EROEI Short #4: Bootstrap-EROEI
Posted by jeffvail on September 6, 2007 - 9:00am
Topic: Alternative energy
Tags: eroei, eroi, net energy, original [list all tags]
One significant issue related to EROEI that must be discussed is the time-lag associated with durable goods and infrastructure. Assume that the aggregate EROEI of our society is declining. Energy was invested 15 years ago in a large piece of coal mining equipment that will last for 15 years. The energy used to build it was, for the sake of example, “100 EROEI” Saudi Crude. As a result, the EROEI of the coal mined by that machine includes an input from the energy required to make that machine—we’ll say this is X. The machine is at the end of its useful life, and a new machine has been ordered. This machine is made with today’s energy, we’ll call it “50 EROEI” Saudi Crude. As a result in this halving of the EROEI of the energy used to make the machine over the past 15 years (just an example), the energy input to the same quantity of coal mined by the new machine is now 2X...
This is an illustration of what I call “Bootstrap EROEI”—the energy that we are producing today is still using, to some extent, machinery and infrastructure that was made in an earlier, higher-EROEI era. Why does this matter? IF we accept that a “first tier” EROEI calculation of coal mining today only accounts for the energy used to operate these coal mining machine and the energy used to produce these machines (i.e. there is no diminishing marginal returns on how easy it is to find and extract the coal), then we will still see a declining EROEI for this operation over the next 15 years as the EROEI of energy used to make each new replacement machine is lower than that of the machine it replaces.
I apologize if that was a laborious explanation, but I think that this is an extremely important concept. Let’s take a current renewable energy favorite: wind. Today’s giant wind turbines are being built with a long-tail of industrial machinery and infrastructure that was largely assembled using higher-EROEI energy. Admittedly, there are brand-new factories being built for wind generation. But there is also an extensive and aging infrastructure upon which this depends. What about the fleet of oversize-load trucks that transport the giant blades? Or the asphalt and concrete to construct, pave, and re-pave the highway (and bridge) infrastructure over which they travel from factory to site? Or the copper wiring for generation and transmission that today costs over $3 a pound (a price representative of the greater energy now required to mine copper). To a significant extent, it seems that today’s “renewable” energy infrastructure is being built on yesterday’s, non-renewable, higher-EROEI energy. Can we build the day-after-tomorrow’s renewable infrastructure on today’s renewable energy and still maintain an EROEI of greater than 1? Maybe if we use the optimistic EROEI figures (with artificial boundaries for considered energy inputs) offered by some.
This is certainly a problematic area for precise calculations—my goal is to spur discussion rather than to definitively answer my own question. My point is this: the problem of “Bootstrap-EROEI” is one that is not being accounted for, and one that (to my knowledge) has no reliable means of calculation. Yet it has a potentially very significant impact on our plans to transition to a renewable energy infrastructure. How can this be addressed?
jeffvail,
I'm not sure that it can be accounted for in a totally meaningfull way. As a practical matter, maybe we should make the choices such as to use wind over coal for electric generation on the subjective consideration that since wind uses no depleteable fossil fuel for energy and coal has terrible pollution problems from CO2 and various other pollutants, that wind is generally better for the purposes.Bob Ebersole
The EROEI stupidity saga lives on...
Don't take offense, jeffvail, this is not personal. But I kinda hoped for more, since the posts' quality in here is pretty tremendous.
But you make a TREMENDOUS ERROR. And that's calculating energy twice. You can't do that, my friend!
Now, who CARES with which energy was made the truck? That's not how you should math it. You should only calculate how MUCH energy it takes to manufacture the truck. EROEI is a mathematical construct defined to see if you can manage to create more energy than use in its process. Therefore, you should try to know how much energy was spent. You've get x joules. Then, you add up all the joules necessary in the process. Then, you see how many joules you got back. That's it.
No previous saudi arabia is required. That's accounting for twice the same energy, because with that, you can only learn that with previous SA oil you could build more trucks than with now's oil. You won't learn that today's trucks are twice energy expensive. Just that you can only build half as much.
And that's WAY different.
