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USDA Takes a Fresh Look at Ethanol’s Lifecycle Greenhouse Gas Emissions

January 13, 2017
Today, the USDA released a newly completed report reexamining the lifecycle greenhouse gas impact of corn ethanol. Where prior studies have relied on modeling and projections (often driven by assumptions) about these impacts, USDA’s new report reviewed hard data on farming and biorefinery performance over the past decade. The bottom line from USDA is that as of 2014, corn ethanol reduced greenhouse gas emissions by 43 percent in comparison to the 2005 lifecycle baseline for gasoline. USDA estimates that corn ethanol is reducing U.S. GHG emissions by 35.5 million metric tons per year.

That estimate relies on direct evidence from the past ten years that farmers have increased crop productivity and efficiency, adopted land conservation measures that reduce carbon emissions – such as conservation tillage and cover crops – and restrained indirect land use change. Farmers have also improved crop yields —between 2005 and 2015, U.S. corn yields increased by more than 10 percent.

The USDA further finds that if these trends continue, by 2022 corn ethanol could reduce greenhouse gas emissions by 50 percent in comparison to 2005 gasoline. And in a scenario where all U.S. farmers and ethanol producers adopt efficiency measures, corn ethanol could achieve a comparative reduction of 76 percent.

Importantly, the USDA report uses the 2005 baseline for gasoline, which is enshrined in the federal Renewable Fuel Standard. Renewable fuels are required to achieve at least a 20 percent reduction of GHG emissions to qualify for the program. And in 2010, the Environmental Protection Agency – using its own modeling and projections – determined that corn ethanol would meet that reduction by 2022. Today’s USDA report finds that the benefits have been accelerated significantly. At the same time, EPA is more than three years late in conducting and releasing a required report on the greenhouse gas impact of the RFS program.

In 2015, BIO conducted its own study of the impact of the RFS, which was first established in 2005. We found that over the first 10 years the program had displaced 1.9 billion barrels of oil and reduced associated greenhouse gas emissions by 589.33 million metric tons. BIO’s study also took into account the fact that gasoline produced today is far more carbon intensive than the 2005 baseline. USDA’s findings add evidence that biofuel production and the RFS are powerful tools to reduce greenhouse gas emissions. BIO’s World Congress on Industrial Biotech – this July in Montreal – will provide opportunities to discuss and measure the progress of companies in meeting the goals of the RFS.