Three biofuels interest groups have leveled official criticism at EPA's so-called "anti-backsliding" study released in May, in official comments made to the agency this week.
The proposal calls for no further action to mitigate potential adverse air quality effects from renewable fuels. The study is required by the Clean Air Act and was released as part of a consent decree from February 2019.
The industry attempted for years to convince the agency to modernize the data it uses to account for renewable fuels emissions. That's because renewable fuels groups contend updated modeling on greenhouse gas emissions and other emissions shows fuels such as ethanol are far more beneficial to the environment than previously assumed.
"We agree that no additional 'fuel control measures' are necessary, but we reach this conclusion for a different reason than EPA," Renewable Fuels Association President and Chief Executive Officer Geoff Cooper wrote in comments to EPA.
"We believe no additional measures are necessary because the scientific evidence demonstrates that increasing the concentration of ethanol in gasoline generally improves air quality and does not cause 'adverse air quality impacts.'"
Cooper said the agency's anti-backsliding study "misrepresents" ethanol's air quality record.
"We remain concerned that the anti-backsliding study used to inform the proposed determination continues to rely upon an outdated and unreliable emissions model, the Motor Vehicle Emission Simulator, (or MOVES) to estimate the emissions impacts of ethanol-blended motor fuels," RFA said in comments.
"The agency itself has acknowledged the ABS 'has a number of limitations.' Indeed, it does. We firmly believe this model and the resulting ABS report are inappropriate tools for assessing the real-world air quality impacts of renewable fuels. We have repeatedly asked the agency to look at empirical data and real-world emissions measurements when assessing the air quality impacts of ethanol-blended gasoline, and we renew that request today."
Growth Energy said in written comments the Renewable Fuel Standard has "stood the test of time."
The group provided a detailed technical analysis on the clean air benefits of homegrown ethanol, illustrating areas where "the anti-backsliding study overstates the RFS' potential adverse impacts on air quality and understates the emissions and air quality benefits of ethanol-blended fuels."
Further, Growth Energy said, "Correction of the anti-backsliding study to address these errors would reinforce EPA's conclusion that new fuel regulations are unnecessary under Section 211(v). In any event, even without such corrections, EPA's existing analysis amply supports that no new fuels regulations are necessary.
"Using the actual fuel properties of E10 in conventional areas to recreate EPA's emissions analysis results in substantial decreases in NOX, VOC, and PM emissions, as well as even greater reductions in benzene and 1,3 butadiene, both potent air toxics, as well as carbon monoxide."
USDA data shows ethanol reduces GHG emissions by 39% compared to gasoline with corn's relative carbon benefits reaching as high as 70%.
Prior to EPA launching the study last year, groups such as the RFA expressed the need for the agency to incorporate real-world data in its modeling.
The RFA said since the RFS was adopted in 2005, agency data shows carbon monoxide concentrations have fallen by 31%, nitrogen dioxide is down 22%, ozone is down 13%, fine particulate matter is down 37%, and sulfur dioxide is down 81%.
The National Biodiesel Board said in comments because the anti-backsliding study only considers blends of 5% biodiesel, "fails to acknowledge the known linear beneficial decrease in emissions from increased use of higher blends of biodiesel.
"Furthermore, according to the Diesel Technology Forum, only 43% of U.S. commercial trucks have zero-emissions diesel technology (engines equipped with selective catalytic reduction and particulate control technologies), leaving upwards of 57% of on-road engines without the significant emissions reductions controls," NBB said.
"As a result, the impact that biodiesel will have on on-road engines alone is greater than the anti-backsliding study suggests."
Todd Neeley can be reached at email@example.com
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