I stopped reading when I saw your error. Correct that. Then I'll read the rest. Gosh, the horror, I've said similar stuff regarding EROEI back in here. PLEASE, please, think before writing?
Please?
luisdias -
I really don't see how you can say that Jeff is counting the energy input twice.
By way of analog, say it is essential for my business that I have a certain size and type of truck, and say I pay $40,000 for it and it gives me 15 years of service before I have to replace it with a new one. And then let's say that when I go to buy a new truck, I discover that the price (in real dollars) has shot up to $60,000, largely due to increased manufacturing costs. If I state that the identical replacement truck now costs me 50 percent more than the original truck, would I be guilty of counting the cost of having a truck for my business twice?
I think what Jeff is getting at is that as the overall EROEI of a modern industrial society starts declining, it gets progressively harder to keep the whole thing going, and that if this EROEI drops fast enough, the system can degenerate into a sort of death spiral. This may or may not happen, but I think this concern is what the whole discussion is all about.
You are absolutely wrong and the original thesis is correct. EROEI is a recursive industrial life-cycle energy accounting that measures the accumulated energy required to produce primary energy. So for instance, early Spindletop petroleum pumped itself out of the ground and into a nearby refinery. Thus the Spindletop petroleum had a high eroei and required very little other energies to extract and process. In contrast today's deep water petroleum must be pumped up from the depths at a cost in additional petroleum. Yes, the fuel is in effect measured twice.
Spindletop preceded refineries closer than Pennsylvania, docks, pipelines ect and spewed out on the ground and was hastily contained by an earth dike. The first 600,000 barrels caught fire and burned up about a week after the Lucas gusher blew in.So the EROEI was negative for quite a while. Reference; "Spindletop" by James Clark & Michael Halbouty, 1953
This is an interesting history book, and could remind people of how difficult it was to start the modern fossil fuel age. The oil business didn't just start by magic, and neither will any alternative that will replace it. It was only when the British and American navies switched from coal to oil around WWI that a steady enough market was assured to make sure oil became the main fuel for the industrialisation of the world. People tend to denigrate the growth of wind and solar as not being fast enough to make a difference in the future, but they are making proportionate progress just like oil did against coal a 100 years ago or so.
Bob Ebersole
No. It is you who is absolutely wrong and the original thesis is junk. See down below.
This is no excuse for lower EROEIs, get me. People tend to think that I'm somehow escusing low EROEIS. I'm not. Of course a good EROEI is better. But you're making WRONG MATHS.
Bear with me while I try out a couple of analogies. Say the joules come in a tin. It's as if each time you open a new tin, you find the supplier has dipped into it themselves in order to bring it to you. And each day there's less. So you need more tins. The energy content has not diminished, it's just that more is being consumed before it gets to you.
Well you'll get back less and less. The truck collects lower-quality coal with a lesser energy payload for the thermal power station down the road, so it has to make 8 trips where 5 used to suffice in the past. And that power station is supplying the electricity to the factory that's making new trucks...
Sorry if I'm being a bit thick, but if Mr. Vail's reasoning is wrong, your argument doesn't make it clear to me as to why. It appears that what you are saying amounts to the same thing.
People just don't understand me. Listen. Less EROEI is as bad as it gets, but please, don't count it twice. A Truck that was built with a EROEI petrol of 100 will use the same energy than a truck built with a EROEI petrol of 50, 30 or 20. That's not the issue with EROEI at all. You're confusing stuff. You're saying that a truck spends the energy it requires PLUS the energy that the pumps and refineries require to function. But those are different things. The problem is how much energy does the production of ENERGY takes out of the system. If you subtract them, there's your real energy output for the society.
Well it almost would if I wasn't wrong saying what I said. The thing is, a truck spends 10 energy cubes. Imagine. You have 1000 energy cubes produced. You could have built 100 trucks. But to build those energy cubes, you required 10 energy cubes (EROEI = 100), so you can only build 99 trucks with what is left (990 cubes). If EROEI = 50, then a truck won't cost you 20cubes, but still only 10. It's the energy cost that doubled. That means that for producing 1000 energy cubes, you spent 20 cubes. That leaves 980 cubes, which goes to produce 98 trucks. Like someone above said, this doesn't have much influence until it reaches values much closer to 1 (where it reaches infinity).
