Surely you have heard the claim. Proponents of ethanol will claim that it takes less fossil fuels to produce a BTU of ethanol than to produce a BTU of gasoline. Here is the claim from a Minnesota Department of Agriculture site (1):
A United States Department of Agriculture (USDA), Economic Research Service Report number 814 titled “Estimating The Net Energy Balance Of Corn Ethanol: An Update” was published in July of 2002. The Conclusion states in part: “Corn ethanol is energy efficient, as indicated by an energy ratio of 1.34; that is, for every Btu dedicated to producing ethanol, there is a 34-percent energy gain.” A similar study done in 1995 indicated only a 1.24 energy ratio.
The concept of “input efficiencies for fossil energy sources” was introduced as a component of the study. This was meant to account for the fossil energy used to extract, transport and manufacture the raw material (crude oil) into the final energy product (gasoline). According to the study, gasoline has an energy ratio of 0.805. In other words, for every unit of energy dedicated to the production of gasoline there is a 19.5 percent energy loss.
In summary, the finished liquid fuel energy yield for fossil fuel dedicated to the production of ethanol is 1.34 but only 0.74 for gasoline. In other words the energy yield of ethanol is (1.34/0.74) or 81 percent greater than the comparable yield for gasoline.
I have dealt with the USDA studies in previous essays, showing the shoddy and misleading methodology they use. But let’s now examine this claim of energy efficiency. Would it surprise you to know that not only is this claim false, it is WAY FALSE?
Let’s do some quick calculations to demonstrate this. A barrel of crude oil contains 5.8 million BTUs (2) of material that will ultimately be turned into gasoline, diesel, jet fuel, etc. It is well-documented that the average energy return on energy invested (EROEI) for crude oil production is around 10/1 (3). Therefore, we will use up about 580,000 BTUs from our barrel getting it out of the ground. The other major input occurs during the refining process, and it also takes roughly 10% of the contained BTUs in the barrel of oil. The total energy input into the process is 1.16 million BTUs, and the energy output was 5.8 million BTUs. The EROEI is then 5.8 million/1.16 million, or 5/1.
For ethanol, the USDA study reference above showed that for an energy input of 77,228 BTUs, an energy output (when co-products were included) of 98,333 BTUs were generated. The EROEI is then 98,333/77,228, or 1.27/1. The efficiency of producing gasoline is then 4 times higher than for ethanol, which makes sense when you think about it.
Crude oil is a highly energy dense mixture. It is contained in underground deposits, and just needs to be pumped out of the ground. During the refining step, large amounts of water don’t need to be distilled out of the product. Contrast this to ethanol. The corn must be planted, grown, and harvested. Processing must take place to turn the corn into crude ethanol. The crude ethanol is actually mostly water, which must be removed in a highly energy intensive distillation. The final product, ethanol, contains only about 70% of the BTU value of the same volume of gasoline. So it would appear that even without doing any rigorous calculations, producing ethanol would be far less energy efficient than producing gasoline.
So, where did the claim that ethanol is more energy efficient originate? I believe it originates with researchers from Argonne National Laboratory, who developed a model (GREET) that is used to determine the energy inputs to turn crude oil into products (4). Since it will take some amount of energy to refine a barrel of crude oil, by definition the efficiency is less than 100% in the way they measured it. For example, if I have 1 BTU of energy, but it took .2 BTUs to turn it into a useable form, then the efficiency is 80%. This is the kind of calculation people use to show that the gasoline efficiency is less than 100%. However, ethanol is not measured in the same way. Look again at the example from the USDA paper, and lets do the equivalent calculation for ethanol. In that case, we got 98,333 BTUs out of the process, but we had to input 77,228 to get it out. In this case, comparing apples to apples, the efficiency of producing ethanol is just 21%. Again, gasoline is about 4 times higher.
OK, so Argonne originated the calculation. But are they really at fault here? Yes, they are. Not only did they promote the efficiency calculation for petroleum products with their GREET model, but they have proceeded to make apples and oranges comparisons in order to show ethanol in a positive light. They have themselves muddied the waters. Michael Wang, from Argonne, (and author of the GREET model) made a remarkable claim last September at The 15th Annual Symposium on Alcohol Fuels in San Diego (5). On his 4th slide , he claimed that it takes 0.74 MMBTU to make 1 MMBTU of ethanol, but 1.23 MMBTU to make 1 MMBTU of gasoline. That simply can’t be correct, as the calculations in the preceding paragraphs have shown.
