375 comments on The Energy Balance of Ethanol versus Gasoline
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So let's say you expend 1 unit of energy. For oil production, you get, say, 5 units of raw material for producing your gasoline. If those 5 units are converted at 80%, then you end up with 4 units of energy available for every unit of energy expended. With ethanol, the 1 unit of energy expended results in some biomass that is then converted to 1.2 units of available energy. So the available energy with gasoline production is far higher than ethanol (4 units, versus 1.2 units), for the 1 unit of energy expended in producing those fuels.
You can do the same calculations with coal. I think it's only confusing for those who want a different outcome from those calculations.
Tony
I'm sorry if I am seeming oppositional. I don't want to believe one outcome or the other. I have said separately that I do not think corn-based ethanol is viable. I appreciate your patience.
However, I am still not convinced. Here is how I see it (oversimplified):
Ethanol:
Start with one BTU of coal
End up with 0 units of coal and 1.25 BTUs in the form of ethanol
Gasoline:
Start with one BTU of oil
End up with 0 BTUs of oil and .8 BTUs in the form of gasoline
I still see the distiction between converted and consumed as meaningless. Energy can not be created or destroyed, so really both are converted.
Actually, I also agree that this conversation is a side issue and not that important. I think the process of growing corn and running an ethanol refinery is more destructive and expensive than running a refinery. Again, corn ethanol is not worth the effort and the oil to gas / energy to ethanol comparison is trivia rather than analysis. However, I do not think you can say Robert is right and other are wrong.
If the process produced more energy (like sugar cane) or used less resources (water, land, etc), ethanol can make sense.
- Corn: You consume 1.0 BTU of coal to convert one unit of raw material (corn) into 1.2 BTU of ethanol.
- Crude: You consume 0.2 BTU of coal to convert one unit of raw material (crude) into 1.0 BTU of gasoline.
IMHO, the energy content of the raw material is irrelevant.Jack
Think of the problem as follows.
1 bushel of corn contains X Kcal of raw energy. Produced from an input of sunlight, water, fertilizers, natural gas (or coal,) inputs from liquid fuels that go into cultivation and harvesting equipment. Of that raw energy (corn energy + other input energy) only E% gets converted to ethanol.
This E% is what you should be comparing to the 80% figure that is quoted for gasoline.
The solar energy in ethanol and the original energy content of the crude oil are 'found' energy sources and aren't properly included in the equation.
If you want to speak of closed systems and account for all externalities, then every single chemical process has a negative ROIE.
Vinod is arguing that taking all our fossil fuels, putting it 1 BTU at a time into the "black box farm" equipment + fertilizer, and getting 1.3 BTU of ethanol out, is better than taking 1 BTU of oil, putting it into a "black box refinery", and getting 0.8 BTU of gasoline out. I think I'd agree with him on that narrow point, IF it's completely sustainable, esp because it's more useful fuel than, for example, coal.
The reality is that
A) Capacity is almost as important as efficiency. If your average farmer can make an energy profit, but isn't making enough total to drive to walmart every weekend and buy groceries, you have a problem. Likewise, yields are low enough that we are highly farmland limited, meaning that we can't really offset a significant portion of the country on corn ethanol, no matter if someone works out the microeconomics (which I think Vinod is working on, entirely dependant on government subsidies) or the energy economics.
B) 1.3 ROI is horribly difficult to work with. Right now we have an oil infrastructure that supplies hundreds of thousands of people with margins on which to live, and those margins are taken out of a 10-20x energy balance. Do you think our current version of society can survive if it requires 30x as many people to be working the mines or the fields?
No. But two points:
The thing that strikes me here is starting with one BTU of coal. As ever, we're still depleting a fossil resource. Where is the renewability factor?
Again, with sugar cane-based ethanol, the non-renewable inputs are far smaller (10-15%) and could come from hydropower (which haas its own problems - but is "renewable"). Given this ratio the ethanol is far closer to renewable and the impact on the climate is far less.
I think I would be more comfortable with:
Start with one BTU of ethanol
End up with 0 units of ethanol and 1.25 BTUs in the form of ethanol
It's the same as RR's challenge to run an ethanol plant on its own energy stream. (like we routinely do in petroleum refineries). I mean this literally: run the farm equipment on ethanol, the transport trucks (to/from) the distillery on ethanol and the distillery on ethanol. Test a closed loop system.... measure everything... the irrigation water volume, the fertilizers, all ethanol inputs to equipment and distillery operations.
No sarcasm is intended here... this seems like a terrific project for the University of Iowa. Let's prove out the facts on the ground.