But get this: the truck ALWAYS costs 10 energy cubes. Not 2X it. That's different. That's WAY different.
Okay?
Not quite so. You've spent X of energy to build the machine, and 1/EROEI * X to gather that energy. For the earlier case, that was X + 0.01 * X = 1.01 * X. For the later case, that was X + 0.02 * X = 1.02 * X. So, you've spent a bit less than 1% more energy, not 100% more.
For highter EROEI, the difference is negligible. But it skyrockets when you approach 1.
...when it reaches infinity. But that's not the point, is it? The point is if wind, solar and the likes are really EROEI positive or negative. That's what it all comes down to, and to which there are people here trying to instill doubt about the rather good EROEI of these machines.
But you cannot count energy twice. You cannot say that the "truck" uses X plus 1/EROEI*X and then sum it back to see if the production of energy is EROEI positive.
You should only do the obvious: sum all the required energy spent. And for that I couldn't care less if it came from EROEI 100 or 1000 or if it was a gift from God himself. Just count it. Divide it from the energy produced. Voilá, there's your EROEI.
Why do people keep inventing what's been already invented? Move on people, don't stray in the primary school.
You are probably one of those who absolutely can not abide a negative eroei.
It's a grammar error I usually make. By "negative" EROEI, I wasn't meaning a value of <0, but a value <1. I added to the confusion. Sorry about that.
Actualy, I had two points. One is to evidence an error of the post, that does not take away all its meaning, but can lead to wrong interpretations sometimes.
My second point it that it doesn't really matter if our energy source has EROEI if 50, 100, 1000 or 10^9. But it really does matter if its EROEI is 1.3.
It is of limited value to talk about EROEI in isolation.
What if the EROEI was 1.3 but it had a 1 sec turnover rate.
Every second you would have 30% more energy that you had the second before. Or what if the the EROEI was only 1.3 but required almost no equipment or labor. Would it really matter then?
You are correct in one sense that eroei only becomes an issue as the net energy (see clifman's analysis) approaches 1 or zero. Then the externalities of the effort (labor devoted to energy acquisition 'stolen' from other social goods, negative environmental damage,et) become very important issues.
If as you said the primary energy source requires no equipment or labor to harvest and process then it would have an infinite energy return.
If the primary energy source requires lots and lots of equipment and labor to extract (for instance a fossil fuel from the ground or wind from the air) then it could have negative eroei.
... which is an assumption without real study. If the energy used would be more mechanized and without human input (a perfect machine that would function without human intervention for centuries, for example - and yes, I know it sounds like sci-fi, but we are getting into that), it wouldn't really mean a thing if the EROEI was 1.3. It would only be of importance if the energy output was not enough for our needs. Machines would be restless.
Of course, I'm not endorsing it. The problem with EROEI = 1.3 or smth like it is that it is more risky. If the production line explodes, or major malfunctions, or whatever, you may easily get EROEI < 1. And that's very bad.
It is precisely these type of picayune arguments that obfuscate and trivialize the entire problem we face. These accounting procedure arguments ignore the basic fundamental question, TO WIT:
Could a wind turbine produce in its lifetime all the energy that was used in every aspect of its own manufacture? From mining, to transit infrastructure, to manufacture, to feeding and housing the people who do that work.
See. Pretty damned simple.
NO need to worry about how coal mining is going or if old trucks are depreciated energy-wise. Just a simple question.
Hi Cherenkov,
I confess I'm having a hard time getting my head wrapped around this topic, so bear with me as I try to muddle my way through this. I guess my question is really this: When we assign a value to a particular energy source, do we do so solely on the basis of the energy inputs that went into its development/production (e.g., steel, concrete, etc.), or would it be more appropriate to assign a value based on the energy inputs it displaces?
