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Earth Biotech Politics

Biofuels From Corn Can Create More Greenhouse Gases Than Gasoline 159

Posted by timothy
from the as-long-as-it-looks-good dept.
New submitter Chipmunk100 (3619141) writes "Using corn crop residue to make ethanol and other biofuels reduces soil carbon and can generate more greenhouse gases than gasoline, according to a study published today in the journal Nature Climate Change. The findings by a University of Nebraska-Lincoln team of researchers cast doubt on whether corn residue can be used to meet federal mandates to ramp up ethanol production and reduce greenhouse gas emissions."
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Biofuels From Corn Can Create More Greenhouse Gases Than Gasoline

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  • by caseih (160668) on Sunday April 20, 2014 @08:08PM (#46802189)

    No it's not that simple. Plants require nutrients from the soil, which have to be replenished each year[1] partly by natural in-soil processes that break down residue from previous crops, but mostly from the application of synthetic fertilizer, which is synthesized using a process that burn natural gas. See the wikipedia article on the Haber Process [wikipedia.org].

    Also there are fossil fuels used in the planting, cultivation, harvest, and irrigation of the crop.

    If corn could fix its own nitrogen like legumes do, it might be a lot closer to carbon neutral.

    [1] In many parts of the world, including the Brazillian rainforest, farmers are actively "mining" nutrients from the soil. The soil left from burning the rainforest is extremely rich in nutrients, allowing intensive farming for a few years. After a while, though, the soil is depleted of nutrients and organic matter and yields drop. Sadly many farms just burn down more forest. Some methods of farming, including zero-till, try to foster natural soil processes to produce more nitrogen in natural ways, reducing synthetic inputs.

  • by dgatwood (11270) on Sunday April 20, 2014 @10:09PM (#46802585) Journal

    E85 is 85% ethanol, 15% gasoline, not the other way around. A 10% ethanol blend (10% ethanol, 90% gasoline) is called E10, not E90. Using E10 reduces your fuel economy by about 3–4%, and a 15% blend reduces your miles per tank by about 4–5%, assuming a modern, fuel-injected engine. I would expect the impact to be worse for an engine with a carburetor, but I don't know for certain. Either way, I'm pretty sure it's nowhere near 20% even with older engines.

    Yes, if it were legal to sell E90, it would reduce your fuel economy by somewhere in the neighborhood of 20%. Of course, your car wouldn't start in the winter, and in most cars, parts of your fuel system would likely rust out pretty quickly, spewing fuel all over the hot engine, thus ending your life in a blaze of glory, so fuel economy would be the least of your problems....

  • by taiwanjohn (103839) on Monday April 21, 2014 @10:57AM (#46805595)

    Modern agriculture essentially converts oil into crops

    "Modern agriculture" is based largely on annual crops, which deplete the soil and require massive inputs. Methanol can be made from perennial crops which can be harvested economically with little to no inputs.

    And since perennials do not require tillage, there is very little environmental degradation. Indeed, if herbivores are incorporated in the farming scheme, the combination can actually increase the topsoil. [youtube.com] Without tillage, such crops can be raised on lands which are currently considered marginal or unusable for conventional row-cropping. So methanol (unlike ethanol) would not compete with food crops at all.

    How do you think methanol would be produced at industrial scale?

    It already is produced at industrial scale. It's one of the most common "industrial" chemicals on the market. Unfortunately, a good chunk is currently produced from natural gas, but it is (and has been) made from various feedstocks for more than a century.

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