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Robert Rapier vezeti le, aki az olajszektorban dolgozik, kutató. Geofizikus. Valószínűleg jobban ért hozzá nálunk (és nem is armageddonista). Hosszú lesz, de benne van a válasz a kérdésre. (Bolddal jelölöm a lényeget.)

 

http://i-r-squared.blogspot.com/2006/04/challenge-to-minnesota-dept-of.html

 

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Challenge to Minnesota Dept. of Agriculture’s Ethanol Claims

Disclaimer

First, I want to make a little disclaimer. In this essay, I will again be discussing the energy balance of gasoline versus ethanol. I am not doing this to suggest that gasoline is a great fuel of choice, but merely to show that grain ethanol is not. Gasoline has its own set of baggage, most notably that it is not sustainable. But the purpose of this essay is merely to examine claims from ethanol advocates who would have us believe that ethanol is actually more energy efficient to produce than gasoline.

Correspondence With Minnesota Dept. of Agriculture

Following my last posting on the energy balance of corn ethanol versus gasoline, I got into an e-mail exchange with an official from the Minnesota Department of Agriculture. I pointed out to the official that a claim that can found on their website is simply not correct. In part, the claim reads:


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 won’t identify the official by name, but I will show that his responses were vacuous and devoid of any logic or calculations to back up his point. In his first response, he wrote:


It appears that you may not be considering that all 115,000 (more or less) BTU's of energy that exist in a gallon of gasoline are solely derived from the crude oil that was also used to extract, distill and refine it. Only in this way could you come to the conclusion that the gasoline production and refining process yields more energy than it consumes. In fact, no matter how efficient the process of oil exploration and refining becomes, the energy yield for gasoline can never be positive because each unit of energy in the finished product also must be added to the total oil consumed in the production and refining of crude oil.
So, he is suggesting that by definition, the energy yield for gasoline can’t be positive. That’s all well and good, and I understand that, but then they do not use the same definition for calculating the energy yield of ethanol. I responded:


No, I understand quite clearly. What the USDA, and you by extension, have done here is to make an apples and oranges comparison. Consider that I wish to produce 10 BTUs of energy. I can use 1 BTU to pump oil out of the ground, and 1 more to refine it, netting 8 BTUs. This is where the claims of roughly 80% efficiency come from.

Now, let's do the same exercise for ethanol. To produce 10 BTUs of energy, given an energy return of 1.3, requires that I invest 10/1.3, or 7.69 BTUs. I only net out 2.3 BTU, or barely over 1/4th of what I would get for investing my BTUs into gasoline production. That is a true apples to apples comparison using the same metric.

There may be some legitimate reasons for producing ethanol, but energy efficiency is not one as my calculation has shown. My calculation and conclusion are correct. If you work through the math, you will see the same thing. What is shown on your website is misinformation.

Sincerely,

Robert Rapier
He then followed up with:


I disagree with your contention. You are still ignoring 80% of the energy required to provide gasoline. According to the report you reference, one Btu of fossil energy yields 1.34 Btu of ethanol.
No calculations or logic to support his position. He is simply ignoring the fact that the two methods of measuring efficiency are using completely different methodologies. When you compare ethanol to gasoline using the same metric, ethanol always turns out to be far less efficient. So, I again responded:


I am not ignoring anything. I am just showing the energy investment required to produce 10 BTUs of gasoline, versus 10 BTUs of ethanol. The energy investment is always much higher for producing ethanol. That is a true apples to apples comparison. The "80% that I am ignoring" are the contained BTUs in the crude oil that end up getting turned into gasoline. This is comprised of captured solar energy, as in the case of ethanol, but in the case of gasoline the solar energy was captured over many years instead of a single growing season.

Again, let me put it to you another way, and I think you will see the problem. Assume I have 10 BTUs of energy to invest. How many BTUs of usable energy will I have left if I invest into producing gasoline from scratch (i.e., starting from crude oil in the ground) versus investing the 10 BTUs into producing ethanol?

