How then, do we move backwards? How does a society, with most of the people having no clue of future events, move from being dependent on a vast and intertwined network of goods and services produced by the indigenous people of whereever, to a local resource and renewable energy based society, and do so in the timeframe available (20-30 years using the most liberal extimates, 10-20 with resonable estimates, 5-10 with worst case scenarios), all the while prices on everything increasing, world politics getting more militaristic, governments continuously reducing civil liberties, shortages of goods on the market and weather patterns resembling bad Hollywood movies?
Joined: May 19, 2004 Posts: 892 Location: San Francisco, California
Posted: Sat May 07, 2005 2:57 pm Post subject:
CalgaryEng wrote:
I understand very well the fact that humans have been exploiting an enormous resource (fossil fuels) for which they did not have to pay. When that resource starts to run out, it is going to be exceedingly difficult to replace it with something equivalent. However, I do not need EPR or EROEI or other useless measures to make that evaluation. If it costs $20 to make a solar panel and the total energy it produces can only be sold for $15, it does not take any more than that to convince me that it is not worth making the solar panel.
So we agree. Effectively, that's the argument I'm making. That is, let's say it costs twenty bucks worth of electricity, raw materials, and labor to make the solar panel. But in the lifetime of the solar panel, it will only produce $15 worth of energy. That's your EROEI/EPR measurement right there. Production cost is the way our society determines the "starting point" for the EROEI/EPR calculation. Problem is, the profit/loss calculation is currently distorted by the energy subsidy renewables currently get from fossil fuels.
However, when it comes to renewables alone, EROEI/EPR values greater than one are effectively the same as just, "very high." The producer will rationally focus on minimizing other factors, such as labor, land area, or cost of materials. EROEI/EPR doesn't really come into the picture for renewables, as long as it's greater than one.
Specifically in the case of solar, the energy source (the sun) is effectively limitless. That's why I say, "It's all about footprint."
Posted: Sat May 07, 2005 2:57 pm Post subject: EROEI
How much energy does someone get from eating an apple versus how much energy it took to climb the tree? That is EROEI. When the apple is very far up the tree, it might take more energy to climb the tree than can be obtained from eating the apple, and it makes no sense for the human to eat it for sustanance. He may eat the apple for reasons like vitamins or pleasure, but it can no longer provide the net energy needed to run the body. That is the idea behind EROEI. If oils EROEI declines enough, it ceases to provide the net energy needed to run our current civilization.
Maybe you should think of industrial civilization as like an engine. Just like in thermodynamics, a very high quality energy source (high EROEI) like cheap oil makes for high effficiency in the engine's cycle. If the fuel quality decreases (low EROEI), then the engine doesn't produce as much work as it did before. This work is all the goodies we have come to demand from industrial civilization.
Joined: May 19, 2004 Posts: 892 Location: San Francisco, California
Posted: Sat May 07, 2005 3:20 pm Post subject:
I've noticed that the people with physics, chemistry, and engineering backgrounds tend to avoid EROEI/EPR, probably because it is imprecise. EnviroEngr or Devil (or any other physicist, chemist, or engineer) can you please weigh in on EROEI/EPR and the objections that have been made to it?
Now, Howard Odum created a concept called emergy, which is rather complicated but which is much more thoroughly defined than EROEI/EPR (everything comes down to solar "emcalories"). But even that idea has some problems. For example, Odum uses emergy to quantify the energy value of human thought. I haven't investigated it thoroughly enough to understand how this is done but the idea of quantifying human thought in units of energy seems a bit dodgy to me.
Although I'm not a scientist (just a wannabe), I did take a few college level physics and chemistry courses back in the day (early 90s). And I'm not talking about, "Physics for Poets," either. I'm talking about science classes for majors. The kind some people flunk. When I first read about EROEI/EPR (I think from Matt Savinar's site), it seemed to make sense. But the more I thought about it and the more I read other people's objections to the idea, the less sense it made. Now I'm in the doubter camp.
