get 1150 kWh/y/m2 (slope 35 deg, aimuth 0deg –> south-oriented, 14% losses).
      If install the same panel on a 2-axis tracker you get 1490 kWh/y/m2… a whopping 30% higher.
      Clearly if one installs his/her PV system on an accessible roof, which allows frequent cleaning of the panels, then the production can be easily 10-15% higher as compared to an un-cleaned system… at least this is what I’ve read somewhere… can’t remember where though… 🙁

  20. clivebest says:

    After the Big Bang there were only hydrogen atoms and a few helium atoms. The first stars and galaxies formed about 1 billion years later eventually fusing larger nuclei a couple of billion years later once they ran out of fuel and exploded. The Solar System formed out of primeval hydrogen and remnant star dust from a local supernova. 2 billion years later bacterial life started on earth, but it took another 5 billion years for cyan-bacteria in the oceans to evolve photosynthesis.

    Suddenly oxygen was being generated by photosynthesis whose imprint is clearly seen in the geological record beginning with the Great Oxidation about 2.3 billion years ago. However the long term build up of oxygen in the atmosphere is is still not fully understood. Essentially 99.5% of emitted oxygen is consequently reabsorbed, but its relationship to CO2 levels is particularly interesting.

    – Current levels of photosynthesis on earth would deplete all CO2 in the atmosphere in just 9 years.
    – Photosynthesis in the Oceans depletes all available phosphorous needed by aquatic plants and algae in just 86 years.
    – Most of the CO2 absorbed by plants is soon liberated to the atmosphere when they die or are eaten by animals, while only a tiny amount of carbon is buried in sediments. Even by including this recycling effect we still find CO2 depletion of the atmosphere takes a mere 13,000 years while phosphorous depletion takes only 29,000 years.
    – The incredible story is that these trapped sediments are not lost from the environment for ever because plate tectonics recycles material over very long timescales today. Subduction, mountain building and sea level change continuously re-exposes the raw materials for life through weathering. Plate tectonics is essential to re-cycle the raw materials for life on earth !
    – CO2 re-enters the atmosphere from the mantle through out-gassing of Volcanoes and also through deep ocean vents near mid ocean ridges. CO2 is removed from the atmosphere by weathering mainly due to the abundance of water on the earth. Such weathering does not happen for example on Venus. The ‘natural’ carbon cycle essentially regulates the temperature on earth because weathering by liquid water is a temperature dependent phenomenon.

    The total content of Oxygen in the atmosphere is equal to the total buried carbon in sediments. This results in the current 21% oxygen content. The total CO2 content in the atmosphere is fine tuned to the temperature of the earth. Once photosynthesis and multi-cellular life evolved, the balance of CO2 levels shifted coincident with the rise in O2. Firstly became possible to bury underground large quantities of biotic carbon including fossil fuels. Secondly there was an enhanced formation of sedimentary rocks caused by the compression of dead sea creatures. Thirdly the large amount of oxygen in the atmosphere now led to the formation of ozone in the upper atmosphere which is also a strong greenhouse gas. The explosion in plant and animal life coincident with a huge rise in oxygen content occurred during the Cambrian period about 540 million years ago. Since then the optimum temperature climate control for CO2 has shifted because the carbon cycle now includes life.

    Current interglacial climate conditions on Earth have an average surface temperatures of ~288K with a stable CO2 concentration of around 300 ppm which is nearly 1000 times less that the oxygen content of the atmosphere. Are rising CO2 levels from fossil fuel threatening life on earth ?

    No it is a trivial perturbation, because too much CO2 and slightly higher temperatures lead to a reduction in the long term weathering of rocks with a consequent fall in CO2 levels causing the planet to cool. Underpinning everything is plate tectonics because carbon and the raw materials for life must eventually be recycled to maintain the balance. Such balance will continue to stabilize the climate so long as the earth’s internal energy continues to drives plate tectonics. Life is therefore safe for at least another couple of billion years.

    • singletonengineer says:

      That comment is a good demonstration of the difference between the perspectives of geologists and climate scientists. The “trivial perturbation” of the former is the end of civilization and, possibly, of vertebrate life on land and in the oceans to the latter.

      They are both, in my estimation, correct.

    • “2 billion years later bacterial life started on earth, but it took another 5 billion years for cyan-bacteria in the oceans to evolve photosynthesis.”

      Where did you get those figures from Clive? My understanding is that the age of the earth is only 4.6 billion years.

      • clivebest says:

        Sorry – I should never write posts late at night! Those figures are just plain wrong. The correct chronology is :

        4.6 billion years ago – Solar System and Earth forms
        3.8 billion years ago – first life on earth – bacteria
        2.3 billion years ago – Cyanobacteria evolve photosynthesis – Oxygen appears
        0.5 billion years ago – first plants and animals

  21. Pingback: Another study on the ERoEI of solar PV | Damn the Matrix

  22. “Solar panels lose about 1 percent of their production every year. Take that to 50 percent and it’s 70 years. In Great Britain a panel will produce about $3000 worth of power in it’s lifetime. It costs about $300 for a panel. The panel only costs about $150 to produce. So how can $150 of materials, energy and manufacturing effort actually cost more than $3000. The panel produces 10 times it’s retail cost and close to 30 times it’s energy cost.
    How can this be an energy loser?
    Bogus studies…” ~ GoneFishing

    “Gone Fishing has nailed it perfectly.
    Using money to estimate embedded energy might not be a GOOD way to measure that embedded energy, but it puts an upper limit on the amount of energy embedded in any given product, because manufacturers are not in the habit of doing business at a loss. A three hundred dollar panel cannot contain more embedded energy than can be bought with three hundred bucks worth of DELIVERED coal, which on average is about six tons in the USA. Then you lose HALF the energy in the coal just in the generator plant, and more in distribution of the electricity. Never mind that the coal plant requires a truly substantial amount of embedded energy in the building, partisans always over look such DETAILS… (edited)

    I have a great deal of respect for Euan, but there is little to no acknowledgement at his site of the one absolutely critical fact about depending on fossil fuels. They aren’t going to last forever in a world with an increasing population and a growing economy.

    And in actual fact, the long term trends of both population and economy are sharply UP, and likely to remain UP until resource shortages FORCE them to turn down.

    We may have another generation, maybe two at the outside, before the depletion of fossil fuels results in the mother of all economic crashes, followed on by the Four Horsemen.

    Prudence dictates that we keep it pedal to the metal on renewables.” ~ Oldfarmermac


    What do you think, guys?

    • Thinkstoomuch says:

      “Solar panels lose about 1 percent of their production every year. Take that to 50 percent and it’s 70 years. …”

      After that start it is hard to take anything in the article seriously.

      If the person can’t be troubled to learn what causes failures …

      Perhaps you should refer them to this.

      Or after they say that was then this is now, this one.


    • robertok06 says:

      “Prudence dictates that we keep it pedal to the metal on renewables.” ~ Oldfarmermac

      What do you think, guys?”

      Ithink that even if you are right (which I don’t) renewables will not save our ass*s, because if you install intermittent renewables at an annual rate which is too high then you run an energy deficit (fossil fuel consumption, that is since the “devil” nuclear must be avoided at all costs… as per green mantra)… and then what you actually do is to ACCELERATE the demise of the human specie.

      How fast is “too fast” as a rate of installation of intermittent renewables? Typically it depends on several parameter, like country of production (China at 70% now for PV, coal-intensive), country of installation (for instance France, where some green geniuses think of saving the planet by installing Chinese-made PV in place of French made nuclear… made using nuclear electricity, i.e. CO2- and fossil-free)… and the typical parameter is the capacity factor of the intermittent technology.
      Example: if you install PV which has on average 14% CF at a rate higher than 14% increase per year then tou end up with a negative energy/emission profile… and if you use this kind of CF values as a limiting increase for the installation rate (annually) then you end up with a time too long to replace fossil fuelled generation… so you are (at best) simply buying some time to the human species…. but not much, not generations, for sure.

      The solution to this is ALREADY known, and it start with “n”… I know that many, too many… people won’t even want to hear it… but that’s the only solution scalable at will which would allow the human species to fall off the energy/population cliff.
      There are 6 billion tons of U in sea/ocean waters alone, enough to run all power of the earth on it for millennia…. which is equivalent to forever.

      I won’t be around to see how this process develops until the end, but I have faith in the spirit of my specie and the neverending improvement of our lives via science and technology. Politics and ideology play against it, but history tells us that in the end science wins… otherwise we wouldn’t be here discussing it, right?

      Time is short, though… I must admit that.

    • mark4asp says:

      The proper way to answer Ferroni & Hopkirk would be another extended ERoEI for solar PV. It looks like pro-solar brigade are not competent enough to do that. As such I’ll take Ferroni & Hopkirk.

      • Euan Mearns says:

        Mark, well we have another extended ERoEI study by Prieto and Hall which gave 2.45 for Spain. Lets assume 15% capacity factor for sunny Spain compared with 9% for UK and adjust for insolation and cloud we get 1.47 for high N latitude. And that needs to be adjusted down further for the higher cost of mitigating for seasonal intermittency the farther N you go. So these two studies are not really materially different, especially when we are aiming for ERoEI > 5 and ideally >>10.

      • sunnnv says:

        check all the references herein

        Renewable and Sustainable Energy Reviews 47 (2015) 133–141

        There is a fast growing interest in better understanding the energy performance of PV technologies as evidenced by a large number of recent studies published on this topic. The goal of this study was to do a systematic review and a meta-analysis of the embedded energy, energy payback time (EPBT), and energy return on energy invested (EROI) metrics for the crystalline Si and thin film PV technologies published in 2000–2013. A total of 232 references were collected of which 11 and 23 passed our screening for EPBT/EROI and embedded energy analysis, respectively. Several parameters were harmonized to the following values: Performance ratio (0.75), system lifetime (30 years), insolation (1700 kWh m 2 yr 1), module efficiency (13.0% mono-Si; 12.3% poly-Si; 6.3% a:Si; 10.9% CdTe; 11.5% CIGS). The embedded energy had a more than 10-fold variation due to the variation in BOS embedded energy, geographical location and LCA data sources. The harmonization narrowed the range of the published EPBT values. The mean harmonized EPBT varied from 1.0 to 4.1 years; from lowest to highest, the module types ranked in the following order: cadmium telluride (CdTe), copper indium gallium diselenide (CIGS), amorphous silicon (a:Si), poly-crystalline silicon (poly-Si), and mono-crystalline silicon (mono-Si). The mean harmonized EROI varied from 8.7 to 34.2. Across different types of PV, the variation in embedded energy was greater than the variation in efficiency and performance ratio suggesting that the relative ranking of the EPBT of different PV technology today and in the future depends primarily on their embedded energy and not their efficiency.

