Monday, May 18, 2009

The Renewables Hump 2: Digging Out of a Hole

In the first post in this series, I introduced the general notion that renewable energy requires an up-front investment of energy, and that this may dramatically impact our ability to transition to a renewable-energy economy because the transition effort will initially exacerbate the very energy scarcity that is its impetus.  Beyond this general notion that the transition to renewables first requires exacerbating our current energy scarcity, the time that it takes a renewable source of energy to return the up-front energy invested in it becomes especially critical.  Here’s a quick example (for the simplicity of these examples, I'm assuming that 100% of energy requirement is up-front with no maintenance requirement): 

Let’s say you want to transition 1 million Barrels of Oil Equivalent per year (mBOE/y) of current global energy to a renewable source this year.  If this renewable source (a concentrating solar power plant, for example), has an EROEI of 20:1, and will generate for the full-power equivalent of 40 years, then it will take roughly 2 years for the solar plant to return the energy invested in it.  Over the course of 40 years it will generate 40 mBOE, and it will take the equivalent of 2 mBOE of energy invested up-front to enter operation.  While this return-on-investment seems excellent, this up front investment of 2 mBOE is still very significant—it is an increase in global energy consumption roughly equal to the decrease caused by the current economic crisis—but the reward of a mBOE of renewable generation capacity every year for the next 40 years seem well worth the price.  With this kind of EROEI, a transition to a renewable energy economy seems feasible, and it may be possible to affect such a transition quite quickly. 

What happens if the EROEI of that renewable is actually only 4:1?  Now it takes 10 mBOE to bring this renewable capacity into operation, and you won’t pay this back for ten years.  In the meantime, where are we going to find an extra 10 mBOE beyond what we currently need to fuel our economy?  The answer is that, of course, we won’t.  We’ll instead reallocate our existing energy supply, displacing the most highly elastic 10 mBOE in demand.  Prices will spike.  And this is only to create 1 mBOE of renewable capacity each year.  That’s enough to compensate for a decline rate of about 1.2% in global oil production—far lower than most post-peak projections, and less than ½ of 1% of total global energy use.  Of course, renewables with an EROEI below 4:1 would present an even less feasible scenario. 

This is an extremely simplistic example intended only to introduce the problem (more detailed examples will follow), but it highlights two issues:   

First, the type of net-energy barriers illustrated by these examples only become an issue when significant amounts of renewable capacity are in the pipeline at once.  If we continue to bring insignificant amounts of renewable energy online each year (compared to what will be needed to affect a transition within a few decades, or to keep pace with fossil-energy descent), then the impact of the up-front energy investment will be similarly insignificant.  This may seem like a tautology, but it explains one important point:  this “renewables hump” is a novel issue lurking below the surface of current discussion precisely because we have not yet encountered it with current renewable energy projects—and we won’t until we begin a serious effort to transition to renewables.  At that point, failure to understand this problem may be catastrophic. 

Second, EROEI--how we measure it, and what its true value is for a given technology--is critical to the feasibility of any transition to renewable energy.  If EROEI is high enough, then it is possible to rapidly transition to renewable energy sources and get ahead of the peak oil (and peak fossil fuels in general) decline curve, especially because renewables will soon be able to provide enough energy to bootstrap their own production to a significant degree.  However, lower EROEI values will make transition increasingly challenging, and below some threshold a low net-energy value will render transition entirely impracticable. 

In order to facilitate a transition of our civilization to renewable energy, renewables must offer more than a high EROEI ratio alone.  Time to pay back energy invested also becomes critical, as does generation/production life after payback—these figures must be considered separately and in unison.  Consider, for example, the difference between two renewable sources, both with an EROEI of 5:1, but one with a lifespan of 10 years and another with a lifespan of 50 years.  The 10-year option may appear inferior, but it represents a payback time of only 2 years—this means that the renewable can begin to bootstrap the energy for its replacement at a much more rapid pace, making it far more scaleable from a net-energy perspective.  Conversely, the 50-year option won’t pay back its initial investment for 10 years, making it much more difficult to scale rapidly enough to address time-critical issues such as peak oil without an increased (and likely impractical) up-front investment of energy.  To consider the mechanics of transitioning to renewable energy, we must be aware of all these measures:  EROEI ratio, payback time, production/generation lifespan.   