"It takes energy to acquire or develop energy resources. A potential source that contains more energy than was expended in the effort to acquire it yields an energy profit. One that takes more energy to acquire than it ultimately yields is not an energy source at all, but rather an energy sink."
_________________ "By the time individuals discover that remaining resources will not be adequate for the next generation, the next generation has already been born. " David Price
I will try one last post before I leave for the day.
Suppose it costs $20 to produce a barrel of oil. Suppose you can sell the barrel of oil for only $15. Do not do this. You will go broke. Case closed.
Suppose it takes four barrel equivalents of natural gas to produce one barrel of oil. Should you do this. The EROEI ratio is 0.25 (negative according to at least one person on the planet). I do not know. It depends on how much the natural gas costs and what the price is for oil. The EROEI tells you nothing useful. If the gas is really cheap and the oil is really expensive, then do it. If the gas is expensive and the oil is cheap, then do not do it.
Suppose it takes one barrel equivalent of super oil to extract 30 barrels of regular oil. Should you do it. The EROEI is 30. Again, I do not know. It depends on the cost of the super oil compared to the regular oil.
Not all energy is the same. A can of gasoline in my garage is a very concentrated and convenient form of energy. The equivalent energy in the form of warm sand at the beach is much less useful. When you convert everything to energy units all these important distinctions are lost. The calculation of EROEI requires that you convert everything to energy units. Converting to dollars allows you to take account of dozens of other factors.
For those of you who prefer fruit and climbing trees:
Suppose an apple contain 100 energy units. It is at the top of a tree. It takes 200 energy units to climb the tree. Other food is available at the bottom of the tree (otherwise you would soon be dead). Should you climb the tree? Well, it depends on the value of the apple compared to the value of the food at the bottom. The apple may contain nutrients that are essential to life that are not contained in the food at the bottom. Using 200 energy units to get the apple becomes essential. The fact that EROEI is 0.5 is irrelevant. Converting food to energy units removes important information about the quality of the food. Not all food is the same just because it has the same energy content.
Incoming solar radiation gives the earth an enormous amount of energy. Oil buried in the ground is another source of energy. Oil is really easy (cheap) to use to move things like cars around. Using solar energy to move cars around is much more difficult (expensive). Unless we start preparing for peak oil in about 1970, I think we are going to have a really tough time. Oh, it is already 2005! I think we are going to have a really tough time.
Should I buy a solar heating unit to preheat my domestic hot water? Suppose it costs $500 to install the new system and I save $50 per month. Suppose the system has a life of twenty years. Sounds OK. But no. I should figure out the EROEI. I should spend hours tracking down how much energy (in joules) was used to create the system and then calculate how much energy I will get in return. Yeah, right.
I thought my original post was really clear. Apparently it was not. Actually, after spending 12 years teaching in a classroom, I should not be surprised that the inability to read simple English sentences is a real challenge for so many.
Finally, special thanks to pstarr who seems to think that EROEI is a useful concept because I am angry. Thanks for taking the blinders off my eyes. Everything becomes so much clearer when one abandons rationality.
Joined: May 19, 2004 Posts: 892 Location: San Francisco, California
Posted: Sat May 07, 2005 4:49 pm Post subject:
CalgaryEng wrote:
Consider a tree. Huge amounts of energy in the form of sunshine fall on it. The tree takes a tiny fraction of this energy and turns it into wood. Considering the amount of energy you get from burning the wood compared to the amount of energy needed to produce the wood the EPR is way less than one. So what. Sunshine is free. As far as I can tell, without the Sun, the earth is not self sustaining and never will be. That does not stop trees from growing.
Yeah, the fact that we get energy for free from the sun is one of the things that makes EPR a fuzzy number. As far as I'm concerned, it doesn't make sense to count the free sunshine embodied in the wood as part of the energy "invested." Invested by whom? So the energy invested is really just the energy used by the lumberjack to chop down the tree, the energy used to carry the wood back to the woodpile, and the energy used to split the wood before throwing it on the fire. Basically, when we talk about EROEI/EPR, we're talking about lumberjack energy, not photosynthesis energy.
