The drive to grow biofuels for transport has focused on converting crops to ethanol which can be used in internal combustion engines. However, that is the wrong approach, according to a study published on Friday in the journal Science: it is much more efficient to convert biomass to electricity for battery-powered vehicles.

The authors, from the Carnegie Institution at Stanford and the University of California, Merced, calculated that generating electricity, by burning biomass in an efficient power station, delivered 80 per cent more mileage per acre of crops than conversion to ethanol for liquid fuel. It also doubled the greenhouse gas offsets to mitigate climate change.