Now that the problem has been more clearly defined, the future course of this series will make more sense.  In the next post I will look at problems in EROEI measurement methodology, and discuss both the potential to address system-boundary issues and the challenges posed by our inability to precisely measure EROEI.  In the following two posts, I will analyze the possible EROEI measures for current renewable energy options presented by solar and wind energy.  I will also discuss the transition potential presented by these technologies.  If I have time, I will also look at the EROEI for geothermal, tidal, nuclear (with a discussion of the issue that fission reactors are non-renewable, and that so-called "fast-breeder" reactors have yet to be proven), and biofuels.  More likely, however, I will skip these later renewable options for the moment to continue with this series as a whole, and revisit them individually at a later date...


Big Gav said...

Glad to see you are tackling this topic - its very important one for people to understand.

Rice Farmer said...

Of the greatest interest to me here is the idea of bootstrapping because I'm still highly skeptical that renewables can do it. Things like wind turbines, hydroelectric generators (and their dams), wave-power machines, plant and equipment for geothermal and nuclear, and what have you all need the concentrated energy of coal and oil to manufacture, deploy, and maintain. So far renewables supply mainly electricity, with some combustible fuels thrown in. We need to think about how we're going to keep the sub-infrastructure for renewables operating. For example, how are we going to manufacture steel? It reminds me of a debate I once had with a nuclear power advocate. He approached the problem with the simplisting thinking that nuclear plants generate electricity, so we just switch to electric cars, thereby eliminating the need for fossil fuels.

So I especially look forward to your analysis of bootstrapping.

Sal said...

The last time a serious attempt at a planned transition was made was over 32 years ago when Jimmy Carter unveiled his national energy plan. See

Aside from establishing the strategic petroleum reserve and the DOE, the plan has failed. Most of its failure can be attributed to subsequent administrations which switched to a laissez-faire approach domestically while working towards lower energy prices internationally.

The significance of this is goal and policy perseverance over a time period significantly longer than the political time horizon. Metrics, schedules and projections are all susceptible to manipulation allowing even one administration to entirely derail this effort if special interests don't inflict the death of a thousand cuts first.

Your analysis will simply establish physical constraints when we all know that the limiting factor is political.

Neven said...

"with a discussion of the issue that fission reactors are non-renewable, and that so-called "fast-breeder" reactors have yet to be proven."

Jeff, if you'd like to read up on interesting discussions concerning fast breeder reactors, you might want to check This guy, Barry Brook, an Australian climate scientist, writes very interesting stuff about climate science and the climate debate. Now, I was always against nuclear power, but after reading several of his pieces about Gen IV reactors I'm not so sure anymore.

One more thing, but I'm reasonably certain you've heard of it already: a recent book on renewable energies by David MacKay called Sustainable Energy, Without the Hot Air. I have only read the introduction and first chapter, but it has got some good reviews.

quatre_brass commentary said...

It takes energy to make energy. What if we waited until the oil and coal ran out, then we would not be able to even put forward the start up costs you are talking about. Consequently, we must make these decisions while we still have the energy to carry them out. (pun intended)

Jeff Vail said...


Precisely where this series is going... The key questions are how fast must we invest energy in renewables technologies of what EROEI in order to achieve a transition, and what magnitude of transition is required by what date? Tough questions, but we'll try to answer...

Simon Tegg said...

Similar discussion occuring at Worldchanging. Focused on the carbon payback. One commentator argues (without references) that solar PV manufacturers are successfully 'bootstrapping'. See

Theo_musher said...

The reason you are a disinformation agent is because you focus only on what WON'T Work.

You blog endlessly ONLY about the problems and why this solution hypothetically won't work, why that solution hypothetically WON'T work, etc..

Contrary to your thesis Memes are not these mechanical things that simply arise on their own replicating and spiraling out of control-memes are just IDEAS that PEOPLE come up with.

These Climate change memes, Peak oil, Over population. they are products of elite think tanks, like the Club of Rome, the Bilderbergs etc. They Put these "problems" out there because they have a solution. A solution of Orwellian Centralized control on a Global level.

So you spend all your time shooting down any solution on a grass roots or even National level. To do your part to ensure people just think about the problem. Spread the word about the problem. Once consensus is reached about the problem, people will grudginly accept the "SOLUTION" elites had planned all along.

