U.S. biofuel capacity slips, renewable diesel holds steady

The U.S. Energy Information Administration on May 29 said operable U.S. biofuel capacity slipped to 25.235 billion gallons per year in March, down 56 million gallons from February as ethanol and biodiesel eased while renewable diesel held steady. Fuel ethanol capacity fell to 18.388 billion gallons per year, biodiesel dipped to 1.955 billion gallons per year, and renewable diesel and other biofuels stayed unchanged at 4.892 billion gallons per year.

That split marks a more selective phase for the sector after the recent buildout cycle. Renewable diesel and other biofuels, which EIA says includes renewable heating oil, renewable jet fuel, renewable naphtha, renewable gasoline and other biofuels and biointermediates, also captures refineries co-processing renewable feedstock and petroleum. The unchanged capacity base suggests the market is digesting earlier additions rather than rushing into another wave of nameplate growth.

Ethanol remains the anchor of the U.S. biofuels complex, but it is no longer where the sharpest expansion is happening. EIA’s 2024 capacity review said fuel ethanol accounted for 73% of all U.S. biofuels production capacity and was almost 18.5 billion gallons per year, underscoring how concentrated the industry still is even as renewable diesel has grown into a much larger segment. EIA also said in an October 27, 2025 Today in Energy update that U.S. biofuels production capacity growth slowed in 2024, a trend echoed by the smaller moves in the latest monthly table.

The feedstock data showed the same unevenness. Total soybean oil used for biofuels reached 1.283 billion pounds in March, including 697 million pounds at biodiesel plants and 587 million pounds at renewable diesel plants. Corn use for biofuels rose to 26.594 billion pounds from 24.118 billion pounds in February, reinforcing ethanol’s continuing pull on the grain market even as ethanol capacity itself edged lower. March biofuel capacity was still 235 million gallons per year above March 2025, but the gains were concentrated outside ethanol, where the industry is now looking more to debottlenecking, efficiency upgrades and feedstock economics than to major greenfield additions. EIA’s next monthly update is scheduled for June 30.