Study shows corn ethanol lowers GHG emissions by 46%

By Erin Voegele | January 26, 2021

A new study published by researchers from Environmental Health and Engineering Inc., Harvard University and Tufts University shows corn ethanol emits 46 percent fewer greenhouse gas (GHG) emissions than gasoline.

According to EH&E, conventional wisdom based on a prior analysis completed by the U.S. EPA estimated that corn ethanol achieved only a 20 percent GHG reduction. EH&E’s topical review of the latest science, however, shows that corn ethanol is less carbon intensive and more climate-favorable than previously thought.

"This research provides an up-to-date accounting of corn starch ethanol's GHG profile in comparison to that of gasoline refined from crude oil," said David MacIntosh, chief science officer at EH&E. "The results of this research are timely for the scientific, public health, legislative, and business communities seeking to establish a net zero carbon economy while addressing related technological, political and economic challenges."

A statement released by EH&E stresses that the new research delivers a transparent, state-of-the-science assessment on life cycle analyses of corn starch ethanol in the U.S. To complete their study, the researchers critically reviewed earlier lifecycle analysis modeling and data. They also consulted with more than two dozen experts from government, academia and nonprofits. Their findings uncovered significant reductions in carbon intensity made possible by advances in farming technology, soil conservation practices, and the production of animal feed coproducts, EH&E said.

The study cites a 2018 White Paper published by the American Coalition for Ethanol, titled “The Case for Properly Valuing the Low Carbon Benefits of Corn Ethanol,” which highlights how U.S. farmers and ethanol producers are improving efficiencies, investing in technologies, and adopting practices to dramatically reduce GHG emissions from corn ethanol.

“The findings in this report reinforce what we have been promoting for the last several years; the greenhouse gas reduction benefits of corn ethanol have been significantly undervalued because too many regulatory bodies refuse to apply or use the latest lifecycle science,” said Brian Jennings, CEO of ACE. “Today’s corn ethanol indeed reduces GHGs by approximately 50 percent compared to gasoline, and given improvements occurring in corn farming and within ethanol facilities, corn ethanol’s carbon footprint will continue to decline over time.”

“As elected leaders at the state and federal level look to craft new policies to tackle climate change and meet net-zero emission goals, we strongly encourage them to appreciate that corn farmers and ethanol producers are part of the solution,” Jennings added. “Agriculture and ethanol can make even more meaningful contributions to GHG reductions if new policies reward farmers for climate-smart practices and expand the use of mid-level ethanol blends.”

The Renewable Fuels Association is applauding the study. “This new study provides further validation that ethanol is a highly effective tool for decarbonizing liquid transportation fuels and significantly reducing greenhouse gas emissions from the transportation sector,” Geoff Cooper, president and CEO of the RFA. “And with ethanol, we don’t have to wait and hope for technological and economic breakthroughs. It’s here today at a low cost and already has a proven track record. Ethanol can and should be allowed to do more to contribute to the fight against climate change, and that starts by breaking down the barriers to higher blends like E15, E30, and flex fuels like E85. As President Biden’s administration and the new Congress consider actions and policies to address climate change, we encourage them to examine the best available science and properly account for the critical role ethanol and other renewable fuels can play in securing immediate GHG reductions.”

Cooper pointed out that the scientists found that emissions from land-use change are only “a minor contributor” to the overall carbon footprint of corn ethanol, accounting for just 7 percent of total GHG emissions.

Growth Energy said the study shows that further improvements in technology and practices will lead to net zero renewable fuel in the future.

“In light of the United States’ renewed effort to achieve a net zero carbon economy, our research team believes this critical review is a timely contribution to establishing an accurate, common understanding of the greenhouse gas profile for corn ethanol in comparison to gasoline refined from crude oil,” said MacIntosh. “Our findings indicated that displacement of gasoline with ethanol produced from biofuels yields greater greenhouse gas benefits than are generally recognized and that prior analyses of the payback period for conversion of land to corn production should be updated.

“We believe the results of our analysis are relevant to continued development and refinement of low carbon fuel standard programs in the U.S.,” he continued.

“The evidence proves time and time again that ethanol should play a key role in our nation’s climate goals of decarbonizing the transportation sector and reducing greenhouse gas emissions,” said Emily Skor, CEO of Growth Energy. “This latest report from EH&E provides a much-needed update to ethanol’s carbon intensity score to highlight as our country, and our new Administration, make climate change a top priority moving forward.”