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 

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.


alice_friedemannAlice Friedemann  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 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 — 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]

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 :    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.


  • 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

PV ERoEI may be negative…

16 01 2017

Well THIS will stir the hornet’s nest……. Pedro Prieto now thinks many solar panels won’t last 25-30 years, EROI may be negative……


Pedro Prieto

It must be remembered that Pedro, whose work has been published here several times, has vast experience in this, having been involved in large scale PV and wind installations in Spain. I don’t know if this article is how he wrote it in English, or whether it was poorly translated from the Spanish, but it is often difficult to read, even when you have the technical knowledge to know what he’s talking about. I had a go at editing it, see what you think… This piece certainly didn’t make me feel good about my new power station, especially after seeing ads on Tasmanian TV by someone who thinks he sells better equipment showing blown up inverters and burnt out connectors on the front face of panels….. there is a lot of rubbish out there, that’s for sure, I’ve had first hand experience of this myself, but if even best quality gear won’t last 25 years, then we will be going back to the stone age……


Our study concluded that, when what we called “extended boundaries energy inputs” were analysed, about 2/3 of the total energy inputs were other than those of the modules+inverters+metallic infrastructure to tilt and orient the modules.

So even if the cost of solar PV modules (including inverters and metallic infrastructure) were ZERO, our resulting EROI (2.4:1) would increase by maybe 1/3.

Without including the financial energy inputs (you can easily calculate them if most of the credits/leasing contracts at 10 years term with interests of between 2 and 6% were included, even if you consider energy input derived from the financial costs, only the interests (returning the capital, in my opinion, would theoretically only return the previous PREEXISTING financial (and therefore, energy) surplus, minus amortization of the principal, if any (when principal is tied to a physical preexisting good, which is not the case, I understand in most of the circulating money of today, but you know much better than me about this).

We also excluded most of the labor energy inputs, to avoid duplications with factors that were included and could eventually have some labor embedded on it. And that was another big bunch of energy input excluded from our analysis.

As I mentioned before, if we added only these two factors that were intentionally excluded, not to open up old wounds and trying to be conservative, plus the fact that we include only a small, well-known portion of the energy inputs required to stabilize the electric networks, if modern renewables had a much higher or even a 100% penetration,  it is more than probable that the solar PV EROI would have resulted in <1:1.

And I do not believe we can make solar modules with even 25 ~ 30 years lifetime. There are certainly working modules that have lasted 30 years+ and still work. Usually in well cared and maintained facilities in research labs or factories of the developed world. But this far away from expected results when generalized to a wide or global solar PV installed plant. Dreaming of having them 100 or 500 years is absolutely unthinkable.

Modules have, by definition, to be exposed more than anything else, to solar rays (to be more efficient). Just look at stones exposed to sun rays from sunrise to sunset and to wind, rain, moisture, corrosion, dust, animal dung (yes, animal dung, a lot of it from birds or bee or wasp nests on modules) and see how they erode. Now think of sophisticated modules  exposed to hail, with glass getting brittle, with their Tedlar, EVA and/or other synthetic components sealing the joints between glass and metallic frames eroding or degrading with UV rays and breaking the sealed package protecting the cells inside, back panels with connection boxes, subject to vibration with wind forces and disconnecting the joints and finally provoking the burning of the connectors; fans in the inverter housings with their gears or moving parts exhausted or tired, that if not maintained regularly, end failing and perhaps, if in summer, elevating the temperature of the inverter in the housing and provoking the fuse to blown or some other vital components, etc.

I have seen many examples of different manufacturers of all types of modules (single/mono, multi/poli, amorphous, thin film high concentration with lenses, titanium dioxide, etc.) in the test chambers, after warranty claims by the clients to the manufacturers. I have attended test fields of auditing companies contracted by retailers, detecting hot spots in faulty internal solder joints straight from the factory to the customers.

I have seen a whole batch from a promising leading US brand specializing in thin film modules(confidentiality does not permit me to name, as yet) having to return it because it did not comply with specs. Now, as I mentioned, I am in contact with a desperate retailer, seeking replacement modules or reimbursement (the manufacturer is broke and has disappeared) that will last a little loger than those he purchased (not Chinese) about 6 years ago and of which about 2/7 of the total have failed, without a practical replacement being available because present modules in the market have higher nominal output power than those originally contracted for and with different voltage and currents that do not permit unitary replacements in arrays or strings, being forced to a complex and costly manipulation to reconfigure arrays with old modules and creating new arrays with new modules and adapting inverters to the new currents and voltages delivered (Maximum Power Point Tracking or MPPT)

We mentioned many other examples of real life affecting functionality of solar PV systems in our book. The reality, 2 years after the publication of the book, proved us very optimistic. Imagine when you install a solar village in a remote area of Morocco, or Nigeria or Atacama in Northern Chile and the nearest replacement of a single broken power thysristor or IGBT that is stopping a whole inverter from operating, plus the entire plant behind it (not manufactured in the country) and about 2,000 Km -or more- from the factory that needs to pass customs like the one in Santos (Brazil), where tens of thousands of containers are blocked for more than one week (plus the usual 6 to 10 weeks custom procedures) because of a fire in a refinery close to the only motorway leaving the Santos port to Sao Paulo..

100 or 500 years lifetime? ha, ha, ha.

Carbon bubble toil and trouble

27 03 2014

There has been of late quite a few articles on the blogosphere about the potential for a Carbon bubble.  A bubble about to burst.  That this will occur is utterly undeniable, but the outcomes featured by different writers are a bit off the mark in my opinion……

First, let me start with Paul Gilding.  I have a lot of time for Paul.  I’ve even published some of his writings here; but his optimism often leaves me flabbergasted…….