Ignoring free energy "investments" from photosynthesis, wood almost certainly has an EPR > 1. If it didn't, the lumberjack would say, why bother chopping down trees to throw wood on the fire? I can produce more energy by rubbing my hands together (or with the pedal-powered generator or whatever). But that would be absurd. On the other hand, wood has other problems. If we use it too fast, we run out. Also, burning it pumps carbon dioxide into the atmosphere.
One more thing -- the concept of energy density certainly plays a part here, as you have mentioned. That is, wood, oil, and natural gas all store a lot of easily used energy in a small volume and mass. Solar energy, by comparison, is abundant but diffuse. It is likely that in a world based on renewables, applications that require a lot of high-density energy will become a lot more expensive. However, I'm not so sure that's a totally bad thing.
Last edited by johnmarkos on Sat May 07, 2005 5:02 pm; edited 1 time in total
Joined: May 19, 2004 Posts: 892 Location: San Francisco, California
Posted: Sat May 07, 2005 4:58 pm Post subject:
CalgaryEng wrote:
If the two barrels of oil equivalent energy come from a cheap natural gas source and the one barrel of oil equivalent output energy is expensive jet fuel, then this seems like something that one might do for good reason.
Acknowledged. However, this doesn't help us with our energy problem per se. It only helps us with our dense energy problem. Dense energy is useful for stuff like flying planes and shooting rockets into space. We don't need really dense energy to make our laptops go or for growing food.
Joined: May 19, 2004 Posts: 892 Location: San Francisco, California
Posted: Sat May 07, 2005 5:00 pm Post subject:
CalgaryEng wrote:
Not all energy is the same. A can of gasoline in my garage is a very concentrated and convenient form of energy. The equivalent energy in the form of warm sand at the beach is much less useful. When you convert everything to energy units all these important distinctions are lost. The calculation of EROEI requires that you convert everything to energy units. Converting to dollars allows you to take account of dozens of other factors.
Most PO-aware folks agree that the dollar value of oil does not take into account depletion. That is, if everyone knew that only 1000 Gb of oil would ever be produced and that PO was now, it'd be a lot more expensive than $50 US a barrel.
Joined: Oct 14, 2004 Posts: 1203 Location: Left the cult
Posted: Sat May 07, 2005 5:39 pm Post subject:
You keep giving examples about EROEI, then talking about costs in dollars. The point of EROEI is that it purposely ignores the monetary cost, so you are never going to understand it that way.
The comparison with apples at the top containing special nutrients is obviously spurious, it is assumed that commodities are fungible. You are getting bogged down in irrelevant details. Consider the big picture. Think about what EROEI can be used for, and what its implications are.
If this represents the quality of modern teachers, I am not surprised that the students never learn to read. You should be quite capable of researching and understanding this stuff yourself.
Assignment EROEI 101.
1. What is a common definition of EROEI?
2. How does EROEI differ to monetary evalations?
3. Why is considering EROEI useful?
4. What are the limitations of considering EROEI?
5. What are the implications of EROEI when considering
a) finite energy sources
b) renewable energy sources
6. What alternative evaluation methods to EROEI are there?
You may use the web for your research.
Hint: www.eroei.com _________________ It's all downhill from here
I will try one last post before I leave for the day.
Suppose it costs $20 to produce a barrel of oil. Suppose you can sell the barrel of oil for only $15. Do not do this. You will go broke. Case closed.
Suppose it takes four barrel equivalents of natural gas to produce one barrel of oil. Should you do this. The EROEI ratio is 0.25 (negative according to at least one person on the planet). I do not know. It depends on how much the natural gas costs and what the price is for oil. The EROEI tells you nothing useful. If the gas is really cheap and the oil is really expensive, then do it. If the gas is expensive and the oil is cheap, then do not do it.