Wind power might be a case in point... here in Nova Scotia, each kWh of wind could, in theory, displace up to 10,000 BTUs of thermal coal. Which would be a more appropriate measure of its true value? How about investments in energy conservation? When I add loft insulation to my home, would I assign a value based on the resources that were consumed in its production and transportation, or should I my accounting be based on the energy it saves?
Cheers,
Paul
You are raising a question that is slightly off the EROEI issue, but no less important in a world choked by our excesses.
I think EROEI ratios are important too though, unlike some posters above. And here is why:
If you have a total production of xGJ with a total EROEI of 4:1, then you have 0.8xGJ available for use.
If you have a total production of xGJ with a total EROEI of 2:1, then you have 0.33xGJ available for use.
A stricking difference, even before you get to values close to 1:1. Why not just build more capacity at lower EROEI? Simple - waste and materials. The whole "just build more/bigger" meme is part of the problem that got us to where we are today...
"You can never solve a problem on the level on which it was created."
Albert Einstein
This is a problem with biofuels. A major one.
But not with solar and wind and the likes, which have EROEIS in the order of 6-20.
Thing is, there's no other stuff that so easily substitutes oil as biofuels do. That's why such a bad investment is being done. We should question though its wide implications. Ecological, social, etc.
Thanks for sharing your insight; much appreciated. In the words of Stephen Leacock, my thoughts often go "madly off in all directions", but one more tangential question, if I may. Is any credit given to the recovery of energy inputs at the end of a product's service life, assuming some or all of the hardware can be recycled or reused? In the case of a solar panel, say, I take it the aluminium frame can be salvaged and perhaps some of the other components as well, in which case, at least some of the embodied energy is recoverable. On the other hand, I'm assuming much of the concrete and steel used in the construction of a hydroelectric dam or nuclear reactor cannot. Do these types of calculations normally take into consideration residual value when comparing one option to another?
Cheers,
Paul
I think that you want 0.66xGJ for EROEI 2:1. For EROEI 1:1 it is still 0.5xGJ. I think the way you want to look at this is the way you put it terms of scale of the operation. So, start by asking how much energy you want, then pick some quantity like land surface area that has a definite limit, and ask what EROEI is feasable to produce the amount of energy you want from the resource available. That way you know what your minimum target EROEI is. You'll have to put in other details like raw productivity or, for oil, the amount of surface area that has oil under it. In terms of raw productivity, you can accept a lower EROEI for higher productivity since you need less land all other things being equal.
So, lets take, for example, 35 billion gallons of ethanol per year by 2017 set by the president. The raw productivity is about 400 gallons/acre/year for corn so we need about 86 million acres or 137,000 sq mi or 2.4 Iowas. You can do this with any EROEI that you like, but if you want be sure that you get the whole 35 billion gallons for use other than say growing corn, you need to give a limit on how much land you are willing to devote, say 4 Iowas, and look for a target EROEI that lets you do this. In this case you would be using 1.6 Iowas to support net energy production from 4 Iowas so your target EROEI is 2.5. Now you have said something helpful. You are not going to use more than 2.4 Iowas to meet your production target but you know where the self-sustaining EROEI is. Then you are fine using natural gas and oil to grow corn because you are not putting a greater burden on those resources that is not compensated for elsewhere by the ethanol. As it turns out, getting to an EROEI of 2.5 does not appear to be feasable using natural gas and oil, so you need to think of something else. One thing you might do is ask how many Nevadas it would take to produce nitrogen fertilizer using solar power and a low pressure aluminum nitride process instead of Haber-Bosch because then you effectively increase the usable land area to non-arable land. If you innovate in various way, you might get to the target EROEI. The usefulness of EROEI is to be able to ask and answer what if questions of this type.
Chris
"Could a wind turbine produce in its lifetime all the energy that was used in every aspect of its own manufacture? From mining, to transit infrastructure, to manufacture, to feeding and housing the people who do that work."
Yes.
"For highter EROEI, the difference is negligible. But it skyrockets when you approach 1."
I think this is a critical issue that is being grossly overlooked. Here's a little table I built to illustrate the basic concept:
EROEI % net Representative Source
100:1 99 Early oil
50:1 98 Mid 20th century
33:1 97 Late 20th century
25:1 96 Turn of 21st
20:1 95 Century oil
15:1 93 Oil now?
