A type of renewable diesel fuel produced by reacting vegetable oil or animal fat with hydrogen is helping meet growing demand for renewable biofuels, according to the U.S. Energy Information Administration. In a departure from predecessor biofuels made from alcohols, hydroprocessed esters and fatty acids (HEFA) fuels are hydrocarbons and nearly indistinguishable from traditional petroleum fuels. Because of their similarity to petroleum fuels, HEFA fuels can be used in diesel engines without blending with petroleum diesel fuel, EIA says. The standards organization ASTM International approved HEFA fuels for use in jet engines at up to a 50% blend. Since 2011, carriers including Alaska Airlines, KLM, and United have demonstrated the use of HEFA fuels on commercial flights. Currently, 10 plants worldwide produce renewable diesel, contributing some 380 billion L to meet global demand in 2014, EIA says.