Not only is his claim incorrect, but it is terribly irresponsible for someone from a government agency to make such a claim. I don’t know whether he is being intentionally misleading, but it certainly looks that way. Wang is also the co-author of the earlier USDA studies that I have critiqued and shown to be full of errors and misleading arguments. These people are publishing articles that bypass the peer review process designed to ferret out these kinds of blatant errors. I suspect a politically driven agenda in which they are putting out intentionally misleading information.
One of the reasons I haven’t written this up already, is that 2 weeks ago I sent an e-mail to Wang bringing this error to his attention. I immediately got an auto-reply saying that he was out of the office until March 31st. I have given him a week to reply and explain himself, but he has not done so. Therefore, at this time I must conclude that he knows the calculation is in error, but does not wish to address it. In the interim, ethanol proponents everywhere are pushing this false information in an effort to boost support for ethanol.
Look at the Minnesota Department of Agriculture claim again: “the energy yield of ethanol is (1.34/0.74) or 81 percent greater than the comparable yield for gasoline”. If the energy balance was really this good for ethanol and that bad for gasoline, why would anyone ever make gasoline? Where would the economics be? Why would ethanol need subsidies to compete? It should be clear that the proponents in this case are promoting false information.
1. Ethanol versus Gasoline
2. BTU Content of Common Energy Units
3. Alternative energy: evaluating our options
4. Allocation of Energy Use in Petroleum Refineries to Petroleum Products
5. Updated Energy and Greenhouse Gas Emissions Results of Fuel Ethanol
21 thoughts on “Energy Balance For Ethanol Better Than For Gasoline?”
Therefore, at this time I must conclude that he knows the calculation is in error, but does not wish to address it. In the interim, ethanol proponents everywhere are pushing this false information in an effort to boost support for ethanol.
You are correct Robert,
If corn ethanol returned more energy than it consumed, our country would be awash in energy. One of Wang’s and Shapouri’s USDA studies even makes the ridiculous claim that making corn ethanol is 167% efficient. If that were true, it would be a license to print money, and every company in the U.S. would be jumping into the corn ethanol energy business to make a quick profit.
Think of the possibilities:
* Invest 100 units of energy and get 167 units back.
* Re-invest those 167 units and get back 278.
* Re-invest those 278 units and get back 466.
In only three cycles they could more than quadruple the original investment. I’m sure you get the idea — any CEO who didn’t take advantage of that profit potential would soon be kicked out the door by the board of directors.
Yet that isn’t happening, and the corn ethanol industry and their lobbyists continually ask for mandates, tax credits, and tariffs protecting them from Brazilian sugar cane ethanol.
If the USDA study were true, why would they need those mandates, tax credits, and subsidies? The obvious answer is that they wouldn’t. One can only conclude the USDA study has a fatal flaw.
I am having an e-mail exchange with someone from the Minnesota Dept. of Agriculture. I think he really doesn’t see the problem, even though I have pointed it out with various examples. He really seems to believe that ethanol is more energy efficient to produce than gasoline. I will post some of this exchange when it concludes.
I am having an e-mail exchange with someone from the Minnesota Dept. of Agriculture.
The same here. Yesterday I sent him the USDOT data showing the large differential between fuel economy in Minnesota with E10 and Wisconsin without ethanol, and he is having trouble getting his mind around that. Says it can’t be true.
Wonder if it’s the same guy? I found his name on an official State of Minnesota webpage explaining why ethanol has a positive net energy balance.
Ah, that ethanol debate. Here’s the way that I figure it. Assume that the claim that 10 BTUs can be applied to get 13.4 BTUs of ethanol is correct. Assume further that the 10 BTUs includes all the costs for soil conservation, fertilizer, etc — that this really is a complete accounting.
Under those assumptions, some fixed piece of land produces a surplus of liquid fuel in the amount of 3.4 BTUs of ethanol per some time unit forever. Well, essentially forever, since what’s really happening is that solar energy is being converted into liquid fuel using a slow, inefficient process. 10 BTUs are needed to jump-start the process, which presumably comes from fossil fuel.
Alternatively, I could take those 10 BTUs of fossil fuel (in particular, 10 BTUs of crude oil), use 1.5 BTUs to refine the crude into 8.5 BTUs worth of liquid fuels, use one of those 8.5 BTUs to produce 10 BTUs of additional crude (assume 10:1 energy return) and have a surplus of 7.5 BTUs of liquid fuel, again per some time unit. A much shorter time unit than in the ethanol case. But my energy return for producing crude oil will shrink over time, and eventually my surplus fuel per unit time goes to zero.
