The sunflower
It bows down to the Sun
The image of resilience.

Monday, June 5, 2023

And yet it moves. Why the EROI of renewables may be higher than that of fossils


Eppur si move; (yet it moves). Galileo is said to have pronounced these words after having been condemned for supporting the heliocentric model of the solar system. New ideas take time to be accepted, and often the resistance against them is tenacious. This is especially true when the new ideas change an existing paradigm. It was the case for the heliocentric model; it may be the case for renewable energy technologies. So far, they have been considered little more than toys for greens, but now we face a radical change of paradigm: they may be able to do better, -- even much better -- than fossil fuels. That's far from certain, of course, but it is what's emerging from the data and the calculations. And if it will turn out to be true, our future will be completely different from what we thought it would be.   

The idea that renewable energy can provide a better energy return (EROI) than fossils is often met with not just skepticism; as it would be normal for a still unproven hypothesis. It is seen as absurd, impossible, unbelievable, outworldly, and worse. If you mention it in the discussion on social media, you risk being insulted, berated, accused of nefarious intentions, and your mental sanity questioned. It happened to me with the comments on my previous post

It is understandable that radical changes in paradigms upset people, making them worried and even angry. It happened with the heliocentric view of the Solar System at the time of Galileo, and if it turns out that renewable energy is a technology superior to fossil fuels, then it is an even larger change of paradigm. You know how deeply fossil fuels changed the world. Renewables may have similar effects, although in different ways. 

Now, please don't make me say that the higher EROI of renewables is an established truth. It is not. But from the data we have, I suspect that it might be. In any case, it is surely an idea well worth exploring. For a long-term view, you can see a paper of mine. Here, I'll try to discuss some available evidence that favors this possibility. 

The central point of this discussion is a paper by Murphy et al., who re-examined the available data about the EROI of energy sources, making sure that the evaluations were carried out in comparable conditions. That is, ensuring that the yield was compared at the "point of use" (POU) rather than at the "well mouth," which would give an unfair advantage to fossil fuels. Renewables directly produce usable energy, unlike fossil fuels which, after being extracted, need to be processed into fuels and turned into useful energy in inefficient thermal engines. 

The data presented by Murphy et al. indicate that the EROI of photovoltaics may be about five times larger than that of crude oil. Of course, all data and their interpretation are affected by uncertainties. So, let me propose some additional evidence that goes in the same direction. 

One obvious consequence of a high EROI for a technology is that you expect it to grow fast. It is the same mechanism of compound interest that generates exponential growth in the yield of a financial investment. This growth is proportional to the return on investment (ROI), the financial equivalent of EROI. Ultimately, in our economic system, energy is worth money, and a technology that has a good energy yield also has a good ROI, so we expect it to grow fast. (*)

On this point, there is no doubt that renewable energies are growing fast; very fast, especially for photovoltaic energy. Here are the current growth curves for photovoltaic energy (from "Our World in Data")

PV energy production is growing at an approximately exponential rate of about 25% yearly, leading to doubling every three years. Actually, the rate has been closer to 35% during the past few years, with a doubling time as low as two years. PV grows faster than any other modern renewable technology; the whole sector is growing at 16% yearly

But how fast does PV energy need to grow to prove that it has a higher EROI than fossils? At the very least, it should grow faster, and it does. Let's take a look at the data for global oil production:

During the heyday of the age of oil, in the 1950s and 1960s, production was doubling every 8-10 years, corresponding to a growth rate of 7%-8% yearly. Much slower than PV is doing nowadays. 

We can carry out the same evaluation for other energy technologies. In the 1970s, nuclear energy had a doubling time of a little more than 2 years. Meaning a growth of 25% per year. For coal, during the late 19th century, production doubled in no less than 20 years. Finally, biomass for power production never grew at high rates nor produced amounts of energy comparable to those of renewables. 

Overall, these data indicate a qualitative proportionality of the growth rate of a technology with its EROI. The fastest growth rate is observed for PV, in agreement with the proposals by Murphy et al. for an EROI around 20 on the average. Nuclear also fits this interpretation with a high EROI reported by Murphy et al, but for a plant lifetime larger than that of PV. The POU EROI of oil is reported by Murphy as around 5; and that fits with the slower growth rate. Note that the EROI at the well mouth may have been high in the 1960s -- over 30; but the POU EROI may have been similar to the current one. About the slow growth of biomass power production, it fits with the data indicating a low EROI. Regarding coal, the proportionality seems to be lost, since coal may have had a large EROI. But the data for more than a hundred years ago can't be compared with those of our times. 

In the end, I think the main evidence for the high efficiency of renewable energy is this graph that comes from recent Bloomberg data, (Figure by R. Craig)

You see how, for the same investment, renewable energy is growing fast (16% for the average, 35% for PV), whereas fossil fuel production is growing very slowly, if at all. 

These data strongly support the idea that renewables, and PV in particular, have a larger, actually much larger EROI than fossil fuels. That seems to be true for the present situation, but the question is for how long the growth of renewables can maintain this high EROI and continue growing. At some point, the curve will necessarily start flattening out, as it has already happened for oil and nuclear. The limits of the availability of solar energy are far away, but mineral resource bottlenecks are possible and even probable. These bottlenecks would have the effect of increasing the energy costs of new plant, and cause their EROI to plummet. Also, political factors are not to be discounted. Nuclear energy was rapidly growing in the 1960s, and you might have thought that it would soon replace fossil fuels. Indeed, people were speaking about the upcoming "nuclear age." But the technology was killed mainly by political and strategic factors. Today, if governments want to kill renewable energy, they can do that (and may be preparing to do exactly that). 