Investing in ethanol is investing in politics (and subsidies). Right now it is rewarding venture capitalists, farmers, and politicians at the expense of precious fertile land and water resources in an attempt for continuing our "nonnegotiable" lifestyle. A big issue in addition to debating EROI with these guys is how the time, resources, and government money could be better spent. One of the big absurdities of ethanol is its temporary nature. Each year the corn needs to be grown and transported and processed under a different set of circumstances (drought conditions, storms, etc.) Let's compare that to spending our efforts on expanding rail in this country, and wind and solar into our electrical grid. Those efforts would be much more long-lasting as well as meeting future needs in our "nonnegotiable" powerdown. Ethanol is leading us farther down the road to industrialized farming and an inability to feed ourselves if and when we face oil shocks. These ethanol supporters assignment should be to read "Omnivore's Dilemna". It is my own belief that these ethanol plants won't be operating in the near future because of increasing cost of fossil fuel inputs, constrained government budgets limiting subsidies, GW causing increased crop failures and increasing public acceptance of the fallicies of ethanol. As soon as politicians realize that more votes can be gained by opposing ethanol, their story will change. Robert, keep up the good work and thanks for all that you do.
The production of green fuels benefits each and every one of us, not just venture capitalists, farmers and politicians.
Moreover, as the US ethanol industry is in its infancy, I suggest that it will be around for some time to come as new technologies, best practices and 2nd generation production paths begin to take hold -elements all- of a rapidly expanding and exciting sector whose actors are well aware of the hurdles in front of them.
It's naive to assume that ingenuity does not have a place in the grain->ethanol world especially as ethanol producers such as E3 and others are right now proving otherwise by implementing cogen energy streams wherever possible.
Or build a windmill using just wind. Try that!
Actually in the case of ethanol it can be done, it is just impractical and expensive to create a custom, parallel infrastructure.
I could come close with the industrial structure of Iceland.
Electric arc smelting today creates ferro-silicon alloys and could be used for simpler alloys. Massive sources of aluminum (Al blades instead of fiberglass). Towers from Al.
Recycled copper from autos melted down by electric arc.
Ammonia plant closed down recently, could be used for many organic chemicals with modest changes.
Iceland has superb wind resources, but better hydro & geothermal resources.
But seriously, why do you feel that the closed loop operation "has to be done" for ethanol, but not for other renewable energy energy sources?
I just proposed that we compare wind to ethanol.
Maybe you should contribute the $100 million
Actually, if an existing Iowa ethanol plant could be used, as well as existing wind generators already near Ames, and EROEI data were collected for 1 year's time by Iowa State, it could and probably would end up saving taxpayers millions in ended ethanol subsidies, both on a federal and a state level.
Why do you not want to see this done??
If Iowa or any other state would retrofit farm equipment and tankers to run on pure ethanol and produced all of the fertilizer from ethanol and waste, it would improve the EROEI greatly by subtracting from the numerator and denominator. Building the hardware for a windmill or distillery is going to be tough.
I think what you would find is that ethanol does have a positive EROEI, but that wind is much better. If the analysis also included other externalities, such as water use and environmental/climate impact, the gap would be greater. If you were to extend the comparison to end use at the cars tires, even better.
I am pro-wind and unenthusiastic at best about corn-based ethanol. I just want to be fair.
So if you are going to do it, let me know. I'll even contribute.
A combine can cost a farmer $250,000 and not even include the header(the big part in front).
Most all equipment runs on diesel. Long life is one reason. They are built tough. Storage of fuel is not a big problem. It also used to be cheaper than gas.
Asking them to shuck all their diesel equipment and invest in new E85 or ethanol running engines is just not going to happen IMO. At least not in any short time frame.
Refit? I doubt that diesel engines would be 'convertible'. The injection pumps and the compression ratios would likely not be prone to such modifications. Gas in a diesel engine spells destruction.
Farmers run on a very tight budget. Sometimes a crop year is just break even and I am not talking 'corporate farms' nor am I talking 'family farms'.
I am talking the 'operator' who owns manybe 200 - 500 acres and rents or sharecrops another 1500-2000. This is enough acreage (in the midwest) to give him a reasonable ability to make some large expenditures and expect a reasonable return.
They tend to always be in debt also. Without the lender signing off on such purchases that also will not happen.
The deep south,plains and other areas may differ.
Also I do not see them jumping thru hoops to trash all their seeders and combines/headers just to go to 'switch grass' or some other exotic. They have been into corn,wheat and soybeans for a long enough period that they can be sucessful with a background of knowledge. Throw milo in as well.
Most here who speak of 'we'll grow sugar cane or whatever' just don't seem to grasp the real concepts of agriculture/farming. Like they can and will just switchover with no problems.
Proposing ethanol and assuming that farmers would just switch over is not a viable assumption IMO. I think they would just stick with what they have or sell out.
I see very few of the younger generation out here in the fields. Most who try it don't care for it. The ones that are hired to do the work are your basic 'day labor' types. They do not understand much beyond what they are told to do. Putting them on a $80,000 tractor is senseless in my opinion but thats exactly what happens.Myself I wouldn't trust most on a go-cart.
Late model tractors and other equipment is quite hi-tech these days. Lots of sensor based equipment. Lots of controls and actuators that are driven by embedded modules.
