A group of 10 senators led by Sens. John Thune, R-S.D., and Amy Klobuchar, D-Minn., on March 18 sent a letter to Agriculture Secretary Tom Vilsack urging the USDA to complete a full lifecycle assessment of soybean oil-based biodiesel, including direct and significant indirect emissions, before the end of the year.

“As the Department of Agriculture (USDA) works to ensure the inclusion of agriculture-based biofuels as part of the effort to decarbonize our fuel supply, it’s critical that lifecycle carbon assessments of biofuels be based on current and sound science,” the senators wrote. “Fuels like biodiesel offer a sustainable, readily available source of emissions reductions, but full acknowledgement of such contributions require accurate data and modeling.”

The letter references USDA’s recent updated emissions assessment of corn ethanol, but stresses a similar analysis has not yet been conducted for biodiesel. The USDA review, according to the senators, should consider the most recent assessment conducted by the U.S. Department of Energy’s GREET model, USDA’s indirect land use change assessment, and the indirect land use change assessment conducted by Perdue University.

“We believe an updated assessment will show significant reductions in the overall lifecycle emissions of biodiesel, reinforcing the fact that America's soybean farmers and biodiesel producers are among the most sustainable in the world,” the senators wrote.

“Our request comes at a critically important time as states, regions, and municipalities are designing new or expanding existing greenhouse gas reduction targets,” they continued. “We believe that biofuels have already demonstrated their value as a readily available fuel that is compatible with existing vehicle fleets and fueling infrastructure. However, providing an updated, federally supported lifecycle assessment of soybean oil-based biodiesel will help ensure that this product is given accurate credit when considering carbon reduction strategies. Additionally, since EPA generally benchmarks new RFS pathways petitions against soybean oil, USDA providing EPA with an updated assessment could help facilitate new pathway approvals for burgeoning areas of agriculture like winter oilseed cover crops.”

In addition to Thune and Klobuchar, the letter is signed by Sens. Chuck Grassley, R-Iowa; Jerry Moran, R-Kan.; Deb Fischer, R-Neb.; Michael Rounds, R-S.D.; Joni Ernst, R-Iowa; Tina Smith, D-Minn.; Josh Hawley, R-Mo.; and Roger Marshall, R-Kan.

A full copy of the letter can be downloaded from Thune’s website.