How long does the curve need to continue growing? Right now, wind and solar produce about 3500 TWh per year, a little more than 2% of the world's primary energy (about 160,000 TWh/year ). Actually, we don't need to ramp up production to such a level. Taking into account the losses in turning fossil fuels into energy and the various inefficiencies of the current infrastructure, Jacobson estimates that we need no more than half of that to match the current demand. Even with 50,000 TWh, our civilization would survive, although rather battered. Yet, it is a steep climb that we face, from about 5% to 100%. (For a more quantitative estimate, see this paper of mine with Sgouridis and Csala). Can we make it? It is a fighting challenge, but it is not impossible. At the current growth rates, renewables could reach 100% of what we need in one or two decades.  

The future, as usual, is obscure. But we have one of those opportunities that happen once in a lifetime (the lifetime of a civilization!).  


(*) No energy technology can start its growth by pulling its own strings. In the beginning, it needs the support of energy from an already established technology (it is what we called "the sower's paradigm"). Coal grew on wood and human energy, oil grew on coal, and, at present, renewables are growing using the energy produced by oil and gas. The capability of a technology to grow on itself appears only when it has reached a significant fraction of the total production; it depends on the EROI -- and only technologies with a good EROI can reach this stage. Surely, the EROI of renewables is more than sufficient for them to support themselves. 

Wednesday, May 31, 2023

Is the Energy Return of Renewables Really Higher than that of Fossil Fuels? A Rebuttal to Art Berman's Criticism


The "net energy cliff," a popular graphic often used to demonstrate that renewables will never be able to support an industrial society. It is mostly wrong or at least obsolete. The EROI of crude oil never was so high as shown here, and the idea that there is a "minimum EROI needed" to support modern society is debatable, to say the least.

It is a very good thing that Art Berman, a well-known expert in oil and fossil fuel matters, has intervened in the EROI debate on renewables with a recent post. It means that the EROI is becoming the focus of the debate, as it should be. The most recent data indicate that the EROI of renewables significantly surpasses that of oil when examined at the "point of use" rather than at the "well mouth." And, of course, as users of energy, the point of use it is what we are interested in.

First of all, a note: nowadays, the debate on the energy transition is almost purely political. As such, it is based on slogans, and we know that slogans are not based on data or facts. So, it is a pleasure to see that Art Berman, a well-known expert in matters related to oil and fossil fuels, engages in a fact-based debate. That allows me to respond with a different interpretation, still remaining within the boundaries of what a debate should be; with the discussants respecting each other. 

This said, let me go to Berman's criticism which is specifically directed to a recent paper by Murphy et al., where the authors make the point that the EROI of renewables is now significantly larger than that of fossil fuels when a correct comparison is made. 

The problem, here, is that social media are flashing with messages that say that Murphy's paper is "wrong" or that it contains "mathematical errors." It is not true, but when everybody keeps repeating the same thing, it becomes true. It has already happened with the 1972 study, "The Limits to Growth," which was said so often to contain "wrong predictions" that it became common knowledge that it did. Except that it didn't. But that's the way the memesphere works. 

I think that the element that has generated the idea of "errors" in Murphy's paper is described here by Berman.

This statement from that paper was a huge red flag for me.

“Even if crude oil were measured to have an EROI of 1000 or more at the point of extraction, the corresponding EROI at the point of use, using global average data for the energy “cost” of the process chain, would still only be a maximum of 8.7.”

This means that the supply-chain energy costs for refining and product distribution create a permanent penalty that prevents oil from reaching an EROI of more than 8.7. It furthermore implies that refining must be a marginally profitable business at best which it is not.

At first sight, the statement by Murphy et al., looks strange, even unreasonable. But it is not so. It is a correct interpretation of how the concept of EROI works. 

The EROI is the ratio of the energy produced to the energy spent to make a certain energy production system work. It is something deeply embedded in the concept of "biophysical economics." It derives from the idea that the human economy works in the same way as an ecosystem. Not just because they have the same term "eco" (from the Greek oikos) in the name, but because they are both "dissipation structures," in the sense described by Prigogine long ago. A dissipation structure turns energy into waste or, if you prefer, does its job of increasing the entropy of the universe. (see some references at the bottom of this post).

So, the EROI is analogous to the economic return on investments. In mathematical terms, it is the same as the "effective reproduction rate" in biology, and also to the "reproduction number" (Rt) that was so fashionable during the pandemic, when people struggled to "flatten the curve." In EROI terms, they were striving to reduce the EROI of virus replication. The opposite of what we are trying to do with energy sources!

Unfortunately, as they say, "the devil is in the details," and the discussion on EROI is affected by misunderstandings and by the unavoidable uncertainty involved in evaluating complicated systems such as the oil industry. The paper by Murphy et al. that Berman discusses is aimed at clarifying a fundamental problem: "energy" is a well-defined physical quantity, but we are not interested in energy as such, but in energy potentials. A concept that defines how much useful work can be obtained from energy. The energy potential is a mix of the two fundamental concepts of energy and entropy. We are interested in, basically, how much entropy we can create using what we call an "energy source" (sun, oil, wind, whatever). 

