I’ve heard several posters on these boards mention the idea that ethanol isn’t a viable substitute for gasoline because it takes more energy to produce it than it can provide.
Okay, that’s obviously a stupid position – but as someone stated in this Great Debates thread, the claim is actually that it takes more oil to produce ethanol fuel than the ethanol can substitute for.
Is this actually true?
According to this study, modern ethanol production from corn comes out slightly positive- it produces a little more energy than the production consumes.
One thing the article mentions is that many of the other studies date from the mid 1970s, when agricultural equipment, fertilization, crop yield and other stuff weren’t as efficient as they are today, accounting for the sligthly negative energy balance in those studies.
Here’s another article by an environmental group that corroborates the points above concerning increased crop yields and efficiency increases.
Based on what I’ve read, it sounds to me like a good deal. The main thing from using a lot of ethanol would be reduced dependence on foreign oil- I haven’t done much research, but I seem to recall reading that ethanol fuel emissions are not as bad as gasoline, but still not all that great.
Brazil has being using ethanol from sugarcane since the mid 70s.
We mix up to 25% ethanol in gas, in order to elevate the octanage without need of other additives. There are vehicles that burn only ethanol and lately there are bi-fuel vehicles, that can burn gas or alcohol.
In the 70s, most of the vehicles burned ethanol, but since then the drop in the price of oil and the rise in the value of sugar made it not so economically interesting.
Anyway, we can produce ethanol wasting less energy than it will furnish.
But it’s still expensive to produce – whether or not there’s a net energy gain.
I can’t remember the exact number, but the price of crude oil would have to be significantly higher than it’s ever been before it would be cheaper to use ethanol for the equivalent amount of energy.
Distillation of ethanol from water takes an enormous amount of energy – far more than distillations of gasoline and other petrochemicals.
At the ethanol plant at which I worked, we measured the heat input from steam to do the distillation, and the energy used was roughly equal to the energy that could be supplied by the ethanol, and this was a fairly new and energy-efficient plant.
The conversion of coal to steam is not 100% efficient, so the coal energy that it took to make the ethanol was most certainly greater than the energy supplied by the ethanol.
However, in the case of ethanol, it’s claimed that the tailpipe emissions are less. That, of course, is made up by the fact that smokestack emissions are greater. Which is worse, tailpipe or smokestack? Probably tailpipe, since individual cars aren’t loaded with emissions-reducing equipment (except for catalytic converter) or tested for emissions every year (in most places) like coal-burning plants are. Also, most ethanol plants are probably fired by natural gas instead of coal, and that will be cleaner.
Ethanol does reduce dependence on oil (if it replaces foreign or domestic is up for debate), but it does so at the cost of higher corn prices (and therefore general food prices).
Not at all. Every calorie produced in the US costs 9 fossil fuel calories to produce. (produce=plant, grow, fertilize, harvest, process and transport.) This is specific to food calories in produce but ethanol can’t be anymore efficient than this. I know nothing of the refining process for ethanol but that could only add to the calories needed to create it. Ethanol is a losing process right from the beginning.
And what body orifice did you pull this 1 cal = 9 cal out of?
Even back in the 1970’s, ethanol production was only sligtly negative on energy balance, and improvements in crop yield and equipment efficiency have tipped it into the positive category.
Do you think the US Department of Agriculture can be considered an unbiased source? (This isn’t meant as an accusation, it’s an honest question.)
— I can’t remember the exact number, but the price of crude oil would have to be significantly higher than it’s ever been before it would be cheaper to use ethanol for the equivalent amount of energy.
According to Pimentel, “Ethanol from corn costs about $1.74 per gallon to produce, compared with about 95 cents to produce a gallon of gasoline.” [Link provided by scr4 in GD thread] Of course, if the price of crude oil rose, the price of ethanol would rise as well, since producing ethanol requires a lot of non-solar energy.
bump: Pimentel (2001) still maintains that ethanol production is still in the negative territory vis a vis energy balance. According to the Dept of Ag paper though, most studies put it slightly in the positive territory.
Although the Dept of Ag paper tried to compare methodologies across studies, it wasn’t clear to me (admittedly based upon a 5-10 min skim) whether they had actually identified the actual sources of the discrepancy.