        • Euan Mearns says:

          Thanks for the paper. I’m going to write a review post on ERoEI and will certainly include data from that paper in it. On email list with Charlie, Dave and Nate the main message they are trying to convey is that you can only compare ERoEI if same methodology is used throughout. The paper you cite has a vast range of “audited” values. Do any of them mean anything?

          Its not clear to me that any of them are “extended” and include for example labour, system failure, mounting, inverter, maintenance and mitigation of intermittency which are all energy costs that need to be met somehow for SYSTEM operation. And I imagine that the energy return part is optimised and not real world.

          This post is specifically about high latitude solar that produces next to nothing for three months a year. At time of peak demand at 18:00 in winter it produces absolutely nothing at all and it produces most in the middle of a summers day when the energy is least required. This is the reason for my scepticism.

          From Graeme No3 up thread

          I did the same after working out the costings using 4 year old figures from my neighbour (whose system packed up in 9 years).

    • Euan Mearns says:

      Caelan, I have been presented with similar numbers on an email thread. I have taken $300 and compounded 5% per annum finance costs over 30 years and get $1235. Add cost of inverter, installation, inverter replacement and maintenance and I don’t see much difficulty in doubling that. And then add the additional costs for intermittency. This is why subsidies are needed. Consumers are being asked to pay the bill for 30 years electricity today. This is the same argument as my CO2 argument. 30 (or 25) years worth of CO2 is already up there.

      Of course its difficult to find a place for money that pays 5% these days and an argument can be made that is because we are living more and more in a low ERoEI environment. The net energy just isn’t there to create wealth and pay rent.

      And I think its important to get to the root of the ERoEI. And by that I mean i don’t think we know the answer for high latitudes. I’m unimpressed by those who simply state solar PV is great we must build it everywhere, especially if the ERoEI is close to unity.

      • Hi Euan and company,

        Thanks for your replies so far, it’s appreciated.

        Here is one from sunnnv from Peak Oil Barrel who has availed themself to step over here in the hope, perhaps, that some semblance of the truth may be revealed about the paper.

        If understood correctly, sunnnv may be suggesting that Ferruccio Ferroni’s ‘apparent affiliation fragments’, etc., may cast some doubt to the findings of the paper-in-question, along with some ostensible errors contained within.

        “n.b. Ferruccio Ferroni is/was president of the NIPCC-SUISSE,
        a climate change denier group.
        His (apparent) Linked-in page (in German)
        has some fragment of “Head Division Safety bei Leibstadt Nuclear Power Plant”.

        Gee, wonder if he has any axe to grind???
        (in 2011, the Swiss authorities decided to phase out nuclear power).

        The hysteria over greenhouse gases used in the PV industry ignores:
        (a) they aren’t used as much anymore
        (b) they can be controlled via burn boxes/gas scrubbing systems.

        A few of the comments on Euan’s site are pretty good – there are definitely some errors in the paper.

        If you want real EROEI / Energy-payback-time data, go to people who have been studying this for decades: V Fthenakis or M de Wild-Scholten (and their colleagues).

        A review of PV ERoEIs:

        The Preito/Hall Spanish PV study is a wrong on many counts:” ~ sunnnv

        • Euan Mearns says:

          Standard operating procedure for Green Trolls, if you don’t like the message then shoot the messenger 😉 In this case its interesting information. You see it as evidence he may be biased. But to be head of safety at a nuclear power plant, I see it as evidence that he must be a very smart and careful guy. He’s probably able to analyse and understand wide boundary risks to society resulting from Swiss energy policy.

          And while I’d agree that there may be some errors in the paper, show me a paper where there isn’t. The first target for criticism on this thread was the energy return part of the equation, where after some quick checks, I found that the Ferroni number was not too wide of the mark. That leaves me in the frame of mind that there are solar advocates here who will say anything to support their advocacy. So who to believe? State side I have Nate Hagens and Dave Murphy, both who have PhDs in net energy analysis telling me to be cautious about all ERoEI numbers but at the same time Ferroni is probably not too wide of the mark. And Pedro is commenting here saying same thing. Set against others claiming ERoEI for solar is thirty or above.

        • Again the same references and now, another famous one: Fthenakis, frequently cross-fertilizing themselves with circular references, therefore excluding fundamental works like the Prieto/Hall that is a clear sign of inaccuracy.
          We do not need reviews or meta-analysis anymore, we have now available the real world data including $5 trillion invested in so called renewable sources, the bankruptcies among thousands of Bp Siemens Bosh solar dept, LDK, Suntech, Solindra, Sunedison, Abengoa, Production facilities closed with wasted investments, the country economies like Italy and Spain in great trouble paying subsidies. The early huge emission of CO2 of massive deployment of unproven energy sources. You certainly misunderstood the point about greenhouse gas emissions of PV: Refine the silicon to obtain the solar grade, the special reactors consumes electrical energy, as building and maintaining production facilities or solar farms. All the needed energy is coming mainly from fossil fuels.

    • A C Osborn says:

      I think you have not been coming to this site for very long when you make stupid statements like this
      “I have a great deal of respect for Euan, but there is little to no acknowledgement at his site of the one absolutely critical fact about depending on fossil fuels. They aren’t going to last forever in a world with an increasing population and a growing economy.”

  23. Thinkstoomuch says:

    Just because it was asked for nicely the entire German Production for 2015 broken down by months. What can I say I am retired, anal retentive and opinionated. 😉


    Well I did leave all those other peaky things in there to show that surprisingly Germany has the same problem as CA though not quite as bad.

    I did not want to cherry pick or anything. Figured all last year was good enough.

    Good news about Neil.


    • Euan Mearns says:

      Thanks for the links. Looking at July, it seems that Germany simply dumps a lot of solar on its neighbours.

      • Auss says:

        OR the neighbours simply buy a lot of cheap solar power to replace peaker plants. Prices during the day when export happens are still higher then at night (, when e.g. france used to “dump” a lot of nuclear power in germany.
        So dumping at premium prices is usually no dumping.

        • Euan Mearns says:

          Cheap high cost electricity? Brussels, we have a problem. And it means that the neighbours cannot replicate what Germany has done or we will have the Mexican Stand Off of the energy market.

          • Auss says:

            Hmm where’s the Problem, and where’s the connection to bruxelles?
            At the average July day, there is still a lot of coal & gas capacity which can be switched off if there is no more expensive peaker plant outside germany which can be priced out of the market by them.
            And so far there is zero inventive for the 8GW Pumped storage in germany to pump during noon, as well as there is no incentive for the pump storages in austria and swizerland. They still keep pumping most of the days during the night to balance excess baseloadpower.
            MArket prices tell very well what happens in a system, and german market pricess tell, that there is no excess power during usual July noons due to photovoltaic power.
            A power production >50GW during weekends and >65GW during workdays on regular base are neccesary to start diurnal storage of the energy by pumped storage as the market data tells. And to make the Combined generation adopt itself to maket needs, which today often produces not needed electric power (because so far they follow heat demand not electricity demand, although storing heat is much more easy)
            But this is outside the EROEI-Discussion.

          • gweberbv says:


            it is important to always look at export/import quantities together with electricity prices at that time. (This is also important for the correct interpreation of the direction of power flows through the interconnectors between UK and the continent.)

            Germany does not only have wind and solar that it needs to dump on its neighbours but is also has about 20 GW of lingite plants among whose a few plants seem to be the cheapest FF plants in Europe. Given that the necessary transmission capacity is available, these lignite plants – if in operation – will beat out most other plants in Europe in terms of production costs.
            Thus, as long as the neighbours are willing to pay more than maybe 20 Euros per MWh, Germany will always export in case the lignite plants are not absorbed to cover German demand.

            If Germany had only high-cost plants – say CCGT – to backup renewables, then indeed you would see export only in those case where it is technically necessary to keep the grid stable. And then you can conclude that if Germany needs to export at that moment for technical reasons, it would be technically impossible for the neighbours to also seek to export (if they had coppied the German renewable installations). But this is not the case. So, unless power prices are not falling below 10 to 20 Euros/MWh, the export from Germany can also be explained by pure economics. Clearyl, if you export at negative power prices, there are technical reasons for it (as it happened last weekend – but is still a very rare event).

          • “Thus, as long as the neighbours are willing to pay more than maybe 20 Euros per MWh, Germany will always export in case the lignite plants are not absorbed to cover German demand.


            That as I have explained to you before is complete tosh so can you stop repeating it? It is obvious that Austria, the largest consumer of exported electricity from Germany is not, I repeat not going to be getting lignite generated electricity as there are few (if any) such plants in Germany in that location.

          • gweberbv says:


            you can replace lignite plants by NPP if you are particular concerned with the exports to Austria. But that might result in the (false) assumption that these exports will stop once the NPP in the south of Germany are shut down.

          • Auss says:

            donoughshanahan, the internal power connections can transport about 20GW (or more) North South, so they are not just toy connections.
            So economical seen (MErit order) Austria gets lignite power. If you look at the closest power station, this will be a mixture of nulear and PV at the moment. but both will remain in the market if Austria does not buy power, while somwhrer blelow 1ct after some time lignite will shut down some fractions of cents before nuclear.
            At the german austrian border, close behind Bregenz for eample there are 6 parallel 1,7GW systems running parallel into Austria.
            Along the Rhine in germany south of the Ruhr area, there are today up to 8 Systems rated between 1,7 and 3,2 GW running south, and that’s not the only transportation corridor.

          • @Gw

            Again more falsehood Gw but good to see you climbing of your coal is export falsehood. There is far more renewable capacity and generation in that area than nuclear. So the obvious conclusion is….

          • Auss

            Thanks for that. So clearly it will be a renewable dominated market.

      • Thinkstoomuch says:

        You are welcome.

        My apologies for the double post of the info.

        Thought one disappeared into thin air. It wasn’t there when I posted the second set. Of course I hadn’t saved it.

        I want to thank you for getting me to go look up the info, It had been bugging me. The treatment of things in isolation that are very much connected is one of my many pet peeves.

