The Renewable Fuels Association, Growth Energy and the American Coalition for ethanol on Sept. 21 challenged the U.S. EPA’s Science Advisory Board’s flawed remarks on the climate impacts of corn ethanol. 

The SAB provides independent scientific and technical advice to the EPA on scientific and technical basis for agency positions and regulations. During a two-day public meeting that kicked off Sept. 21, the SAB discussed draft commentary on the agency’s final Renewable Fuel Standard “set” rule, which was released in June 2023 and sets renewable volume obligations (RVOs) for 2023, 2024 and 2025. The draft commentary includes claims that “there is a reasonable chance” that corn ethanol provides minimal or no climate benefits when the fuel is substituted for gasoline or diesel. The draft commentary recommends that the EPA conduct more extensive research into the role the RFS plays in reducing greenhouse gas (GHG) emissions. 

In testimony before the SAB, RFA President and CEO Geoff Cooper challenged the group’s flawed commentary on the climate impacts of corn ethanol and the RFS, specifically urging the SAB to review EPA’s own analysis showing a significant reduction in cropland since the RFS was enacted and Argonne National Laboratory’s extensive research demonstrating ethanol’s significant carbon savings. 

“We adamantly disagree with the SAB’s assertion that ‘the best available science’ suggests there are ‘minimal climate benefits’ associated with using corn ethanol in place of gasoline,” Cooper said. “Indeed, the best available science shows just the opposite. Extensive research conducted by government laboratories, major universities, state and federal agencies, NGOs, and private lifecycle analysis experts all demonstrates that corn ethanol is 40-50 percent less carbon intensive than petroleum on a full lifecycle basis—including emissions from hypothetical land use change scenarios.”

Argonne’s latest work, Cooper said, found that average corn ethanol reduces GHG emissions by 44 percent compared to gasoline. The Argonne researchers noted that corn ethanol “can play a critical role in the U.S. desire for deep decarbonization of its economy.”   

And while the SAB questioned cropland expansion, suggesting the “facts are difficult to pin down,” Cooper noted that in 2010, EPA began quantifying U.S. agricultural cropland every year to determine whether any expansion has occurred beyond 2007 levels as a result of the RFS. “EPA’s assessments clearly show a steep downward trend in the amount of land dedicated to crops since 2007,” Cooper said. “U.S. cropland continues to shrink—not expand. This fact is incontrovertible.”

Cooper concluded by calling on the SAB to supplement its commentary after conducting a much more expansive and inclusive examination of the science on corn ethanol’s carbon footprint and said that the board should specifically consider recent lifecycle analyses from DOE, USDA, state air agencies, academia, and other sources to evaluate what is really happening in today’s corn ethanol industry.

Growth Energy also defended the RFS and its contributions to climate progress during the meeting and urged the SAB to withdraw its anti-ethanol commentary. 

Growth Energy Senior Vice President of Regulatory Affairs Chris Bliley pointed to numerous studies that demonstrated the emissions benefits of ethanol, and urged SAB to ultimately withdraw its original draft. 

"Years of peer-reviewed research from scientists at the U.S. Department of Energy’s Argonne National Lab, the U.S. Department of Agriculture, Environmental Health and Engineering have all concluded that today’s ethanol reduces greenhouse gas emissions by nearly 50 percent compared to gasoline," Bliley said. "Studies claiming otherwise consistently ignore hard data in favor of questionable assumptions and outdated projections about land use." 

ACE set the record straight on the GHG impacts of ethanol in a letter to the SAB. In the letter, ACE CEO Brian Jennings refuted the misleading claims made by the RFS workgroup centering on the degree to which corn starch ethanol reduces lifecycle GHG emissions compared to gasoline.

In the draft commentary, the SAB workgroup letter makes the outrageous claim that corn starch ethanol may not meet the necessary scientific requirement of having no more than 80 percent of the lifecycle GHG emissions of gasoline. In fact, corn starch ethanol greatly exceeds the necessary scientific requirements as demonstrated by the best available lifecycle science (via the GREET model), which shows corn starch ethanol is at least 50 percent cleaner than the GHG emissions of gasoline on average, according to ACE.

“There is no fact-based debate regarding the lifecycle GHG emissions of corn starch ethanol compared to gasoline,” Jennings wrote. “To the degree debate exists at all, it is not vigorous, unless one takes into consideration the vigor of misinformation campaigns orchestrated by various groups who are self-interested in their opposition to ethanol.”

ACE again called on EPA to replace its badly antiquated approach for assessing the GHG impacts of corn starch ethanol with the GREET model in the comments. The SAB letter provides no mention of the GREET model but makes multiple references to discredited studies by Tyler Lark et al., with land use change (LUC) at the center of Lark’s attacks on corn ethanol. “While the Lark paper received outsized attention from the RFS workgroup letter, his biased methodology led to a LUC “result” which is far outside GREET CCLUB [Carbon Calculator for Land Use and Land Management Change from Biofuels production] results and other comprehensive and authoritative research done on this topic,” Jennings wrote.

The workgroup letter closes by referring to N20 emissions from corn farming. Jennings responded with additional information on the critically important topics of how farming practices can play a meaningful role in reducing lifecycle GHG emissions for corn starch ethanol, as well as reduced tillage practices to increase soil carbon sequestration. 

In closing, Jennings highlighted the ingrained bias of the six-person RFS workgroup established by the SAB, including one member employed by an organization which has called for repeal of the RFS in Congress. “Should the SAB expect any credibility from the RFS workgroup in the future, I call on you to withdraw their misleading draft letter and reconstitute the workgroup to represent a more balanced range of expertise and interests,” Jennings concluded.

A full copy of the SAB’s draft commentary on the RFS “set” rule is available on the EPA’s website.