Try explaining then how to pull up the DTC's and understand what they say is nigh impossible. They use these men/boys because they can't afford to pay much in wages and thats all thats available.
In fact, hydro is limited and its use already has knock on effects that were not envisaged. All energy sources are limited, because it takes limited resources to harness them.
The key is to get to a state where we are using resources sustainably (or effectively sustainably). Let's not distinguish between renewable and so-called non-renewable resources, since renewable can become non-renewable if consumed too rapidly.
Tony
Start with one BTU of coal
End up with 0 units of coal and 1.25 BTUs in the form of ethanol
Gasoline:
Start with one BTU of oil
End up with 0 BTUs of oil and .8 BTUs in the form of gasoline
In chemical engineering terms, your numbers are correct, but meaningless. Those numbers are apples and oranges; they represent two different energy balances. The ethanol numbers are an approximation of the total overall energy balance for ethanol production, including farming, transportation, etc. The gasoline numbers are a refinery energy balance. Expand the gasoline energy balance to be on the same basis as the ethanol one and there is no 1 BTU of oil input; there is .2 BTU of energy input to get the oil. The oil, unlike the coal, no longer crosses the boundary of the energy balance.
Setting correct boundaries for mass and energy balances is ChemE 101. I find I agree with RR; to get something so elementary wrong is deliberate obfuscation.
I know oil has a positive EROI because there is gas at the gas station. I'm with Will upthread. Lets see it done completely independent of any other energy source.
Call it the original car .
Now get to 600 million descendants with corn. It's just preposterous.
Take a barrel or a BTU or crude oil, use a fraction of it to heat it up and it will fractionate for you. No simple McCabe-Theile diagram, to be sure, but the principles are still the same. For many light and medium crudes you end up with a straight-run gasoline/naptha cut that is a blend of alkanes and aromatics. It does not burn well in ICE's except at high altitude where lower octane ratings are acceptable, but with a little more processing (energy), you get mixtures that are acceptable as gasoline with the proper vapor pressure and and resistance to predetonation (knock).
Moreover, there are many products you get from the processing and all can be derived from the original heat content of that barrel (or BTU) of crude (I know this is a simplification of the many refining process steps and internal loops within a refinery, but it can be argued that the energy required to make all the refineries products is self-contained within the feed itself. On this point, the fact that any products actually leave as a result of the crude feed is evidence of the "relatively small" amount of energy required to refine oil to useful products including gasoline).
What is missing from this ethanol discussion, however, is the energy content of the stuff (cellulose, corn, whatever) used to derive ethanol as part of the original heat input. To be "competitive" with crude oil used in making a gasoline product, biomass derived ethanol (including corn) would have to derive all the energy for processing from the biomass itself. This has been a great sticking point for ethanol production for many years. Adding coal (and then forgetting the required mass and heat content of the biomass) leads to the incorrect conclusion that you and others have summarized....use a BTU of coal get 1.25 BTU of ethanol.
CHE 101 should tell you there is something fundamentally wrong with that part of the energy equation, particularly since you are totally relying on a chemical reaction to derive ethanol. A CHE 300 course (or higher) would tell you why that is so (thermodynamics and PChem).
Remember with most conventional oil, the gasoline fraction is already there "dissolved" in the mixture. We might use cracking and reforming to derive a larger fraction of gasoline from the original crude, but the gasoline cut is almost always "there" and all the energy required to derive it is there also.
Corn has an advantage over most cellulosic biomass in that it has containers sugars that are amenable to fermentation processes to create ethanol. Note that this requires a "weak mash" to have the yeast fermentation process work with subsequent separation/distillation required to bring the ethanol up to usable strength. Also not that about half of your mass (and energy) leaves as carbon dioxide.
Cellulosic ethanol has other added disadvantages. First, most biomass under consideration (on a dry weight basis) contains only about half that weight as cellulose. The other 50% is split pretty evenly between hemi-cellulose and lignins. About half of your available energy for chemical conversion is "lost" right here in the separation of cellulose from the dry biomass. You can concentrate and burn most of those lignin/hemicellulose based materials to provide energy for the process (much as an acid sulfite pulp mill does, and other pulping processes which have their own chemical recovery processes).
The trick in recovering the cellulose from the biomass is not to dissolve the cellulose into an unrecoverable form. However, once you've separated the cellulose, it's easy to see (from it's chemical structure) why it prefers to degrade to methanol. The steps of hydrolyzing the cellulose to glucose and then fermenting to ethanol are the next hurtles to get over. Just as with corn ethanol, even if your conversion of cellulose is very efficient, you have the same loss of mass/energy associated with the carbon dioxide fermentationation process.