In Carbon Crash Solar Dawn, published in Cockatoo Chronicles 

I think it’s time to call it. Renewables and associated storage, transport and digital technologies are so rapidly disrupting whole industries’ business models they are pushing the fossil fuel industry towards inevitable collapse.

Some of you will struggle with that statement. Most people accept the idea that fossil fuels are all powerful – that the industry controls governments and it will take many decades to force them out of our economy. Fortunately, the fossil fuel industry suffers the same delusion.


Paul Gilding

I don’t think the oil industry is under any such delusion.  Unable to make a profit with oil floundering around $100 a barrel, a price the market forces on them to accept, that industry is taking to selling its assets to prop up its bottom line, even borrowing money to pay shareholders’ dividends….

The only idea I struggle with Paul, is that “renewables, electric cars and associated technologies build the momentum needed to make their takeover unstoppable“.

Take here in Australia for instance; the coal fired power lobby has twisted the politicians’ arms (I don’t think much twisting was required either…) to thwart any further growth in the development of renewables.  In Queensland where I still live, the Newman government has indicated that the paltry 8c feed in tariff that the poor beggars who installed PVs on their roofs after the frankly overgenerous 44c feed in tariff was terminated, will become a zero FiT after July 1.  We who are on the overgenerous 44c FiT are ‘safe’ (until TSHTF that is – then all bets are off), because we are on a contract that lasts until 2028….. but everyone else misses out.  Why are they doing this?  It’s all explained very well here on The Conversation, but basically it’s to protect the dinosaur industries’ shareholders.  There’s no way they are borrowing to pay their shareholders like Shell had to do….  Money rules, and f*** you the consumer.

Paul also further writes:

I think it’s important to always start with a reminder of the underlying context. As I argued in my book The Great Disruption, dramatic economic change is not a choice we get to make it, but an inevitable result of physical science. This is because business as usual, with results like ever increasing resource constraint or a global temperature increase of 4 degrees or more, would trigger economic and social collapse. So the only realistic outcomes are such a collapse or an economic transformation that prevents it, with timing the only big unknown. I argued transformation was far more likely and, to my delight, that’s what we see emerging around us today – even faster than I expected.

In parallel, we are also seeing the physical impacts of climate change and resource constraint accelerating. This is triggering physical, economic and geopolitical responses – from melting arctic ice and spiking food prices to the Arab Spring and the war in Syria. (See here for further on that.) The goods news in this growing hard evidence is that the risk of collapse is being acknowledged by more mainstream analysts. Examples include this commentary by investment legend Jeremy Grantham and a recent NASA funded study explained here by Nafeez Ahmed. So the underlying driver – if we don’t change in a good way, we’ll change in a very bad way – is gathering acceptance.

Hang on……..  is he saying the Arab Spring is about people demanding “renewables, electric cars and associated technologies”?  Because collapse is exactly what is happening in Egypt and Syria.  Collapse does not begin in boardrooms, it begins in the streets when people run out of food, water, and petrol….

And where is the debt problem mentioned in this “dramatic economic change“?  How exactly will the “renewables, electric cars and associated technologies” be paid for?  More growth?  Has he never heard the saying “the best way to get out of a hole is by not digging any deeper”?

Over at Nature Climate Change, I found this too……

…major players in the financial markets are becoming increasingly uneasy about the extent of the impact of future climate policies on power companies. A supposition — fostered by the Carbon Tracker Initiative — is that fossil fuels may be nowhere near as profitable in the future as they have been so far. This is not simply because the costs of prospecting and drilling for oil, for example, are increasing, or that the fossil fuel resources that give the oil, coal and natural gas companies their value are about to run out — they are not. The problem is more that a large portion — perhaps as much as 80 per cent — of these reserves will have to be left untouched if society has any chance of limiting global temperature rise to 2 °C this century.

So, pray tell, what will we build the new energy system with…?  Let me remind you of just how many resources it takes to build wind turbines… or a solar thermal power plant

Paul ends his article with:

So, as I see it, the game is up for fossil fuels. Their decline is well underway and it won’t be a gentle one. Of course they won’t just be gone in few years but once the market and policy makers understand what’s happening, it will become self-reinforcing and accelerate rapidly. Markets come into their own in situations like this. They rarely initiate change, but once they’re racing down the hill, it’s time to jump on board or get out of the way. It’s an ugly and brutal process for those involved, but it gets the job done quickly.

When that occurs, we may find that those forecasts by myself and others like Tony Seba from Stanford University, that the oil, coal and gas companies will be all but obsolete by 2030, might turn out to be conservative after all. Interesting times indeed.

Yes, it is game over.  But not for the fossil fuel industries alone.  When they go down, everyone goes down.  Even the central bankers, to whom the global debt which has soared more than 40 percent to $100 trillion since the first signs of the financial crisis, will go down….. why do so few people see the big picture…….?  For someone who claims to understand the “inevitable result of physical science” as the driver of economic change, Paul truly puzzles me.

Tilting at windmills

24 02 2014

pedroI have ‘known’ Pedro Prieto online for many many years, and have featured his work here, and here on DTM.  Pedro is an expert on renewable energy, and is one of the few engineers I’ve ever read who understands ERoEI (Energy Return on Energy Invested), and has practical experience in deploying both wind and solar energy system in his native Spain.  Pedro has recently dropped a bombshell in a book he co authored with Charles Hall  (EROEI is the ratio of energy output over energy input, a measure that was developed by Professor Charles Hall).  This book, titled “Tilting at Windmills, Spain’s disastrous attempt to replace fossil fuels with Solar Photovoltaics”, is the first in-depth look at the ERoEI of large-scale PV in any developed nation. And the results do not bode well……

This is the first time an estimate of Energy Returned on Energy Invested (EROI) of solar Photovoltaics (PV) has been based on real data from the sunniest European country, with accurate measures of generated energy from over 50,000 installations using several years of real-life data from optimized, efficient, multi-megawatt and well oriented facilities.

