Industry debunks Minn. report shedding bad light on corn ethanol

By Susanne Retka Schill | December 19, 2014

An analysis of conventional and alternative vehicles and their air pollution-related public health impacts from researchers at the University of Minnesota got a swift debunking from the ethanol industry. The university researchers found electric vehicles could reduce the deaths from air pollution by 70 percent and concluded the use of corn ethanol or electricity from coal is worse than gasoline for public health.

The co-authors of the report, published in the Dec. 15 Proceedings of the National Academy of Sciences, were Bioproducts and Biosystems Engineering assistant professor Jason Hill and Chris Tessum, a researcher in the Department of Civil, Environmental and Geo-Engineering.

The team look at how particulate matter (PM) and ground-level ozone change as a result of using various options for powering vehicles, and included not only tail-pipe emissions but a life-cycle analysis (LCA).

The Renewable Fuels Association released a three-page analysis that says the paper’s conclusions “…stand at odds with real-world data showing decreases in ozone and PM2.5 concentrations...” and that “Data from 222 EPA sensing sites show that ozone and PM2.5 concentrations have trended downward during the period in which the use of ethanol-blended gasoline has dramatically increased.”

The RFA response goes on to show that “On a full lifecycle basis, the study’s results are contradictory to the results from the Department of Energy’s latest GREET model” and that “There is a substantial body of evidence proving that ethanol reduces both exhaust hydrocarbons and CO emissions, and thus can help reduce the formation of ground-level ozone.”

The study’s reliability is also called into question as it omitted key factors when reaching conclusions on the environmental impact of gasoline and electric vehicles. RFA points out that the University of Minnesota conclusion “…excludes NOx and SOx emissions associated with crude oil extraction, a decision that grossly underrepresents the actual lifecycle emissions impacts of gasoline.” RFA concluded, “Omitting key emissions sources from the lifecycle assessment of EVs and crude oil inappropriately skews the paper’s results for the overall emissions impacts of these fuels and vehicles.”

The Minnesota Biofuels Association echoed RFA’s response. “While the U of M's report states that [ozone and particulate matter] increase with ethanol usage, data from the EPA suggests otherwise. According to the EPA, the amount of ozone in the air has decreased 18 percent from 2000 to 2013. In the Upper Midwest, ozone levels have fallen 11 percent during the same time period. Similarly, particulate matter has decreased 34 percent nationwide from 2000 to 2013. It is important to note that the drop in ozone and particulate matter coincide with the increase in ethanol blended gasoline.”

Growth Energy’s statement following the release of the report added to the critiques from another angle. “This report also fails to account for the numerous environmental benefits ethanol provides,” the Growth Energy statement said. “According to Argonne National Laboratory, ethanol reduces greenhouse gas (GHG) emissions by an average of 34 percent compared to gasoline, even when the highly controversial and disputed theory on indirect land use change (ILUC) is factored into the modeling ... Argonne has found that without ILUC included, ethanol reduces GHG emissions by 57 percent compared to gasoline.”

Growth Energy also pointed out the University of Minnesota report left out another important benefit ethanol brings to fuel. “Ethanol, with its high octane content, reduces the need to add toxic aromatics to gasoline to bolster octane and engine performance such as benzene and 1-3 butadiene that are known carcinogens. Additionally, ethanol plays a major role in reducing ultra-fine particulates in exhaust emissions that are linked to a large number of adverse health outcomes.”