First conclusion: investing the initial 10 BTUs of fossil fuel in collecting additional fossil fuel yields more surplus (ie, usable for other purposes) energy in the beginning. Second conclusion: investing the initial 10 BTUs of fossil fuel into jump-starting the ethanol process yields more total surplus energy over a sufficiently long planning horizon. Observations: the ethanol process is limited by the amount of land available and the (ridiculously low) efficiency of the conversion process; there may be competing energy demands for the biomass, eg, to burn to generate electricity; how does the efficiency of producing ethanol compare to using the biomass and Fischer-Tropsch to produce octane?
Ethanol can only challenge gasoline on the energy balance as oil becomes so scarce that the EROEI for finding crude oil drops substantially. It is still not clear to me that the ethanol energy balance is even positive. Look at tar sands. The energy balance is very poor, at 1.5 to 1. Yet tar sands are being scaled up, and the oil is being sold at a profit. No subsidies are required to achieve this. So it is puzzling to me how something with such a poor energy balance can outperform ethanol by such a wide margin, unless the energy balance for ethanol is even worse than we have been led to believe.
I certainly favor renewable energy, but I want to see us invest in things that are definitely sustainable. I see things like wind, solar, and biodiesel being far better investments than our infatuation with ethanol. We talk about the poor EROEI of ethanol, but things like pollution from intensive farming techniques and soil erosion always seem to get a free pass in the discussion. If you add up all the negatives, plus the questionable energy balance, I just don’t think (grain) ethanol makes any sense at all.
Those of you interested in the thermodynamics of ethanol vs. gasoline might like to look at
and other sites at Cal-berkeley that you can find via links. It is not easy to explain or understand any of this without referring to “free energy” vs. “total energy” ; also, the bottom line in car transport is dollars spent per mile travelled, which involves many factors beyond the “raw energy” numbers comparisons.
While I too find it misleading I don’t read that slide in exactly the same way that you do. The inconsistency I see is that he seems to be assigning 100% of the cost of extracting and refining the oil to the production of gasoline, even though that’s only 30% to 40% or so of the output of the refining process (depending on the type of crude). There’s an arrow at the bottom of the gasoline side of the slide labelled “Other Petroleum Products”. There could be quite a few BTUs hiding in the kerosene/naptha/etc that make up the other 60-70%.
This is a little bit tangential, but I wanted to sound you out about one point.
One of the serious problems with EROEI is that it aggregates all forms of energy into a single “E”. For example, if I read you correctly, the natural gas input for synthesizing nitrogen fertilizer and distillation is counted as part of “EI” when calculating the EROEI of corn ethanol. (I’m assuming here that distillation is generally done with natural gas, not liquids. Is that true?)
However, I think that a low EROEI can only be regarded as a losing proposition when the amount of energy invested in liquid form is too large relative to the amount of energy returned in liquid form.
Consider GTL. Clearly this method has an EROEI<1, and yet it makes sense because liquid fuel has higher value than gaseous fuel.
You could take the same approach to ethanol. If, for example, all the farming and processing was done with NG, and the output is liquid ethanol, then the slightly >1 EROEI of the corn ethanol method would make it superior to GTL.
So my point is this. I think EROEI is a poor measure of the value of different ethanol processes. A better measure would be energy returned in liquid form on energy invested in liquid form — ER(L)OEI(L). Do you have a rough idea of what this value is for corn ethanol, or sugar cane ethanol? Generally, what percent of the EI of these processes is actually in liquid form?
BTW, your blog is coming along nicely, and I’m very much looking forward to your upcoming posts on other liquids processes!
You are correct in that the vast majority of inputs into ethanol are not liquids. The vast majority is in natural gas. (The distillation is done by steam, produced generally by natural gas). I know that the claim is that for 1 liquid input of fossil fuel, you get 6 back out for ethanol. I don’t have a reference handy, but I have read that claim on pro-ethanol sites. However, since you can run vehicles on natural gas, it still doesn’t make sense to me to turn natural gas into ethanol unless you have a very good EROI. Coal, I can understand, since you can’t run a vehicle on coal.
GTL doesn’t make sense from an EROI standpoint, true, but the only place that big GTL plants are going in happen to be locations with large fields of stranded natural gas. It is the stranded nature of the gas that drives GTL, because otherwise there is no way to get the gas to market.