The point is that before you've gotten very far, nearly 75% of your energy potential (as ethanol) is gone. This does not include any additional steps such as distilling/concentration that are futher energy drains on the original heat content of the raw material. So, if you've consumed 0.75 BTU of the original biomass content just to get to 0.25 BTU of ethanol, there is no easy way to 1.25 BTU out of the process alluded to in several posts throughout this thread. Rather, it might take you 5 BTU of biomass and 1 BTU of coal to produce 1.25 BTU of ethanol.
You cannot forget what already crossed that imaginary boundary to act as the source of ethanol when you draw the energy box. And this does not consider any of the energy required to get it there in the first place.
Besides, if the numbers were that good, we'd skip this biomass stuff and just go to direct conversion of coal to ethanol and figure out the energybalance later.
One can develop an energy cycle not dependent upon coal but it requires a substantially greater amount of biomass AND a certain amount of that biomass bypassing the ethanol process just for it's energy content.
Please feel free to visit www.syntecbiofuel.com.
Here you will learn that there are many ways to produce ethanol and more than one way to make cellulosic ethanol.
Cheers.
I suggest some references to see that another feedstock are possible to make ethanol, for example :
http://www.bluefireethanol.com/technology.htm
http://www.brienergy.com/pages/resources01.html
I can suggest a lot of projects which are studying celluslosic ethanol from wastes if you are interested.
Xatt from Barcelona
As mentioned in another reply, my comment was not meant to suggest that there are not other routes. Only that "gasoline" already exists as a cut from the distillation of crude oil.
In the Four Corners region of New Mexico, you can pump oil out of the ground, run it through a distillation column, take the gasoline "cut", distill it a little more to clean it up, and put it into your gas tank and it will run most spark ignited internal combustion engines (ICEs). The octane rating sucks, but at 6,000+ feet above sea level anything above an octane rating of 78 is pretty much a waste (unless you really do have a gasoline guzzling high performance engine). You couldn't burn it sea-level.
The Blue Fire link, very much mirrors the description I gave. Note that converting the cellolose to glucose is one additional step beyond what is used in acid-sulfite pulp and paper mills. If you've ever used vanillin (artificial vanilla), one source is the acid sulfite digestion of cellulosic materials that ultimately ends up as paper and other cellulose materials. The chemistry of cellulose -> glucose -> EtOH and CO2 is fairly basic. Getting it to go that way with acceptable yields is the issue.
As for the other "sources" for conversion, as mentioned elsewhere, you eventually have to end up with enough energy and the right mass ratio to produce a liquid that is 52.17% carbon, 13.04% hydrogen, and 34.79% oxygen. Otherwise you do not have EtOH.
My point was that "gasoline" already exists in solution with crude oil and it's a matter of distillation to recover at least the first cut. A small portion of the heat content of the oil is all that's needed to start and sustain the process. Additional chemical processing steps (that require more energy) can be used to increase the yield of components that make up gasoline.
One cannot argue that "ethanol" already exists in solution with any of these other feedstocks (not even crude oil). You might have carbon, hydrogen, and oxygen to be able to tease out ethanol through a number of chemical reaction steps. As for cellulose, when one looks at the structure, it's pretty easy to see why "wood alcohol" is a result of fermentation of cellulosic materials.
This does not deny that there are other approaches such as gasification and the various synthesis reactions from "simpler" compounds that can be put forward. In the end, you must balance the mass and energy equations so that you end up with a liquid that is 52.17% carbon, 13.04% hydrogen, and 34.79% oxygen.
But to throw in one pound of dry, ash-free, sulfur and nitrogen-free coal with a HHV of 14925 BTUs and have it yield 18,656 BTU (or the equivalent of 1.42 pounds of ethanol) as suggested by the 1 BTU of coal=1.25 BTU of ethanol just does not work.
In theory, a typical low sulfur coal (after processing away sulfur, nitrogen and ash) would have enough oxygen (the limiting factor) to produce about 0.3 pounds of EtOH. Obviously you could use the left over carbon and hydrogen in a standard reduction reaction with water to produce syngas for addition reaction. However, this is mass (and energy) that the 1 BTU coal = 1.25 BTU of EtOH, mentioned above,ignores.
Gasifying biomass for syngas puts you in a better chemical balance for EtOH production (C/H/O ratios) but it does not solve the energy balance problem (since you gasification step requires energy from somewhere) and the demand that various shift reactions require to work properly. For example, you would not want to produce acetaldehyde instead of EtOH.
It may be debatable whether it's "better livng" or not, but it certainly is and would be living through chemistry.
Both scenarios eliminate the energy balance problem you highlight.
Still, one must also balance the chemical equations and neither of us can do anything to change that.
As for landfill gas, it contains (as do most anaerobically derived gases) a signifcant proportion of CO2 (we typically see around 40% from our landfills and various other anaerobic digesters). And the system(s) to extract the LFG must be designed to accomodate varying flow rates over the life of the landfill cells while maintaining anaerobic conditions within the cell. Separating the CO2 from the methane (and other contaminants) is an important step for any further shift reaction that may be contemplated. Many the LFG projects projects use the gas as fuel for something else (say to "run" a gasifier).
