University of Nebraska cellulosic GHG study sees rebuttals

In Nature Climate Change, a recent study performed at the University of Nebraska that cast doubt on whether biofuels produced from corn residue could meet the federal mandate for cellulosic ethanol has garnered criticism also published in the same journal. The criticism notes that the model ignored some of the carbon benefits associated with cellulosic ethanol byproducts, and that it used extreme parameters.

Niclas Scott Bentsen, Søren Larsen and Claus Felby from the University of Copenhagen commented that: “We do not dispute the main findings that harvest of residues has a negative impact on SOC levels and that this impact should be addressed when evaluating the potential benefits of cellulosic biofuels. We do, however, find that the conclusion, that cellulosic biofuels increase CO2emissions, builds on an incomplete analysis and that the analysis could have reached the opposite conclusion had it been more complete.”

The study was led by University of Nebraska-Lincoln assistant professor Adam Liska and funded through a three-year, $500,000-grant from the US Department of Energy. The findings stated that using corn crop residue to make ethanol and other biofuels reduces soil carbon and under some conditions can generate more greenhouse gases than gasoline.
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