Here is the math, if you don't wish to work it out. In the case of gasoline, my 10 BTUs will generate about 100 BTUs of crude oil, since the energy return on energy invested for crude oil is about 10 to 1. It will then take about another 10 BTUs to refine the oil into gasoline. So, for my 10 BTU investment, I netted back 80 BTUs of gasoline.

In the case of ethanol, for a 10 BTU investment, I only got back 13.4 BTUs. I only netted 3.4 BTUs.

I can understand that you might disagree. But your disagreement needs to be backed up with some actual calculations showing where my contention is wrong. Please set up any case you like, as long as the comparison is apples to apples. I am confident that you can't show a case in which ethanol production is more energy efficient than gasoline.

Sincerely,
Robert Rapier
After my last response, I never heard from him again. I really wanted to see him back up his claims with some calculations. Perhaps he tried to do it, and got my point. Or perhaps it doesn’t matter anyway to him, since a lot of people involved in agriculture don’t seem to care about the energy balance, as long as it benefits corn farmers.

Gary Dikkers Reports a Similar Experience

I would also point out that Gary Dikkers indicated that he had a similar exchange with the MN Dept. of Agriculture. Gary had previously written in the comments section of an earlier essay:

Last month the USDOT released the fuel consumed/miles driven for each of the 50 states in 2004. Just for kicks I compared Minnesota (which has mandated ethanol) to Wisconsin (which does not.) The two states are near twins with similar weather, topography, and about the same mix of urban/rural population.

In 2004, the average fuel economy for the entire State of Minnesota using E10 is 20.62 mpg. The average in Wisconsin is 23.30 mpg.

By adding 10% ethanol to their fuel, Minnesota drivers ended up burning 13% more fuel than their Wisconsin neighbors.
After my last essay, Gary indicated that he had also corresponded with the MN Dept. of Agriculture:

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.
Correspondence With Michael Wang

Finally, I had tried to elicit a response from Michael Wang at Argonne, who seems to be the source of these claims about energy efficiency. I had also written to him to show him that his claims could not possibly be accurate. He finally responded. In part, he wrote:

Our calculations on energy are separated into total energy, fossil energy, and petroleum energy. Depending what type of energy you are looking at, results are very different. I believe that you are talking about total energy.
Well, of course I am talking about total energy. Can you make ethanol or gasoline without the total energy? Why on earth would someone not count the total energy, unless they are playing games? Frankly, this statement from him didn’t make much sense to me. I know that these guys are just playing games to exaggerate ethanol’s allure, so I responded:

Hi Michael,

Thanks for the response. I have read quite a few of your publications, as well as Shapouri's. I also exchanged e-mails with Shapouri last year on this subject. It really seems to me that you are playing games with numbers to try to make ethanol look better than it really is. I think that you are not making consistent comparisons between gasoline and ethanol production. When I see someone say that gasoline is 80% efficient and ethanol is 130% efficient, they are always using different measurement metrics.

Can you show me any case in which an apples to apples comparison shows ethanol to have a better energy balance? We can do solar energy if you like, but fossil fuels are a very rich source of captured solar energy with a much greater BTU value per unit volume. It is hard for me to see how ethanol is going to win that matchup. But if you have a specific publication, or a specific example in which you can show that ethanol has a superior energy balance, I would like to see it. I can tell you that if I have X BTUs to invest any way I like, I will get about 4 times the BTU value by investing in gasoline over investing in ethanol. That is quite an easy calculation to show, and is essentially the calculation I showed in my first e-mail.

I would support ethanol if I thought the energy balance was very good, but from what I have seen it is not. All I see are some very misleading arguments designed to show ethanol in a more positive light than reality would dictate.

Sincerely,

Robert Rapier
So far, no response. I don’t expect to get one. It seems that whenever I ask an ethanol advocate to back up their assertions with some calculations to support their argument, they immediately clam up.

Are there any ethanol advocates out there who would like to back up some of these claims with some calculations? I guess I need to issue a debate challenge to see if I can get someone to actually actually defend ethanol with calculations.