The use of jet fuel from renewable sources is now well demonstrated, but it costs more than double what fuel made from petroleum does, according to airlines, aircraft companies and suppliers. One way to cut the cost may be to tinker with the plants that biofuel is made from.
Take jatropha, for example. Lufthansa said last week that it had completed a series of more than 800 flights by an Airbus A321 that shuttled between Hamburg and Frankfurt while burning a 50 percent biofuel mix in one of its two engines. The biofuel was derived partly from jatropha, a tropical shrub with an oil-rich nut, and it cost about two and a half times what ordinary petroleum-based fuel does.