        Which actually why I am so glad you posted this whole topic. [i]Especially[/i] with the author giving more insight to his thought processes.

        Have fun,

  24. Thinkstoomuch says:

    Just because I am retired, anal retentive and opinionated. Thought I would go through and look at those production graphs for Germany in 2015. Instead of being unable to eyeball match used stacked graphs with all the information included. Roger done showed I see what I want. 🙁

    All the charts were copied from this site.

    Monthly charts above each other hopefully matches people’s screens.




    Oct –Dec

    Have a look see what you think. I do have them as individual months at twice the size if anybody is interested.

    For what little it is worth,

  25. Euan,

    It is very curious how we have been modeled our minds. Gross and net energy seems not so simple, but if you ask the people por gross and net salary, a paycheck or a payroll they will understand immediately, where the difference is and who takes this difference. This is the consequence of having been educated more as neoclassic economicists than as physics.
    In a paycheck, people would immediately notice that it is not only tax that deducts, but probably national insurance and other varied deductions. Well, why in an energy system we should only deduct the energy that has costed the system in itself and not the externalities or extended energy input costs that were indispensable to have an energy system being manufactured (after having explored, mined, transported, refined, purified, preformed assembled with all the multiple materials) and then packed transported again, installed maintained and repaired when required?

    Why not consider other externatilities that may be SINE QUA NON CONDITIONS for that energy system to be up and running and operating throughout its life time? I am thinking in the proportional part of roads to access to the site, the laborers, de them partial or full time (and they are not hunter-gatherers; they consume like everybody else in our consumerist society) , the public officers in the ministers, expressly devoted to attend the necessary papers to have this system registered and legalized; the, cranes, the fences, the power lines connecting the energy systems to the grid, the security and surveillance, the police vigilating and avoiding looting of premises. Everything, if you wish, in their rational and proportional part, which may be negligible or not, but that adds up to the energy inputs. This is what is EROIext at the end.

    You are very right when you state that systems like solar PV, that require a complex society to be manufactured cannot be easily be breed by themselves efficiently. In the case of solar, for instance, complex machines able to cut ingots in fractions of mm thick wafers to make the cells, or microfilters to prevent micrometer particles in the air entering the clean chambers where silicon is manufactured or doped and one thousand complex things more will not be able to be produced in a lower entropy society. There are no low consumption countries able to manufacture 7 MW wind turbines or monocrystaline PV modules. It is a paradox, like the one of my grandma when going to the fishmonger and asked him for a big cod which weighs very little.

    Life cycle. As the massive deployments in solar PV have already several years of real life operation, more and more voices are raising to change the 30 years considered in the IEA PVPS Task Force. Manufacturers do not give more than 25 years and this is a power guarantee, that is superseded by the material guarantee that usually is given for 5 to maximum 10 years. Then one has to expect that the seller is going to be alive within these 5-10 years to honor and replace at no cost (there is always an energy cost, however) failed modules. This in a world that has seen most of the European factories closing down in the last 5 years and/or outsourcing their premises to China or Malaysia or wherever the labor is cheap and the technological critical mass is sufficient. The data of PV Cycle, the entity taking the decommissioned faulty modules in Europe in the last 5 years shows a number of failed modules versus the total installed ones that shortens the 25 years expectancy to an even lower figure. And they are not counting the failed or abandoned modules that are not sent to recycle to PV cycle. Real life imposing itself over theoretical labs or individual bottom up studies of particular, well controlled and maintained plants under a short period of time in well irradiated areas.

    As for the energy cost of capital, the debate is still open. There are formulas to estimate or guesstimate. I/O tables will be preferred to know how much energy a $ represents in a given sector, but in some countries are not easy to find. A gross, generalized method is to take the imperfect GDP and the total primary energy used in a given country and get the $/kWheq. This has some imperfections, because many advanced countries generate more GDP with the same amount of money, precisely because they parasite poor countries and send to their maquilas the activities with higher environmental or energy burdens, while accounting for them the benefits of these manufacturing units under their control. But in any case, is an approach.

    IMO if the cost of a capital invested in creating a given energy system is, let’s say 100, this represents preexisting capital, that is (or rather should be, even it is not today due to the perversion of the financial system) a lien of a preexisting physical good or service, which has an amount of preexisting energy embodied on it. But the interests the investor has to payback to the bank are new demands of capital (that is extra demands of energy equivalent) to get from it. Capital definitely and specially bank interests should have an energy equivalent and be included. We decided not to include in our study for the solar PV systems in Spain, because the difficulties in getting a commonly agreed figure in $/kWh. So we put them as sensitivity analysis only. But they are far from being negligible. In fact, about 40,000 out of the +60,000 solar PV plants in Spain are today in the hands of the banks.

    We did something similar for direct labor. There are some formulas (I/O tables also ), but a general approach is to get all the active labor force in a given country and get the total primary energy consumption and get the national average equivalence in terms of active worker/kWheq. In knowing that renewable systems require skill labor, usually with higher than average national level workers, the resulting figure should be conservative (lower than in reality). However, we knew that even we had a lot of very precise data from the solar PV industry itself, the figures declared for that industry versus the installed power capacity were probably exaggerated, because the industry, these happy days of wine and roses were not precisely thinking in EROI terms, but in selling to the audience and to the government how good they were in creating jobs. So, we refrained from including direct labor energy input costs. But should we had included in our study for 4 GW for Spain working for 3 consecutive 3 year cycles, would have given a figure much closer to that of Ferroni/Hopkirk for Germany and Switzerland.

    Bu the way, the data of PV Cycle and that from Ferroni/Hopkirk about the performance of solar PV systems in such advanced and well developed countries like Germany and Switzerland gives a number of failed modules which is much higher than those we considered for Spain. This totally debunks the critics we have received since 2013, that our final low EROI 2.4:1 was mainly because Spain had done a lousy job. Well, in fact is just the opposite. Spain generates TEICE as much per Mwp installed than Germany or Switzerland. And the outcome is not only because Spain has better irradiance, (probably a 50% more in average, but not 100% more), but also because Spain choosed mainly scale-utility plants on the ground, while Germany and Switzerland choosed rooftop private and scattered installation. Being the first much better oriented, tilted, more efficiently maintained and monitored than the second. This in line with some of your photos showing ridiculous shadowings of many private and particular investors in rooftop installations .
    Finally, I will not comment on the comparison on solar PV versus nuclear for two important reasons: one, I am totally antinuclear. Second, because I will never make an EROI study of nuclear, unless the total energy spent in a full treatment of nuclear waste give us all the complete assurance that humans in the next 1,000 generations are going to be free from artificially created ionizing radiations. Excluding this ABSOLUTELY UNKNOWN but I fear huge (in view of Chernobyl/Fukushima) energy input expense from nuclear EROI is, in my opinion, like cheating oneself playing to solitaire.


    Pedro A. Prieto

    • gweberbv says:


      I have a few remarks:

      1) Could you explain, how the mean lifetime of PV installation can be obtain from PV Cycle numbers? Am asking because the method described by Ferroni/Hopkirk is useless.
      Moreover, in my humble opinion the warranty period offered by the manufacturers/sellers is a very poor measure. For consumer electronics the typical warranty period is two years. But from a washing machine you will expect a lifetime ranging from 5 to 15 years. For buildings we have a 5 years warranty in Germany, but usually with a new house you have about 25 years before major repairs are necessary.

      2) The idea that you need high-skilled labour to erect a PV installation is very strange. Soem high-tech is involved in the production of the parts, but when they are put together on the construction site this can be done by a bunch of farmer boys and a few electricians that received maybe a week of training. Rooftop installations are slightly more challenging. High sklled personal is only necessary for the planning of installations, some areas of production PV cells and of course R&D, but this is a minuscle part of the total workforce – in particular for utility-scale installations.

      3) It is okay to include energy used by workers and capital to obtain the ERoEIext. But then one has to take into account that society needs a lower ERoEIext number than ERoEI. A simple example. If one farmer has to feed himself and 150 other people, he has to be very productive. If one farmer has just to feed 15 other peoples, he can be less productive. Still nobody is starving, if only society allocates ten times the workforce for farming. More specific: An ERoEIext of only 2 might be enough if half of the workforce and the capital is allocated to the energy sector (because in that case, the holiday trips of half of the population are already included in the EI value).

      4) Bank interests are denoted in currency, not in units of energy. If I have to pay the bank anuual interests of 1500 $, this was equal to 10 barrels of oil at some point around 2008 and 50 barrels of oil in late 2015. Of – if you are a residential customer in Germany – this money bought you more than 10.000 kWh of electricity in 1998, but less than 5000 kWh today.

    • robertok06 says:

      “give us all the complete assurance that humans in the next 1,000 generations are going to be free from artificially created ionizing radiations.”

      So, you are saying that hospitals should close down all X-ray facilities and nuclear medicine departments?

      Please, think rationally before writing bogus statements like this.

  26. RDG says:

    They don’t care. Electricity is now a byproduct of “renewables” generators. They make more money with credits than from power. Its designed to rent seek and drive out baseload.

    Financial deregulation, energy deregulation…

    A Mafia.

  27. A couple of additional comments:

    1. I have been hearing since we published our book that the EROIext methodology we used to include the extended energy input expenses in solar PV systems, was not fair because the same procedure was not made for fossils and that was for our critics as to compare pears with apples. This has been mentioned also here in this forum.

    Well, this is simply not true. There are also several studies of EROIext for fossil fuels. And of course, the values of this net energy, much closer to reality, come down in some cases substantially. But whatever the resulting EROIext of fossil fuels, even low, I believe there is no need to demonstrate that fossil fuels were able to energetically pay for their own exploration, drilling, extraction, creation of the industry and social infrastructure around, transportation of the energy obtained, refining, fractioning, purifying, and transporting again for distribution to the most remote places in the world, from the Sahara desert to under the North Pole….And besides, offering a substantial amount of free, net fossil energy to create the big megacities of today (more than half of world population lives in them today; which were impossible dreams for cities of more than 1 million inhabitants before fossils were massively used as fuels. They gave enough free, net and readily available energy to develop very consumeristic armies around the world. Free and net energy to create schools, hospitals, police stations, roads and motorways, smelting factories, air and sea massive transportation, discretionary expenses, like modern tourism (more than 1 billion/year), universities everywhere, even philharmonic orchestras not only in big capital cities, but even in medium size cities, with all the members permanently enrolled by municipalities and the one thousand and one wonders we enjoy today, even at the expense of heavily deteriorating the environment. This is a situation that has been growing in energy availability and probably also in higher EROIext for the last 150 years of massive fossil fuels exploitation, until reaching the global production peaks of conventional sources.