There is one anaerobic digester project I am familiar with that is using the biogas (from pig manure) to create methanol. It's working (not necessarily working well) and the methanol is used elsewhere in the production of a biodiesel product.
As for MSW gasification, we could do that with the same limitations that current MSW mass-burn or RDF facilties face to get the "fuel" to remain in a satisfactory operating range. The second law of thermodynamics gives us some insight into the energy costs associated with that "fuel mixture."
Bu, at fact making ethanol from wastes (they could be MSW, which are thrown to a landfill, or crop which are burned or thrown) is to live in a bit more sustainable world. So, if the process is ecomically viable (we must not forget that money move the world), Could the energetic efficiency be our first objective? In the energetic balance, BTU inputs of biomass are count, if it is thrown to the landfill?
Technological progress and efficiency have mostly come about because we have had an energy reserve to make the next transition. Unfortunately, we don't often see the the initial energy costs associated with that transition. An example of this is in the PV solar cell arena. But that's a whole separate discussion.
Much of the point of the discussion, of course, is how self-sustainable these alternative processes really are as an alternative to oil. If biomass or other derivatives of past wastes really had to sustain themselves independent of other finite resources, we might find that it realy does take 5-10 BTU (or KJ) of biomass to create 1 BTU (or KJ) of usable ETOH. That a portion is lost as a result of chemical reactions required to get a usable product and/or as energy to drive the process.
In that case, you must have enough biomass and enough land to keep producing biomass at an adequate rate. We might find this tradeoff acceptable. But the correct way of looking at it is that there is, for example, 6 KJ of energy total and it's going to take 5 of them to leave us with 1 KJ to do something else.
What you are doing is moving the starting point to the refinery, where 1 BTU in gets you 0.8 BTUs out, but that's only the back-end of the calculation and so not a true comparison with the energy return on ethanol production. Now, start at the beginning with ethanol - no plant, no energy expended. At the end of the chain (after planting the seed, tending the crop, harvesting and converting), you get 1.25 BTUs of ethanol but have expended 1 BTU of energy getting there (if Argonne's figures are accurate). Starting at the beginning with oil, you end up with 4 BTUs (or more, for most conventional oil) for that 1 BTU expended.
Is that any clearer, Jack? As RR said, some people compare apples and oranges, which is what you've been doing in your posts. When you compare apples and apples, the picture (hopefully) becomes clear.
Tony
your converted and consumed argument is false
arguing that all energy is converted is the same as consumed is wrong
it is more helpful to think in terms that the resulting energy in the gasoline remains "untouched" in a "potential state" throughout the process
your use of energy is never lost and appeal to the laws of thermodynamics is a misunderstanding on the nature of stored energy available in the present .. not to mention a misuse of terms.
if your reasoning was correct no process of acquiring energy density for any end user use would be inefficient in practical terms
HTH
Boris
London
From the site
http://bioenergy.ornl.gov/papers/misc/biochar_factsheet.html
We see that oil has approximately 2.5x the raw energy content of switchgrass or sugarcane. So if we 'find' a tonne of oil, ignoring the cost of discovery and extraction for the moment, we will be 2.5 times better off at this stage of the energy 'creation' process than if we 'find' a tonne of switchgrass. Then, for each 'finding' process we need to calculate the energy input. For oil it is primarily exploration and extraction (yes, getting higher all the time but try to grasp the EROEI of an oil well spouting 5000 bbl/day of crude oil). For cellulosic biomass it is planting, irrigation, harvesting. Only then do you get to the refining step that is being talked about with the oil/gasoline and corn/ethanol. I haven't done figures on these, but I strongly suspect that by the time you get to the refining step, oil is more than 2.5x ahead of the biomass in terms of energy content and that the ratio becomes even more skewed after that.
It is just hard for me to understand how anyone can conceive the notion that energy 'creation' via ethanol can be more efficient than energy 'creation' via crude oil. Unfortunately it is a dead horse that some influential people seem to think is still alive and kicking.
Please see my post above for Trooper RE: there are many ways to make ethanol and more than one way to make cellulosic ethanol.
Situation before, must assumed equal for both cases.
One BTU Biomass
One BTU crude in ground
One BTU Coal in ground
Zero BTU transportation fuel.
Raw energy before: 3 BTU
--------------------
Ethanol, after:
Zero BTU Biomass
One BTU crude in ground
Zero BTU coal in ground
1.25 BTU ethanol in car
Raw energy after: 2.25 BTU. Processing loss = 0.75 BTU
Fuel gain: 1.25 BTU
Processing loss / Fuel gain = 0.75 / 1.25 BTU = 0.5
----------------------------
Gasoline, After:
One BTU Biomass
Zero BTU crude in ground
One BTU coal in ground
0.8 BTU gasoline in car
Raw energy After: 2.8 BTU. Processing loss 0.2 BTU
Processing loss / Fuel gain = 0.2 / 0.8 = 0.25
I suspect that the human labor in making one BTU of coal plus one BTU of biomass is larger than that making one BTU of gasoline.