And here is the point of the discussion: you can measure the energy embedded in a barrel of oil and compare it to the energy embedded in a lithium battery. But the battery will dissipate that energy in the form of electric power at more than 90% efficiency. To obtain the same amount of work from the oil contained in the barrel, you have to go through a series of steps, including transporting, processing, refining, more transporting, and finally burning it inside a thermal engine that, typically, has an efficiency of about 30%. Not all energies are created equal!

That's the key point of the reasoning in Murphy's paper. They note, correctly, that the EROI of crude oil is often measured at the "mine mouth" or "well mouth." That is, it does not include the energy lost in the various steps needed to turn the oil into useful energy. They use the term EROI(POU) (point of use) to indicate the correct way of estimating the EROI of crude oil when it is a question of comparing it with that of solar or wind energy, which directly produce useful electric energy. 

In this procedure, it is perfectly reasonable that the EROI of oil at the "mine mouth" or "well mouth" has no importance in determining the EROI at the point of use (POU). It is because a multi-stage EROI chain works like a metal chain: it is as strong as its weakest link. In the ratio of "Energy Out" to "Energy In," the first term is the energy produced by the last step of the chain, instead, the "Energy in" is the energy lost (and hence in need to be replaced) at each step. We could write that:

EROI = Eout/(Ein(1) + Ein(2) + Ein(3) +.....).

And you see that if, say, Ein(2) (refining) is much larger than Ein(1) (extraction), then reducing Ein(1) (increasing the EROI of extraction) will have no significant effect on the overall EROI. Note that in this view, all energy inputs are treated as the same. They may not be in terms of monetary costs, but it is another matter. 

Having established that Murphy et al.'s proposal that oil's EROI is no more than 8.7 is not a mistake but a correct interpretation of the definition of EROI, we need to examine whether it is a likely interpretation of the current situation. Berman criticizes it on the basis of several observations; for instance, that it would mean that refining would be at best an unprofitable business, which is not. 

I trust Art completely if he says that refining is profitable. But we don't have a precise correspondence between profitability and EROI. Besides, if we think of an EROI of 8.7 in financial terms, you would be very happy the return on your investment is more than 8 times the capital invested! The problem, here, is that the EROI is a ratio of two energy flows, but it says nothing about how large these flows are. If they are very small, of course, it matters little how large the EROI is. Here, Berman makes a correct point when he notes that, 

"Society does not function and survive on the per-unit net energy to society but on the full-system net energy delivered to society. This is like saying that I can solve my personal financial problems by delivering newspapers because the per-unit returns are so high. The net income from the paper route is so small, however, that it wouldn’t even help with the monthly escrow payment on my mortgage."

Equivalently, we could say that engaging in a career as a beggar requires a very small initial investment, and hence it has a high ROI, but it is not a good way to make a living. Nevertheless, while this is true in financial terms, in terms of energy production it is a restatement of what I called the "Godzilla Egg" fallacy: a small egg does not mean that the adult creature will be small. Obviously, renewables will not solve any problem as long as the energy they provide to society is small -- no matter how low the cost. But, of course, renewables can grow

Their potential of renewables in terms of solar energy available is enormous, even though we may run into other kinds of limitations in terms of mineral resources. But, at present, these limits are not preventing renewables from growing fast, and their good EROI indicates that the materials used can be effectively recycled using the energy that renewables themselves produce. Some European economies already produce half or more of their electric power from renewable sources, for instance, Germany. So, it is possible to move onward and create a sustainable energy infrastructure that will last for a long time and that will sustain a resilient human civilization, not anymore depending on the vagaries of the depletion of mineral energy resources.   

There are many more points that could be discussed in relation to Berman's post, mainly about the idea that the low EROI of fossil fuels cannot be so low as some studies indicate because it would be insufficient to sustain a complex industrial civilization such as ours. That would require a long discussion. Let me just say, here, that the "minimum EROI needed" for civilization is, at best, a debatable concept and that the value of "5-7" should be understood as highly uncertain, to say the least. 

I think these are the main elements of the story. If you want to know more about the concept of EROI as an essential element of biophysical economics, I suggest two recent papers that I published together with my coworkers Perissi and Lavacchi

The Role of Energy Return on Energy Invested (EROEI) in Complex Adaptive Systems, by Ilaria Perissi, Alessandro Lavacchi, and Ugo Bardi), Energies, 2021

Peaking Dynamics of the Production Cycle of a Nonrenewable Resource, by Ilaria Perissi, Alessandro Lavacchi, and Ugo Bardi, Sustainability 2023

Friday, May 26, 2023

Godzilla's Egg: Why Renewables Will Never Replace Fossil Fuels (Or Maybe They Will?)

An early incarnation of the most famous Japanese monster. Source

Being a reptile (maybe), Godzilla is supposed to be born from an egg. But it would be a big mistake to think that the adult beast will be small because the egg is small. Something similar applies to renewable energy, often criticized because it provides only a small fraction of the total energy in the world. In this post, I examine the "Godzilla's Egg Paradox" in view of two recent books, "How the World Really Works" by Vaclav Smil, and "The Economic Superorganism" by Carey King. 

The concept that "renewables will never be able to..." takes many forms, perhaps the most common one being that they provide today just a minor fraction of the energy produced by fossil fuels. And, hence, this fraction is destined to remain small. I often use the joke that it is the same as saying that Godzilla couldn't be but a small beast judging from the size of its egg.