    So, there is no doubt, for any rational mind, that fossil fuels, whatever their EROIext were able to breed themselves and BESIDES to power our global society until today as we are today.

    That is why we have to take with a pint of salt the IEA WEOs when commenting about fossil fuel ‘subsidies’ as being much higher than renewable ‘subsidies’. In fact, if money is a lien of energy and subsidy is ‘money that is paid usually by a government to keep the price of a product or service low or to help a business or organization to continue to function’ (Webster), then we first need to have a surplus of money (that is, preexisting surplus of energy used) to subsidize anybody else. And if this society we have today is more than 82% fossil fuel based and powered, we could hardly and honestly say that fossil fuels are subsidized. By whom? Perhaps by wind power, hydropower or nuclear power? The concept of subsidies for the IEA is in fact a trick to disclose the countries that have internal or domestic prices for fuels lower than those we would like in the OECD countries and that we have and can afford. It is, to say the least, a form of pressure to these energy producing and exporting countries to raise their internal prices so that their internal consumption lowers and more energy can be released for the market; that is for the OECD (the riches), usually big importers.

    But much on the contrary, hydro, nuclear and more recently, modern renewable energy systems could well be SUBSIDIZED and are de facto SUBSIDIZED (not only monetarily speaking, but also energetically speaking) by a fossil fueled global society, precisely with the energy and monetary surplus they still enjoy

    So, as the EROI (be that EROI or EROIext) for fossil fuels obviously dwindle to dangerous levels, we start feeling that our way of living is threatened. Then, it becomes more and more important to know if modern renewables will be able to take the baton from the depleting fossil fuels in both volume and time. It is of essence to know, as much as it is possible and in advance, if modern renewables could do it in absence of fossil fuels and on at least as permanent basis as fossil fuels (circa 150 years), rather than for the first round of lifetime deployments, 25 years at best.

    And for that purpose, we cannot use the conventional EROI, but the EROIext, because modern renewables have to be able to repair roads and motorways, to find alternatives (or energy carriers for the case, obtained from renewables), maintain water purifying stations, sewage systems water pumps, even in remote places to the world modern merchant fleet or civil aviation with close to 7,000 civil planes on the air in every moment; to keep the Ministries and the zillions of public officers/civil servants working in warmed or refrigerated offices, maintain the telecommunications infrastructure (in which only the Internet is already consuming some 9% of total global electricity and growing exponentially), power the subways and not only our own home, light the streets and roads in the nights, the shop windows in Christmas and the whole world infrastructure, move the heavy trucks to bring food from remote non electrified fields to cities, etc. etc., after having spent the energy to raise a totally new energy infrastructure that it took 150 years for fossil to reach the point at which we are today.

    This is the challenge, not thinking in powering our flat TV, washing machine, hair dryer and to plug our hybrid or electric car at the garage as individuals. The challenge is social and is global. It is not a individual solution in the rooftop.

    2. The second comment is about the myriad of comments praising that if prices of modules have come down now to the level of 0.5 $/Wp, then everything is fine and we are in the heaven of the grid parity, only stopped by perverse fossil fuel corporations dirty maneuvers. All the comments of feasibility to expand solar PV systems to replace fossils to a great extent are based on this assumption.

    In this respect, these memories fall short a little bit. Prices went down from much higher levels to 0.5 $/Wp, only when several European governments decided to remove or lower the subsidies to the renewable programs, or to reduce the fiscal holidays or tax exemption in several states in the US. That happened in a moment, when Chinese, with a well known labor force costs, prepared a dumping policy to cope the global markets and forced the European industry to almost go to bankrupt. The period of lowering down prices goes from the sixties of last century, but when solar PV was an anecdote. However, there is an exception in this trend, that people praising our technical and endless ingenuity to increase efficiencies and improve processes would make the miracle to reduce prices of the solar systems to almost zero (too cheap to meter, was the promissory expression in the beginning of the nuclear era). The exception was the years 2007-2011, when the global manufacturing capacity was in the order of few GW/year and two/three countries dislocated the market with their orders, powered by the greed of high subsidies promising very fast financial ROI. In that case, the unexpected increase forced the modules to raise from 3 to almost 5 $/Wp. And nobody seems to have recorded this step. It is still dubious IMO that present prices are only due to cost reduction programs, technological ingenuity and new techniques, rather than to a huge level of stocks of those who got to dominate the global market share and prepared a manufacturing industry to supply on exponential growth basis and now they’ve found themselves with the stores piled up to the ceiling with modules. The jump of China in the last two years in installed base, may be rather a sign on how capable Chinese are to swallow their perspectives of growth in Western countries.

    Well, now imagine that we are in the level of 40-50 GW/year of manufacturing capacity (probably a little bit more idle), but that a program a la Jacobson materializes and we have to install 5 Twp in let us say 20 years (before fossil fuels go down for the count and cannot continue SUBSIDIZING the story). Do you really believe that the prices of Indium, gallium, silicon grade ingots, aluminum, copper, and many other elements are going to continue lowering down, just because the miracolous economies of scale? Really I do not buy this tale.

    Take it easy.

    Pedro Prieto

    • Auss says:

      Well, then the price of the electricity generated should show much more weather the investment is enegetic efficient or not. because if all financial contributions are calculated, too. If this is done it is much more easy and reliable to let them remain finances, and calculate the electric output also on financial base. And then compare it with fossile fuels. Either as thermal enegrgy at the well, or as electrcity (the later is a better comparison) E.G. if the Project in UAE is taken with the minimum price of 2,99ct/kWh this is equivalent to a oil price of 54,29ct/kWh thermal at the well. Or around 250$/t for coal at the mine. This is why I think it relevant if this project is sucessful or not. In the sun belt of the earth mostly diurnal sorage is neccesary for less than half of the electricity, if only PV is in the sight, and some regional balancing. Storage needs are also further dininished by Grids extending east-west by some hours – the bigger the grid the less storage needs exist.

      That 0,5$/W are economical reasonable can be seen in the balace sheets of western companys produsinc modules as well, which are comming back into black with this prices, too.
      It is well kown how much Aluminium, glass, silicon, copper, silver, plastic goes into a solar module, and what are the costs for these materials as raw materials which are the price base to which economy of scale reduces the costs of modules over time in a asymtotic way. This price bottom is well below todays prices.
      It is easy to check this in a pack of a envelope calculation to see where things are heading to roughly.
      A modern Panel (PERC or similar ) has 300W and a weight of 16-17kg.
      300W at 0,5 $/W is 150$ for 16kg
      Which is a pricetag of close to 10.000$/t.
      The biggest part of the module in weight is the glass, it has a weight of about 12kg and costs acording this source including manufacturing (so above raw material price) 7,36$
      Which leaves 142,64$ for the remaining 4kg of material.
      Only about 1,26kg is SIlicon, at the price of 13$/kg for raw material this is 16,38$.
      About 2kg of the remaining material is Aluminium, at a raw material price of 1500-2000$/t which makes a raw material price of 4$.
      With the last 1kg of copper, foil, and similar materials, a price tag of <20.000$/t should be enough for this rourh calculation, giving another 20$ for material prices.
      Which leaves for the modules alone something like 47,74$/Module, or at 300W/Module a price of 0,159$/W towards which the economy of scale can otptimize the price of solar modules. If the efficiency of the modules rises further, the price tag in $/W can become lower.
      This is not to promote solar, but to come frome the point "I have the feeling that…" to some more substancial numbers about which can be discussed.
      Materials used in manuafacturing are usualy subject to the economys of scale, by optimisation and recycling processes.

      • gweberbv says:


        do you know if there is a way to efficiently substitute silver that is used for PV cell production? According to a source from 2014, already between 5 and 10% of silver production goes into PV cells. This I would consider as a show stopper for increasing production capacities much further – even when the costs for other materials are still decreasing and demand is taking of.

        • Alex says:

          On current trends, you can predict that silver is a show stopper for PV. But that would be as misleading as saying a constricted supply of Uranium is a show stopper for nuclear.

          Silver can normally be replaced at some loss of performance – copper or aluminium. I’m sure the technologists can find a way to minimise that loss of performance. And a higher price will make more silver available – the same is more true of Uranium and Lithium.

      • The casting out nines rule or the rule of wet thumb for solar PV should be an explosion of orders worldwide when it comes to a real life grid parity (if it is really REAL) with coal or natural gas producing electricity of between one and two orders of magnitude higher than today. I have stored plenty of reports of very authoritative people since the early nineties forecasting the arrival to grid parity three or four years ahead, in a sort of donkey and carrot race. Still expecting the boom.

        But real grid parity not only is not happening, precisely because the ingredients included in the resulting c$/kWh did ignore or hide many indispensable or SINE QUA NON societal energy input expenses. Quite on the contrary, the supposed spectacular growth it is moving somehow in reverse: from a spectacular exponential growth, approximately from years 2008 till 2012 to a much moderated linear growth from 2012 onwards and with even some decay in 2015. Something similar happens with wind energy, showing symptoms of tiredness in its exponential growth. Both renewable systems and a much higher exponential growth, should badly be needed in a sustained form for at least 30 years, to take over the fossil fuels.

        Economies of scale work up to certain limits and have constraints. Whale oil or whale sperm could not follow economies of scale. Rare materials in particular, but any finite material in general, are subject to depletion and do not necessarily follow economy of scale rules, when approaching to some mineral/ore ratios in the lower quality deposits, if the demand continues to grow and there is a need to go to poorer deposits and remove much more earth crust every time -this is energy-to obtain the same amount of materials….to produce energy!. It rather applies here the law of diminishing returns.

        Recycling has also a lot of limits -cheap energy availability, among them- I recommend to pay a look to some presentations on recycling in the last conferences on EROI in the School of Physics of the University of Grenoble Alpes

        specially those of Philippe Bihouix on minerals availability and recycling limits or the energy-material nexus for energy production by Olivier Vidal and Cyril François.

        Others on grids and demand control by Andréi Nekrassov and another one by Nouredine Hadjsaïd; electrical grids by Johannes Dorfner, Intermittency and Resources, by Mathieu Arnoux are also worth a view.