Suppose it takes one barrel equivalent of super oil to extract 30 barrels of regular oil. Should you do it. The EROEI is 30. Again, I do not know. It depends on the cost of the super oil compared to the regular oil.
Not all energy is the same. A can of gasoline in my garage is a very concentrated and convenient form of energy. The equivalent energy in the form of warm sand at the beach is much less useful. When you convert everything to energy units all these important distinctions are lost. The calculation of EROEI requires that you convert everything to energy units. Converting to dollars allows you to take account of dozens of other factors.
For those of you who prefer fruit and climbing trees:
Suppose an apple contain 100 energy units. It is at the top of a tree. It takes 200 energy units to climb the tree. Other food is available at the bottom of the tree (otherwise you would soon be dead). Should you climb the tree? Well, it depends on the value of the apple compared to the value of the food at the bottom. The apple may contain nutrients that are essential to life that are not contained in the food at the bottom. Using 200 energy units to get the apple becomes essential. The fact that EROEI is 0.5 is irrelevant. Converting food to energy units removes important information about the quality of the food. Not all food is the same just because it has the same energy content.
Incoming solar radiation gives the earth an enormous amount of energy. Oil buried in the ground is another source of energy. Oil is really easy (cheap) to use to move things like cars around. Using solar energy to move cars around is much more difficult (expensive). Unless we start preparing for peak oil in about 1970, I think we are going to have a really tough time. Oh, it is already 2005! I think we are going to have a really tough time.
Should I buy a solar heating unit to preheat my domestic hot water? Suppose it costs $500 to install the new system and I save $50 per month. Suppose the system has a life of twenty years. Sounds OK. But no. I should figure out the EROEI. I should spend hours tracking down how much energy (in joules) was used to create the system and then calculate how much energy I will get in return. Yeah, right.
I thought my original post was really clear. Apparently it was not. Actually, after spending 12 years teaching in a classroom, I should not be surprised that the inability to read simple English sentences is a real challenge for so many.
Finally, special thanks to pstarr who seems to think that EROEI is a useful concept because I am angry. Thanks for taking the blinders off my eyes. Everything becomes so much clearer when one abandons rationality.
there is no way of knowing that the costs are the result of EROEI if the context is limited to the infomation in that post..
the gas to crude example is the case in point you have to create an equivalency to start with even in your example..
the marriage of EROEI to money is implicit..
moreover the calculation of a return in a monetary sense has the same problems of definition as investment in a gas production industry for synthetic crude production may make financial sense in the present but accelerates depletion (poor EROEI) and thus necessitates further investment in a new infrastructure to replace that!
this very example fails to address depletion itself while having the inherent contradiction of being an example of substitution.
to calculate the cost/return/profit in money you have to calculate the EROEI as this will relate to your inputs!
you said it yourself
4 barrel equiv. to make one of oil or whatever you have to make that calculation .....doesn't matter what you say you can not escape the ratio both in terms of depletion and production choices
YOU HAD TO MAKE THE CALCULATION TO MAKE YOUR POINT!
Joined: May 31, 2004 Posts: 920 Location: Brno, Czech rep., EU
Posted: Sat May 07, 2005 5:43 pm Post subject:
I have to agree with CalgaryEng ..
EROEI is not defined properly, and it's possible applications are very limited.
Even if you have clearly defined process, calculating all energy investments is not easy and might not be usefull..
Suppose you have process of manufacturing running and dismantling a wind turbine..
Calculating energy output (usefull for us) is easy, calculating input for manufactoring is not that hard, you can check how much energy intensive is material production, assembling etc. But should you also count in energy costs of growing food for people who are working in this process? If so, should you add costs of producing fertilizers? Even if it's just a crap from animals? Where do you stop?
I think that this concepts make sense only in very elementary processes, and even so, it's applications are limited.. money profit might well make more sense. It represents more correctly what is feasible and what not..
Only problem of economic indicators is, that it's not affected by resource depletion that much (until we start to have troubles extracting resource, or there are limits and demand cannot be met).
