Forget all of the ads about turning corn into ethanol. An acre of corn produces only about 480 gallons of ethanol, according to Patrick McCroskey, chief financial officer at Ceres, the California Environmental Resources Evaluation System, a government agency that facilitates access to environmental data. Instead, researchers are looking at switchgrass and other leafy plants for making cellulosic ethanol. These plants potentially could produce twice as much or more energy per acre as corn, and the ethanol could be processed with microbes, pictured here. These plants would also fertilize themselves, ideally, and consume less water. Some companies, like Greenfuel Technologies, based in Cambridge, Mass., are looking at ways of harvesting algae for ethanol.