Other life cycle and energy payback time analyses used models that left out dozens of energy inputs, leading to overestimates of energy such as payback time of 1-2 years (Fthenakis), EROI 8.3 (Bankier), and EROI of 5.9 to 11.8 (Raugei et al).

Prieto and Hall added dozens of energy inputs missing from past solar PV analyses. Perhaps previous studies missed these inputs because their authors weren’t overseeing several large photovoltaic projects and signing every purchase order like author Pedro Prieto. Charles A. S. Hall is one of the foremost experts in the world on the calculation of EROI. Together they’re a formidable team with data, methodology, and expertise that will be hard to refute.

Prieto and Hall conclude that the EROI of solar photovoltaic is only 2.45, very low despite Spain’s ideal sunny climate. Germany’s EROI is probably 20 to 33% less (1.6 to 2), due to less sunlight and efficient rooftop installations.

Here is what Gail Tverberg has to say on ERoEI…

Commenters frequently remark that such-and-such an energy source has an Energy Return on Energy Invested (EROI) ratio of greater than 5:1, so must be a helpful addition to our current energy supply. My finding that the overall energy return is already too low seems to run counter to this belief.

Adequate Return for All Elements Required for Energy Investment

In order to extract oil or create biofuels, or to make any other type of energy investment, at least four distinct elements described in Figure 1: (1) adequate payback on energy invested,  (2) sufficient wages for humans, (3) sufficient credit availability and (4) sufficient funds for government services. If any of these is lacking, the whole system has a tendency to seize up.

EROI analyses tend to look primarily at the first item on the list, comparing “energy available to society” as the result of a given process to “energy required for extraction” (all in units of energy). While this comparison can be helpful for some purposes, it seems to me that we should also be looking at whether the dollars collected at the end-product level are sufficient to provide an adequate financial return to meet the financial needs of all four areas simultaneously.

My list of the four distinct elements necessary to enable energy extraction and to keep the economy functioning is really an abbreviated list. Clearly one needs other items, such as profits for businesses. In a sense, the whole world economy is an energy delivery system. This is why it is important to understand what the system needs to function properly.

Source of the EROI 5:1 Threshold

To my knowledge, no one has directly proven that a 5:1 threshold is sufficient for an energy source to be helpful to an economy. The study that is often referred to is the 2009 paper, What is the Minimum EROI that a Sustainable Society Must Have? (Free for download), by Charles A. S. Hall, Steven Balogh, and David Murphy. This paper analyzes how much energy needs to be provided by oil and coal, if the energy provided by those fuels is to be sufficient to pay not just for the energy used in its own extraction, but also for the energy required for pipeline and truck or train transportation to its destination of use. The conclusion of that paper was that in order to include these energy transportation costs for oil or coal, an EROI of at least 3:1 was needed.

Clearly this figure is not high enough to cover all costs of using the fuels, including the energy costs to build devices that actually use the fuels, such as private passenger cars, electrical power plants and transmission lines, and devices to use electricity, such as refrigerators. The ratio required would probably need to be higher for harder-to-transport fuels, such as natural gas and ethanol. The ratio would also need to include the energy cost of schools, if there are to be engineers to design all of these devices, and factory workers who can read basic instructions. If the cost of government in general were added, the cost would be higher yet. One could theoretically add other systems as well, such as the cost of maintaining the financial system.

The way I understood the 5:1 ratio was that it was more or less a lower bound, below which even looking at an energy product did not make sense. Given the diversity of what is needed to support the current economy, the small increment between 3 and 5 is probably not enough–the minimum ratio probably needs to be much higher. The ratio also seems to need to change for different fuels, with many quite a bit higher.

So there you have it folks…….  solar will never keep civilisation as we know it going.  But you already knew that. And before Eclipse jumps in, I found this on Nuclear Power…:

The seemingly most reliable information on ERoEI is quite old and is summarized in chapter 12 of Hall et al. (1986). Newer information tends to fall into the wildly optimistic camp (high EROI, e.g. 10:1 or more, sometimes wildly more) or the extremely pessimistic (low or even negative EROI) camp (Tyner et al. 1998, Tyner 2002, Fleay 2006 and Caldicamp 2006). One recent PhD analysis from Sweden undertook an emergy analysis (a kind of comprehensive energy analysis including all environmental inputs and quality corrections as per Howard Odum) and found an emergy return on emergy invested of 11:1 (with a high quality factor for electricity) but it was not possible to undertake an energy analysis from the data presented (Kindburg, 2007). Nevertheless that final number is similar to many of the older analyses when a quality correction is included.

Notice this was written in 1986.  As the quality of Uranium ores worsen, (they’ve worsen rapidly since 1986…), nuclear will be no more able to keep Business as Usual running than solar.

As extraction and depletion have operated over time, the average ore grade has decreased and the uranium has become more and more dispersed within the background substrate, plus the total amount of uranium we can extract can decrease as well. Leuwen (2005) argues that the empirical extraction yield declines much more sharply than the hypothetical one, which could come into play if there is a large increase in nuclear capacity in the coming decades.