        • gweberbv says:


          I never understood this grid parity thing.

          What solar PV really needs to beat to become the technology of choice from an economic point of view are the running costs minus ramping down costs of existing (FF) plants. This means plants that were already built and having their investment costs already covered in some form. In Germany this means less than 15 to 20 Euros/MWh which is roughly the running costs of lignite plants. If (new) solar PV would significantly drop below these costs, even the operators of the lignite plants would prefer to use PV during daytime and seeking a way to ramp their plants down during the PV peak.

          I doubt that PV (in Germany) will ever be that cheap. But it seems possible in Dubai (where of course the competition is not against lignite).

          • Gweberbv,

            Perhaps the issue is a little bit more complex than just considering the running costs of a solar plant minus the ramping down costs of FF plants.

            Giving economic figures per unit of energy is always a risky and nebulous assumption, because then we have to enter to determine what type of costs were included to get the Euros/Mwh. This figure vary very much, because it needs to include a number of things such as but not limited to

            Cost of production, transport and installation of the plant.

            In the case of FF plants, the variable costs of the fuel over the life time (if it is 40 years for a coal plant, imagine the price variations of the fuel over that time at a given purchasing Power Parity (PPP) time or if coal is imported, for instance, from South Africa, even the costs of currency exchange.

            The considering life time (essential, because the Mwh that the plant will generate in its life time are being generated on year/year basis). For nuclear plants, the initial lifespan was usually considered 40 years. Now, when many of them approach to this age, many operators are struggling to avoid the closure and huge decommissioning costs and pressing the governments with powerful lobbies to extend the life time to 60 years. How much should we reduce the euros/Mwh from 40 to 60 years and how much should we increase the potential risks of a catastrophic failure for this abuse or for the repair works to readapt the plant?

            And then, last but not least, the societal energy input costs that brought this plant into operation: access roads, ports to offload the fuel, labor, taxes and many societal etceteras.

            As I commented before, there is no doubt that with fossil fuels and during their FF era, we were able to cover all these costs, whatever they were, and still having net energy free to dedicate to other discretionary activities.

            Now, when studying the new modern renewable plants life time, or making the life cycle assessment (LCA) versus other FF technologies or trying to figure out when they will arrive to the grid parity (always a movable point in time, not only the real costs of solar systems are continuously changing, but because the real price of the Mwh in thermal plants is composed of many changing variables and the fuel is just one of them), we always tend to forget that any plant has to serve a given model of society and this implies to assure that with the same energy source, we are going to be able to keep all these energy expenses and activities running.

            For instance, I am thinking in paved roads and motorways maintenance of the asphalt; in the Ministries working like a Swiss clock, in armies of laborers maintaining the national power grids even with helicopters equipped with thermal cameras to detect losses as hot spots, in factories providing a myriad of complex and very elaborated spare parts. In a park of cars, vans or trucks going forth and back from homes to the sites and from factories to delivery points. In courier services to deliver the spare parts from one side of the world to the other (this is the globalization). In a very complex, powerful and at the same time fragile telecommunication network, which is indissolubly tied up to the energy network today as the DNA double helix (if one fails the other collapses and vice versa) and thousands of activities and interrelated things that we give for granted but they aren’t, unless there is sufficient net energy surplus.

            All of the above aspects of a modern industrial and technological society have been made possible, because the gift of fossil fuels powering more than 85% of the global primary energy. There is no the singlest doubt that, until now, they provided enough net energy to cover all of them.

            Therefore, what it will give us complete assurance that solar of wind power could be able to replace fossil fuels, in volume and time, will not be only the momentum of surpassing a given manipulated or encapsulated Euros/Mwh of fossil fuel plants versus de Euros/Mwh of the solar or wind, but the ability to handle, with that generated electricity, all the societal energy expenses we have today to keep the complex structures on which the modern renewables are absolutely underpinned and besides to cover their own self-breeding energy needs.

            As I said in one of my presentations two months ago, in concluding with such a low EROI of solar PV for Spain, it seems that if any, the net energy surplus solar PV plants installed in Spain will give will suffice, in the best case, just for a hunter-gatherer’s society (EROIext 2-3:1), but they need to be manufactured and maintained a complex industrial and technological society (EROIext of perhaps 10:1, but always higher than 5:1). It is an oxymoron (contradictio in terminis)

  28. RDG says:

    “Fossil fuel depletion” should read more like significant loss of crude oil inputs to some regions because almost all the new finds are natural gas.

    Natural gas gets overloaded with all the functions. Then what happens to EROEI of fossil fuels when natural gas is almost its entire content? Can you afford to use it for tar sands? The nuclear competence disappears which might be useful for mining heavy oil.

    An energy system dependent on fracking part 2? The price of natural gas and battery components go to the moon and then what?

  29. singletonengineer says:

    Pedro Prieto’s two contributions are excellent. I dips my lid to the man.

  30. RDG says:

    I detect extreme complacency within Pedro Prieto and Academia in general. The Green Idealism that they seem infatuated with can only be due to their naive belief that natural gas makes for a better and more secure energy foundation than crude oil because its “cleaner” and that there is lots of gas left to be discovered. Combined with substitution (eg. EV replaces ICE) they have convinced themselves that coal, crude oil, and nuclear are remnants of a primitive chapter in human history and that the extreme poverty that surrounds them is a progressive move ahead for society. Certainly, they don’t expect dwindling crude oil stocks to affect their lives. Meanwhile, they look on in awe of the renewable advances that are in vogue (today batteries) and preach patience as they have always done, completely uncaring to the urgency of the situation.

    EROEI, net energy analysis, …only thinly addresses why crude oil is meat and potatoes to an economy and natural gas is icing on the cake. How many times have we seen them lump coal, gas, and crude oil together into the fossil fuel pot unworthy of individual analysis?

    Bottom line: Academia doesn’t understand how crude oil provides instant wealth for building a substantially larger economic foundation than other fossil fuel sources and at this stage cannot be reversed. The never ending dream of electricity as some ideal form that is trending in price towards $0 is reason I expect Academia to fail and certainly the anger from a broken populace won’t be pretty to watch.

  31. RDG,

    I am not looking for complacency, but for contrasted data, which I expect and I am open to receive, if my data is considered to be wrong.

    I am not a Green Idealist, much on the contrary. My book offered dire results on solar PV as one of the main hopes of renewable energies to keep our present way of living up and running.

    Of course, belonging since 2003 to the Association for the Study of Peak Oil and Gas (ASPO) and being a member of the international panel of this organization, it is clear that I do not have any naïve belief on natural gas or on oil as saviors or having continuous and permanent flows and for the case, even beyond the charter of ASPO, the same for coal or uranium. And of course, I do not think natural gas is a clean fuel, although is cleaner (less dirtier should be the case) than coal or oil for the same energy content.

    Of course, I expect that dwindling crude will affect our lives, not only those of future generations. One of the three main charters of ASPO is precisely to raise awareness of people about the serious consequences for mankind of the post peak situations. The subject is certainly urgent, that is why is of essence to check and double check if renewables are going to suffice to replace fossils in volume and time.

    As for the EV I don’t hold any hope that they may replace one day to the 1 billion passenger cars (ICE) moving in the world and the 80 millions being manufactured every year. Not because only the lower density per weight of fuel (Li-ion batteries or fuel cell considered), but also for the reasons expressed in my post before on the expected price evolution of some raw materials or elements to achieve this miracle. Just a marketing announcement of a home battery (Powerwall 7 kW; the 10 kW has already been discontinued before it virtually reached to the market) or the announcement of 300,000 orders for the Tesla 3 and the lithium carbonate in the market has almost doubled.

    Finally, academia is a very ample word. I have worked and conferenced many times for universities, but I do not belong to the academia in the strict sense. Within the academia there are all types of characters and I’ve seen many that do not understand many key things in energy, but many others understand very well what is going on and work hard to prevent or minimize the global impact we all should expect sooner than later.


  32. Pingback: Gert-Jaap van Ulzen » Blog Archive » Zonnepanelen economisch rendabel? Niet echt …

  33. mark4asp says:

    To all the posters here who continue to quote Hinkley C for nuclear power price comparisons.

    The AREVA EPRs at Hinkley C are cost outliers (at ~ US $7000/kWe overnight build cost). Moorside, at similar power output, is projected to be $10bn (at ~ US $4300/kWe, ONB) for the Westinghouse AP1000. I suppose one could be forgiven for not knowing what an outlier Hinkley is since all green websites only ever quote Hinkley as a typical cost for new nuclear power. In comparison in:
    * India: the VVER-1000 is US $1300/kWe, ONB. [ 2 × VVER-1000 are being built at Kudankulam, India by NPCIL (of India) with assistance by Rosatom (of Russia). Total project costing US $2.6bn. One is already complete. ]
    * UAE: the APR1400 is US $3505/kWe, ONB. KEPCO, of South Korea, are building 4 × APR1400 in UAE for US $20.4bn.

    • robertok06 says:

      “* India: the VVER-1000 is US $1300/kWe, ONB. [ 2 × VVER-1000 are being built at Kudankulam, India by NPCIL (of India) with assistance by Rosatom (of Russia). Total project costing US $2.6bn.
      One is already complete. ]”

      The second one is completed too… started charging fuel few days ago, will go critical in a month or so.

  34. Alex says:

    I’ve read most of the comments and I’m still not any closer to seeing the “correct” number. It does seem that opinion sets the results, whereas results should set the opinion.

    At times like this, I like a simple BOTE calculation to sanity check the results. So the figures I’m using are:
    – Cost of solar panels: €2,000/KWp. There’s some nutter on the Guardian saying $500/KWp, but I’ve gone for a fully installed cost that comes from guidance websites. I’m sure you can get cheaper off the back of a lorry, but you could also buy a second hand soviet nuclear reactor.
    – Chinese energy intensity, converted to KWh, comes to 2.685 KWh / $ of GDP.
    – Using Chinese energy intensity, the 1KW panel requires 6,172 KWh (of primary energy) to make.

    Of course, using Chinese Energy Intensity is the biggest estimate. On the one hand, some of the cost is incurred in Europe, where energy intensity is much lower. On the other hand, refining of silicon may use more energy. But, a large chunk of the energy is in profit, factory overheads, employees having to live, and the silicon content is not that great. Most of the mass is glass, aluminium – normal stuff. So without an analysis of the factories’ energy bills, I’m treating it as a “normal product”.