10:1 90
9:1 89 Deep water oil?
8:1 88
7:1 86 Tar sands?
6:1 83
5:1 80 Polar oil?
4:1 75
3:1 67 Biodiesel
2:1 50
1.5:1 33 Oil shale?
1.33:1 25 Ethanol best
1.25:1 20
1.1:1 9
1:1 0
1:.7 -43 Ethanol worst
The next steps are to consider increasing population and declining extraction in concert with declining EROEI. Together, those three trends cut useful per capita energy in half before 2030, which is only a college student's lifetime away, and which places us where we were before the green revolution, which raises the issue of feeding ourselves - seen grain prices lately? Another student's lifetime and we're back where we were before the Great Depression. But I think by then we may think of that "Great" in a whole different vein, as in that was the Great Depression, and this is the Terrible One.
(sorry I don't know how to insert a table nor align these columns 'freehand')
Words, words and more words.
But some neat words too.
Perhaps we all should think how to translate these words into ACTION.
Hey, do something. Then POST. Start a PROJECT.
Just don't write words which are sure to be lost aka the bit bucket.
regards from senior techie.
We're just learning maths here with each others.
Easy on us :).
Each thing on its time and place.
Greets
"For highter EROEI, the difference is negligible. But it skyrockets when you approach 1."
It may skyrocket when it approaches 1:1, but I think it becomes extremely important well before that - at least in ratios under 10:1. See my reasoning in my post above...
"You can never solve a problem on the level on which it was created."
Albert Einstein
"For the later case"
What case are you refering to? The importance to EROEI and any percentage will depend on how much energy the machine processes over its lifetime.
What you say is correct: the factor is not 2X but 1.0099X. In order to get 2X you would need the second input EROEI to be less than 1.
Chris
Mr. Vail,
I think I see your point. As an analogy, the 3 foot log I burn in a (make-believe) fireplace puts out the same number of BTUs regardless where it comes from... you point out that the EROI difference is between a log from the backyard and a log that comes from 100 miles away (so to speak).
The Hidden EROI costs are those that happen between tree-stump & fireplace. To me the BTUs from the log appear the same, but the EROI costs are hidden in the transport.
The same applies to the coal. It now take MORE energy INVESTMENT to build the truck (because today's coal is deeper); even though the ABSOLUTE energy needed to build the truck STAYS THE SAME. (We get less truck per same amount of energy invested).
"As a result in this halving of the EROEI of the energy used to make the machine over the past 15 years (just an example), the energy input to the same quantity of coal mined by the new machine is now 2X..."
Why is this so important? The energy required to make the machine is only a small part of the energy required to mine the coal. Most of the energy will be in the form of the fuel used. The energy required to make the machine is spread over the 15 years. What is the ratio of the energy used to make the machine to the energy processed over its 15 year life?
The general form of the equation for EROEI would be something like
x/ax+b)
where:
x is the energy of the processed coal
a is the ratio of fuel energy to coal energy
b is the energy required to make the machine
As the amount of coal processed rises, the constant (b) becomes less important. The extra energy required, might easily be offset by increased quality, giving the machine a longer life.
I think there is something more important than just the cost of making the machinery here. You have to fuel the machinery, you have to maintain the machinery, you have to move/feed/cloth the people who are involved with the machinery. In short, the price of that machine is costantly adding up over the years. It's almost like asking whether I should spend $15,000 for a new car that will be maintenace free for 10 years?.. or $2,000 for an almost antique that will cost me $1,300 in maintenace/per year over 10 years. Both will "cost" $15,000 over that 10 year period, but the newer car will have less downtime, thus be more productive.
Also, if hypothetical space-aliens came down and suddenly exchanged all our planet's oil for an energy equivalent amount of coal, we'd be hard pressed to use it. The diesel-powered mining trucks and mechanical shovels would stop, the gas-powered cars the miners used to get to the mine wouldn't work, the food trucks wouldn't feed the miners, the diesel powered trains couldn't deliver the coal, etc.
