EROI explained and defended by Charles Hall, Pedro Prieto, and others

29 05 2017

Yes, another post on ERoEI……  why do I bang on about this all the time…?  Because it is the defining issue of our time, the issue that will precipitate Limits to Growth to the forefront, and eventually collapse civilisation as we know it.

There are two ways to collapse civilisation:
1) don’t end the burning of oil
2) end burning oil

And if that wasn’t enough, read this from srsroccoreport.com 

While the U.S. oil and gas industry struggles to stay alive as it produces energy at low prices, there’s another huge problem just waiting around the corner.  Yes, it’s true… the worst is yet to come for an industry that was supposed to make the United States, energy independent.  So, grab your popcorn and watch as the U.S. oil and gas industry gets ready to hit the GREAT ENERGY DEBT WALL.

So, what is this “Debt Wall?”  It’s the ever-increasing amount of debt that the U.S. oil and gas industry will need to pay each year.  Unfortunately, many misguided Americans thought these energy companies were making money hand over fist when the price of oil was above $100 from 2011 to the middle of 2014.  They weren’t.  Instead, they racked up a great deal of debt as they spent more money drilling for oil than the cash they received from operations.

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alice_friedemannAlice Friedemann   www.energyskeptic.com  author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report ]

Questions about EROI at researchgate.net 2015-2017

Khalid Abdulla, University of Melbourne asks:  Why is quality of life limited by EROI with renewable Energy? There are many articles explaining that the Energy Return on (Energy) Invested (EROI, or EROEI) of the sources of energy which a society uses sets an upper limit on the quality of life (or complexity of a society) which can be enjoyed (for example this one).  I understand the arguments made, however I fail to understand why any energy extraction process which has an external EROI greater than 1.0 cannot be “stacked” to enable greater effective EROI.  For example if EROI for solar PV is 3.0, surely one can get an effective EROI of 9.0 by feeding all output energy produced from one solar project as the input energy of a second? There is obviously an initial energy investment required, but provided the EROI figure includes all installation and decommissioning energy requirements I don’t understand why this wouldn’t work. Also I realise there are various material constraints which would come into play; but why does this not work from an energy point of view?

Charles A. S. Hall replies:  As the person who came up with the term  EROI in the 1970scharles-hall (but not the concept: that belongs to Leslie White, Fred Cotrell, Nicolas Georgescu Roegan and Howard Odum) let me add my two cents to the existing mostly good posts.  The problem with the “stacked” idea is that if you do that you do not deliver energy to society with the first (or second or third) investment — it all has to go to the “food chain” with only the final delivering energy to society.  So stack two EROI 2:1 technologies and you get 4:2, or the same ratio when you are done.

The second problem is that you do not need just 1.1:1 EROI to operate society.  We (Hall, Balogh and Murphy 2009) studied how much oil would need to be extracted to drive a truck including the energy to USE the energy.  So we added in the energy to get, refine and deliver the oil (about 10% at each step) and then the energy to build and maintain the roads, bridges, vehicles and so on.  We found you needed to extract 3 liters at the well head to use 1 liter in the gas tank to drive the truck, i.e. an EROI of 3:1 was needed.

But even this did not include the energy to put something in the truck (say grow some grain)  and also, although we had accounted for the energy for the depreciation of the truck and roads,  but not the depreciation of the truck driver, mechanic, street mender, farmer etc.: i.e. to pay for domestic needs, schooling, health care etc. of their replacement.    Pretty soon it looked like we needed an EROI of at least 10:1 to take care of the minimum requirements of society, and maybe 15:1 (numbers are very approximate) for a modern civilization. You can see that plus implications in Lambert 2014.

I think this and incipient “peak oil” (Hallock et al.)  is behind what is causing most Western economies to slow or stop  their energy and economic growth.   Low EROI means more expensive oil (etc) and lower net energy means growth is harder as there is less left over after necessary “maintenance metabolism”. This is explored in more depth in Hall and Klitgaard book  “Energy and the wealth of Nations” (Springer).

Khalid Abdulla asks: I’m still struggling a little bit with gaining an intuition of why it is not possible to stack/compound EROI. If I understand your response correctly part of the problem is that while society is waiting around for energy from one project to be fed into a second project (etc.) society needs to continue to operate (otherwise it’d all be a bit pointless!) and this has a high energy overhead.  I understand that with oil it is possible to achieve higher external EROI by using some of the oil as the main source of energy for extraction/processing. Obviously this means less oil is delivered to the outside world, but it is delivered at a higher EROI which is more useful. I don’t understand why a similar gearing is not possible with renewables.  Is it something to do with the timing of the input energy required VS the timing of the energy which the project will deliver over its life?