So here is a test of this hypothesis. Do you perpetuate other deceptive poisonous memes planted by elites?

The answer is yes. You perpetuate the phony war on terror meme. There is no Al Qaeda. You know that. But you lie and perpetuate the lie that Al Quaeda is real. according to you the State can;t compete with Al Queda because its structurally unable to do so. Its eating away our national sovereignty according to you and to you that's a good thing, because the "paradigm of the Nation State" needs to be done away with.

What a coincidence! That just happens to go along with the long term goals of the global elite, for establishing World Government!

Do away with the Nation State, because Al Qaeda can so easily defeat it. Can they? No. 9/11 as you know was an Operation Northwoods style false flag Operation, and there is No Al qaeda. How stupid do you think people are? Al Zarqawi has been killed what 8 times now?

So your message is to become isolated and grow all our own food in tiny little nodes with a totally flat organizational structure. OK Why don't you? Oh that's right, because you are too busy being a Corporate Lawyer, defending mining companies from having to suffer the consequences of polluting the environment.

Your plan is for the Corporate State to triumph over national sovereignty. That's what your actions say. You are a disinformation agent.

Theo_musher said...

Here's your Al QaedaYou are fully aware of these kinds of set ups, you definitely worked with people doing them you probably planned some yourself.

Jeff Vail said...

I hope I'm at least getting paid well for doing all that!

Neven said...

Well, "Theo", you really have come out of the closet recently, haven't you?

Like I said on your blog, you have a few interesting ideas, but there are several flaws as well. It's too bad you're resorting to lashing out.

Theo_musher said...

I am not "resorting" to anything. This is the way I see it. This Armageddon stuff is all "predictive programing."

Its about shaping and controlling people's perception of the future.

Its not about "doing anything" its about being afraid for some point in the future and getting everyone to think about it in the same way.

Its not about money either. I am not accusing you Jeff of selling out for money. I am not saying you are some major player either high up in the hierarchy. You are probably more like a soldier obeying orders. I am accusing you of deception. You are either lying or mistaken about "global terrorism". As an intelligent person with connections to the intelligence establishment, its very unlikely that you are simply naive about 9/11 and the War on terror. Maybe you think a certain level of dishonesty is required to shape peoples thinking on what you see as a positive goal.

Either way your focus is only on problems, why they can't be fixed etc. Why everything will only break down and not get any better. Its psychological warfare.

You can blow it off. That's a smart move. But you certainly aren't transparent.

You operate best in the dark. So I'll you leave you to your dark plans. No point in debating you any further here.

Lonnie said...

Wow…Could you possibly be projecting here? I’m not hearing any Armageddon hype on this site. It is more about getting ahead of the curve at the same time we are on the downslope. Given our current knowledge base it should seem impossible for anyone with common sense to deny carrying capacity and the laws of physics.

It is about doing something and qualitative change.

Neil1947 said...

The time it takes to payback energy invested is important when comaring wind(months) with hydro and nuclear(years) even though they may have similar EROEI.
More importantly for a post-peak oil world would be oil saved on oil invested(OSOOI). Thus wind, nuclear don't use very much oil in producing steel and cement and transporting components is minor(<5%). However, presently in US, electricity can only save heating oil use, at least until electric vehicles are manufactured(more energy investment).
I look forward to you next article

TH in SoC said...

I am enjoying this series. I definitely fall into the camp of those who think that we are headed for a future of energy descent and societal simplification. I don't think that technology will save us from this end. Yet it is necessary for the sake of intellectual honesty to examine such an assumption and to check from time to time to see whether it still holds. What you are doing is valuable work.

Jeff Vail said...

Neil and TH, I hope I'll achieve what you suggest... That's certainly the goal. I'll be making the argument shortly that even the payback time for wind is many years, not months. No new post this week, though--simply too much to do and not enough time at the moment (TH, sorry I haven't responded yet, also on the list for this week).

Robert Martini said...

I once calculated that for a 1.5 MW Wind turbine, it takes up to almost a month to just pay off energy cost of transporting the blades and respective blade materials around.


With this example, in a portion, I calculated the energy in the diesel and used the semi-trucks average miles per gallon. However you really need to calculate the energy cost of the blades plastic components being transported to the operation that forms the blade. Also you need to include the energy cost the machines use. Further expanding your system boundaries, you need to include the energy cost included in the operation and transportation of blade forming machines. all the way down to the energy cost in manufacturing the screws and components on that machines.

