The Environmental Protection Agency late last week opened a comment period on what it calls an “anti-backsliding study” to determine whether the renewable fuel volumes required in the Clean Air Act adversely impact air quality as a result of changes in vehicle and engine emissions.

After considering the results of the study, EPA is required to either (1) promulgate fuel regulations to implement appropriate measures to mitigate, to the greatest extent achievable, any adverse impacts on air quality; or (2) determine that no such measures are necessary, the agency said.

Growth Energy noted in a news release that the study was released as part of a consent decree reached in February 2019, but said it “rehashed outdated information while omitting critical data on the environmental advantages of low-carbon biofuels.”

“It’s disappointing to see this EPA miss another chance to correct outdated claims which minimize contributions of U.S. biofuels to clean air and a healthy climate,” Growth Energy CEO Emily Skor said. “The Renewable Fuel Standard has stood the test of time as America’s single most successful clean energy policy, driving down greenhouse gas emissions while displacing toxic petroleum-based aromatics, like benzene, a known carcinogen.

“The latest U.S. Department of Agriculture data show that ethanol reduces greenhouse gas emissions by 39% or more compared to traditional gasoline, with corn ethanol’s relative carbon benefits reaching as high as 70%. And a vast trove of public, private, and academic studies shows how continuous innovation has allowed us to ramp up biofuel production year after year, without expanding our environmental footprint. The data is clear. Without ethanol, we would be rolling back the clock, with higher emissions of particulate matter, carbon monoxide, and smog-forming pollutants linked to cancer, as well as neurological, cardiovascular and reproductive damage.”

The Renewable Fuels Association said it is worried that EPA has relied on what RFA calls a “flawed” modeling system called MOVES to generate the result.

RFA President and CEO Geoff Cooper noted that EPA explicitly acknowledges there are “limitations and uncertainties” associated with the MOVES model it used, and admits that “updates and improvements have been suggested and are underway” but ignored the advice of RFA to either replace the MOVES 2014 model or make major modifications to it prior to embarking on the anti-backsliding study.

“Why does EPA continue to rely on flawed modeling tools, doctored data, and unrealistic hypothetical scenarios, when it has real data on air quality collected from hundreds of monitors across the country?” Cooper asked.

“The real-world air quality data speaks for itself,” Cooper said. “In the years since ethanol went from 1% of our nation’s gasoline to more than 10%, emissions of all major mobile-source pollutants have fallen. There are several reasons for that, but ethanol and the RFS certainly played a role.”