What happened to biofuels?

SCIENTISTS have long known how to convert various kinds of organic material into liquid fuel. Trees, shrubs, grasses, seeds, fungi, seaweed, algae and animal fats have all been turned into biofuels to power cars, ships and even planes. As well as being available to countries without tar sands, shale fields or gushers, biofuels can help reduce greenhouse-gas emissions by providing an alternative to releasing fossil-fuel carbon into the atmosphere. Frustratingly, however, making biofuels in large quantities has always been more expensive and less convenient than simply drilling a little deeper for oil.