A recent restatement of the Godzilla's egg problem can be found in the book by Vaclav Smil, "How the World Really Works." (Viking, 2022). Honestly, it is a disappointing book, especially comparing its content with the ambitious title. Not that there is anything specifically wrong with it. Smil has excellent capabilities of reporting quantitative data; his approach is simple and direct; a good example is his analysis of the average risks faced by an ordinary person in terms of their probability and frequency. 

But this book? Well, it reports a lot of data, but all in a conversational form, not a single diagram, not even a table. Maybe it is the way a book has to be if it has to become a "New York Times International Bestseller." After all, it is known that most people cannot understand cartesian diagrams. Yet, data are not sufficient if they are not interpreted in a correct time frame, and Smil's analysis is almost always static; it tells you about the current situation but not how we arrived at it nor what we can expect in the future.

The problem is especially visible with Smil's treatment of renewable energy. The whole discussion on energy is weak, to say nothing of the typical mistake of reporting that, during the oil crisis of the 1970s, OPEC (the organization of oil exporting countries) "set the prices" of oil. OPEC does not and cannot do anything like that, although its management of oil production surely affects prices.

About renewables, the main point that Smil makes is that, today, they represent only a small fraction of the world's energy production. Considering the huge task ahead, he concludes that renewables would need a very long time to replace fossil fuels, if they ever will. The main problem in this discussion is that Smil does not use the "EROI" (energy returned for energy invested) parameter. This parameter tells you that, nowadays, renewable energy is more efficient and yields more than fossil fuels and any other energy production technology. Missing this point, the whole discussion is flawed. Renewables can, and will grow rapidly, at least in the short term future. And, in the medium and long run they are destined to replace the inferior technology of fossil fuels. The same is true for many other data reported; they remain scarcely useful if not analyzed in a way that gives some idea of how they are going to evolve and change. Paradoxically, what this book lacks is exactly what the title promises: an explanation of how the world works.

The weakness of Smil's arguments does not mean that renewables will quickly replace fossil fuels. One thing is what is feasible, and another is what can actually be done within the limitations of time and resources. For some dynamic scenarios of their possible growth, you may take a look at a paper that I wrote together with my colleagues Sgouridis and Csala. It is a little old (2016), but its basic methods and conclusions are still valid. And the conclusion is that it is possible to replace fossil fuels with renewables, but not easy. What we can say at present is that renewables are growing fast: will they hatch into a full-size Godzilla, able to overcome the obstacles it faces?  


If you really want to know how the world works and what role energy has in it, you can learn a lot more from Carey King's book "The Economic Superorganism" (Springer 2021). It is the opposite of Smil's book in terms of methodology. King's approach is based on the fundamental tenets of biophysical economics: it is an attempt to explain how the world's economic metabolism functions and dynamically evolves. Hence the title, "superorganism," a way to define the economic system in terms akin to that of a biological system (I prefer to use the term "holobiont" but it is the same idea.)

The idea that the economy is a superorganism derives from the concept that energy drives the economy, just like it does for living beings. The Economic Superorganism book provides stories, data, science, and philosophy to guide readers through the arguments from competing narratives on energy, growth, and policy. Among many other good things, it is remarkable for its honest attempt to present different points of view in a balanced way. It also helps to distinguish the technically possible from the socially viable, and understand how our future depends on this distinction. At global scales, the combination of resource-rich environment, coordination in groups, corporations and nations, and the maximization of financial surplus, tethered to energy and carbon, results in a mindless, energy-hungry, CO2 emitting Superorganism (a concept also examined in depth by Nate Hagens).

Now, the superorganism is in trouble. Just like living beings, it risks dying of starvation. Could it be a good thing, considering how the economic leviathan has damaged more or less everything in the biosphere? Or perhaps it is still possible to tame the big beast and force it to behave a little better. Maybe. Even though we may all be just cells of a huge beast, there is a lot that you can learn from this book. Unfortunately, even though it is clearly written and well argumented, it will never be a New York Times Bestseller. And that may be one of the reasons why the superorganism deserves to collapse.

And how about renewables? King's book doesn't take a yes/no position, and correctly so. It provides instead a complete discussion of the various facets of the issue. Just the description of the value of the EROI concept is worth the whole book. And, eventually, we'll go where the superorganism takes us.

Sunday, May 21, 2023

Solving Renewables' Communication Problem. Don't Tell, Show!


Renewable Energy has a serious problem of communication: most people don't understand it. Since all communication is based on storytelling, I propose to face it by using the technique used in storytelling called "Don't tell, show." Telling people that renewables can produce energy is not enough; we need to show that they are useful. And that means focusing on "resilience." (image source)

Years ago, a colleague of mine told me a story about the photovoltaic plant he had installed, one of the first in Italy. He said that a high-rank politician came to visit it. To show him that the plant was really working, my colleague connected its output to a small electric heater, showing how the resistive heating elements could be rapidly brought to a nice red glow. The politician refused to believe that the energy came from the PV panels, and he asked, "Where is the trick?" Apparently, he left still unconvinced.  

I have my own stories about this kind of cognitive dissonance, and you probably have yours. Many people don't deny that renewables can produce energy but consider them little more than nice toys for Greens. Come on, to really produce energy, you need to burn something; coal, oil, or gas; you need a big fire and engines turning. Otherwise, it is a joke, no more than that. 

You can see this attitude expressed, over and over, in the comments on social media. In its basic form, it goes as, "Renewable energy will never be able to replace fossil fuels." Similar statements are common, including the idea that renewables are not really renewable but "substitutable" or "replaceable," meaning that fossil fuels will always be needed to replace old plants as they wear out. Normally, these statements are presented as self-evident, and some people seem to be offended and to become aggressive when told that the opposite may be true.  