    I’m also going to add 10% to cover a mid-life inverter replacement, so I get 6,789 KWh/KWp.

    On the yield side, I know my panels are getting more (in far south Germany), but I’ll take the figure from the German Government mandated costings. A 1KW panel should deliver 1,000KWh in a year. Some will do better (I get 1,143KWh/KWp/year, over thefirst four years), and some will do worse. Go to Shetland, and this might fall to 700.

    I’m going to assume they last 20 years (that’s the German FIT length – it’s 25 years in the UK). Lifetime is very difficult as we don’t know about today’s panels, only about those from 17 years ago which were probably crap.

    I’ll go with Government guidelines of a 1% (of original) fall per year. Evidence suggests this is over stated. But then some panels are too flat, don’t get cleaned, and get covered in bird crap. So I multiply the yield by 0.9

    So for south of Germany, Switzerland, and perhaps Cornwall, I get 2.65 units of electricity for every unit of primary energy.
    Image of sheet:

    I think that is a result which will please neither side of the debate, which gives me some confidence in it.

    • Euan Mearns says:

      I’ve read most of the comments and I’m still not any closer to seeing the “correct” number.

      🙂 ditto! So many thanks for this! I have a group of experts (actually Green RE enthusiasts) telling me 30. And another group of widely published experts telling me likely less than 2. Reduce your number for poor orientation and poor maintenance; for the energy cost of intermittency; and for share of grid construction and maintenance and the conclusion is that this is a marginal technology.

    • gweberbv says:


      I agree with everything, but I think it would be more appropiate to take the costs for utility-scale PV installations as a basis. This is much more likely to be in the order of 1000 €/kWp (now, not 4 years ago) than 2000 €/kWp.
      Which would bring your number up to 5 (extended ERoEI derived from the flow of money) for state-of-the-art PV utility-scale installations. But without taking into account additional costs for grid upgrading, additional FF plant ramping, etc. as Euan mentioned.

      From my perspective this looks not too bad, in particular when one is not primarly intersted in ending the usage of FF, but to extend its temporal range (and – to be cynical for a moment – in doing so to put the burden of coal burning and other environmental issues on the producer countries of PV cells).

    • Andy Dawson says:

      Not unreasonable – but nothing on costs/implications for grid integration? Recall the discussions on the impact of wind on Irish CCGT; the effects here would be at last as large.

      • Alex says:

        Yes, as Euan points out, I left off grid integration. That’s close to zero at low levels, but dominating at high levels, and already we see Germany exporting most of the problem.

        On the other hand, my calculation relates it directly to price, and price is falling, though not as fast as previously.

        Also, if we go to near tropics, not only is the return higher, but grid integration is less.

        ” This is much more likely to be in the order of 1000 €/kWp”
        Though commercial providers have to pay for land, fencing, insurance, profit*, and probably some guy to watch the panels. In addition, the grid integration costs may be higher as you have no self-usage to offset against.

        And some commercial installations cost a lot of money. I recall Blackfriars station coming in at something £10,000 / KW.

        *I like the idea of accounting for the capital and labour costs, but this justifies the use of the energy intensity figure. After all, a solar cell is part manufacture, part service; part labour, part capital, all with opportunity costs. It’s a microcosm of GDP – though still an estimation. (A bit like The Economist’s Big Mac index).

        • Alex says:

          Speaking of the £10,000/KW solar panels at Blackfriars, there is an aerial view here:

          I just happened to travel via Blackfriars station yesterday. The solar may be expensive (and not visible from inside), but it is, by a long way, the nicest City centre station I’ve seen.

          • gweberbv says:


            this is as much a power plant as the fireplaces that were built in the offices of a few high-ranked investment bankers can be regarded as heating systems. I would call it an interesting and expensive architectonic feature.

      • gweberbv says:


        grid integration has two parts:
        1) Ramping up/down of other plants, usage of fast reaction buffers (batteries, hydro, etc.).
        2) Grid enforcement.

        Compared to the 20 years life time that Alex assumed for PV cells, the grid enforcement will last much longer. Thus, you have not to pay for it everytime you install PV cells but only the first time. Therefor, I assume point 2) from above will not influence the ERoEI significantly (same with a hydro scheme that may last for hundred years and more).

        • singletonengineer says:

          Grid extensions to accommodate PV are of the same order of magnitude as the cost of the PV itself. I have stated elsewhere, and Geunther has reluctantly agreedm that technical subsidies of PV include:
          1. Grid reinforcement
          2. Backup plant for the more-than-half-of-the-time that unreliables cannot be relied on, ie their very low capacity factor.
          3. Grid services such as frequency control and spinning reserve.
          4. And more.

          Yet Guenther persists in the fallacy that only grid reinforcement is necessary and then he waves that into oblivion because money spent on grid upgrades might have value beyond the life of the PV.

          What’s it to be, Guenther? Does PV have a lifetime of ten years, thus enjoying upgraded grid for perhaps 5 or more generations?

          Or does PV have a 20 or 30-year life, thus having only two or three generations in which to repay the cost of the additional grid?

          Of course, there is no answer to this question, because the Green Army have decided, through Guenther, to completely disown all of the costs that they don’t like.

          One thing remains certain, and that is that whatever the SYSTEM COST and SERVICE LIFE of the various components which are essential for the Green Dream, they should all be accounted for.

          It follows that it is not honest or reasonable to claim that grid augmentation “will not influence the ERoEI” of PV.

        • gweberbv says:


          the costs of grid enforcement is for sure not on the same scale as the cost for the installation of renewable capacity (if you are interested in reality, in phantasy world you can require every kWh from renewables to first run through a hydro storage scheme). This can be seen very clear from German data where we already have a lot of PV and wind on the one hand and several years of grid enforcement to cope with the challenges from this intermittent producers on the other hand.
          Here you see the development of the renewable sourscharge which pays for the installation (for residential customers):
          And here you see the development of the grid usage charge (residential=light blue, medium size=dark blue, bif industry=grey):
          The latter covers everything from grid extension to ordering power plants to ramp up and down to stabilize the grid. And it increases barely by 1 Eurocent/kWh from 2009 to 2015. When you now consider that the building of new transmission lines creates value that can be used (without complete exchange of all parts) for 50 to 100 years, you can conclude that these costs and also the energy used for it is marginal compared to the money/energy that goes into the installation of the plants.

          • Alex says:

            So barely 1c/KWh, paid by all electricity buyers, to support the 15℅ solar and wind? That translates to about 6c/KWh, at current penetration levels. As penetration increases, costs will rise – to date, Germany has not had to build new storage, but that will change.

          • robertok06 says:

            “the costs of grid enforcement is for sure not on the same scale as the cost for the installation of renewable capacity ”

            You shouldn’t bet your farm on it, Guenter!… just to make an exemple… pumped storage costs a fortune… 600 million Euros and 6 years construction time to build the Campolattaro basin in southern Italy, originally owned by the Swiss company REPower and quickly sold to the Chinese, since it was loosing money big time. Total stored electricity?… a mere 10 GWh… i.e. 1/150 (or even less) of the daily demand in Germany on a cold winter day.

            PV’s and wind’s electricity is going to cost more and more as their penetration increases… that’s a well known thing… grid installations included… get over with it Guenter!


          • gweberbv says:


            we need much more PV in Europe before hydro storage schemes will find a business case again (pumping during night, generating in the morning, pumping during the PV peak, generating in the evening). For the moment, it seems that most planned projects were stopped. See here:

            I would love to see support from the government, as after the initial investment these plants will basicly last forever (with some reparis/exchanges of parts from time to time) and benefit society with their service. My wife was raised near to this barrage (not a storage plant):
            Construction started in 1912. And I guess that it will still exist in 100 years from now.

    • Andy Dawson says:

      “There’s some nutter on the Guardian saying $500/KWp,”

      Let me guess….

    • Alex

      I did a review about a year ago based on 4kWp system in the UK and found the cheapest non sale price to be around £4500 installed. That could go up to 8K if using the most modern and highest efficiency cells.

      Using Fraunhofer data available I was getting around €1200/kwP in 2014 compared to around €6K for 2006 data. The difference of course is residential versus utility scale I suspect.

      • Alex says:

        Thanks – that is about €1,500 / KWp. If we use the “Energy intensity of GDP” method, that improves the ERoEI. Utility may be cheaper on the panels, but then they have to pay for the land, and sometimes can have high access costs.

  35. Thinkstoomuch says:

    Been debating posting this on energy matters for quite a while. I might have and forgotten I did. If so please delete this post. I have posted it other places.

    It is a company presentation and needs to be taken with that in mind! FPL is approaching all this the way a conservative business should. Mostly based on the economics

    Bear in mind currently electric rates are absurdly cheap in this area, ~$0.08 USD to the customer (me).

    First they tried one axis tracking PV, Desoto Solar Plant. Then concentrated solar at the Martin plant (you guys called that one big time). Then pole mounted utility scale PV plant at Cape Canveral. Then a $2 a watt residential and school rebate for roof top installations. Take all the data, figure out what works. And what doesn’t.

    So now that I got the disclaimers aside.

    This year they are installing (3) 74.5 MWp plants. Look at how many things they had to get to make it even slightly economic. 30% off federal taxes. Free Land. Near existing power lines. Heck the only reason they went forward at all because when they made the decision the tax credit was set to go away.

    Then of course to convince people how green they are, installed a couple of smallish systems at the Palm Beach Zoo and Daytona Internal Speedway.

    All those things that people say shouldn’t be figured into the energy cost. Those contractors installing roof arrays could just as easily be installing new roofs before the next hurricane. Or maybe cheaper more comparative home improvements like tankless hot water heaters. Or even better yet a solar hot water heater. The factory could be producing those water heater components cheaper. Instead they are producing PV modules. This IS a zero sum game in a lot of ways. What is actually the best way to do things?

    My Apologies if this post offends, it really is not meant to. Which is why I like the comments made by the study’s author.

    have fun all,

  36. Knut says:

    Looking at some of the debates above, I see that there is some amount of talking past each other going on with respect to the role of labour and capital in ERoEI.

    Let us distinguish two (rough) notions of ERoEI

    – the energy a given installation produces, divided by the energy consumed in producing it, and in producing the materials that went into it, transport, grid integration, etc.