I don’t know about the production of ethanol from corn. In Brazil ethanol is produced from sugarcane. The cane is pressed to extract the juice that will be fermented.
The residue(cellulose fibers) is burned to produce part of the heat needed for distillation.
So, at least part of the energy consumption is provenient of waste products and cost nothing.
Regarding Brazil’s experiemnts with alcohol-powered cars. As was pointedout, Brazilhas the advantage that they can use the sugar-cane refurse (bagasse) to burn and provide the heat to distill the alcohol. The problem is this: alcohol doesn’t vaporize as well asgosoline-so when an ethanol-fueld car starts up on a cold morning, youusually get explosions in the muffler! Its OK for Brazil, but would NOT work in Alaska.
Also,ethanolhas less energy content than gasoline…so you get about 3/4 the MPG as with gas.
The other main problem-in brazil, the ethanolproduced for fuel wasactually better than the rum produced for human consumption-so the drunks started drinking the motor fuel!
Ethanolwillonly make sense if the price of gasoline goes up to at least $4.00/gallon.
What is this cite SCR4?
Did you even read it?
(please for the love of god ALWAYS question my cites. Especially for a claim that seems so ludicrous)
They state that when you look at the data the “right” way then you get an energy benefit. The “right” way being that you throw out all the energy needed to produce and transport the fertilizer and ALL energy required to refine the produce into ethanol. That’s just a self justifying form of accounting for all the money the USDA threw away on it.
As for my cite, the 1:9 ratio is an average of all produce and the book it is from is not with me.
IF you would like me to get the book and tell you what the cite is please respond in this post
(would have posted it but it is in storage and I can’t remember the name of it)
BUMP you should re-read SCR4’s cite and then talk
Having recently attended a presentation from Lionel Labelle about this very thing.
cite:http://agrivision.sk.ca/Presentations/Ethanol-Jan-02/LaBelle.ppt
(presentation at The Real World of Ethanol Conference, January 2002) [power point]
Another reason many places are mandating the use of Ethanol is because it replaces MTBE as a fuel oxygenate. MTBE being a toxic chemical that is starting to be found in ground water.
Perhaps you missed Table 1 of the report, the columns titled, “Nitrogen fertilizer application rate” and “Inputs for nitrogen fertilizer”.
Perhaps you missed the section of the report titled, “Estimating Energy for Ethanol Conversion”.
I do not know the basis for your claim, but I only skimmed the report. Please provide quotes. Thanks.
No offense meant flowbark but my post says read the cite. You didn’t, stand down from your high horse. If your going to claim that my info is inaccurate, you provide the quotes. Here are mine from the site. (can’t get quote to work, check it out yourself)
The underlining is mine.
Results
Table 5 summarizes the energy requirements by phase of ethanol production on a Btu-per-gallon basis. It includes energy losses from line loss, venting losses at the ethanol plant, and losses associated with mining, refining, and transporting raw materials. Also presented is the NEV of corn ethanol without coproduct credits for wet-milling, dry-milling, and a weighted average of wet and dry milling. The weighted average is based on production capacity, that is, two-thirds of U.S. ethanol capacity is from wet-milling and one-third is from dry-milling. The average conversion rate for the two processes is 2.525 gallons per bushel. The NEV for dry-milling was the highest, 5,880 per gallon. The NEV for wet-milling was slightly negative, -1,199 Btu per/gal, but the weighted average of the two processes has a positive net energy balance, 1,137 Btu/gal. The energy ratio, which is the ratio of energy-out to energy-in, is close to 1 in all three cases. In other words, the Btu in a gallon of ethanol is about equal to the energy required to produce a gallon of ethanol even when energy coproducts are not considered.
Estimating Energy Credits for Coproducts
The coproducts used in this analysis include DDGS from dry milling, and corn oil, CGM, and CGF from wet milling. There are basically four ways to estimate energy credits for coproducts. First, the energy content of coproducts can be used to estimate energy credits. For example, a pound of corn gluten meal or corn gluten feed has a caloric content of 8,000 Btu. This results in about a 40-percent coproduct energy credit. The disadvantage of this method is that calories are a measurement of food nutritional value and are not a good proxy for energy in a fuel context.