There is an energy disadvantage for ethanol, except for the critical fact that we will be depleting crude faster than coal, and the cost in energy and labor to extract the next barrel of crude will be increasing with time.
Ethanol:
Start with one BTU of coal
End up with 0 units of coal and 1.25 BTUs in the form of ethanol
Gasoline:
Start with one BTU of oil
End up with 0 BTUs of oil and .8 BTUs in the form of gasoline"
Jack;
Here's the problem I see with your summary above. (regardless of what form the original btu's are coming in)
That One, original BTU of 'fuel' is not heading into the refinery, but running the Oilfields, at which point, it gives us some 10 BTUs of oil from the ground (assuming the 10:1 EROEI of crudeoil production), THEN, you take that to the refinery with it's 80% yield, and end up with 8:1, as opposed to Ethanol's 1.2:1. This is why the '.8 efficiency' of the gas refining process cannot be evaluated without the original input of drilling, pumping and shipping the crude, which carries all the 'energy profits' of the deal.
(I hope I got the numbers reasonably close, but I think the concept is sound)
Bob Fiske
But why does an oil refinery have a greater claim on raw materials than an ethanol refinery? Why does one use "original energy" and the other doesn't?
At the end of the day, I think this discussion is silly and close to meaningless. Trying to compare these things head to head requires so many simplifying assumptions that you can steer it where ever you want. I see Robert's arguument with Wang, etc. as a fight over whose assumptions are right. I see why Wang backed out. I am sure he has better things to do.
I don't think corn-based ethanol is a viable solution. I have mentioned elsewhere that it is a pure subsidy play and folly for the US.
By the way, the World Resources Institute/German government study below lays this out a bit in terms of energy efficiency and energy balance (see page 16)
http://www.worldwatch.org/node/4078
Again, this discussion is energy balance trivia and we are not getting anywhere, so I will sign off on this topic now. Other parts of this thread are more productive.
That's where you are wrong. It's a fight over whether I will allow the country to be led down the wrong path based on false arguments, when we should be directing our resources elsewhere. To assume this is just some turf war tells me you don't quite get it.
However the fixation over whether one method of calculating an equation is gospel and the other a fraud is certainly turf war like. The emotional arguments against me in this thread underline that.
People rage against ethanol subsidies, are fine when they are directed towards wind or solar. They insist that ethanol plants must be run as a closed loop with ethanol alone, but don't apply that to any other technology. Have you ever heard someone say a solar cell factory must only use solar energy as an input? They say I am willfully distorting facts to support corn-based ethanol, when I have clearly stated over and over that I do not.
Robert, I commend you for you efforts to bring light to the ethanol debate. However, I wish you were as rigorous with your facts as you demand others to be with theirs. But if your war is righteous, this little battle is trivial at best and a losing distraction in reality. Wang may be midleading the public by drawing their attention to a meaningless statistic. In a multi-step process, it doesn't avail us to look only at one step. However, I do not think that on this one minute, trivial issue he is wrong.
Wang is an ethanol boosetr, Pimentel an enemy. But let's listen to their arguments and not dismiss one or the other on anything but the facts.
A specific example is always preferable to painting with a broad brush.
However the fixation over whether one method of calculating an equation is gospel and the other a fraud is certainly turf war like.
That's not it. It is about rebutting a specific argument that ethanol proponents often use. And the incredible part is that some people here still don't seem to get it, although most do. It is not about calculating via one method versus another. It is about whether it is more efficient to use BTUs to produce gasoline or ethanol. That's a no-brainer, it's not even close, and yet ethanol proponents claim exactly the opposite of reality.
In calculating Return on Investment in finance, practitioners often disaggregate the process using a Dupont analysis. In that case also, one could point to a single ratio out of five and claim that it shows a business is profitable. For example a company with huge debt would have a very high financial leverage and on this measure alone could look better than another company.
In reality, there are problems associated with high debt levels and debt alone does not a business make. This is the error that I see Wang committing. I think his point is useful, but it does not justify grain-based ethanol production.
I regret getting involved in this discussion, but I am about 70% as stubborn as you are and so neither of us can withdraw. In the greater scheme of things, I don't think we disagree on any of the crucial elements of the merits of grain-based ethanol.
I have pointed this out on numerous occasions.
Insisting that your method of calculating it is inviolable and theirs worthless is a distraction.
It's not worthless, if comparing apples to oranges is your thing. I prefer my metrics to be consistent. In your analogy on finance, I have no problem with that if we compare the next business in exactly the same manner. The problem comes when we compare Business A with one ratio and Business B with another. It's like looking at the gross for one business, and claiming that since it's higher than the net for the second busines, that the first business is better. There's your relevant analogy.