Figure 6 – % of Uranium Extracted from Ore as a Function of Ore Grade (Leeuwen 2005).
Click to Enlarge.An increasing portion of the world’s uranium comes from in-situ leaching (ISL) (Hore-Lacy 2007).

Just enjoy life in the quiet lane…….  it’s not that bead, really…..

Ten Reasons Intermittent Renewables (Wind and Solar PV) are a Problem

26 01 2014

Gail Tverberg

Gail Tverberg

raises many points that have already been posted here…..  I only reproduce her dot points one and nine, because they are the most relevant to DTM, but I recommend you read the entire article on her website if you have the time.  It is, as usual, an excellent well researched piece of journalism

Intermittent renewables–wind and solar photovoltaic panels–have been hailed as an answer to all our energy problems. Certainly, politicians need something to provide hope, especially in countries that are obviously losing their supply of oil, such as the United Kingdom. Unfortunately, the more I look into the situation, the less intermittent renewables have to offer.

1. It is doubtful that intermittent renewables actually reduce carbon dioxide emissions.

It is devilishly difficult to figure out whether on not any particular energy source has a favorable impact on carbon dioxide emissions. The obvious first way of looking at emissions is to look at the fuel burned on a day-to-day basis. Intermittent renewables don’t seem to burn fossil fuel on day-to-day basis, while those using fossil fuels do, so wind and solar PV seem to be the winners.

The catch is that there are many direct and indirect ways that fossil fuels come into play in making the devices that create the renewable energy and in their operation on the grid. The researcher must choose “boundaries” for any analysis. In a sense, we need our whole fossil fuel powered system of schools, roads, airports, hospitals, and electricity transmission lines to make any of type of energy product work, whether oil, natural gas, wind, or solar electric–but it is difficult to make boundaries wide enough to cover everything.

The exercise becomes one of trying to guess how much carbon emissions are saved by looking at tops of icebergs, given that the whole rest of the system is needed to support the new additions. The thing that makes the problem more difficult is the fact that intermittent renewables have more energy-related costs that are not easy to measure than fossil fuel powered energy does. For example, there may be land rental costs, salaries of consultants, and (higher) financing costs because of the front-ended nature of the investment. There are also costs for mitigating intermittency and extra long-distance grid connections.

Many intermittent renewables costs seem to be left out of CO2 analyses under the theory that, say, land rental doesn’t really use energy. But the payment for land rental means that the owner can now go and buy more “stuff,” so it acts to raise fossil fuel energy consumption.

Normally the cost of making an energy-related product gives an indication as to how much fossil fuel energy is involved in the process. A high-priced energy product gives an expectation of high fossil fuel use, since true renewable energy use is free. If the true source of renewable energy were only wind or solar, there would be no cost at all! The fact that wind and solar PV tends to be more expensive than other electricity generation gives an initial expectation that the fossil fuel energy requirements for creating this energy source are high, rather than low, if a wide boundary analysis were to be done.

There are some studies based on narrow boundary studies of various types (Energy Return on Energy Invested, Life Cycle Analysis, and Energy Payback Periods) that suggest that there are some savings (from the top of the icebergs) if intermittent renewables are used. But more broadly based studies show that the overall amount of fossil fuel energy used by intermittent renewables is really so high that we don’t come out ahead by its use. One such study is Weissbach et al.’s study in Energy called  Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants. Another is an analysis of Spanish installed solar power by Pedro Prieto and Charles Hall called Spain’s Photovoltaic Revolution: The Energy Return on Energy Invested.

I tend to use an even wider boundary approach: what happens to world CO2 emissions when we ramp up intermittent renewables? As far as I can tell, it tends to raise CO2 emissions. One way this happens is by ramping up China’s economy, through the additional business it generates in the making of wind turbines, solar panels, and the mining of rare earth minerals used in these devices. The benefit China gets from its renewable sales is leveraged several times, as it allows the country to build new homes, roads, and schools, and businesses to service the new manufacturing. In China, the vast majority of manufacturing is with coal.


Another way intermittent renewables raise world CO2 emissions indirectly is by making the country using intermittent renewables less competitive in the world market-place, because the higher electricity cost raises the price of manufactured goods. This tends to send manufacturing to countries that use lower-priced energy sources for electricity, such as China.

A third way that intermittent renewables can raise world CO2 emissions relates to affordability. Consumers cannot afford high-priced electricity without their standards of living dropping. Governments may be pressured to change their overall electricity mix to include more very low-cost energy sources, such as lignite (a very low grade of coal), in their electricity mix to keep the  overall price in an affordable range. This seems to be at least part of the problem behind Germany’s difficulties with renewables.

If there is any savings at all in CO2 emissions, it would seem to be from inexpensive intermittent renewables–ones that don’t really need subsidies. If renewables need a subsidy or feed in tariff, a red danger light should be flashing. Somewhere the process is  using a lot of fossil fuels in its production.

9. My analysis indicates that the bottleneck we are reaching is not simply oil. Instead, a major problem is inadequate investment capital and too much debt.  Ramping up wind and solar PV tends to make those problems worse, not better.

As I described in my post Why EIA, IEA, and Randers’ 2052 Energy Forecasts are Wrong, we are reaching an investment capital and debt bottleneck, because of the higher extraction costs of oil. Adding intermittent renewables, in which huge costs are paid out in advance, adds to this problem. Because of this, ramping up intermittent renewables tends to make collapse come sooner, rather than later, to the countries trying to ramp up these energy sources.

More on the Energy Cliff

5 05 2013

Remember my post about Pedro Prieto‘s email to me regarding the energy cliff?  Well here’s a new article I found about his latest views on Photo Voltaics……

Solar Dreams, Spanish Realities

Facing limits to sun-powered renewable energy. Latest in a series.