Charles A. S. Hall replies: Indeed if you update the QUALITY of the energy you can come out “ahead”.  My PhD adviser Howard Odum wrote a lot about that, and I am deeply engaged in a discussion about the general meaning of Maximum Power (a related concept) with several others.  So you can willingly turn more coal into less electricity because the product is more valuable.   Probably pretty soon (if we are not already) we will be using coal to make electricity to pump out ever more difficult oil wells….

I have also been thinking about EROI a lot lately and about what should the boundaries of analysis be.  One of my analyses is available in the book “Spain’s PV revolution: EROI and.. available from Springer or Amazon.

To me the issue of boundaries remains critical. I think it is proper to have very wide boundaries. Let’s say we run an economy just on a big PV plant. If the EROI is 8:1 (which you might get, or higher, from examining just the modules) then it seems like you could make your society work. But let’s look closer. If you add in security systems, roads, and financial services and the EROI drops to 3:1 then it seems more problematic. But if you add in labor (i.e. the energy it takes to make the food, housing etc that labor buys with its salaries, calculated from national mean energy intensities times salaries for all necessary workers) it might drop to 1:1. Now what this means is that the energy from the PV system will support all the purchases of the workers that are building/maintaining the PV system, let’s say 10% will be taken care of, BUT THERE WILL BE NO PRODUCTION OF GOODS AND SERVICES for the rest of the population. To me this is why we should include salaries of the entire energy delivery system (although I do not because it remains so controversial). I think this concept, and the flat oil production in most of the world, is why we need to think about ALL the resources necessary to deliver energy from a project/ technology/nation.”

Khalid Abdulla: My main interest is whether the relatively low EROI of renewable energy sources fundamentally limits the complexity of a society that can be fueled by them.

Charles A. S. Hall replies: Perhaps the easiest way to think about this is historical: certainly we had lots of sunshine and clever minds in the past.  But we did not have a society with many affluent people until the industrial revolution, based on millions of years of accumulated net energy from sunshine. An affluent king, living a life of affluence less than most people in industrial societies now, was supported by the labor of thousands or millions of serfs harvesting solar energy.  The way to get rich was to exploit the stored solar energy of other societies through war (see Plutarch or Tainter’s the collapse of complex societies).

But most renewable energy (good hydropower is an exception) are low EROI or else seriously constrained by intermittency. Look at all the stuff required to support “free” solar energy. We (and Palmer and Weisbach independently) found EROIs of about 3:1 at best when all costs are accounted for.

The lower the EROI the larger the investment needed for the next generation: that is why fossil fuels with EROIs of 30 or 50 to one have led to such wealth: the other 29 or 49 have been deliverable to society to do economic work or that can be invested in getting more fossil fuels.  If the EROI is 2:1 obviously half has to go into the next generation for the growth and much less is delivered to society.   One can speculate or fantasize about what one can do with some future technology but having been in the energy business for 50 years I have seen many come and go.  Meanwhile we still get about 75-80% of our energy from fossil fuels (with their attendant high EROI).

Obviously we could have some kind of culture with labor intensive, low energy input systems if people were willing to take a large drop in their life style.  I fear the problem might be that people would rather go to war than accept a decline in life style.

Lee’s assessment of the traditional  Kung hunter gatherer life style implies an EROI of 10:1 and lots of leisure (except during droughts–which is the bottleneck).  Past agricultural societies obviously had a positive EROI based on human labor input — otherwise they would have gone extinct.  But it required something like a hectare per person.  According to Jared Diamond cultures became more complex with agriculture vs hunter gatherer.

The best assessment I have about EROI and quality of life possible is in:  Lambert, Jessica, Charles A.S. Hall, Stephen Balogh, Ajay Gupta, Michelle Arnold 2014 Energy, EROI and quality of life. Energy Policy Volume 64:153-167 http://authors.elsevier.com/sd/article/S0301421513006447 — It is open access.  Also our book:  Hall and Klitgaard, Energy and the wealth of nations.   Springer

At the moment the EROI of contemporary agriculture is 2:1 at the farm gate but much less, perhaps one returned for 5 invested  by the time the food is processed, distributed and prepared (Hamilton 2013).

As you can see from these studies to get numbers with any kind of reliability requires a great deal of work.

Sourabh Jain asks: Would it be possible to meet the EROI goal of, say for example 10:1, in order to maintain our current life style by mixing wind, solar and hydro? Can we have an energy system various renewable energy sources of different EROI to give a net EROI of 10:1?

Charles A. S. Hall replies:  Good question.  First of all I am not sure that we can maintain our current life style on an EROI of 10:1, but let’s assume we can (Hall 2014, Lambert 2014).  We would need liquid fuels of course for tractors , airplanes and ships — I cannot quite envision running those machines on electricity.

