Ethanol-blended Fuel
By using 13.9 billion gallons of ethanol in our nation's motor fuel supply, it reduced tailpipe CO2-equivalent emissions by 25.3 million metric tons. That's equal to removing 4 million vehicles from the road.
Challenges to Ethanol's Green Credentials
Detractors of renewable fuels like ethanol are seeking to assess unproved and speculative carbon penalties on such fuels. Specifically, the flawed and unproved theory of international indirect land use change (ILUC) penalizes U.S. ethanol production with carbon emissions resulting from the land use decisions made by farmers and others in nations around the world. However, such a theory does not stand up to scrutiny.
The dramatic improvements in on-farm productivity are allowing farmers to meet market demands through virtual acres. American corn growers are producing twice as much grain today as they were in 1980 on virtually the same amount of land. In 1980, farmers averaged a yield of 91 bushels of corn per acre and produced a crop of 6.6 billion bushels. In 2009, just a generation later, farmers produced an average yield of 164.7 bushels per acre and harvested 13.1 billion bushels. This doubling of the American corn crop was achieved by planting just 3% more corn acres in 2009 than was planted in 1980. This dramatic increase in output has come without needing to increase the amount of fertilizer, pesticide, or water use per bushel of production. In fact, input use per unit of output has dropped considerably.
Whether produced from corn or other biomass feedstocks, ethanol generates more energy than used during production. A 2010 USDA study of ethanol production – from the field to the vehicle – found that ethanol yields about 40% more fossil energy than is used to grow and harvest the grain and process it into ethanol, even without allowing for the processing component of the byproduct credit. After fully allowing for heat used to produce byproducts, ethanol yields between 90-130% more energy than is used to produce it. Also, according to a University of California-Berkeley study, the production of ethanol reduces petroleum use by about 95% on an energy basis compared to gasoline refining.
The total energy and environmental impacts of producing ethanol continue to decrease dramatically. Most recent studies have concluded that corn ethanol reduces GHG emissions by 30-50% compared to average gasoline. Even when hypothetical land use change emissions are included, today’s average corn ethanol is 25% better than gasoline, according to the latest research from Argonne National Lab and Purdue University. In fact, the continued refinement of theories about ethanol’s carbon intensity are showing fewer and fewer emissions from ethanol and greater GHG benefits compared to increasingly environmentally dangerous sources of oil, like Canadian tar sands.
An Unfair Dichotomy
Similar penalties are not being assessed to other potential sources of motor fuels such as Canadian tar sands, oil shale, and electric generation from coal. All of these fuel sources have significant indirect environmental impacts which are accounted for in the same manner ILUC is charged to ethanol. By disadvantaging domestic renewable fuels, the playing field is tilted to favor imports of fuel, including ethanol and petroleum.