Contrasting this attitude using data is nearly impossible. The scientific argument in favor of renewables is mostly based on life cycle analysis (LCA) that currently leads to favorable estimates for their EROI (energy return for energy invested). It means that renewables can be recycled and can sustain a circular economy. But most people (including politicians) don't understand EROI. They don't understand that the uncertainty in the EROI estimates is typical of all scientific matters; they want certainties. The attitude of scientists does not help. They tend to avoid public debates and disseminate their results only as papers in scientific journals. Papers that nobody reads and which are ignored when it is time to make policy choices. It is the same problem we have with climate science. 

So, I believe we have to change tack. Since all communication is based on storytelling, we may use a well-known rule in storytelling that says, "Do not tell, show!" That is, it is not enough to tell people about quantitative estimates of this or that. We need to show people how renewable energy can be useful for them here and now, not a hundred years from now,

It is, in the end, a question of positioning: in the current historical phase, renewables can be seen as a tool for resilience, a concept that most people understand and appreciate. Many people interpret this idea in terms of PV panels on their roofs and batteries at home as an emergency supply in case of blackouts. It is not a bad idea in itself, but it is expensive, and many people don't have the kind of space needed to install PV panels. "Resilience" is a wider concept, and, at present, it implies not only a defense against blackouts but a most needed help for people who are facing high energy prices affecting their activities and their personal budgets. 

In Italy, we are experimenting with an interesting initiative called "Energy Communities," legislation that allows citizens to link together their energy production plants, forming a local community that gives advantages to both producers and consumers. These communities are on a small scale, but the same concept can be enlarged as a general barrier against emergencies and supply disruption. It is a question of networking at various scales. It also includes large-scale plants; they are certainly more efficient than home-based ones. But they need to be accepted by the public, otherwise it is hopeless. 

Framing renewables in this way, we see that we are not aiming at "replacing fossil fuels." It is possible, in principle, but it can't be a short-term goal. If we aim at resilience, we don't need a 100% replacement of fossil fuels. A country like Germany already produces about 50% of its electric energy from renewable sources. At this level, the renewable infrastructure may act as a national-level UPS (uninterruptible power supply), keeping the lights on, and the essential services going (food, transportation, health care, and others). These are achievable objectives in the short and medium term. They are also steps forward to creating a truly sustainable, large scale energy system. 

My colleague had chosen the right way to tell the story when he showed a politician how he could operate an electric heater using his PV plant. But that wasn't enough. We need to show that renewables not only produce energy, but produce useful energy for the community. It will also be a concrete set of actions to fight climate change. It is the right path for the future.   

Saturday, May 20, 2023

The Garden of Forking Paths: Renewables are an Opportunity we Cannot Afford to Miss


"El jardín de senderos que se bifurcan" (J.L. Borges)

Recently, Simon Michaux argued that the transition to renewable energy is not possible for the lack of sufficient mineral resources. This conclusion was criticized by Nafeez Ahmed in a recent post. As usual in our polarized world, that led to a heated discussion based on opposing views. My opinion is that both Michaud and Ahmed are right but they see the question from different points of view. If you allow me, Ahmed is more right because he shows that the future is not running on a fixed path. Rather, it is a garden of forking paths. If we choose the right path, the transition is possible and will lead us to a better world. 

Do you remember the story of the boy who cried wolf? It tells you that you shouldn't cry wolf too many times but also that the wolf will eventually come. It illustrates how our destiny as human beings is to always choose extreme viewpoints: either we are too afraid of the wolf, or we believe it doesn't exist. Indeed, Erwin Schlesinger said, "human beings have only two modes of operation: complacency and panic.

This dichotomy is especially visible in the current debate on the "Energy Transition" that recently flared in an exchange between Simon Michaux and Nafeez Ahmed, the first maintaining that the transition is impossible, the second arriving at the opposite conclusion. In my modest opinion, Michaud's work is correct within the limits of the assumptions he made. But these assumptions are not necessarily right. 

Models may be perfectly correct, but still unable to predict the future. 

If you really believe that they can, you are bound to make enormous mistakes -- as we saw in the way the recent pandemic was (mis)managed. 

Models are there to understand the future, not to predict it. 

The future is a garden of forking paths. Where you go depends on the path you choose. But you still need to follow one of the available paths. 


Now, let me try to examine Michaux's work and Ahmed's rebuttal in light of these considerations. I went through Michaux's report, and I can tell you that it is well done, accurate, full of data, and created by competent professionals. That doesn't mean it cannot be wrong, just like the peak oil date was proposed by competent professionals but turned out to be wrong. The problem is evident from the beginning: it is right there, in the title. 

Assessment of the Extra Capacity Required of Alternative Energy Electrical Power Systems to Completely Replace Fossil Fuels 

You see? Michaux assumes from the start that we need "extra capacity" from "alternative" energy in order to "completely replace" fossil fuels. If the problem is stated in these terms, the answer to the question of the feasibility of the transition can only be negative. 

Alas, we didn't need a report of 985 pages to understand that. It was obvious from the beginning. The limits of mineral resources were already shown in 1972 by the authors of "The Limits to Growth," the report sponsored by the Club of Rome. We know that we have limits; the problem is which paths we can choose within these limits. 