The problem with wind is that it tends to blow only 30% of the time, so we would need massive storage.  To the degree that we can meet intermittency with hydro that is good, although it is tough on the fish and insects below the dam.  The energy cost of that would be huge, prohibitive with respect to batteries, huge with respect to pumped storage, and what happens when the wind does not blow for two weeks, as is often the case?

Solar PV may or may not have an EROI of 10:1 (I assume you know of the three studies that came up with about 3:1: Prieto and Hall, Graham Palmer, Weisbach — but there are others higher and certainly the price and hence presumed energy cost is coming down –but you should also know that many structures are lasting only 12, not 25 years) — — this needs to be sorted out ).  But again the storage issue will be important.   (Palmer’s rooftop study included storage).

These are all important issues.  So I would say the answer seems to be no, although it might work well for let’s say half of our energy use.   As time goes on that percentage might increase (or decrease).

Jethro Betcke writes: Charles Hall: You make some statements that are somewhat inaccurate and could easily mislead the less well informed: Wind turbines produce electricity during 70 to 90% of the time. You seems to have confused capacity factor with relative time of operation.  Using a single number for the capacity factor is also not so accurate. Depending on the location and design choices the capacity factor can vary from 20% to over 50%.  With the lifetime of PV systems you seem to have confused the inverter with the system as a whole. The practice has shown that PV modules last much longer than the 25 years guaranteed by the manufacturer. In Oldenburg we have a system from 1976 that is still producing electricity and shows little degradation loss [1]. Inverters are the weak point of the system and sometimes need to be replaced. Of course, this would need to be considered in an EROEI calculation. But this is something different than what you state. [1] http://www.presse.uni-oldenburg.de/download/einblicke/54/parisi-heinemann-juergens-knecht.pdf

Charles A. S. Hall replies: I resent your statement that I am misleading anyone.   I write as clearly, accurately and honestly as I can, almost entirely in peer reviewed publications, and always have. I include sensitivity analysis while acknowledging legitimate uncertainty (for example p. 115 in Prieto and Hall).  Some people do not like my conclusions. But no one has shown with explicit analysis that Prieto and Hall is in any important way incorrect.  At least three other peer reviewed papers) (Palmer 2013, 2014; Weisbach et al. 2012 and Ferroni and Hopkirk (2016) have come up with similar conclusions on solar PV.  I am working on the legitimate differences in technique with legitimate and credible solar analysts with whom I have some differences , e.g. Marco Raugei.  All of this will be detailed in a new book from Springer in January on EROI.

First I would like to say that the bountiful energy blog post is embarrassingly poor science and totally unacceptable. As one point the author does not back his (often erroneous) statements with references. The importance of peer review is obvious from this non peer-reviewed post.

Second I do not understand your statement about wind energy producing electricity 70-90 percent of the time.  In England, for example, it is less than 30 percent (Jefferson 2015).

Third your statement on the operational lifetime of actual operational PV systems is incorrect. Of course one can find PV systems still generating electricity after 30 years.  But actual operational systems requiring serious maintenance (and for which we do not yet have enough data) often do not last more than 18-20 years, For example Spain’s “Flagship ” PV plant (which was especially well maintained) is having all modules replaced and treated as “electronic trash” after 20 years : http://renewables.seenews.com/news/spains-ingeteam-replaces-modules-at-europes-oldest-pv-plant-538875    Ferroni and Hopkirk found an 18 year lifespan in Switzerland.

Pedro Prieto replies: The production of electricity of wind turbines the 70-90% of time is a very inaccurate quote. Every wind turbine has a nominal capacity in MW. The important factor is not how many hours they move the blades at any working regime, but how many EQUIVALENT peak hours they work at the end of the year. That is, to know how much real energy they generate within one year. This is what the industry uses as a general and accurate measurement and it is the load factor or capacity factor.

Of course, this factor may change from the location or the design choices, but there is an incontrovertible figure: when we take the total world installed wind power in MW (435 Gw as of 2015) from January 2004 up to December 2015 and the total energy generated in Twh (841 Twh as of 2015) in the same period and calculate the averaged capacity factor, the resulting figure slightly varies around 15% AT WORLD LEVEL. This is REAL LIFE, much more than your unsupported theoretical figures of 20 to over 50% capacity factor in privileged wind fields for privileged wind turbines.

Interesting enough, some countries like the US, United Kingdom or Spain have capacity factors reaching 20% in the last years, but the world total installed capacity has not really improved so much in the last ten years, despite of theoretically much more efficient wind turbines (i.e. multipole with permanent magnets), very likely for the reasons that good wind fields in some countries were already used up. Other countries like China, India or France show, on the contrary very poor capacity factors even in 2015.

