Grist, quoting a recent study in Science, reports that the production and use of ethanol may make a larger contribution to global warming than the same amount of oil would have. These results are reached by considering the forests and grasslands being razed for biofuel crops plantations.
This is no surprise for ethanol skeptics. But it does underline the importance of detailed assessments, from source to end use, when comparing the environmental and climate impact of different type of fuels.
What will be the primary source of energy for our vehicles in 20 years? Electricity? Hydrogren? DME? One can only make a qualified guess. It is clear however that it is something that will depend upon political decisions as much as market logics.
And ethanol makes food prices soar as well.