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Study casts doubt on climate benefit of biofuels from corn residue | News Releases | University of Nebraska-Lincoln

The researchers, led by assistant professor Adam Liska, used a supercomputer model at UNL's Holland Computing Center to estimate the effect of residue removal on 128 million acres across 12 Corn Belt states. The team found that removing crop residue from cornfields generates an additional 50 to 70 grams of carbon dioxide per megajoule of biofuel energy produced (a joule is a measure of energy and is roughly equivalent to 1 BTU). Total annual production emissions, averaged over five years, would equal about 100 grams of carbon dioxide per megajoule -- which is 7 percent greater than gasoline emissions and 62 grams above the 60 percent reduction in greenhouse gas emissions as required by the 2007 Energy Independence and Security Act.

Importantly, they found the rate of carbon emissions is constant whether a small amount of stover is removed or nearly all of it is stripped.