you start with one unit of crude (in BTU terms) and wind up with .8 units, albiet far more useable ones
No, Jack. The raw material is crude, in this case. The energy input is the cost of producing that one unit of raw material. That energy input has been something like .05, in the past (or lower) and, I believe, is typically more than 0.2, for conventional oil. When refining that raw material into gasoline, a bit more energy input is used, but you'd still end up with most of the raw energy that was produced at the well head. The energy inputs you cited for ethanol are really energy inputs, not the raw material (which is CO2, sunlight and soil). So your simple comparison is not a comparison at all. Kind of like what robert was talking about when he was pointing out the different metrics being used to talk up ethanol.
Isn't the difference between raw materials and energy inputs semantics?
What is the difference between the coal that goes into ethanol and the oil that goes into gasoline?
In either case you start out with one of them (coal or oil) and at the end you don't have them anymore, but you do have a liquid fuel.
I understand and agree that the energy input to crude is something along the lines of the figures you cite. I acknowledged this in my initial comment.
But isn't the same true for coal. The energy input to get the coal is much less than the BTU content. It seems to me that you count one way or other, but make it consistent for both.
Isn't the difference between raw materials and energy inputs semantics?
No, it's not semantics. We are talking about the energy available for us to use. That 1 unit of crude, that you mentioned, is not expended, it's available for use (or 0.8 is available after it's been refined), it wasn't expended. The 1 unit of energy that went into ethanol was expended and no longer available; what we got out was 0.2 units (if the figures are to be believed).
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.
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.
I agree with how you are looking at this, but disagree that the energy content of the raw material is irrelevant. We are on this website because we think oil is running out. If you could substitute corn in the first equation in your comment with something that is abundant and harmless, it would save the world. Unfortunately, corn doesn't meet that requirement.
I agree that corn is probably the worst possible feestock for ethanol. But I was trying to illustrate the 1.2 / 1.0 ethanol EROI (= 1.2) versus the 1.0 / 0.2 gasoline EROI (= 5.0). This I believe is the crux of the debate.
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.
This only makes sense if you subtract the solar energy in the ethanol process from the ethanol equation. In this case, the ethanol process would be extremely energy negative.
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.
The solar energy is not practically limited - the oil is, and the fertilizer necessary to utilize that solar energy is.
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?
"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:
We will have to/be able to cut out a lot of wasteful or luxury energy use. I do think we can live as well or better using less energy than we do now.
Ethanol could account for a very small portion of overall energy use. If oil gave use a 1:10 EROEI, but we had 10% less upply which was met by ethanol at 1:1.2, we would have an overall EROEI of 1:9.2.
Actually we were just using the one BTU of coal to simplify the analysis. In reality, the fuel stock can be broader. You are right in the cast of grain-based ethanol that it is only 20-30% renewable.
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.
Ethanol:
Start with one BTU of coal
End up with 0 units of coal and 1.25 BTUs in the form of ethanol
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.
It really is as simple as that. It needs to be done.
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.
But you're forgetting how valuable moonshine is -- maybe our cars won't run on ethanol, but when we go back to muscle power, farm workers will "run" on liquor from the ethanol plants. Probably be paid with it too, Captain Cook partly paid his men's' wages with booze.
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.
When you disconnect a refinery from the grid and run it on crude/new product alone, then the challenge could be legitimate. Until then, it is hoop jumping.
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.
OK, good idea. Let's give them a $10 million ethanol plant and lets give the wind farm $10 million worth of wind generators. Then we'll start keeping track of EROEI's.
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.
I didn't say I didn't want to do it. I just say treat 'em all equally.
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.
could come from hydropower (which haas its own problems - but is "renewable")
I think it's important to point out that all the fuels we use are renewable. There are two important issues though. One is the quantity of the resource and the second is the rate at which we use that resource. If the resource quantity is way beyond our ability to use it up, in the likely span of the human species, then it is effectively infinite and, provided we don't use up other resources beyond their renewal rate, when harnessing the infinite resource, then we are sustainable (in terms that are meaningful to humans). If we use any resource (either the energy source itself or resources consumed to harness that energy source) beyond its renewal rate then that is not sustainable. That goes for hydro, wind, biomass, etc., just as much as oil (though oils renewal period can be measured in millions of years).
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.
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
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.
All of this discussion of conversion efficiency brings up what I think is the primary source of confusion. Whats being sold to the public is not that ethanol is a better way to convert fossil fuels to liquids. Rather, its that crops can be the energy source.
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.
But ChE 201, where you learn about heat transfer and distillation, can't be ignored.
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.
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.
Thank you for web address. My focus on cellulosic ethanol was not meant to conclude or infer that it's the only chemical path to form ethanol.
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.
The gasification of biomass requires an energy source for start up however the pyrolitic process itself can be self-sustaining meanwhile, landfill gas and MSW biogases can also be used for syngas->ETOH conversion.
Both scenarios eliminate the energy balance problem you highlight.
Tony
What is the difference between the coal that goes into ethanol and the oil that goes into gasoline?
In either case you start out with one of them (coal or oil) and at the end you don't have them anymore, but you do have a liquid fuel.
I understand and agree that the energy input to crude is something along the lines of the figures you cite. I acknowledged this in my initial comment.
But isn't the same true for coal. The energy input to get the coal is much less than the BTU content. It seems to me that you count one way or other, but make it consistent for both.
NO!
It it very precisely stated by sofistek and you just reject it with NO backing argument, hand-waving isn't an argument.
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.