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The Renewable Fuels Association (RFA) has sent another letter to the Environmental Protection Agency (EPA) regarding what they call errors in the calculations of biofuels’ carbon intensity under the Renewable Fuels Standard (RFS2). In the August 4th letter, RFA writes, “according to [EPA’s] own analysis, EPA grossly overestimated potential emissions from land use change (LUC) attributable to the [greenhouse gas] lifecycle of corn ethanol and other biofuels.”

The result of correcting this error, says RFA, is that it would greatly increase the greenhouse gas reduction benefits offered by ethanol under EPA’s calculations.

“Correcting this miscalculation reduces net LUC emissions (international and domestic) assigned to corn ethanol by 62% from 28.4 grams of CO2-equivalent/mega joule (g/MJ) to 10.8 g/MJ. Such a reduction in LUC emissions means overall lifecycle GHG emissions for 2022 average corn ethanol would be 38% less than baseline gasoline emissions, rather than the 21% estimate finalized by EPA.”

Regardless of RFA’s analysis, they still maintain that the inclusion of LUC impacts, particularly international impacts over which the U.S. has no control, is flawed policy and that EPA misinterpreted the intent of Congress when it passed the RFS.

In a recent blog post discussing their letter to EPA, Geoff Cooper, RFA’s Vice President of Research and Analysis, writes, “Despite the fact that real-world data and events have disputed the ILUC theory at every turn, EPA’s final rule for the RFS2 institutes a net LUC penalty (domestic and international) against corn ethanol of 30 kg CO2e/mmBTU (or 28.4 g CO2e/mega joule). This represents nearly 40% of the total GHG intensity of corn ethanol as estimated by EPA. When LUC emissions are excluded, EPA found corn ethanol from a natural gas dry mill reduces GHG emissions by 50% compared to gasoline. With LUC emissions, that benefit falls to around a 20% reduction.”

RFA says that this overestimation occurred as a result of the questionable methodological choice EPA made to isolate the LUC impacts of individual biofuels by increasing their production one at a time and holding all other biofuels at constant levels. More appropriately, the RFA notes, if EPA felt compelled by the statute to penalize biofuels for ILUC, it should have based those penalties on modeling that simultaneously increased production for all biofuels in accordance with the RFS requirements.

RFA notes that these problems are endemic of larger concerns regarding attempts to limit emissions from vehicles by unfairly penalizing biofuels.

You can read RFA’s letter to the EPA here and read Cooper’s comments regarding this issue here.