GoodFuels

Blinded By Junk Science

Two different university studies in the past few weeks have come to two completely different conclusions regarding the greenhouse gas emissions of corn ethanol, which clearly proves there is no scientific consensus on this issue.

The first study, by the University of Nebraska, concluded that “recent improvements in crop production, biorefinery operation, and coproduct utilization in U.S. corn-ethanol systems result in greater GHG emissions reduction, energy efficiency, and ethanol-to-petroleum output/input ratios compared to previous studies. Direct-effect GHG emissions reductions were found to be 48% to 59% compared to gasoline, which is two to three times greater than estimated in previous reports.”

The second study, just released last week by the University of Minnesota, comes up with a conclusion that only a rocket scientist could decipher. “If C is valued at $120 Mg_1, the societal climate-change cost from production and consumption of gasoline is $0.10 L_1 ($0.37 gal_1), between $0.08–$0.14 L_1 ($0.31 and $0.52 gal_1) for corn ethanol, but only between $0.01–$0.02 L_1 ($0.03 and $0.09 gal_1) for cellulosic ethanol.”

Unfortunately, the UMN study is getting lots of media attention because the sound bite is that corn ethanol “can be as harmful to the environment as gasoline, and that the combined costs to climate-change and health exceed that of gas.”

That simplistic conclusion is based only on certain hypotheses, including the baseless assumption that additional corn demand for increased ethanol production will cause conversion of large amounts of grassland enrolled in the Conservation Reserve Program.

The paper itself states that if the authors’ assumed land use change emissions are removed from the analysis, average corn ethanol reduces greenhouse gases by 30% compared to gasoline and advanced corn ethanol reduces GHGs by 46%. According to the report, “Whether corn ethanol has lower life-cycle GHG emissions than gasoline depends on biorefinery heat source, assumptions about technology, and land-use change.”

In other words, the authors of the UMN study considered several different land use scenarios and process heat sources, and came up with DIFFERENT CONCLUSIONS. The headlines come from the worst possible scenario which assumes all corn ethanol is produced in one way and relies on debatable methodologies for which no scientific consensus exists, including land use change and carbon social cost.

The sad thing is that journalists get blinded by all this junk science and report whatever translates into a simple sound bite. It is imperative that the industry constructively engage in this issue to insist that it is driven only by sound science.