A bipartisan group of 18 senators on June 11 sent a letter to U.S. EPA Administrator Michael Regan urging the agency to boost Renewable Fuel Standard renewable volume requirements (RVOs) for biomass-based diesel and advanced biofuels in its upcoming 2026 rulemaking. 

Within the letter, the lawmakers ask Regan to set the volumes for biomass-based diesel and advanced biofuels “that are consistent with production and availability, while ensuring an equivalent increase in total volumes to preserve demand across all categories of biofuels.”

The senators stress that a strong RFS bolsters the domestic fuel supply and is critical for ensuring the U.S. continues to make progress with efforts to decarbonize its roads, seas, railways and skies. Increased production and availability of biofuels also benefits consumers at the pump and supports farm income. 

“The RFS volumes set by EPA last June for 2023-2025 are the highest in history,” they wrote. “However, new evidence shows that volumes need to be set significantly higher across the board to account for increased production capacity for biomass-based diesel and advanced biofuels.” The letter cites information published the U.S. Energy Information Administration last fall that shows RVOs for biomass-based diesel and advanced biofuels were set significantly lower than production trends. The letter also cites data showing that renewable identification number (RIN) values have fallen by an average of 66% since last summer, sending a discouraging market signal to farmers, feedstock producers, biofuel producers, blenders and investors. 

“Domestic fuel production facilities are closing as a result, putting Americans out of work and disrupting local economies,” the senators continued. “The negative signal to renewable fuel producers threatens billions of dollars of investment in feedstock and fuel production, including sustainable aviation fuel. Without EPA action, America will miss out on the energy benefits and carbon reductions delivered by advanced biofuels.”

The letter is signed by Sens. Amy Klobuchar, D-Minn.; Chuck Grassley, R-Iowa; Richard Durbin, D-Ill.; John Thune, R-S.D.; Maria Cantwell, D-Wash.; Jerry Moran, R-Kan.; Tammy Duckworth, D-Ill.; Joni Ernst, R-Iowa; Mazie Hirono, D-Hawaii; Roger Marshall, R-Kan.; Sherrod Brown, D-Ohio; Michael Rounds, R-S.D.; Tammy Baldwin, D-Wisc.; Deb Fischer, R-Neb.; Debbie Stabenow, D-Mich.; Pete Ricketts, R-Neb.; Tina Smith, D-Minn.; and Gary Peters, D-Mich. 

Clean Fuels Alliance America has spoken out in support of the senators’ request. "More and more heavy-duty transportation industries are looking for reliable, cost-effective, low-carbon solutions that are available now,” said Kurt Kovarik, vice president of federal affairs at Clean Fuels Alliance America. “U.S. clean fuels producers and feedstock suppliers have made significant investments to build the capacity to deliver those solutions right now. Those investments expand markets for U.S. agriculture, support domestic energy security, and drive economic opportunities for rural communities. EPA must act in a timely manner on the 2026 RFS volumes and utilize the best available production data to support advanced biofuel market adoption.”

A full copy of the letter is available on the Clean Fuels website.