The U.S. Environmental Protection Agency (EPA) has been considering several new "pathways" to advanced ethanol, including grain sorghum (see WPI 30 October). As of 17 December, EPA approved the sorghum pathway for both advanced and conventional ethanol.According to the EPA, its "analysis indicates that ethanol made from grain sorghum at dry mill facilities that use natural gas for process energy meets the lifecycle [greenhouse gas] GHG emissions reduction threshold of 20 percent compared to the baseline petroleum fuel it would replace, and therefore qualifies as a renewable fuel under the conventional category." EPA also suggests that "grain sorghum ethanol produced at dry mill facilities using specified forms of biogas for both process e...