By on August 6, 2009

Corn-based ethanol took another blow from the scientific literature this week. University of Minnesota scientists published an article revealing that corn into E85 could require three times as much water as previously estimated. The bottom line: it takes more than 2,100 gallons of water to produce a single gallon of ethanol. That’s bad news for corn-etoh’s partisans; water supplies in the US are not exactly ample (as the NYT Mag pointed out a couple of years ago in its article, “The Future Is Drying Up“). Ethanol has also been bashed for competing with food, and for raising carbon emissions over a period of decades, rather than reducing them. The researchers, led by Sangwon Suh, note that the water needs vary widely depending on irrigation practices. In a dozen Corn Belt states, production of a gallon of E85 requires less than 100 gallons of water. I still wouldn’t buy any stock . . .


In general, land plants require huge amounts of water—so much so that Harvard University forestry professor Michele Holbrook considers growing on land one of the six “impossible tasks” that plants do. The problem is that pulling carbon dioxide—which becomes the structural material of plants—is like sifting needles from haystacks. CO2 makes up 3.8/100ths of a percent of the stuff we breathe in, while the concentration is considerably higher in water.

Thus, the plant needs to ingest huge quantities of air vial the leaves, but the extensive surfaces for absorbing the air lose water fast. Thus, about 500 water molecules must cycle through the plant for every carbon dioxide molecule the plant captures. “If I turned the mass of my body into sunflower leaves, I’d have to drink two liters every 30 seconds,” says Holbrook.

Holbrook recently added a 7th task to her list of impossible tasks of plants: sustainably producing liquid fuels from crops. There’ll be no joy in Mudville over this one . . .

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19 Comments on “E85 Boondoggle of the Day: 2100 Gallons of Water Per Gallon of E85?...”


  • avatar

    I’ve actually done laboratory calculations of the amount of energy, food and water wasted to produce E85. Its horrendous.

    However, I think it would be more intelligent to use GARBAGE and organic waste to produce Ethanol because even if you have to spend large amount of energy to produce it, you are simultaneously funding recycling and waste management rather than using energy for seperate ventures.

  • avatar
    menno

    Why on earth would anyone wish to make garbage into ethanol, when you can actually make garbage, offal and sewage – into bio-light crude oil?

    Actually what comes out of the process, already invented and put into place, is #1 diesel/home heating oil, which could be ‘cracked’ and made into gasoline. Pellets for plastic mfg. and also fertilizer also come out the ‘other end’.

    Unfortunately the company is now having problems since the Butterball factory that it parked next to (and which used to have to PAY to take away offal) charges the company for the offal….

    http://www.changingworldtechnology.com

    Ethanol is a complete foolish dead-end.

    If we are so foolish to feed SUVs instead of ourselves, and insist upon it, why not make Butanol (4-carbon alcohol) from sugar beet? Butanol is pretty much a drop-in substitute for GASOLINE. http://www.butanol.com

    I work for neither of these companies, btw.

  • avatar

    This headline seems a little disingenuous; in order to have any meaning you’d need to compare to how much water would be consumed if the same land was being used to grow some other crop. How much water would it take to make a gallon of wine or grow a pound of broccoli ? Assuming the land was not left barren, then it will be consuming water for something. You can argue that the land should be used for some more useful crop, but to just quote a number for producing ethanol without any context is meaningless.

  • avatar
    441Zuke

    ethanol is garbage it is a total waste i would be interesting to compare how much a much energy it would take for a ethanol powered car 40 miles compared to a gasoline powered car. as in water, Diesel for tractors, tax subsidies and all things considered. i bet it would be pretty shocking to even the those skeptical of ethanol but that is for a brighter mind with more time then me.

  • avatar
    ttacgreg

    There is only one gas station in my modestly sized community that sells gas without ethanol.

    That is where I put my money down. The noticeably better fuel economy is also nice.

  • avatar
    lw

    E85 is not practical, it’s political. So the solution is simply more subsidies and a LOT of them!

  • avatar
    B.C.

    What happened to that ethanol from seaweed thing? Any news or studies about that? (Not that I’m an ethanol proponent.)

  • avatar

    I’m in MN and the University published similar findings going back 2-3 years, and not a peep from anyone here. Newsrooms especially. Both local papers actually ran substantial pieces that were met with big, fat yawns from the Little House on the Prairie set. You see, our Governor is firmly behind, in front, and inside this ethanol boondoggle, and fat checks equates to votes. And this in the face of a majority of ethanol refiners going out of business; i.e. consolidation. Follow the money.

  • avatar
    rmwill

    Ethanol is GOP/Red State Socialism. And it is terrible for drivers and cars.

    Is there a “Pure Gas” directory? Is 100LL Avgas pure? Turbo Blue?

  • avatar

    @ [email protected]

    That would be true if ethanol were somehow substituting some other crop that was being used for food, rather than being used de novo for fuel. Thus, the water is water that wouldn’t have to be used in agriculture if we were fueling cars with crops.

  • avatar
    ohsnapback

    Just kill this farm-welfare disaster already.

    Enough is enough.

    It’s bad for the economy, the environment, food prices, the consumer, and internal combustion engines.

    It’s a cruel joke on the American taxpayer, too.

