A new study about the climate impact of using corn residue for biofuel production raises more questions than it answers, according to Brooke Coleman, Executive Director of the Advanced Ethanol Council (AEC).
“In reality, the study confirms what we already know; that excessive agricultural residue removal is bad for the soil and has negative impacts on climate,” said Coleman in a statement, adding that the study uses corn stover removal rates far exceeding those used in the field. “The analysis also models a one-size-fits-all approach to managing soil carbon that, by definition, ignores how farmers manage their land.”
The study at the University of Nebraska-Lincoln used a supercomputer model to estimate the effect of residue removal on 128 million acres across 12 Corn Belt states. Researchers reported that “removing crop residue from cornfields generates an additional 50 to 70 grams of carbon dioxide per megajoule of biofuel energy produced.”
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.
“Our industry is more than willing to engage in important discussions about the climate impacts of using agricultural residues to make fuel, but the headline-chasing strategy of trying to sell extreme modeling assumptions as the norm does not facilitate that process,” commented Coleman. “If you look at the full spectrum of peer-reviewed work, cellulosic biofuel is the lowest carbon fuel in the world.”
Renewable Fuels Association president and CEO Bob Dinneen believes the study is “fundamentally flawed and its conclusions are highly suspect. The results are based on sweeping generalizations, questionable assumptions, and an opaque methodology. The authors offer no robust explanation for why their findings contradict other recent, highly regarded research. Ultimately, this paper should be seen for what it truly is – a modeling exercise of a hypothetical scenario that bears no resemblance to the real world.”