    – as above, but add in the denominator some energy proxy for the labour and capital invested

    Let us also distinguish two questions:

    (1) Does the production and subsequent use of a given installation (e.g. a PV panel) cause a reduction in overall carbon emissions? If so by how much?

    (2) Which energy technologies will allow us to supply civilization’s energy needs?

    Myself and some others have been advocating a narrow notion of ERoEI. That is because we have been thinking of question (1). The reasons we have been giving should make that clear. I still submit that, for question (1), ERoEInarrow is the relevant measure.

    If question (2) is what we are interested in, then yes, some version of ERoEIext is the relevant measure.

    My only plea to those who are working on question (2), and therefore cast their ERoEI nets wide, would to be careful about how they present their results. Suppose we arrive at the result that some installation has a ERoEIext of 1. If we present this as: “It took as much energy (derived from fossil fuels) to produce this installation as it will produce” then people not so deeply into these issues are likely to infer: “This installation does not reduce carbon emissions at all”.

    But that would be a mistaken inference. So please, careful guys.

    • Thinkstoomuch says:

      “(1) Does the production and subsequent use of a given installation (e.g. a PV panel) cause a reduction in overall carbon emissions? If so by how much?”

      Does this include the cost of transport and storage?

      For example if the panel is made in China to get to me. First it has to move from the factory to the port. Then it has to be unloaded from that, to be loaded on a ship. Which then moves to another port then unloaded. Loaded on a transport to a wholesaler. Then once again loaded onto another transport. For another couple of thousand miles. Unloaded at the contractor or local retailer. Loaded onto another transport to the installation site.

      So how much energy is used in all those transport operations? This is no the “I Dream of Genie” world. Stuff doesn’t move unless someone provides the energy to move it.

      Of course. None of that happens unless those panels get installed. Instead there are less trucks on the road. saving the use of all that oil.


      • Knut says:

        Yes. I meant to include that kind of thing in “…transport, grid integration, etc.”

        • Thinkstoomuch says:

          Well then your last line in the post.

          “But that would be a mistaken inference. So please, careful guys.”

          Is a problem. The correct question should be is this the BEST way forward. IMO. The way you word it implies that solar is the best answer. It may not be. Money and energy may best be invested in other places.

          For example the cost of each of those FPL Solar projects HERE is the exact same as the new Waste to Energy 100 MW plant 10 miles from my house.

          Which because it can run on grass clippings those solar plants are not only occupying carbon sinks they are covering an energy source. Which, granted, requires a continuing energy investment.

          But in SIX months last year (brand new plant) produced 5 times the energy of the Desoto Solar Plant. Or about 1.5+ times the energy to be expected in a YEAR at the new solar plants. Simple renewable for a function that is already being done. Saves landfill space as well as gases produced in a landfill.

          Without actually doing the extended ERoEI calculations which is better? Vary depending on location. I haven’t really come across a good one on WTE.

          If it is about limiting CO2 then the best investment for the greatest return REQUIRES knowing all the costs and comparing them objectively. Not chasing chimera’s.

          My opinion of course,

          PS How the heck do you bold and italicize words here?

          • Knut says:

            Oh I wish I knew how to bold and italicize. But I find it actually has a disciplining effect on one’s prose. When you cannot italicize, you have to find a sentence with a rhythm that makes the right word stand out.

            To your post. I don’t think there are correct and incorrect questions, only different ones. My concern is that we not confuse them. Both because that muddles our own thinking, and because it leads to talking past each other. Which in turn can lead to thinking each other stupid.

            For example, Euan wrote above that I “loose all credibility” in his book when I said it is absurd to include labour in ERoEI. And Jan something replied to me with a link to a “Let Me Google That For You” thingy.

            All because I was thinking of question (1), they of question (2).

    • Maury Markowitz says:

      It doesn’t appear I can make a new thread, so my apologies for posting this as a reply.

      The paper in question is utterly bogus. Trivially so. I go into some level of detail here:

      I would love to check every value line-for-line, but I have a day job and a 4-mo-old baby, so I can only invest so much time into this one paper.

      An overview:

      – they use cherry picked numbers for every cited value. When the paper they quote presents a range of values, they always pick one that makes PV look bad, and fail to mention that a range exists.

      – they use uncited values for the main input, the capex. The value is, as the paper states, their “personal experience”. That number is also FOUR TIMES the value that can be found in the industry’s own papers, which are trivial to find on the ‘net.

      – the double-count many values, including interest, labour and faulty equipment, all of which are parts of the capex line but are not backed out of it when they calculate the contribution of that capex.

      – the whole idea that capex is part of the EROEI needs to be treated with care. The cost of a complete PV system has decreased 10 times in 15 years, but the energy needed to make it has decreased perhaps 30%. Clearly the capex is not directly indicative of the real embedded energy. The authors simply ignore all of this.

      I’ve been writing about papers like these for some time. The field is filled with bogus papers like this one, both pro- and con- renewables, and you need to *really* check them every time. Invariably the worse come from people in the nuclear field, like this one.

      • Euan Mearns says:

        The paper in question is utterly bogus. Trivially so. I go into some level of detail here:

        Maury, I had the Ferroni paper and my blog post reviewed by Professor Charles Hall who kind of invented the terminology ERoEI if not the overall concept and also by Dr David Murphy and Dr Nate Hagens who both have PhDs in ERoEI. And while there are many issues with the Ferroni paper and disagreements between us, the conclusion was that it is in the right ball park. Perhaps you would like to share your credentials with my readers that enable you to profess that the paper is “utterly bogus”. Knowing what your day job is would be a good starting point.

        It is noted that you describe yourself as a ***** physicist and run an energy blog out of Toronto called “Energy Matters”. It is quite astonishing that you have run that blog for almost two years oblivious to the existence of this blog that has been going for almost three. Did you not do any research at all before setting up your blog?

        I’d also advise that you avoid using terms like “oil company shill” in any material you write about me and my blogging colleague Roger who is in his mid-70s and is a retired metal mining geochemist who lives in Mexico and who does have a PV array.

        I suggest you re-Christine your blog Matter 2 Energy, which is a great name (I wish I’d thought of that) and appropriately describes our energy future.


        Dr Euan Mearns

        • Maury Markowitz says:

          “the conclusion was that it is in the right ball park”

          WHAT is in the right ball park, the methodology, or the numbers they plug into the methodology?

          Because you will note that my article *uses their methodology*, but plugs in numbers from public sources, and that immediately leads to positive EROEI.

          If you have different numbers you would like to be use, by all means, point them out.

          ““oil company shill” in any material you write about me”

          I believe you are referring to the statement “coal industry shill”, which if you care to click on the link, is referring to Americans for Prosperity.

          AFP spends millions of dollars a year on pro-coal, anti-renewables ad campaigns in the US, funded largely by the coal industry – thus the fully deserved title of “coal industry shill”. However, that is not entirely accurate, because…

          On behalf of other organizations, they also run anti-Obamacare campaigns, basically funded the Tea Party into existence, and continue to oppose any sort of labour union activity. They are as close as anyone can get to a real-life Veridian Dynamics.

          “Knowing what your day job is would be a good starting point.”

          Sure, I’m a bespoke programmer, like 90% of my physics class (which includes one person involved in a Nobel for physics, who also wrote Starry Night, if you’re familiar with that program). Over time I have worked for many customers, including one of Canada’s largest hedge funds.

          Given my background and interests, I sat in on the various pitches circa 2008 when the oil prices peaked. And boy, the pitches! I particularly liked the one from one CSP player who wowed us with $1/Wp cell prices, only to note the tracker cost $7/Wp. They didn’t buy in, as you might surmise. There were some good ones too, including geothermal plays in Chile (which was a no-brainer given the copper smelting sinks), a wind farm out west, and a whole lot of hydro upgrades.

          As you no doubt recall, 2008/09 was also the year the markets crashed, and that company tightened belts. I joined AS Solar’s Canadian division where I ran the tech side of things for several years. As such, I had a (small) hand in hundreds of megawatts of PV installs here in Canada, including my own home. Watching that industry implode will be the topic of a future article, but even today the heartache is too much to bear.

          It is a warning to similar industries in Europe though, the entire system can disappear in months in spite of every other indication being positive. The wreckage was everywhere, taking out long-time players like Sharp and Sanyo, let alone the smaller players. Given what I’m reading about the UK, it’s not too much to suggest you might be in for the same sort of cratering.

          “astonishing that you have run that blog for almost two years”

          I’ve been running my blog since June 2009:

  37. Dubai doesn’t matters, RECs are in the future intentions a free trade worldwide initiative and the specific certificate for solar projects in USA is called SREC that is typically much more rich $20c-$60c/kWh. Italian taxpayers are obliged to heavily supporting this scheme at international scale allowing free trade.
    Therefore the expected selling prices for last solar bids are are PPA+SREC $23c-$63c/kWh, despite a lot of volatility and policy risks.
    ENEL knows: the rules, the status of international negotiations, the premature solar production decline with the incoming rarefaction of SREC, that imply an even higher certificate price in the future, the PPA figure is meaningless.
    In any case is really easy to check the figures, Enel is building solar farms at $2M/MWp of CAPEX if we include the OPEX, is an NPV of another $1M/MWh so a total of $3M/MWh at $230/MWh it will take 3M/230 = 13000h to the breakeven say about 10 years without interest rates computed.
    To avoid insane economics, $230/MWh is really the minimum possible selling price for solar energy, therefore ten times the current coal generation cost.

    • MuellerB says:

      And from which ENEL documents do you take these numbers?

    • Luís says:

      To understand how far off these numbers are, you can check the levelised costs calculated for Pavia in this article:

    • Maury Markowitz says:

      Using PVWatts, I selected the Naples TYM3 dataset, put in a 1 MW system on a 30 degree fixed mount, and hit go. That produces 1,271 MWh per year. That’s the equivalent of a 14.6% capacity factor (and I should note, surprisingly similar to what my panels in Toronto are producing).

      Then I went over to the NREL LCoE tool, put in that CF and the CAPEX you quote of $2/Wp. I changed it to a 25 year period, standard for PV, and used the default 3% discount rate. Instead of using the $1/Wh for OPEX, I used the industry-standard $17/kW-yr that you can find on that page.

      That produces an LCoE of 10.2 cents.

      Then I went here to find recent wholesale rates for Italy:

      The current rate is somewhere between 7 and 8 cents. If I put 7 into the same discount rate, the equivalent value is 9.4 cents over 25 years.