  • avatar

    DuPont is promoting their own butanol process. Sugar beets were mentioned above. With ethanol the energy yield is 8:1 for sugar cane, 2:1 for sugar beets, and 1.3:1 for corn. Michigan is the country’s leading producer of sugar beets so of course Gov. Granholm has been hyping corn ethanol.

    I think methanol makes a lot of sense because anything that can be made into ethanol can be made into methanol, but more important, coal can be easily made into methanol and we have centuries worth of coal in the US.

    The main problem with alcohol fuels is that gasoline is a great liquid fuel, with a lot of available energy.

    1 gallon of gasoline, = 125000 Btu. 1 gallon of ethanol, = 84400 Btu. 1 gallon methanol, = 62800 Btu

    One federal mandate I could live with is having all non-diesel cars completely flexfuel. That would allow lots of liquid fuel options. The technology is way cool too. There’s an infrared spectrometer that constantly monitors the composition of the fuel, sends the info to the ECU, which adjusts timing, fuel injection, variable valves, etc.

  • avatar

    Ethanol is GOP/Red State Socialism. And it is terrible for drivers and cars.

    More like subsidies for ADM and other big agribusinesses. Also, there are plenty of corn farmers in Michigan, that’s why Granholm, a democrat, has been pushing corn ethanol. There are more farmers growing corn than farmers growing sugar beets.

    With all the companies that are working on microbial processes that produce petrochemicals, I think there will be cost competitive biofuels within 5 years.

  • avatar
    niky

    Instead, as many studies have shown and as has been seen in the past two to three years, ethanol production transplants food production, which causes food prices to rise and more land to be cleared for the growing of food crops.

    No matter what some may say… that we will never run out of land… the question is how much arable land resource is left to us, and how much of our carbon-fixing rain-forests and jungles do we have to clear-cut to give over to crop growing? And how do we deal with topsoil degradation when we finally start maximizing the use of that land? We still need to leave “wild” land in places, to preserve our loamy resources…

    http://www.seattlepi.com/local/348200_dirt22.html

  • avatar
    ohsnapback

    Brazil makes sugar cane ethanol work at about 80 cents a gallon because sugar cane grows everywhere down there, and I don’t even believe it needs any irrigation other than normal rainfall because of the climate, soil conditions and nature of the plant.

    Of course, that’s why the U.S. both slaps a massive tariff on Brazilian ethanol, while giving a huge taxpayer subsidy to U.S. corn farmers; so they won’t be put out of commission by very inexpensive, Brazilian sugar cane ethanol.

  • avatar
    twotone

    Algae farms to create bio diesel is the best way to go — low (recycled) water requirement, does not take away from food crops, uses desert land and creates a high-energy fuel (for cars, trucks and jets).

  • avatar
    menno

    Actually, Ronnie, the BTU per gallon numbers are listed this way (as seen in the http://www.butanol.com website which I plucked this from) quote:

    How does butanol compare with ethanol as an alternative fuel?

    Butanol has many superior properties as an alternative fuel when compared to ethanol. These include:

    Higher energy content (110,000 Btu’s per gallon for butanol vs. 84,000 Btu per gallon for ethanol). Gasoline contains about 115,000 Btu’s per gallon.

    Butanol is six times less “evaporative” than ethanol and 13.5 times less evaporative than gasoline, making it safer to use as an oxygenate in Arizona, California and other states, thereby eliminating the need for very special blends during the summer and winter months.

    Butanol can be shipped through existing fuel pipelines where ethanol must be transported via rail, barge or truck

    Butanol can be used as a replacement for gasoline gallon for gallon e.g. 100%, or any other percentage. Ethanol can only be used as an additive to gasoline up to about 85% and then only after significant modifications to the engine. Worldwide 10% ethanol blends predominate.

    As for making coal into methanol (which is highly corrosive and bad news), why not simply make it into diesel and gasoline fuel* as they do in South Africa (with South African coal and manpower). The Fischer-Tropsche (sp?) method is used. This was “invented” initially by the Germans in WWII since Rommel couldn’t hold north Africa (i.e. “oil for the Nazis”) and the Germans had to figure out how to prosecute the war without any oil. Necessity being the mother of invention, and with plenty of coal under Germany, they came up with this – which became part of the war reparations after WWII. Except that we in America have never used it – just allowed others to use it.

    * The North American and most of the world’s fleet of vehicles is currently gasoline fuelled with some proportion of diesel fuelled (much higher in Europe as a percentage). Few cars are flex-fuel capable and just because a vehicle is E85 flex fuel does NOT necessarily make it suitable to methanol….

  • avatar

    Sugar cane is a much more productive crop for ethanol than corn, but if you believe global heating is a problem–and I know many ttac readers don’t, but please lets not get into another argument about THAT–the US tariff is preventing a lot of carbon emissions that would happen if the brazilians increased production of sugar cane. To understand that, you can click on the link I provided in the blog about the carbon impact of biofuels. But ohsnapback is absolutely right about the reason for the tariff.

    Twotone may well be right about algae farms. The carbon impact link covers that as well. (I wrote it.)

  • avatar
    ohsnapback

    David Holzman – Thanks for that link; interesting stuff.

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