This question is often touched on in Michaux's report when he mentions the need to "think outside the box" and to change the structure of the system. But, eventually, the result is still stated in negative terms. It is clear from the summary, where Michaux says, "The existing renewable energy sectors and the EV technology systems are merely steppingstones to something else, rather than the final solution." This suggests that we should stick to fossil fuels while waiting for some miracle leading us to the "final" solution, whatever that means. This statement can be used to argue that renewables are useless. Then, it becomes a memetic weapon to keep us stuck to fossil fuels; an attitude which can only lead us to disaster. 

Nafeez Ahmed perfectly understood the problems in his rebuttal. Ahmed notes several critical points in Michaud's report; the principal ones are underestimating the current EROI of renewables and the recent developments of batteries. That leads him to the statement that renewables are not really "renewable" but, at most, "replaceable." Which is simply wrong. The EROI of renewables is now large enough to allow the use of renewable energy to recycle renewable plants. Renewables are exactly that: renewable. 

You could argue that my (and Ahmed's) evaluation of the EROI of renewables is over-optimistic. Maybe, but that's not the main point. Ahmed's criticism is focused on the roots of the problem: we need to take into account how the system can (and always does) adapt to scarcity. It follows different paths among the many available. Ahmed writes: 

...we remain trapped within the prevailing ideological paradigm associated with modern industrial civilisation. This paradigm is a form of reductive-materialism that defines human nature, the natural world, and the relationship between them through the lens of homo economicus – a reduction of human nature to base imperatives oriented around endless consumption and production of materially-defined pursuits; pursuits which are premised on an understanding of nature as little more than a repository of material resources suitable only for human domination and material self-maximisation; in which both human and nature are projected as separate and competing, themselves comprised of separate and competing units.

Yet this ideology is bound up with a system that is hurtling toward self-destruction. As an empirical test of accuracy, it has utterly failed: it is not true because it clearly does not reflect the reality of human nature and the natural world.

It’s understandable, then, that in reacting to this ideology, many environmentalists have zeroed in on certain features of the current system – its predatory growth trajectory – and sought out alternatives that would seem to be diametrically opposed to those regressive features.

One result of this is a proliferation of narratives claiming that the clean energy transformation is little more than an extension of the same industrialised, endless growth ideological paradigm that led us to this global crisis in the first place. Instead of solving that crisis, they claim, it will only worsen it.

Within this worldview, replacing the existing fossil fuel energy infrastructure with a new one based on renewable energy technologies is a fantasy, and therefore the world is heading for an unavoidable contraction that will result in the demise of modern civilisation.  ... Far from being a sober, scientific perspective, this view is itself an ideological reaction that represents a ‘fight or flight’ response to the current crisis convergence. In fact, the proponents of this view are often as dogmatically committed to their views as those they criticise. ....

Recognising the flaws in Michaux’s approach does not vindicate the idea that the current structures and value-systems of the global economy should simply stay the same. On the contrary, accelerating the energy and transport disruptions entails fundamental changes not only within these sectors, but in the way they are organised and managed in relation to wider society.

My critique of Michaux doesn’t justify complacency about metals and minerals requirements for the clean energy transformation. Resource bottlenecks can happen for a range of reasons as geopolitical crises like Russia's war in Ukraine make obvious. But there are no good reasons to believe that potential materials bottlenecks entail the total infeasibility of the transition.

... we face the unprecedented opportunity and ecological necessity to move into a new system. This system includes the possibilities of abundant clean energy and transport with diminishing material throughput, requiring new circular economy approaches rooted in respect for life and the earth; and where the key technologies are so networked and decentralised that they work best with participatory models of distribution and sharing. This entails the emergence of a new economy with value measured in innovative ways, because traditional GDP metrics focusing on ever-increasing material throughput will become functionally useless.

If you can, please, try to examine these statements by Ahmed with an open mind because he perfectly frames the problem. And never forget one thing: the future is not a single path toward catastrophe. It is a garden of forking paths. We are bound to follow one of these paths: we don't know which one yet, but not all of them lead to the Seneca Cliff. In the transition to a renewable energy system, we can adapt, reduce demand, improve efficiency, deploy new technologies, and simply be happy with a more limited supply of energy at some moments. It is only the rigidity of our mental models that make us think that there are no alternatives to fossil fuels. 

Thursday, May 18, 2023

Renewables are not a cleaner cockroach, they are a new butterfly. A discussion with Dennis Meadows


Dennis Meadows (left in the image) and Ugo Bardi in Berlin, 2016

A few days ago, I received a message from Dennis Meadows, one of the authors of the 1972 study "The Limits to Growth," about a previous post of mine on "The Seneca Effect." I am publishing it here with his kind permission, together with my comments, and his comments on my comments. I am happy to report that after this exchange we are "99% in agreement."


I read with interest you review of the Michaux/Ahmed debate. Normally I greatly benefit from your writing. But in this case it seemed to me that your text totally avoided addressing the central point - replacing fossil fuels as an energy source with renewables will require enormous amounts of metals and other resources which we have no reasonable basis for assuming will be available. It is not true that peak oil was presented principally as a prediction. Rather critics of Hubert's original analysis misrepresented it as an effort to predict in order to ridicule it -  just as Bailey did for the Limits to Growth natural resource data from World3. I was struck that your critique of Michaux did not contain a single piece of empirical data - the strong point of his research. Rather you engaged in what I term "proof by assertion."

I am personally convinced that there is absolutely no possibility for renewables to be expanded sufficiently that they will support current levels of material consumption. I attach the text of a memo I recently wrote to other members of the Belcher group stating this belief (*). 