By Andrew Nikiforuk, 1 May 2013,

Reproduced from


The sun showers the earth with more energy every hour than what civilization currently burns with fossil fuels every year. Given this tantalizing bounty many greens view the resource as cheap, clean, noiseless and limitless.

Yet despite 50 years of solar innovation the industrial world currently runs on 17 terawatts of primary energy mostly provided by coal, gas and oil.

Solar, a determined energy underdog, provides but one-tenth of one per cent of energy demand. (Only 80 terawatt hours of the world’s 22,000 terawatt hours generated by the global electric grid every year come from solar modules.)

Nevertheless many experts estimate that solar PV and thermal systems if planted on the world’s deserts occupying an area the size of Venezuela — could eventually create about 15 terawatts of energy within 50 years. In fact solar is the only renewable with the potential to challenge the dominance of hydrocarbons.

But many analysts suspect these figures, based on theoretical exercises, are way too optimistic. A group of Spanish engineers, for example, calculates in an unpublished paper that no more than two to four terawatts of solar energy can ever be successfully harvested for human use due in part to many of following realities:

Geography: The sun does not shine brightly or intensely everywhere. As a consequence it costs less to generate more power in places like sunny California than it does cloudy Germany or Ontario. Yet for political reasons much infrastructure has been built in cloudy developed nations with highs of energy spending combined with mediocre levels of radiation. Cheap oil has discouraged use of solar power in the Middle East.

Ownership: Solar is mostly a bipolar operation. It is either used by individuals to provide 20 to 60 per cent of their electrical needs or by large corporations and big utilities to generate hundreds of megawatts with massive installations. Supplying solar power owned and used by local communities for their own needs remains a largely novel idea. Community ownership would use less space, decentralize power distribution and possibly lower energy spending. Yet as one 2010 study noted few such experiments exist and “they often don’t meet their objectives of providing clean, environmentally-friendly energy that is affordable for the community stakeholders.”

Materials: The making of solar photovoltaic cells requires rare elements such as gallium, tellurium, indium and selenium. Called “hitchhiker” metals, most are the byproduct of industrial copper, zinc or lead production. New thin-film solar sheets, for example, depend on indium. Moreover indium reserves are largely located in China and the U.S. Geological Survey predicts global supplies could be depleted within 10 years. Concentrated solar power which use mirrors to direct solar rays to heat water, also employs silver at rates of one gram per square meter. A global boom in such solar units would create silver shortages. Copper shortages are also a concern.

Storage: Solar power offers intermittent bursts of energy, posing storage challenges. The average percentage of time a solar operation pours electricity onto the grid at full rated capacity ranges from 12 to 19 per cent. In contrast a coal-fired plant runs 70 to 90 per cent of the time. Storing sun-derived power in batteries, molten salts or compressed air schemes remains problematic if not costly due to significant energy losses in storage and release.

Energy Density: Just as a slice of cheese offers more calories than a potato, different energy sources pack difference punches. The amount of energy contained in a solar ray versus a lump of coal is reflected in their respective geographical footprint. A 1,000 megawatt coal-fired plant requires 1 to 4 square km to mine and transport the coal. In contrast it takes 20 to 50 square km or the area of a small city to generate the same amount of energy from a photovoltaic farm. A large solar industry will compete with other land uses.

Economic Volatility: Solar power is expensive to install and is only beginning to reach the same price levels as other electrical providers. The U.S. Department of Energy’s SunShot Initiative, for example, seeks to reduce the cost of solar energy systems by 75 per cent by 2020. But investments in alternative energy sources also tend to be highly cyclical. When oil prices are high, communities, industry and government tend to divert dollars to renewables. But as soon as fossil fuel prices fall, that interest wanes and the renewable booms dissolves. Tom Murphy, U.S. physicist, solar advocate and energy blogger (Do the Math), argues that governments should “artificially” keep energy prices high enough “to maintain the impetus for developing alternatives, pumping the revenue into a national alternative energy infrastructure. But governments are bound by voters who simply don’t want sustained high energy prices.”

— Andrew Nikiforuk

“We had a lot of hopes and now we’re more skeptical.”

That’s how Pedro Prieto, a 62-year-old global telecom engineer and solar entrepreneur, sums up Spain’s famous solar revolution.

Spain’s renewable dream, of course, began as sunny-multi-billion-dollar boom. Quasi-religious images of fields of photovoltaics and radiant concentrated solar towers wowed North American greens. (Concentrated solar uses 624 mirrors to focus radiation to a receiver that heats steam to drive a turbine.)

But the revolution rapidly collapsed into a messy economic bust that has left more questions than answers. Moreover, Prieto and his Spanish compatriots are still counting the unpredictable casualties of the nation’s stalled energy transition.

Now the engineer is no stranger to solar power. As a telecom engineer he has worked with photovoltaic panels in remote locations since the 1970s. Nor is he a cheerleader for fossil fuels. As the co-founder of the Spanish Association for the Study of Energy Resources, Prieto has long advocated abandoning oil before its volatile pricing and pollution leave the globe in financial and atmospheric chaos.

Since 2004 he has designed, consulted and helped to build more than 30 megawatts (MW) of solar photovoltaic (PV) plants. He even manages, operates and partially owns a PV plant that spills one megawatt of juice (enough to power up to 1,000 homes) onto the national electrical grid in the province of Extremadura.

Given his vast technical experience Prieto also consults with governments around the world on solar renewable prospects. And he has also teamed up with ecologist Charles Hall to produce a provocative book: Spain’s Photovoltaic Revolution: The Energy Return on Investment.