A second method of estimating coproduct energy values is to use the relative market values of ethanol and its coproducts. For example, if energy used to produce ethanol is allocated between ethanol and coproducts based on their 10-year average market values, about 30 percent of energy used to produce ethanol should be assigned to the coproducts. The problem with this method is that prices of ethanol and ethanol coproducts are determined by a large number of market factors that are unrelated to energy content.
Third, one can allocate energy use among multiple products on an output weight basis, regardless of the operation’s purpose or the coproducts’ economic values. If energy used to produce ethanol is allocated between ethanol and coproducts based on the output weight, about 48 percent of energy used to produce ethanol should be assigned to the ethanol and 52 percent to coproducts. The problem with this method is that weight of a product is not always a good measurement of its energy value.
A fourth method, based on the replacement value of coproducts, is the method chosen for our final results. Energy credits are assumed to be equal to the energy value of a substitute product which the ethanol coproduct can replace. For example, in the case of corn gluten meal and corn gluten feed, soybean meal can be used as a substitute, and soybean oil can replace corn oil. Using this method, about 20 percent of the energy used to produce ethanol would be assigned to coproducts. This method has appeal because the coproduct value is measured by energy units unlike the other methods that use calories, economic value, and weight to represent energy value. Also, since energy replacement values result in fewer energy credits than the other methods, it can be considered a conservative estimate.
Granted it isn’t 1:9 but its just a fancy way of them saying that they ended up right back where they started and the only gain was byproducts of its manufacturing.
Nobody ever said that it’s particularly advantageous, but all the paper I cited said is that in the 1970’s it was slightly negative in terms of energy balance, and that today it’s slightly positive, in whatever terms the paper used.
I think it’s probably reasonable to say that in the real world, it’s probably a wash- it’s probably neither negative or positive.
As for the economic utility, that’s pretty well proven- it’s considerably more expensive than gasoline at the moment, but then again, so is biodiesel(vs diesel), Fischer-Tropsch GTL fuels, oil shale, etc… When the price of gasoline or diesel goes high enough, these other technologies will become more viable.
Um. I’m still having difficulty Mr. Insufferable. Where does it say (or even imply) that they, “throw out all the energy needed to produce and transport the fertilizer”? It seems to me that your quotes indicate that they considered co-products. As did the Cornell study, for that matter.
Fine, when you do not consider coproducts, "the Btu in a gallon of ethanol is about equal to the energy required to produce a gallon of ethanol even when energy coproducts are not considered. " But what does that have to do with throwing out the energy needed to produce fertilizer? 
As for, " ALL energy required to refine the produce into ethanol.", I quoted the chapter heading that dealt with that issue. Nowhere in the link and nowhere in your quote does it suggest that they ignored this aspect.
If you are saying that it is inappropriate to allow energy credits for co-products:
and
As for, “High Horses”, I refer That Insufferable Jerk… to this site’s main page. Our mission here is to fight ignorance (and perhaps make the occasional wisecrack): part of fighting ignorance involves taking care to back up your claims.
TIJ made a claim about the paper. It is his burden to back it up.
FLOWBARK You still have not read the link have you? Go read it for the first time. It specifically talks about throwing out the energy used in the production of the facilities and construction of the vehicles used to transport along with the mining of the minerals for the fertilizer. As for energy credits… How is that a different argument? Energy credits seem to have placed in the report after it was realized that there was no benefit. The report itself cite the questionable reliability of their use. If you READ the cite you will see that the traveling distances are very generalized. If you READ the sight you would see that the calculations for the estimated energy benefits are very vague. (The DATA isn’t cited. No the tables aren‘t the real data. The entire report is a SUMMARY of other reports.) If you READ the cite you will see that the vague calculation are criticized for not being vague in the “correct” manner and supporting the benefits of ethanol. As for me providing cites… IF you had READ the cite that I was referring to we would not be having this conversation.
Let’s not talk about the purpose of this site because you made a claim against my interpretation and didn’t back it up. Now unless you have something to add, lets end this please.