Best regards Dennis Meadows


Dear Dennis, 

first of all, it is always a pleasure to receive comments from you. It is not a problem to be in disagreement on some subjects -- the world would be boring if we all were! Besides, I think our disagreement is not so large once we understand certain assumptions. 

Let me start by saying that I fully agree with your statement that "there is absolutely no possibility for renewables to be expanded sufficiently that they will support current levels of material consumption." Not only is it impossible, but even if it were, we would not want that!

So, what do we disagree about? It is about the direction to take.  The fork in the path leads in two different directions depending on the efficiency of renewable technologies: Path 1): renewables are useless, and Path 2): renewables are just what we need

I strongly argue for Path 2) in the sense that we definitely do NOT need to "support current levels of material consumption" to create a sustainable and reasonably prosperous society. But let me explain what I mean by that.  

First, in my opinion, the problem with Michaux's report is that it underestimates the efficiency of renewable technologies. He says that renewables are not really renewable, just "replaceable." He, like others who use this term, means that the plants that we are now building will not be replaceable once fossil fuels are gone. In this case, creating a renewable infrastructure will be a waste of resources and energy (Path 1). 

This view may have been correct until a few years ago, but it is now obsolete. The recent scientific literature on the subject indicates that the efficiency of renewable technologies (expressed in terms of EROI, energy return on energy invested) is now significantly better than that of fossil fuels. Furthermore, it is large enough that the materials used can be recycled using renewable energy. There is a vast literature on this subject. On the specific question of the EROI, I suggest to you this paper by Murphy et al. You can also find an extensive bibliography of the field in our recent paper,  "On the history and future of 100% renewable research." 

Of course, not everything is easy to recycle, and a future renewable infrastructure will have to avoid the use of rare metals (such as platinum for fuel cells) or metals that are not rare, but not abundant enough for the task (such as copper, that will have to be largely replaced by aluminum). That is possible: the current generation of wind and PV plants is mostly based on abundant and recyclable materials. Doing even better is part of the natural evolution of technology. What we can't recycle, we won't use. 

There is a much more fundamental point in this discussion. It is the very concept that we need renewables to be able to "replace fossil fuels," in the sense of matching in quantitative terms the energy produced today (in some views, even exceeding it in order to "keep the economy growing"). This is impossible, as we all agree. The point is that renewables will greatly reduce the need for energy and materials to keep a complex civilization working. If you think, for instance, of how inefficient and wasteful our fossil-based transportation system is, you see that by switching to electric transportation and shared vehicles, we can have the same services for a much smaller consumption of resources. This concept has been expressed by Tony Seba in a form that I interpret as, "Renewables are not a cleaner caterpillar-- they are a new butterfly"

That doesn't mean that the geological limits of the transition aren't to be taken into account; the butterfly cannot fly higher than a certain height. Then, it may well be that we won't be able to move to renewables fast enough to avoid a societal, or even ecosystemic, crash. On this point, please take a look at a paper that I co-authored, where we used the term "the sower's strategy" to indicate that the transition is possible, but it will need hard work, as the peasants of old knew. But staying with fossil fuels is leading us to disaster (as you correctly say in the document for the Balaton group) while moving to nuclear fission simply means exchanging a fossil fuel (hydrocarbons) for another fossil fuel (uranium). Going renewables is a fighting chance, but I believe it is the only chance we have.   

There is an even more fundamental point that goes beyond a certain technology being more efficient than another. Going renewables, as Nafeez Ahmed correctly points out, is a switch from a predatory economy to a bioeconomy.  Our industrial sphere should imitate the biosphere that has been using minerals from the Earth's crust on land for the past 350 million years (at least) and never ran out of anything. As I said elsewhere, we need to do what the biosphere does, that is:

1. Use only minerals that are abundant.
2. Use them sparingly and efficiently.
3. Recycle ferociously. 

If we can do that, we have a unique opportunity in the history of humankind. It means we can build a society that does not destroy everything in order to satisfy human greed. Can we do it? As always, reality will be the ultimate judge. 


The answer from Dennis Meadows


Thank you for sending me your article. I agree that the main difference of opinion lies in the direction to take. I am reminded of the defining characteristic of professors - two people who agree on 99% and spend all their time focusing on and debating the other one percent. Because I largely agree with you, my only relevant comment on what you say is that you have overly limited our options: 

So, what do we disagree about? It is about the direction to take.  The fork in the path leads in two different directions depending on the efficiency of renewable technologies: Path 1): renewables are useless, and Path 2): renewables are just what we need

I would not choose either path; rather I believe it is time to quit focusing on fossil energy scarcity as a source of our problems and start concentrating on fragility. The debate -renewables versus fossil - is a distraction from considering the important options for increasing the resilience of society.

Dennis Meadows


A minor point. You say, "It is not true that peak oil was presented principally as a prediction." I beg to differ. I have been a member of ASPO (the Association for the Study of Peak Oil) almost from inception and part of its scientific committee as long as the association existed. And I can say that one of the problems of the approach of peak oilers was a certain obsession with the date of the peak. That doesn't disqualify a group of people whom I still think included some of the best minds on this planet during that period. The problem was that few of them were experts in modeling, and models are like weapons: you need to know the rules before you try to use them. By the way, you and your colleagues didn't make this mistake in your "Limits to Growth" in 1972; correctly, you were always careful of presenting a fan of scenarios, not a prediction. Later on, Bailey and his ilk accused you of having done what you didn't do: "wrong predictions." But that was politics, another story. 