These days Prieto ends his presentations, more often than not, by asking to his audience to “pray for alternatives to nuclear.”

Prieto is also the sort of guy that practically beams out inconvenient statistics. In 2007 installed solar power amounted to .0006 of the world’s electrical consumption and did not keep pace with the growth of electric consumption.

Or as Prieto put it in 2008: “The Energy Consumption Chariot goes over 200 times faster than the Solar Power horses.”

Spain, of course, has gained some fame and notoriety as a global solar pioneer. One-tenth in 2009 and one-fifteenth of the world’s installed solar power modules now dot the Spanish countryside. But these expansive operations provide but 4.3 per cent of Spain’s electricity.

The sun’s sheer abundance has always made it the world’s most popular renewable form of energy. Of all green alternatives solar energy is the only one whose potential harvest far outstrips the demand for fossil fuels. Enough radiation hits the earth every hour to meet all of the world’s electrical needs for a year. By some very optimistic estimates the rapidly growing solar industry could account for 10 per cent of the world’s electrical production by 2020.

Sunny climes

Spain, of course, gets more irradiation than any other European country. The nation’s sunny plains and deserts absorb about 1,500 terawatt hours of solar energy every year. That represents at least three times more power than what Spain’s 46 million citizens actually consume. (A terawatt hour by the way represents enough energy to operate one billion washing machines.)

But achieving that goal might come with some staggering financial costs, significant land disturbance as well as disappointing energy returns. Prieto has even come to view solar power in its current big industrial mindset as just “another extension of fossil fuels.”

And he’s not short of examples. The sun is renewable but photovoltaics are not. Just to make the silicon used to trap the sun’s rays on manufactured wafers requires the melting of silica rock at 3,000 Fahrenheit (1,649 Celsius). And the electricity of coal-fired plants or ultrapurified hydrogen obtained from fossil sources provide the heat to do that. It also takes a fantastic amount of oil to make concrete, glass and steel for solar modules.

But Spain’s interest in renewables is no mystery. Not only does the world’s 14th economic power rely on fossil fuels more than any other European nation (consumption has doubled in the last decade), but it suffers from a 90 per cent dependency on foreign imports.

This energy servitude combined with the nation’s concerns about climate change spurred an unusual revolution in 2004. That’s when the government offered generous subsidies or premium tariffs for solar and wind-made electricity added to the national grid. The initiative guaranteed 25-year-long profitable returns of at about 20 per cent for solar entrepreneurs. The government also came up with an inviting mantra, “The Sun Moves Us.”

Solar boom

Within short order farmers signed over orchards and plots of land for solar PV farms. Next came concentrated solar tower installations. Unlike Germany’s solar revolution, which planted thousands of modules on rooftops, Spain focused its solar growth on installed ground facilities. They are, says Prieto, much more efficient and easy to maintain.

In response to the subsidies factories making silicon wafers and/or assembling modules popped up like orange trees across the nation. Sensing a financial killing, global banks and pension funds poured money into Spain’s solar boom the same way they funded financial derivatives or the shale gas revolution in North America.

By 2008 Spain’s solar explosion eagerly swallowed half of the globe’s photovoltaic module production. Facing module shortages the country even started to import products from Germany, the U.S. and China.

This unexpected development undermined the goal of growing a renewable Spanish industry, says Prieto. (At one point China-based Suntech, the world’s largest solar panel manufacturer, sold 40 per cent of its product to Spain. Last month Suntech declared bankruptcy.)

Meanwhile, the boom surpassed every government electrical target says Prieto. The government set an initial goal of creating 400 MW of power from solar power by 2010. But industry surpassed that goal in 2006-7. “Banks and investment funds treated solar like a financial product. These were the days of wine and roses.”

But by 2008 the excesses of the boom became readily apparent. For starters, the government realized that it could no longer subsidize renewables for 25 years to the tune of 2.5 billion Euros a year.

And so it issued new royal decrees cutting promised returns from 46 cents a KW hour to 32 cents for investors. Later decrees forced more reductions putting brakes on the entire solar module industry.

“There have been 15 royal decrees on renewables since 2004,” explains Prieto. “Each one tries to fix the unanticipated problems of the last one. Each one is worst than the last. But each decree makes renewables less credible.” A raft of lawsuits has predictably clogged the courts.

The crash

An industry poised for a massive build-up based on guaranteed returns, explains Prieto, then laid off workers as a debt-heavy government cancelled or lowered promised financial returns from the sun. The solar PV sector now estimates that 44,000 of the nation’s 57,900 installations are on the verge of bankruptcy.

During the solar “craziness” as Prieto calls it, other problems emerged too. Investors often planted installations of poor quality and design across the landscape. Many facilities weren’t even located in the sunniest parts of Spain.

Spain’s renewable boom (wind installations now make up 17 per cent of Spain’s electricity supply with peaks covering up to 56 per cent) also created havoc with the nation’s energy balance. Government investment in natural gas fired plants (a backup for intermittent wind) combined with renewables resulted in overcapacity in the system. Even the nation’s nuclear power plants had to power down from 7.7 to 6.7 gigawatts for a while.

“The energy industry is much more complicated and integrated than anyone thought. The left side of Spain’s energy planning brain didn’t know what the right side was doing.”

But what troubled Prieto most were the paltry energy returns of some 57,900 solar plants, both big and small. He reviewed Spain’s excellent data on the energy outputs of the nation’s solar network and than compared those findings to actual energy inputs. To his dismay Prieto found that solar offered only slightly better returns than biofuels. Or 2.4 to one.