 

With respect to the lifetime of the PV systems, nor Charles Hall neither myself have confused the inverter lifetime with the solar PV system as a whole. The practice has not shown that modules have lasted more than 25 years in general over the world installed base. The fact that one single system is still working after more than 30 years of operation, if it was carefully manufactured with high quality materials, and was well cared, cleaned and free from environmental pollutants, like several modules we have also in Spain, does not mean AT ALL that the massive deployments (about 250 GW as of 2015) are going to last over 25 years.

I have to clarify also a common mistake: almost all main world manufacturers guarantee a maximum of 25 years (NOT 30) to the modules, but this is the “power” guarantee. This means that they “guarantee” (assuming they will be still alive as companies in 25 years from the sales period, something which is rather difficult for many of the manufacturers that went out of business in shorter periods of time than the guarantee of their modules. Of course, this guarantee is given with the subsequent module degradation specs over time, which in many cases has been proved be higher than specified.

But not only that. Most of the module manufacturers have a second guarantee: the “material’s guarantee”. And this is offered for between 5 and 10 years. This is the one by which the manufacturer guarantees the module replacement if it fails. Beyond that date, if the module fails, the buyer has to buy a new one (if still being manufactured, with the same specs power and size), because the second guarantee SUPERSEDES the first one.

Last but not least, there is already quite a large experience in Europe (Germany, France, Switzerland, Spain, Italy, etc.) of the number of faulty modules that have been decommissioned in the last years (i.e. period 2010-2015) as for instance, accounted by PV-Cycle, a company specialized in decommission and recycling modules in Europe. As the installed base is well known in volumes per year, it is relatively easy to calculate, in a very conservative (optimistic) mode the percentage over the total that failed and the number of years that lasted in this period and the average years for that sample that died before the theoretical 25-30 years lifetime and make the proportion on the total installed base.

The study conducted by Ferroni and Hopkirk gives an approximate lifetime for the installed base of lower than 20 years. And this is Europe, where the maintenance is supposed to be much better made than in the rest of the developing world. And the figures of failed modules given by PV-Cycle did not include the many potential plants that did not deliver their failed modules to this company for recycling

What it seems impossible for some academic people is to recognize that perhaps the “standards” they adhered to (namely IEA PVPS Task 12 in this case) and through which they published a big number of papers, should be revisited, because they lacked some essential measurements that could help to understand why renewables are not replacing fossils at the required speed, despite having claimed for years that they reached grid parity or that their Levelized Cost of Electricity (LCOE) is cheaper than coal, nuclear or gas. 

I am afraid that peer reviewed authors are not immune to having preconceived ideas even more difficult to eradicate. Excessive pride, lack of humility, considerable distance between the academy (i.e. imagined solar production levels versus real data from actual solar PV plants and lack of a systemic vision due to an excess of specialization are the main hurdles. Of course in my humble opinion.

References

  • Hall, C.A.S., Balogh, S., Murphy, D.J.R. 2009. What is the Minimum EROI that a Sustainable Society Must Have? Energies, 2: 25-47.
  • Hall, Charles  A.S., Jessica G.Lambert, Stephen B. Balogh. 2014.  EROI of different fuels  and the implications for society Energy Policy Energy Policy. Energy Policy, Vol 64 141-52
  • Hallock Jr., John L., Wei Wu, Charles A.S. Hall, Michael Jefferson. 2014. Forecasting the limits to the availability and diversity of global conventional oil supply: Validation. Energy 64: 130-153. (here)
  • Hamilton A , Balogh SB, Maxwell A, Hall CAS. 2013. Efficiency of edible agriculture in Canada and the U.S. over the past 3 and 4 decades. Energies 6:1764-1793.
  • Lambert, Jessica, Charles A.S. Hall, et al.  Energy, EROI and quality of life.  Energy Policy
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Another study on the ERoEI of solar PV

10 05 2016

Originally posted by Euan Mearns on his blog Energy Matters, this study makes Pedro Prieto’s look very good….. the differences in ERoEI between the two studies must be a function of the difference in latitude between Spain and the UK, and even possibly by the fact that as the ERoEI of fossil fuels drops like a stone, the ERoEI of renewables must follow suit, as they rely entirely on the former.  Is Mearns a fan of nuclear power?  You make up your mind….

As Fort McMurray burns, and its smoke plume reaches the East coast of the USA, it’s occurred to me that the inevitable efforts and energy smoke-plume-from-fort-mcmurray-fire-reaches-us-east-coastrequired to rebuild it once the fire is out (IF, that is, it doesn’t reach the tar sands and sets them alight…), should be included in the ERoEI of fossil fuels.  Whilst it’s impossible to say Climate Change caused the fire in Alberta Canada, it’s impossible to not make the connection that the only reason it was over 20°C when the fire started was entirely down to the jetstream going haywire because of the arctic melt……  in fact, the energy spent rebuilding destroyed infrastructure caused by Climate Change anywhere should now be included in the ERoEI of fossil fuels….

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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).

And

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.

References

[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.