Biofuels From Corn Can Create More Greenhouse Gases Than Gasoline

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."

Comments

Re:Uh ... it's still carbon neutral, isn't it?

[caseih]

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.

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.

Re:10% ethanol also means 20% MPG lost

[dgatwood]

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....