So the source of where this energy comes from is also important.
In short, I see jeffvail's point that we need to discuss this problem more so that we can define it better.
'Why is it important?'
Because we are not interested in a snapshot of time, but the changes which are underway when you live on a permanent upward slope of costs/downward slope of eroei. The point is that a production cost today is actually at a discount to its true total because of lower overheads in the past. So we are constantly underestimating costs and overestimating eroei etc. There are many parallels:
If I say 'oil at $80bbl is high and you say - yes but it was higher inflation adjusted 30 years back, both facts are only partly true. Part of inflation is due to rising costs including oil, so once oil prices begin to climb at a higher rate than 'other' inflation, it becomes an important factor...
I would ramble on, but I'm going for a curry
cheers
"when you live on a permanent upward slope of costs/downward slope of eroei"
This is the fundamental mistake you and the author make. You see some new energy systems have a lower EROEI than oil, although this is debatable, and subsequently conclude that it will continue to go down. A permanent downward slope? How about calculating an actual EROEI for wind or solar and tell us why it is not high enough.
Jeff:
You consider energy cost of first generation 'renewable', and then of second generation 'renewable' for which the cost of infrastructure renewal will surely be higher than for first generation. This is a real complication that should not be ignored.
But perhaps the problem should be restated in a way that makes handling the complication easier:
Think about the 'Nth' generation, somewhere well beyond the first and second. There will be a time when each generation of renewable infrasturcture will have a cost structure that is pretty much the same as the cost structure of the '(N-1)th' generation. If we had a vision of what the economy and technology will be at that future time, we could think about various ways to get from here to there. Call these alternative paths. For each of these paths, we could estimate costs and uncertainties as to whether the path is doable.
Can we make useful guesses about future renewable technology? I think yes. For example, it will involve various forms of solar: ie photovoltaic, wind, biofuels, hydroelectric. But not nuclear, which is not renewable because of its own finite resource issues that have nothing to do with fossil fuels. OTOH, nuclear can be a component of an intermediate step along a path. And, it may be useful to planning to use nuclear waste as a heat and sterilizing resource. There must be much more that can be said about this future, but I can't say much more here.
The idea is that the problem of choosing a path into the future can be discussed and analyzed in great detail. Fixating on the first step is probably not useful.
I see your discussion of the complexity of EROEI as a useful demonstration of the need for a different approach. This is my tentative suggestion for such.
In other words, if and when we reach a steady-state economy, the EROEI in the broadest possible sense will be 1:1 (no growth possible), but that would be OK. Getting from here to there is the problem, and it's a problem of social organization, not technology.
I don't think so. With an EROI of 1:1 you'd be burning all the fuel you got simply to get the same amount of fuel to burn in order to get just enough to keep the cycle going. It would be an unproductive ritual. You'd be burning 100 gals of oil to get only 100 gallons of oil (which you'd use to get another 100 gallons of oil to- oh, whatever).
:-0
That's why I said "in the broadest possible sense". This is the "bootstrap EROEI" thread. In a steady-state economy there is no growth possible. Whatever energy is not used directly to generate new energy, is used indirectly in the societal functions necessary to keep everything, including the energy systems, going.
I don't think you can equate a steady-state economy with an EROEI of 1.0.
An energy-producing system (the 'system' not necessarily being a single physical entity) with an EROEI of 1.0 internally consumes 100% of the energy it produces, with zero energy left over for 'societal functions' or anything else. . It is the thermodynamic equivalent of paying someone to dig a hole and then fill it back up again. Or maybe more accurately, it could be thought of as an engine which has just barely enough power to run itself but has zero ability to do any external useful work.
A steady-state economy, i.e., one with zero growth, need not be steady-state with regard to energy production and consumption. A zero-growth economy can be very energy-efficient or very energy wasteful. But perhaps you are using the term 'steady-state' interchangeably with 'sustainable'.
This is not aimed at you, but while we're on the subject, I also think it misleading and not very useful to talk of the EROEI of society as a whole. The purpose of a society, per se, is not to produce energy. Rather