I think we can agree on one thing, that as you expand your system boundaries your EROEI always decreases. I suspect the renewable optimistic EROEI's come from extremely narrow boundary studies. Extremely wide boundary studies are very time consuming and there are huge informational cost to obtain these simple metrics.

Solar, Geothermal and Wind energy is orders of magnitude LESS DENSE than Fossil fuels.

Solar- about 350 w/m^2

Wind- depends but in great conditions maybe twice that if solar

Fossil Fuels-

Because Renewable energy is so disperse it could be reasoned it would take orders of magnitude more infrastructure to capture that less dense energy.

The biggest problem is people don't think about the difference between how much energy say hits the earth in one day, and how much is actually economically available. its there difference between getting a chocolate bar and getting the equivalent of one chocolate bar chopped up and spread out over an acre. If the ladder were the case, would you still talk about how much chocolate you have? People that don't understand this are the same idiots talking about mining uranium and gold from the ocean's water...

Robert Martini said...
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Robert Martini said...
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Jeff Vail said...


Excellent points. Another point worth considering is the energy required to support the human component. Those diesel trucks, for example, don't drive themselves. And those drivers require food, training, sleep, heating/cooling, a political and medical support structure, etc. Same with all the people involved in all the processes that somehow support the production of that wind turbine blade. And we can't simply dismiss this energy demand on the argument that these people would consumer this energy regardless of their involvement in the production of a wind turbine, because 1) those same people could instead be involved in the production of some other form of energy, and 2) our civilization's very ability to support this marginal population depends on the energy produced by their efforts.

I think this is a fine example of the underlying problem: to do a piece-by-piece accounting of ALL energy inputs is quite simply an accounting impossibility. Therefore we need to find a proxy (I'll discuss two possible approaches to this two posts from now). However, we can't accept proxies that simply create an artificial system boundary because we quite simply have no idea whatsoever how artificially high the resulting figure is. A process-analysis method EROEI calculation could come back with an EROEi of 60:1 (as some such wind studies have found) and yet we have no idea whether the "true" EROEI is 0.5:1 or 25:1. Such numbers are beyond meaningless--to the extent that they serve any purpose they serve only to actively mislead...

Anonymous said...

The most elestic boe is energy efficiency

Jeff Vail said...

Good point on efficiency. A few caveats:

1. Increasing efficiency, without decreasing our society's fundamental need to perform massive amounts of physical work, serves primarily to increase the inelasticity of our remaining oil demand and make us more vulnerable to supply shocks.

2. Improving efficiency usually requires an up-front investment of energy to convert the current use infrastructure. This is something that is rarely measured (never, to my knowledge), so we don't really know the EROEI of efficiency measures.

3. Even if you could magically make every modern requirement for physical work 100% efficient, the minimum energy required to perform the work would still be a significant portion of current energy consumption.

In other words, efficiency is a complementary solution--one with its own dangers that must be watched--but is not a panacea.

Neil said...

While just including the energy inputs to directly manufacture a wind turbine will miss counting some energy inputs, its important not to start double counting energy inputs.
Imagine we have a small island economy that just manufactures one product, wind turbines, using 90% locally sourced steel, cement, glass fiber etc, and this uses 90% of the islands energy(total island energy 1Billion kWh/year) and accounts for 50% of the islands GDP(total 2Billion dollars/year).
If we assume the imported 10%components have 10% of the energy content, then direct energy inputs will be 900Million kWh and another 100Million kWh from imports giving a direct energy content of 1billion kWh/X number of turbines. But the turbines have cost 1Billion to manufacture(labor and materials), lets say 800Million labor. The energy use of the economy is 0.5kWh/$ of GDP so the embodied energy content could be considered to be 400M kWh from the labor,and 1Billion kWh from the materials, so the total energy would be 1.4Billion kWh. But the island only uses 1Billion kWh total! We have assigned too much energy to the half of the GDP ( the service and agricutlure sector)not involved in manufacturing turbines. The sevice sector only uses 0.1kWh/$ GDP so the labor embedded energy can only be 40,000 kWh, so the turbines use 1.04 Billion kWh(only slightly higher than the direct inputs).