Another example:
suppose ethanol or biodiesel production - it's EROEI is often said to be "negative" (ok, lower than 1
But is it?
What do you count as input? Granted we are using some oil to grow the plants, but do we have to? Sun shines for free, so if you dont want to, you dont have to use fertilizers, and you dont have to use mechanization to harvest it. You can also hire people to do it, and those people can be fed by food also produced only using natural grown food. .all energy inputs are 0 so far..
You then have small processing plant that is converting it to biodiesel. Let's suppose the power for this process is again provided by humans (running in a wheel for example) and what happens? You have infinite EROEI source, but you will never make profit and it's not usefull
You can also imagine, that processing plant is powered by solar pannels.
What do you count as energy input then? Usefull that entered the processing, or energy required to manufacture pannels, or the sun's energy impacting pannels?
If you count only energy that entered the process, imagine you are using extremely advanced nanobots. They are doing little usefull work for the processing plant (in energy terms), they are just moving few atoms and rearanging molecules, but they needed HUGE ammounts of energy to create.
Eroei can range from 0 to infinite, and you still know nothing about whether given process is usefull for society or not..
Suppose an apple contain 100 energy units. It is at the top of a tree. It takes 200 energy units to climb the tree. Other food is available at the bottom of the tree (otherwise you would soon be dead). Should you climb the tree? Well, it depends on the value of the apple compared to the value of the food at the bottom. The apple may contain nutrients that are essential to life that are not contained in the food at the bottom. Using 200 energy units to get the apple becomes essential. The fact that EROEI is 0.5 is irrelevant.
Look, if you keep expending "200 energy units," whatever the hell you want to call them, to get 100 in return, then you're going to be dead soon. I'm not fooled by your false analogy: There's not just energy lying around like your "food at the bottom of the tree," which is a sort of trapdoor in your analogy. You're being intellectually unfair.
Once humanity gets to the point of expending more energy to get needed energy, then GAME OVER. You may sit around trying to figure out how many joules can dance on the head of a pin, but I'll continue learning how to manage organic pasture.
Over-intellectualization is just as deadly as ignorance. _________________ "By the time individuals discover that remaining resources will not be adequate for the next generation, the next generation has already been born. " David Price
suppose ethanol or biodiesel production - it's EROEI is often said to be "negative" (ok, lower than 1 Smile
But is it?
What do you count as input? Granted we are using some oil to grow the plants, but do we have to? Sun shines for free, so if you dont want to, you dont have to use fertilizers, and you dont have to use mechanization to harvest it. You can also hire people to do it, and those people can be fed by food also produced only using natural grown food. .all energy inputs are 0 so far..
You then have small processing plant that is converting it to biodiesel. Let's suppose the power for this process is again provided by humans (running in a wheel for example) and what happens? You have infinite EROEI source, but you will never make profit and it's not usefull Smile
Oh my f-ing god, Pollyanna....Do you really think you can maintain the current standard of living this way? Sure--if you have a couple of continents of slaves to capture. _________________ "By the time individuals discover that remaining resources will not be adequate for the next generation, the next generation has already been born. " David Price
Joined: May 31, 2004 Posts: 920 Location: Brno, Czech rep., EU
Posted: Sat May 07, 2005 7:51 pm Post subject:
killJoy - no i'm not.. I'm only agreeing with CalgaryEng .. EROEI as an indicator is simply insuficient and often misleading..
And it's not even possible to calculate it correctly, because it's too vaguely defined.
Thermonuclear explosions have EROEI in the order of millions, and they wont save us, because the energy released is in a completely useless form (unless you wish to drill holes and get rid of some annoying pests).
Process of nitrogen fertilizer production and utilization has EROEI probably between 0 and 0.05, and it's still incredibly usefull and vital process for modern society.. Who cares, that most of energy is lost, if the final product is food you simply NEED, unlike radiation from atomic bombs..
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
News
Discussions
Resources
Members
Forum FAQ
Search
Usergroups
Profile
Log in to check your private messages
Log in