Yeah, I have gotten some pretty nice plugs and traffic has picked up. I still get a lot of referrals from your site. Today, The Oil Drum asked me if I would start contributing over there, so that will be taking a bit of my time. I hope to inject a bit more optimism over there and argue that life will go on, things are just going to be different.
Good Blog Michael,
I’d like to interject another thought into your discussion. Yes Wangs numbers appear to be wrong but you may be misinterpreting his basis. For a very good treatise on corn ethanol balance call up the report “The 2001 net energy balance of corn-ethanol”, at ” http/www.ethanol-gec.org/netenery/NEYShapouri.htm “.
The other thought, we are fouling our nest, this beautiful earth, buy continually upping our fossil fuel usage. Don’t believe it? look up the percentage of CO2 in the atmosphere in last 4 thousand years or so. See the exponetial spike developing for the last 50 years. Then look up average earth temperature for the last 100 or so years. Ladies and gentlemen, we have to get going on using renewable energy, which includes Ethanol, and stop fouling our nest. You can reach me at “firstname.lastname@example.org if anyone wants to dicuss this with me.
Yes Wangs numbers appear to be wrong but you may be misinterpreting his basis. For a very good treatise on corn ethanol balance call up the report “The 2001 net energy balance of corn-ethanol”, at ” http/www.ethanol-gec.org/netenery/NEYShapouri.htm “.
I have read that paper at least a dozen times, and addressed it here:
How Reliable are Those USDA Ethanol Studies?
The other thought, we are fouling our nest, this beautiful earth, buy continually upping our fossil fuel usage.
That’s the whole point about energy balance, though. If you have a marginal energy balance, you are making a marginal reduction in the CO2 emissions. In fact, if you consider that the byproducts feed cows which causes them to produce more methane, it is doubtful that there is any greenhouse gas reduction from using grain ethanol. There are much better solutions. That’s my beef with ethanol. We are mining topsoil, paying steep subsidies, and having little impact on greenhouse gas emissions, while squandering opportunities to really do it right.
Robert, energy balance is certainly important. If a fuel, be it fossil or renewable, causes a release into the atmosphere of quantities of CO2 greater than the natural sinks can remove it we will have global warming. The CO2 sinks are the growing crops of the earth and the ocean where it ends up as Calcium Carbonate. My point was that we are releasing fossil derived CO2 at a faster rate than nature can remove. Ethanol as a fuel returns less net CO2 above the quantity it used in the growing process than CO2 generated by fossil fuel use. So in my mind it is important to see if ethanol or other renewable fuels can return to us a net decrease in CO2 emissions over only fossil fuel use. So maybe we need to look at biofuels from the viewpoint of the use of the renewable versus the use of fossil fuel in producing a quantity of consummable fuel.
The Oregon Evironmental Council has attempt to do just that with a paper that shows the total BTUs of both renewable and fossil fuel used in production, delivery and consuption of 1 million BTUs of fuel. According to that paper, gasoline requires about 1.25 million BTUs in the consumtion of 1 million BTUs propelling our cars and trucks down the freeways and byways. Ethanol (corn starch) requres about 1 million BTUs from renewable and about 6 hundred thousand BTUs of fossil fuel. Ethanol (corn cellulose) requres the same 1 million renewable BTUs and only about 250 thousand BTUs of fossil fuel. Wood ethanol requires about 2.5 million BTUs of renewable and less than 100 thousand of fossil fuel. Diesel is almost equal to gasoline it its fossil fuel tarrif. Biodiesel requires the use of just over 2.5 million BTUs of renewable fuel and about 400 thousand BTUs of fossil fuel.
Now none of what I have said above indicates the social or monetary cost of the various fuels. However, I think it is clear that we as the major user of energy in the world need to really work on reducing our use of fossil fuels by using renewable fuels where appropo and or use of atomic energy for our power plants. If the use of fossil fuels is reduced to levels where the level of atmospheric CO2 can be maintained by natural processes, we will have won the global warming battle, reduced OPEC to an ineffectual group of Jesters and probably rotated some of their wealth back to our country. Keep up the good work, Roland
According to that paper, gasoline requires about 1.25 million BTUs in the consumtion of 1 million BTUs propelling our cars and trucks down the freeways and byways. Ethanol (corn starch) requres about 1 million BTUs from renewable and about 6 hundred thousand BTUs of fossil fuel.
Do you have a link to the paper? I would like to read it.