“That is not enough to maintain society as it is today.”

His finding surprised many researchers and for good reason. Previous studies put solar returns as high as eight or even up to 30 to one in some cases, or almost on par with conventional oil.

But most of this research used the same sort of best-case scenario modelling typically employed by car industry mileage studies. As long as the roads are flat, the fuel is good, the tires full and the driver competent, then great mileage can be achieved.

But real life experience can be different for car mileage as well as the energy output for solar installations.

Solar power, fossil fuel inputs

Spain discovered, for example, that the earth is rarely flat (a big issue for tracking and directing solar rays in the right direction). Moreover the modules (only 15 per cent efficient on average) rarely perform as expected. Not only do the panels require regular maintenance but constant cleaning to remove films of dust. And they only last 25 years.

But Prieto added together another 24 factors illustrating the industry’s profound dependence on fossil fuels. They included road maintenance, rights of ways, module theft, intermittent loads, as well as the cost of natural gas fired back-up stations. In the end he concluded that the solar industry “eats and spends considerable energy.”


Pedro Prieto

Solar energy author Pedro Prieto: ‘We had a lot of hopes.’

Moreover countries such as Germany which receive but two-thirds of Spain’s sunlight in the best case and on average deploy much less inefficient rooftop arrays will probably have returns one-fifth to one-third lower than Spain.

“Solar installations are dependent on a fossil fuel world and there are difficulties scaling up the power of the sun,” says Prieto.

And what does Prieto think of big plans to industrialize the deserts of the U.S. southwest to provide power for the east? Or plans to colonize the Sahara desert of North Africa for European delights?

Not much, he replies sadly. The engineer calculates that just one plan proposed by former French President Nicolas Sarkozy was so big that it was obsolete before it harvested one solar ray. The plan would have covered 400 sq. km of land and burned three to six million tons of coal to erect 1.8 to 3.6 million tons of steel and two to four million tons of glass. Vast amounts of clean water and lakes of desalinated water would have been needed to maintain the plants. Yet the plan would have generated only three per cent of the electricity that nations of the Mediterranean basin now consume. Such a scheme would exchange the political insecurity of oil and gas pipelines with high voltage cable lines.

“It would be far more rational to strive for a world with far lower levels of more localized demand and widely distributed, small and local generation and distribution networks where possible,” the engineer concluded in a recent editorial.

Nations as solar plantations

Big Solar would also turn poor countries like Morocco into virtual solar plantations or colonies that feed electrical power to wealthy at a project cost of $60-billion. (Another unrealistic forecast suggests that industrial solar plants in the Sahara could produce enough energy for 100 million homes for half a trillion dollars by 2050. Prieto says this plan, dubbed Desertec would be lucky to achieve 30 per cent of Europe’s electrical needs.)


But the big issue for solar is simply scaling up the enterprise to capture enough of the sun’s rays to retire just a fraction of fossil fuels. Prieto calculates, for example, that to replace all electricity made by nuclear and fossil fuels in Spain would take a solar module complex covering 6,000 sq. km of the country at the cost the entire Spanish budget (1.2 billion Euros in 2007). It would also require the equivalent of 300 billion car batteries to store the energy for night-time use.

Prieto is not alone in reaching such sobering conclusions. A 2013 Stanford University report, for example, calculated that global photovoltaic industry now requires more electricity to make silicon wafers and solar troughs than it actually produces in return. Since 2000 the industry consumed 75 per cent more energy than it put onto the grid and all during its manufacturing and installation process.

Moreover it won’t pay off this energy debt or energy consumed in its construction until 2016. As a consequence, ramping up of industrial solar production produces more greenhouse gases than it saves for nearly a decade. The study also recommended that reducing the fossil fuel inputs for a next generation of photovoltaic systems be a key priority.

“We have to leave oil before it leaves us,” says Prieto paraphrasing the famous Fatih Birol quote, “and it is not good for nature or the planet.”

Back to the village

“In my opinion we can use solar PV energy, as far as it is available and we can afford it for specific applications,” says Prieto. But he now views solar PV systems as “non-renewable energy systems that can only capture a portion of the renewable energies temporarily.”

Moreover there is no way solar power can sustain “our present wasteful way of living.”

In Spain where nearly a quarter of the workforce sits idle and political unrest smolders in the cities, there is much talk about “La vida buena” or what the French call “decroissance” or degrowth.

The grassroots movement is all about living better by consuming less and sharing more. Prieto suspects the future may be determined more by behavior change than by investments in renewables.

“In general terms, I would suggest we make every possible effort to move towards a lower consumption and lower mobility society,” sums up the 62-year-old.

“We need to deurbanize and localize as much as it is possible, and to return to the countryside, as much as it is possible, and to use more animal draft force.”

When asked for advice on what other nations should do, Prieto thoughtfully pauses.

“It is difficult to give advice.”

More on the Energy Cliff

18 01 2013

Years ago, when I was cutting my teeth on Peak Oil and Peak Everything over at the EnergyResources pedroYahoo group, I met (as you do online these days) a most interesting chap from Spain.  His name is Pedro Prieto.  He is an expert on Spanish renewable energy production, and below is an email Pedro sent me four years ago and which I have just rediscovered….. Oh, and I wish my Spanish was a fraction as good as his English! I’ve left it un-edited, and if you can read with a Spanish accent, it’s improved considerably!