They start with a post production energy source be it crude oil, coal, or natural gas and wind up with a liquid fuel, ethanol or gasoline.
The apples and oranges aspects I see are that coal and NG are useful as they are and crude oil is not. Crude needs to be refined to be useful while coal and NG don't. Also natural gas has actually already undergone some refining.
Again, I don't think you are wrong in pointing out that this metric on its own does not mean much. However, it is a legitimate way of showing that conversions of energy to other forms has costs.
On its own, a 1:1.2 energy balance for ethanol is not a death sentence. The fact that it has such a high cost that is needs to be permanently subsidized and has so many damaging externalities is.
Reading what you wrote and trying to understand what you were meaning and assuming you were able to understand some of the scientific argument being talked here, I came up with an idea.
I think the main problem is only a pedagogy problem, I do think that if you are having some difficulties in understanding what we try to explain to you, there can be only 2 explanations.
- You are not able to understand the difference in metrics.
- We are not able to explain to you and to others in a meaningful way the metrics.
Let's assume that we are just too bad pedagogue and that we need to put it more elegantly.Here is a graph of the yield of ethanol vs the yield of gasoline.
Notice the use of the word energy, I did it on purpose so to not let you mislead by energy container (in the form of ethanol, coal, oil, etc).
What the ethanol is made from and what kind of energy is used is irrelevant here. Here I assume that the eroei is positive.
For the ethanol, we spend 1 BTU to get back 1,23 BTU. Efficiency in the process is irrelevant. Notice here that the increase in BTU available need to take into account the left over that will be used as feed for cattle (hog can't digest it). That part of the equation is available for the cattle but certainly not for you car :).
Because you love so much the 80% efficiency, I have put were it does apply in the oil to gasoline process. It applies when you are refining the crude to gasoline.
Heading out has writen a lot about refining processes and how some of the oil extracted is used in the process to actualy transform the crude into different usable products. Notice that crude not only produce gasoline but also a slew of products.
The laws of thermodynamics also tell us that no process is more than 100% efficient, heck a whole lot are less than 80%.
I realy do hope that this little figure can remove much of the mysteries in the different argument debated here.
For ethanol, you are just looking at the refining stage, while for oil, you are combining two stages: production and refining.
This explanation seems to be the clearest one.
http://www.theoildrum.com/story/2006/8/25/221617/881#236
I think the problem is:
3. The metrics are inconsistent (or at least the processes aren't parallel, so that what you are comparing is two different things)
Energy Return On Energy Invested.
It is not a mysterious or a magical thing. It's only a concept of physics. Physics dont care about boundaries that you put artificialy. When you look at the sytem, you have to look it at whole.
For ethanol, I do include the farming and the capital cost.
You do have to grow any kind of biomass.
You also have to build plants, use machinery (otherwire used for something else) thus the capital cost. Building machinery and plants use energy like any process use energy.
Then you take the biomass and transform it into ethanol, using heat produced either by coal or natural gas.
Energy invested is the sum of :
farming energy requierements + capital + distillation
Energy return is the sum of :
ethanol + distiller grain
For making gasoline, you do know that it takes crude oil? Crude oil is already formed, was formed millions years ago. We are mining this form of energy. We do not produce crude oil. Think about it, no one produce oil. We only extract it.
You then have to take into account the pumping and transport of crude up to a refinery. Then you use some of the energy content available in the crude to power the process.
Energy invested is the sum of :
Finding + extracting + transporting + refining + distributing
Energy return is the sum of :
energy content of all petroleum product produced.
That's why I made you this graph, so you could understand that
EROEI is not efficiency
Like speed is not acceleration. Like time is not a distance.
Because a small background in science is needed to talk about scientific issue, I assume that you are able to notice the difference every one tries to teach you in this thread.
What in those fairly easy concept of eroei you do not understand. Please forget about the ethanol issue, I want to know what could make you understand the difference between efficiency and EROEI.
Can you help me making you this clearer?
"OK, so I have 100 BTUs of oil. I divide it into 2 lots of 50 BTUs.
In the first case I refine it to gasoline and end up with 40 BTUs of gasoline.
In the second case I use it to make fertilzers, pesticides, diesel for the tractor, etc, grow some sugar crop, ferment it, distill it and end up with 67.5 BTUs of ethanol.
What am I missing here? "
It is not a matter of science. It is logic and economics. You have resources in the form of coal, oil, natural gas and biomass. You want to convert them to useful products.
Try to keep them in these categories and maybe you will be able to understand.
It is flawed from the start.
Go see the reply.
That is the most you can argue for. Large amounts of ethanol can't be produced without fossil fuels, but large amounts of gasoline can be produced without ethanol. In this regard, ethanol is a loser, as well as contributing to damaging crop land and depleting fresh water.
If you don't support ethanol, then why continue with the false arguments that you have? The valid comparison is full lifecycle comparison, not comparing partial lifecycle with full lifecycle. And the lifecycle should also be practical (i.e. all of the fossil fuels could not practically be converted to ethanol).
