Ethanol – The Green’s Big Lie

I recently ran across an article concerning the amount of water needed to produce ethanol. It said “It takes three gallons to five gallons of water to produce one gallon of ethanol”.
Three to five gallons of water. That’s clean water, mostly distilled.
So now on top of the energy expended to make ethanol, we now have a water usage issue.
I want to quote from a blog I ran across today. This gentleman, named Robert Rapier, is an expert in the energy field, so I feel confident quoting the numbers from his blog. He says:

“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.”

Sorry that was so long, and some of the numbers can be quite confusing, but in a nut shell, his findings are what I have suspected as well…ethanol is not the answer to the world’s energy needs. It’s just another Greenie ploy to demonize the oil industry again.

Read the rest of Mr. Rapier’s blog here.

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