      That means PV costs 8% more than *wholesale baseload*. Sadly I could not find current peak prices for Italy, but I can only imagine they are well over 10 cents.

      Using the current 23 cent retail rate, the equivalent discounted rate is over 32 cents. So there is ample room for commercial PV sales into that market.

      DO THE MATH.

      • Alex says:

        That tallys roughly with an analysis I did last year, which was somewhat on the “optimistic side”, given the audience.

        That is “raw” price, so excluding any grid costs. It is cheaper than retail price, which is why we have to get used to solar disrupting our base load supply, with or without subsidies.

      • gweberbv says:


        be aware that Italy has already slightly below 20 GW of PV installed. While the average wholesale price might be in the same ball park as utility-scale PV (by this time), I doubt that this will be the case during the PV peak.

        • Maury Markowitz says:

          > I doubt that this will be the case during the PV peak.

          I agree, but do they have negative peaks yet? Does anyone have a source of information on daily spot pricing for Italy?

          I get my own here:

          Note that it was zero again last night. It’s been going negative at night for some time now. And that’s why you make sure your reactors don’t need three days to throttle!

          On the upside, we still have peak prices as high as 25 cents in the summer, although that’s not at all common, and with the local climate moderating (if you live in Ontario, your mantra is “bring on the climate change!”) this will likely decrease over time. We’ll see.

          > which is why we have to get used to solar disrupting
          > our base load supply

          Indeed Alex, although I suspect when you look at Ontario’s currently 1.25 cent/kWh rate you’ll predict a different outcome here 🙂

          > That is “raw” price, so excluding any grid costs.

          A worthy point of discussion on its own.

          I note that the paper in question puts that price at 350 out of 2200, which I found surprisingly low – most papers of this type claim you need a watt of gas for every watt of PV, so this is definitely well on the lower bound of such claims.

          Of course when one looks at the current integration in German, which has significantly more PV and significantly less than 350 CHF/m2 grid upgrades, its certainly worth examining a wider variety of sources.

  38. Luís says:

    Out of the dozens of studies on PV EROEI out there you chose the lowest 2 you could find to trash PV. Is that supposed to be an independent analysis?

    If the EROEI of PV is below 1, how do you explain the levelised cost trends? In the south of Europe PV is now the cheapest source of electricity. How do you explain that?


    • Euan Mearns says:

      In the south of Europe PV is now the cheapest source of electricity. How do you explain that?

      1) it is sunny in the S of Europe and very rarely sunny in Scotland
      2) PV is free loading on the grid for transmission and balancing
      3) perhaps the price of panels does not reflect the cost or the cost has fallen dramatically in recent years
      4) the intrusion of the parasite onto the grid has increased the cost of everything not solar

      Luis, I had my post checked by Charlie, Dave and Nate who in my circle of contacts are the experts. What more do you expect me to do? You should check this out…

      And check out my Figure 1 above. And then appreciate that solar produces next to nothing at high latitude in winter – The Sun is barely above the horizon, and it produces zero at 18:00 in winter when UK demand is at its seasonal high.

    • robertok06 says:

      “In the south of Europe PV is now the cheapest source of electricity.
      How do you explain that?”

      I explain it like this:

    • Luís

      In the south of Europe PV is now the cheapest source of electricity.

      Italy: €6.5 billion FIT for 24TWh of solar PV, each year.
      Coal is about €25/MWh instead.

      To earn €270 Italian people burns about 0.8 MWh of primary energy.
      0.8MWht of primary energy could produce about 0.4MWhe with an existing gas turbine.

      So the €270 produces with the PV a net energy of 0.6 MWhe,
      the final PV cost is €450/MWh.

    • Ajay Gupta says:

      I am unaware of dozens of papers on PV EROI. I only know of a handful. Can you post the a link or maybe even the titles of the papers you are talking about please?

  39. mark4asp says:

    Fab news in the Indy: “UK renewable energy industry is about to ‘fall off a cliff’, says new research”

    Long overdue. Time for it to sink or swim.

  40. Michael Kirby says:

    Maybe a better way of looking at this is not whether or not the enegery return is positive or negative in a global context, but whether it is positive relative to equivalent spend in the market in which it is deployed.

    So Solar in the UK is positive compared to nuclear in the UK, or coal in the UK.

    But not compared to coal in China (where much of the solar cells are made, or the components are made).

    Since we cannot transport electricity from China to the UK, this kind of “negative” investment is okay.

    And then there are the non-economic reasons to do this: (1) Capital spent on solar increases the efficiency of solar over time (both in terms of the voltaics, as well as the manufacutring, distribution, and installation, all of which are expensive from an energy perspective. (2) Leadership in the idea of attempting to reduce your carbon footprint will eventually lead us to a better future. Alternatively we can do nothing.

    There are always inefficiencies in the market. I would be interested in a graph of the ERoEI over the last 2 decades of solar prodution. I’d be willing to bet that 10 years ago it was .5, or .25.

    So we’re trending where we want to be going, and with luck in 10 years it will be 5 or 10.

    But without the investments today it never would have gotten there.

    • singletonengineer says:

      “…never would have gotten there.”

      Gotten where? How is failing to achieve a positive return on energy invested on PV a destination?

      Further, I do not agree that it is an incontrovertible truth that solar PV will be half the price or twice as energy efficient in 5 or 10 years’ time. Such statements are meerly scattering of pixie dust. If, after all the time and support pumped into this industry over the past 4 decades or so it is not yet energy-positive in northern Europe, then there is no guarantee that it ever will be, especially when that guarantee is based on an arbitrary multiple, in this case a factor of two.

      A wise researcher once said in my presence, and I agree, that any claim that a developing drug will be available in 5 years’ time is, in truth, an admission that the researcher making the statement doesn’t know if or when it will be commercially available. That is because the planning horizon of research is generally no longer than 5 years.

      IMHO, this applies also to claims about the rosy future of PV.

      It is essential that we discuss the real world achievements of technologically mature mass-produced products such as PV without clouding the subject with arbitrary claims of unverifiable future progress.

  41. Andy Dawson says:

    A random thought….

    when we do any form of economic analysis, it’s usual to discount future cash flows to reflect uncertainty and risk.

    Is there an argument for doing that here?

    • Alex says:

      There are two elements to the discount rate:
      1. The risk free rate of return – historically about 3-4% pa, but probably lower now.
      2. The risk/uncertainty element.

      We would have the same with ERoEI calculations.
      1. Avoiding 1 ton of CO2 into the atmosphere today is probably worth more than avoiding 1 ton this time next year. However, I don’t know by how much, but I suspect not a lot.
      2. The risk element. However, in this respect solar is probably fairly low risk due it;s diversity. A single mega project would be more risky here – what if our giant PV plant in the desert gets over run by ISIS? What oif our nuclear plant get permission withdrawn after it’s built?

      The linked risk – especially acute for nuclear, is what if something better comes along? It’s a risk for 60 year plants. Hinkley C will look dammed stupid if MSRs come along at £30/MWh, or (LOL) Rossi’s E-CAT at £10/MWh. Hinkley C will look pretty smart if most of our electricity comes from renewables, storage and back up gas at £150/MWh.

      • It doesn't add up... says:

        Hinkley C will look pretty smart if most of our electricity comes from renewables, storage and back up gas at £150/MWh.

        No, our whole energy policy will look extraordinarily stupid – as indeed it already does.

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  47. Marco Raugei says:

    Euan Mearns wrote:

    “the IEA is tending to focus on the energy used in the factory process while the extended methodology of Murphy and Hall, 2010 includes activities such as mining, purifying and transporting the silicon raw material.”

    This is simply false.

    I would advise anyone interested in the facts to just go and download the IEA guidelines on Life Cycle Assessment [1] and Net Energy Analysis [2] of PV.


    • Euan Mearns says:

      I’ve just had a quick look and in your reference [2] they discuss at length why they DO NOT recommend using a wide system boundary as used by Prieto and Hall.

  48. Pingback: environmentalresearchweb blog - environmentalresearchweb

  49. Apollo T says:

    Dear Euan Mearns, you seem to have been caught in a prank.

    I was notified by a contact in Switzerland that Swissolar together with the energy office are preparing to sue Elsevier over this paper. The figures Ferroni and Hopkrik used are mostly made up, totally unrelated to official statistics. If you have not seen it yet, this simple check on yearly electricity generation is elucidating:

    And this is just one aspect of it. I wonder if you have done any number checking yourself. Do you still stand by this study?

    • The novelty with Ferroni & Hopkirk work is that now we have real data, aren’t any more needed meta-analysis or estimations. Sousa is citing Pedro Prieto as the most conservative study, I think he have a curious idea of what conservative is, is much more conservative the Ferroni & Hopkirk work, because our societies needs to be sure that a claimed source of energy is really effective in the real world, including all events that could go wrong. In default of that the risk is to invest coal for production to finally obtain less energy than the coal itself. This aspect reveal this article as a biased source. Pedro Prieto admitted his assumptions too optimistic leading to an excess of Eroei:
      In Italy is recorded an important decay of PV production, the current trend is more than 10%/year, this turn the huge investment in solar in an irrecoverable dead loss.

    • clivebest says:

      If we take instead figures from Luís de Sousa’s blog post then we get a figure EROI = 1.8 for Switzerland. The major difference between the two is the rate of degradation of PV cells over their 25y lifetime (0.5% pa versus 4% pa).

      However an EROI of 1.8 is still disastrously bad. We need an EROI of at least 10 to power a modern society. PV might make sense in the Sahara but not yet in Switzerland.

      • Apollo T says:

        Dear Clive, it seems you misunderstood what is written in that blog post. The major difference is that Luis actually used the official figures published by the energy office, while Ferroni and Hopkrik just made up something. No scrupulous person should stand by this study.

        I acknowledge the claims of a minimum EROEI to run modern civilization. But these largely miss the logarithmic nature of this quantity. Why 10 and not 6? or 2?

    • mark4asp says:

      If their figures are made up, as you claim, tell us which particular numbers are made up and precisely what the correct number is. Fruitcake statements such as “figures Ferroni and Hopkrik used are mostly made up” will otherwise be laughed at, and you’ll probably have your account here censored. Their paper is peer-reviewed. You are libeling the peer reviewers as well as the Ferroni and Hopkirk.

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