Tony
I refer you to Vinod Khosla's text which you can find there. Here you can read about USA resources of biomass.
Xatt
Tony
Actually, his analysis was correct. He considered the BTU inputs and outputs for the entire process. The level of confusion over this issue has been surprising to me. The problem is straightforward.
I can treat BTUs as an investment. Where can I invest my BTUs so that I end up with the highest BTU return? If I invest 1 into ethanol production, I end up with 1.3 BTUs. If I invest the BTU into oil and gas, I end up with 4-5 BTUs of gasoline, diesel, etc.
Or, let's say my objective is to make 1 BTU of liquid fuel. Will I burn up more fossil fuel energy in making ethanol, or in making gasoline? Again, I will burn up 3-4 times the fossil fuel energy in making 1 net BTU of ethanol as opposed to 1 net BTU of gasoline.
That's it for my contribution today. This consumed far too much of my day yesterday, and I am working 12 hour days this week as it is.
I will have to come with a better graphic that could show complete process (somewhat complete) so the lay man can understand it easily.
Thanks for the commentary :)
The energy balances of wind and solar far exceed that of ethanol. Plus, as far as I know, the government wind subsidy has had to have been renewed yearly since its inception, not allowing wind development companies long range planning benefits.
In Brazil, ethanol operated with minimal government support and is unsubsidized.
I would gladly support a shift that would provide balanced subsidies to all technologies (partially as a carbon tax) that would provide an equal footing for all. I suspect in this context grain-based ethanol would not thrive, but sugar would.
I applaud your stance on showing the truth.
As a Chem Engr, I am appalled that they are trying to portray those number jumbles as science.
It is a sleigh of hand trick that any 19 yr old engineering student should be able to catch.
The sad thing is that I fear that 99% of the non-technical community will only hear "Ethanol will save the day. The fuel prices will be back to 1998 levels soon enough."
I'm not sure what you mean by this. What claim? The energy inputs required in getting oil from the ground to your tank as gasoline are economical simply because of the great positive ratio (once far greater) of Energy gained from pumping it out of the ground. The costs of pumping and refining it are not yet bad enough to make the process obsolete. It sure sounds like Ethanol (from Corn) is so marginally positive as to be unworthwhile.
What is the Original Energy?
I don't count the Rain or Sunlight that fuels the Corn's growth, any more than I count the years, pressure or heat that may have been responsible for making that hi-protien crude. But for both processes, I think we should count all that we have to expend to get either one out of the ground and into the tank. Unless you mean by original energy that Ethanol is only considered justified if it can be made with more ethanol, and not a petrol byproduct..
Sorry if you feel like the target today, Jack. I don't agree with some of your position on this, but I didn't write anything intending sarcasm or personal attacks. Hope none of it came off that way. I appreciate your standing your ground, and I know you're only here like any of us, trying to figure out where to go with a huge set of challenges.
Regards,
Bob Fiske
You say "The energy inputs required in getting oil from the ground to your tank as gasoline are economical simply because of the great positive ratio (once far greater) of Energy gained from pumping it out of the ground."
Couldn't you also say that "The energy inputs required in getting <<coal, natural gas and biomass>> from the ground to your tank as << a gasoline substitute>> are economical simply because of the great positive ratio (once far greater) of Energy gained from <<digging and>> pumping it out of the ground."?
If we were comparing CTL to oil production, surely you would start with both in the ground. My claim is that this has to apply equally to all processes including ethanol production.
However, I admit that you can no longer reasonably call the process "renewable" and perhaps it should not be called grain-based, but rather grain, coal and natural gas based ethanol production.
Hi Jack;
I do agree that the energy benefits of the oil's extraction from the ground count for both if they count for either. I guess I see ethanol as simply 'making Toast by retoasting toast', instead of making it from bread. In other words, the crude is already getting refined into transp fuels to run the farms, the NG is already usable in its extracted state as a fuel source before you apply it to this additional process. The 1.3:1 margin, (if it is that much) would be great on my MoneyMarket account, but it is hardly enough 'value added' to justify this elaborate process, only to end up at about where you were beforehand. I don't think it works to look at that pinch of positive EROEI in comparison to interest or investment yields. Energy can be compared in some ways to money, but I don't think that comparison works.
It's not like you're making $130/week and your expenses are the $100, the last $30 being available for savings or reinvestment. It's more as if it costs you that $100 just to have that job (your commute?).. and the rest is what you have to live on. It's the net energy profit that makes it worthwhile or not.. the fuel consumed to get it there is just 'the cost of doing business'
Food energy has a pretty marginal EROEI, but the process of working to get it is also beneficial to People and Animals. Our bodies need to do that work in one form or another to stay healthy, and the natural systems have developed to maximize the work we get out of every calorie.
http://www.theoildrum.com/story/2006/8/25/221617/881#236