Cleaner Biofuels: Alternatives to Corn Ethanol Would Cut Carbon Emissions
WASHINGTON, D.C. – Compared to dirty corn ethanol, biofuels from next-generation feedstocks could greatly reduce carbon emissions that contribute to climate change, according to a new report by EWG and University of California experts.
EWG measured the carbon emitted over the life cycle of ethanol made from switchgrass and from corn stover, the stalks and leaves left on fields after harvest. EWG’s analysis found that the life-cycle carbon intensity of corn stover ethanol is 96 percent lower than gasoline and that of switchgrass ethanol is 47 percent lower than gasoline.
By contrast, EPA studies show that the life-cycle carbon intensity of conventional corn ethanol is greater than gasoline. Yet current federal policy – the Renewable Fuel Standard, or RFS, established in 2005 – strongly favors the production of corn ethanol at the expense of cleaner alternatives.
“When the Renewable Fuel Standard was established, corn ethanol was touted as being cleaner than gasoline, but 10 years later we know it’s just the opposite,” said EWG Research Analyst Emily Cassidy, author of the report. “It’s time to break up the corn ethanol monopoly to make room for next-generation biofuels that could reduce carbon emissions.”
The RFS mandates that by 2022 refiners must blend 36 billion gallons of biofuel into gasoline each year. This has driven the conversion of millions of acres of grasslands and wetlands to grow corn for making ethanol.
But converting grasslands and wetlands into corn fields releases the carbon stored in the soil. Growing corn also requires fertilizers that emit nitrous oxide, another powerful greenhouse gas. As a result, the boom in corn ethanol has contributed to more climate-warming emissions than if there were no mandate, and will do so for at least another 20 years.
The report concludes that Congress should reform the RFS to eliminate the mandate for adding increasing amounts of corn ethanol to gasoline, and to accelerate development of biofuels from lower-carbon feedstocks. If Congress fails to act, EPA should employ the reset provisions of the RFS to gradually reduce the mandate for corn ethanol and encourage development of cleaner second-generation fuels.