(*) Statements about being realistic about technology, alternative energy, and sustainability
Dennis Meadows

April 11, 2023 message to the Balaton Group

Dear Colleagues,

I have often described politics as the art of choosing which of several impossible outcomes you most prefer. It is important to envision good outcomes. It may be useful to strive for them. But it is important to be realistic. The recent discussion about technology, alternative energy, and sustainability are based on several implicit assumptions, which I believe are unrealistic. At the risk of being an old grump, and recognizing my own limited vision, I list here some statements that I believe from the study of science, history, and human nature to be realistic.

#1: There is no possibility that the so-called renewable energy sources will permit the elimination of fossil fuels and sustain current levels of economic activity and material well- being. The scramble for access to declining energy sources is likely to produce violence. 

#2: The planet will not sustain anywhere close to 9 billion people at living standards close to their aspirations (or our views about what is fair).

#3: Sustainable development is about how you travel, not where you are going.

#4: The privileged will not willingly sacrifice their own advantages to reduce the gap between the rich and the poor (witness the US.) They will lose their advantages, but unwillingly.

#5: The rapidly approaching climate chaos will erode society's capacity for constructive action before it prompts it.

#6: Expansion and efficiency are taken as unquestioned goals for society. They need to be replaced by sufficiency and resilience.

#7: History does not unfold in a smooth, linear, gradual process. Big, drastic discontinuities lie ahead - soon. 

#8: When a group of people believe they must choose between options that offer more order or those affording greater liberty, they will always opt for order. 

Unfortunately so, since it will have grave implications for the evolution of society’s governance systems. Dictators will always promise less chaos than Democrats.

Friday, March 3, 2023

Electricity: the universal energy currency


By Harald Desing

Energy is conserved. Counter to common language, energy can neither be "produced" nor "consumed", but only transformed. However, there are more and less useful forms of energy: electricity, for example, is extremely versatile and can be transformed into any other form of energy with close to 100% efficiency. In contrast, low temperature heat cannot do much work anymore; it is the energy "waste" with no work potential. The work potential is called exergy: electricity has 100% exergy content, whereas heat at the same temperature than the surroundings has 0%. Society is driven by useful work provided through different energy resources. So, different energy forms should be compared with the useful work they are able to do.

Commonly, this is not the case. Energy statistics, such as the IEA or from national statistic offices, do compare apples with oranges: "Primary" energy is accounted on different levels: calorific energy content of fuels (that is the heat potential that can be generated by burning the fuel) alongside with solar electricity and geothermal heat at different temperature levels. All of them have different work potentials, and they are later used as different forms of energy: heat for buildings and industry, electricity, or motion for mobility.

When we defossilize the energy system, most of the fossil energy applications, which are not yet electricity, have to be replaced by renewable electricity. For example, instead of internal combustion engines in cars and trucks, we need battery electric vehicles and electric trains; gas boilers can be replaced by heat pumps powered by electricity; and high temperature heat for industry with either direct electric heating (such as an electric arc furnace) or hydrogen produced with renewable electricity (such for hydrogen-reduced steel). Low temperature heat could also be provided by solar thermal collectors, with a similar efficiency than converting to solar electricity first and to heat with heat pumps later. High temperature heat could be provided by concentrated solar systems, however, this is currently not very practical for most applications in industry. In particular cases, it may make sense to provide heat directly from solar, biomass or geothermal. However generally, electricity is the universal and versatile intermediary form of energy for all sectors.

We do not have to replace "primary" fossil energy, but only the useful work they provide to society. Fictively converting all primary energy to electric energy equivalents using state-of-the-art conversion technologies, provides a more reasonable estimate for what really needs to be replaced. It reduces the energy supply to society from almost 19 terawatt (TW) in 2019—as counted by IEA as "primary" energy—to 7.3TW.  Renewable energies already provide 15% of this, so "only" 6.3TW needs to be replaced during the energy transition with renewable electricity.

Sometimes, this reduction is labeled "gigantic efficiency improvements" when switching to RE systems, but actually it is merely counting energies on the basis of usefulness to society. The efficiency of the subsequent energy services remain the same. The efficiency of the energy provisioning system, in contrast, could be measured by tracing energy conversions all the way back to their origin. For most energy forms, this is our sun. Hydropower is nothing but converted sunlight: sunshine on oceans evaporates water, forms clouds and generates winds that carry vapor over land where it falls as rain. The height difference of the runoff back to the oceans is what can be used as hydropower. This description makes it clear already that from the original solar energy, only a tiny fraction can be converted to hydroelectricity. The same applies to wind and biomass. All of them are much less efficient than direct solar energy conversion. Fossil fuels are also nothing but (ancient) sunlight. They had been slowly built over many million years by buried biomass; now we burn them at a rate more than ten thousand times faster than they were built. The solar energy that created coal, oil and gas deposits is again much more than solar energy stored in recent biomass, reducing the conversion efficiency from sunlight to useful work even further. Nuclear, geothermal and tidal energies do not originate from our sun. They originate from exploding stars and need to be traced back all the way to the big bang. The energy from our sun can be traced back to the big bang too, which would be truly primary energy: all the useful work at our disposal originates from there.

Due to all the additional conversion steps for other energy forms, direct solar energy conversion is the most efficient way to provide useful work to society. And electric energy is the embodiment of useful work (100% exergy), which is why it is ideal for comparisons and modelling substitutions among different energy provisioning systems.