EPA overestimates ethanol’s energy use, GHG emissions — industry group

Source: Amanda Peterka, E&E reporter • Posted: Tuesday, December 4, 2012

U.S. EPA’s outdated emissions model is overestimating greenhouse gases associated with ethanol production, the renewable fuels industry told EPA Administrator Lisa Jackson on Friday.

In a letter to Jackson, Renewable Fuels Association President and CEO Bob Dinneen said an improved model shows corn ethanol production producing fewer emissions than EPA estimated for 2022, the final year of the federal renewable fuel standard. He urged EPA to update its modeling to take into account new studies.

“Clearly, the understanding of ethanol’s GHG impacts has progressed rapidly and meaningfully over the course of the last three years,” Dinneen wrote. “Thus, we believe there is ample scientific justification for EPA to revisit its analysis.”

New data show corn ethanol reduces life-cycle greenhouse gas emissions by 24 percent compared with petroleum-based fuels, Dinneen said in the letter, highlighting a 2011 study by Argonne National Laboratory researcher Michael Wang. In 2010, when EPA released a final rule for the renewable fuel standard, the agency estimated that average greenhouse gas savings in 2022 would be 21 percent.

Dinneen said the lower emissions were caused by ethanol producers using less energy than EPA estimated and adopting new corn oil extraction technology, as well as the corn industry using less fertilizer and energy.

Studies also show that indirect land-use change, one of the most controversial elements of ethanol’s contribution to greenhouse gas emissions, is also much lower than EPA’s estimate, the ethanol trade group said. Independent estimates of land-use change range from 8 to 18 grams of carbon dioxide released per megajoule of fuel energy, compared with EPA’s estimate of 28.4 grams, according to the letter.

The improved estimates come from better data on land conversion, Dinneen said.

“While predictive land use change analysis remains highly uncertain, the methods and data associated with LUC estimation have substantially improved since EPA finalized the [renewable fuel standard],” Dinneen wrote. “These improvements have resulted in corn ethanol LUC emissions estimates that are much lower than EPA’s estimate.”

Dinneen also said Brazil’s sugar cane ethanol industry, which exports its product to the United States, is contributing more carbon emissions than EPA estimated.

Updating the life-cycle emissions of ethanol would “allow for fairer comparisons of the two fuels moving forward” and “enhance the public’s understanding” of corn ethanol’s greenhouse gas impacts, Dinneen wrote.