Jeff Vail said...


Good point, and you've highlighted exactly why this is such an accounting nightmare.

It clearly takes engineers to build a wind turbine installation, for example. And those people could not perform that role but for 16+ years of schooling (arguably less is possible, but this is the legal minimum to be a P.E. in the US). What portion of the energy required to provide that education should we count as embodied in one resulting wind turbine? Obviously it's not 100%, and obviously it's not 0%, but beyond that we're really just guessing. And it's an important figure--it takes a LOT of energy to produce one engineer when you think about it. I think you could look at the number of wind energy projects they'll be involved in over the course of life and divide the educational energy by the work output, but even that is just an approximation...

I actually think that your idea of using an isolated island example (what I've refered to before as the desert island thought experiment) is actually one of the best ways to approach the problem--at least to determine if a given energy technology can provide greater than or less than 1:1 EROEI when the full society-as-support-structure is accounted for. said...

Transition is so exciting. Until of course one starts really, really scaling up that transition. Nicely done, Jeff. I will go back now to reading The Coal Question by Jevons, and musing over the fact that the great cache of oil was yet to be tapped in his time. As for us, I am reasonably confident we will indeed have to capture the sun. But just as you note, we'll need to access a lot of power generation and liquid fuels to build it out. Of course, I would point out that no serious transition or even plan for transition is even underway. Accordingly, it would be best if society got busy so that we could run into the problem you describe as soon as possible.

Anonymous said...

Interesting dialogue here on important topics. We agree the whole thingy is complex?
The blog itself is not exactly disinformation, but can easily be dismissed by Goedel's incompleteness theorem.

Robert Martini said...

To the poster above:

I believe if you are going to waste your time making statements about concepts you don't understand you might do it in a more productive fashion. Your incompleteness theorem has no relevance to the above post, however, if we were discussing number theory it might. EROEI is a very real and important concept relevant to the laws of physics, ecology and the physical world.

Anonymous said...

All energy produced by a technology is consumed by the society which creates and supports the technology, thus expanding the scope of EROEI to the whole society just leads to a meaningless 1:1 figure (since almost every activity plays a supporting role at some remove). Since many incurred energy costs of an engineer are similar whichever industry they work in, the "effective EROEI" should be based on the change in energy consumption and production when jobs transfer to the new industry from existing industries. It is wrong to assign the household energy use of an employee to the industry, since in the absence of the industry that person will still be using energy.

Of course the net energy production by the renewables sector must cover the net energy consumption of the other sectors in society, but trying to assign fairly industry-independent energy sinks (such as the energy cost of education or housing) to particular renewable technologies in an arbitrary or subjective way derails or biases comparisons of different technologies, which is usually what EROEI is meant to clarify.

Jeff Vail said...

Three reasons why I disagree with the above comment:

1. While I agree that, with no boundaries, *societal* (not individual energy source) EROEI will approach 1:1, whether we're slightly above or below 1:1 is *critical* because it indicates whether that civilization is expanding or shrinking. A civilizational EROEI below 1:1 indicates a civilizational mode that is unsustainable over the short term, whereas a civilizational EROEI of greater than 1:1 indicates a civilizational mode that *is* sustainable, at least over the short term addressed by that EROEI calculation.

2. There's no folly in accounting for the household energy used by an employee in a given renewable production process. Yes, IF that employee weren't employed in that industry, BUT if she was still employed in another industry, then that energy would still be consumed. But here's the catch: the alternative industry facilitating its consumption would still be a part of the support mechanism of some other energy producing process--if she wasn't working in the wind industry, she could be working in the ethanol industry, or in the marketing industry, or in the oil industry. Either way, her domestic consumption ultimately is a necessary component of that civilizational EROEI, and must be accounted for in determining both 1) whether the civilizational EROEI is greater than or less than 1:1, and 2) the relative EROEI of the specific energy industry in which she is (wholly or partially) involved.

3. Regarding your last point, Theo, what value as a differentiator between different technologies is an EROEI that includes an unknown (and variable) error factor due to its failure to include all inputs? We can (as noted in the next post, now up) however use a proxy to include these values while still providing a differentiating measure--for example, by using price as a proxy to estimate the apportioned energy cost of each of these various inputs (such as energy cost of education)...

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