Adding ethanol to gasoline makes it cleaner and reduces air pollution, right? So biofuel lobbyists would have us believe. However, a study published in Proceedings of the National Academy of Sciences (PNAS) comes to the opposite conclusion.
Lead author Jason Hill of the University of Minnesota Department of Bioproducts and Biosystem Engineering summarized key findings of the study at a recent House Science Committee hearing. To determine which is cleaner, gasoline or ethanol, researchers must “compare these fuels over their full life cycle.” Hill explains:
That is, we need to consider the damage caused by producing them in addition to using them. For gasoline, the life cycle includes extracting and refining crude oil, and distributing and combusting the gasoline itself. The life cycle of corn ethanol includes growing and fermenting grain, and distilling, distributing, and combusting the ethanol itself.
Although combustion emissions from ethanol are lower than those of gasoline, production emissions from ethanol are higher. So much so that on a life-cycle basis, ethanol is the larger source of five different air pollutants: primary fine particulate matter (PM2.5), nitrogen oxides (NOx), amonia (NH3), volatile organic compounds (VOCs), and sulfur oxides (SOx).
Those results are an additional reason EPA should resist pressure from biofuel lobbyists to increase Renewable Fuel Standard (RFS2) blending targets for 2014-2016. As Hill cautions: [click to continue…]