My point about grain ethanol is that even the pro-ethanol USDA papers show a marginal reduction in greenhouse gas emissions. In fact, the BTUs you get out in the form of ethanol are approximately the same as the BTUs in from fossil fuels. But, they claim a BTU credit for co-products, which makes the energy balance (and greenhouse gas) calculation look a little better. However, they do not consider that those co-products end up as methane in the atmosphere after the cows eat them, and methane is a much more potent greenhouse gas than carbon dioxide.
Finally, the greenhouse gas emissions are only part of the problem. Corn farming is very hard on the environment. Soil erosion is rampant, and pesticides and herbicides end up in our rivers. Given that the greenhouse gas emissions are so marginal, is this really worth it? I say “Absolutely not”.
Good morning Robert,
The link you want is ( http://www.biofuels4oregon.org) or contact Program Director Chris Hagerbaumer at ( email@example.com ). His phone number is 503 222-1963. I’m going to ask him if he has figures for sugar cane derived ethanol as well as figures for actual dollar costs for each of the 1 million consumed fuel BTUs.
I’m back Robert,
After your last comment, “My point about grain ethanol is that even the pro-ethanol USDA papers show a marginal reduction in greenhouse gas emissions,” I decided that I really needed to look harder at the entire biofuels picture before responding again. I find that there is an incredible amount of information, both believable an not believable available. One of the believable ones is another Blog of yours concerning biodiesel. A second was your reporting about the potential for algae grown oil. Anyway I have come to believe that you are correct in your opposition to increased corn ethanol production even if it delays the phase out of MTBE.
Having said that, I believe that as a nation we should have goals and plans in place to improve the quality of life for both ourselves and the rest of the worlds populations. Two of the imperatives that would lead to preserving and or improving our quality of life are:
1. Require that any consumption of fossil fuels not be permitted to emit green house gases.
2. Any use of fossil fuels that meet the first imperative, must be domestically produced.
Accomplishing the above is a very tall order. But the benefits of accomplishing them would be tremendous, independance from cartel members who hate our way of life and love the fact that we are willing to finance them by buying their oil, and worse, letting them dictate the price. Then there is the reduction of GHG emissions other than the amounts released from renewable fuel sources. Some of the other blogs you published have convinced me that the imperatives above can be accomplished. We need a strong leader in Washinton who can proclaim the above in the words and manner that President Jack Kennedy began our journey to the moon. Keep up the good work. By the way, if we (our government) had the guts that Richard Nixon had, we could reinstate the 55 mph speed limit. This would reduce the use of fossil fuels as it takes energy to push wind out of your way. Soemething like V cubed relationship I seem to remember. Roland
By the way, if we (our government) had the guts that Richard Nixon had, we could reinstate the 55 mph speed limit. This would reduce the use of fossil fuels as it takes energy to push wind out of your way.
I Can Drive 55
In response to Gary Dikkers comment. Why does the oil companies need subsidies and tax credits.
A 55 MPH speed will cripple the economy in the west at 65 and 75 mph it takes 12 to get from salt lake to phoenix at 55 mph you would triple the time. Truckers can only be on the road so long. Those truckers would idle overnight sleeping in there cab. Or worse the cargo will go by plane.
reducing taxes would give the gov more money, and we could buy new technology with a better economy in the private sector and we could go to a slightly more expensive fuel cell and Advanced Nuclear power plants to create a hydrogens or methane fuel.
I am having trouble w/ the whole greenhouse gas issue. Should we cut emissions? Yes! Have we? Yes! Still, it seems we are making way too much out of a little piece of pie. I looked up the list of greenhouse gases for kicks and was shocked to see that the CO2 numbers were way higher than almost everything else on the list put together and that the water vapor numbers were 25X higher than the CO2!. Maybe we should be trying to keep the oceans from evaporating or all the life forms from exhaling (both ends) if we want to make a significant difference for the “nest” in terms of global warming.
You talk about the total BTU in one barrel of crude, but the ethanol guys are talking about the BTU of just the gasoline. The amount of gasoline in a barrel of crude varies from 10% to 67% depending on the refinery, the oil, etc, so calculating efficiency of gasoline vs. ethanol using BTU from a barrel of crude can yield incorrect calculations
But the rest of that barrel of oil doesn’t just disappear. It is turned into diesel, jet fuel, heating oil, fuel gas, and petroleum coke – to name a few options. So anyone comparing ethanol to gasoline and only considering the gasoline portion is discounting a large fraction of the barrel. That will yield incorrect conclusions.
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