Ken Zweibel, James Mason and Vasilis Fthenakis have recently wrote an article about solar energy in Scientific American. They claim that by 2050, the US could get some 100% of its electricity needs, by installing a combination of 2.9 TW PV fed into the grid, 7.5 TW to cumulate energy with compressed air; 2.3 TW in concentrated solar plants; 1.3 TW of distributed solar plants and just to fill the gap, some 1 TW of wind fields. This ‘just’ is ten times more than today is installed in all the world, just to satisfy a small, collateral portion of the electricity needs in 2050 of the US.

If we succeed in growing at 27% cumulative per year, and we reach, as the report of Science & Technology says, the 3 TW of wind installed power landmark by 2020, this will represent the production of, let us say and maximizing sizes and minimizing costs, some 1,500,000 times 2 MW wind generators in the period. Considering each generator has 150 tons of steel; that every ton of steel requires at least 1.5 tons of coal to be produced; between 500 and 1,000 tons of concrete in the foundations; 30 tons of glass fibre and some 5 tons of copper; the “clean” wind industry will demand from now to 2020 (12 years) 225 million tons of steel, some 350 million tons of coke coal; 45 million tons of glass fibre; some 7.5 million tons of copper and some 1 billion tons of concrete. I am not counting the energy spent in building up factories; transporting the huge wind generators, most of the time at big distances, using heavy weight cranes or huge crane ships when offshore; opening pathways to the generally inaccessible places where the wind blows regularly (in mountain passes, plateau’s edges, etc.) It is neither included the steel to make long evacuating lines (in Spain, a small country with a dense electric network) generally 10 to 25 km of evacuating high tension line, per each 150 MW wind field average), or the copper or aluminium wires used in the power lines; the additional power stations required, etc. Nor it is included the maintenance or the infrastructure needed to stabilize an intermitent source of energy.

This installation of some 1.5 million generators of 2 MW each, from now -2008- till 2020, will require, for your information and order of magnitude, some 2 times the present world annual production of steel; about 30 times the present glass fibre world production and almost the annual concrete world production. I strongly recommend to read the article “Coal Can’t Fill World’s Burning Appetite With Supplies Short, Price Rise Surpasses Oil and U.S. Exporters Profit” By Steven Mufson and Blaine Harden. Washington Post Staff Writers of last Thursday, March 20, 2008; It exemplifies very well how the industry is struggling to get coal and steel and the effect of prices of coal and oil on them. Who says this is a `green’ or non polluting industry? I would ask the people to keep in mind that these are NON RENEWABLE SYSTEMS, able to capture some renewable energies. These systems have a short life cycle, specially when in offshore, or in dusty places, subject to heavy corrosion or grinding of their mechanical parts. They have to be maintained very much and are heavily underpinned in the fossil fuel society (helicopters for maintenance, huge and heavy cranes and ships, long and heavy trucks, maintenance of compacted gravel roads in mountains, the gravel in itself, metallic piece parts, lubricants, high level (hence highly consumerist) people in maintenance tasks with fossil consuming SUVS going everywhere, etc. etc.

All the above assumption of 3 TW of installed wind power by 2020, to generate some 1.5 TW times 2,000 hours/year nominal (if these fields are available for the new parks; in Spain, for instance, they could hardly find onshore fields and from now onwards with this load factor); that is, to generate 3,000 TWh; that is a 15% of today present world electricity consumption. (Not primary energy; just electricity. Not in 2020: today).

When going to global figures and potential increase of wind energy worldwide to cope with the ever growing electricity (or primary) energy needs, I think it is time to make wind energy prospects top down, rather than we make them now as usual: bottom up. I am amazed that supercomputers are not used to simulate these huge dreams of wind installations. An anemometer in Tarifa, close to the Gibraltar Strait gives 2,500 nominal hours a year. Another anemometer offshore in the Cadiz Gulf, some 100 miles of distance from Gibraltar, gives some 2,500 nominal hours. If I put 1 GW in Tarifa and 1 GW in the Cadiz Gulf, perhaps both of them will run at 2,500 hours/year. But what if I put 100, or 500 GW in both places? Is the wind obliged to go the same usual path, if friction reaches certain levels, or could perhaps divert to the natural lowest effort path, leaving the magnificent parks idle or with 1,000 hours/year? When trying to get conclusions from wind maximum capacity, one should remember that all winds at all altitudes in the globe represent some 70 times the present human energy consumption. This is apparently too much, enough for us all. But from that we could hardly capture a small fraction (with a huge use of non renewable and polluting materials) of the energy of wind flows of up to 150 m. over the surface and those in offshore relatively close to the mainland. That a big portion of these winds are at speeds that wind parks could not profit form them (over 80-100 km/h or lower than 5 to 9 km./h). Then, we could perhaps note that these are going to be just a drop of relief in the ocean of the insatiable human consumption. Not to consider the effect of being able to change some wind traditional patterns, when reaching certain values of friction/interception.

All the World wind installed park from the beginning up to 2007 (93,212 MW) produces 5 times less electricity than JUST the increase of electricity consumption worldwide between 2005 and 2006 (765 TWh) and represented just 0.8 of the world electricity consumed.

The increase of the electric consumption worldwide (some 4% annual) goes 25 times faster than the production of the installed capacity in 2007. The industrial kart goes 25 times faster than the ecologic horses. And ecologists still pretend to win that unbalanced and crazy Ben Hur race, without saying a word of the insatiable energy consumption increase that the Caesar Roman model is imposing into the arena of this unbelievable circus!! Sorry if I have poured on optimistic and enthusiastic people a cold jug of water. The above are available worldwide data. I just wanted to put the article in the context and in front of the challenges we are going to face.

Pedro from Madrid P.S. I have not said a word about birds, or about the financial possibilities and sensible timings for these megaprojects in 180 of the 195 countries I see in the UN list.