Biofuels are great, but more is needed

"Most energy experts reckon that using maize-based ethanol as a substitute for petrol can reduce America's demand for petrol by 10-15% at best. As for sugar, its growing value as a biofuel feedstock means that in Brazil, which is now one of the world's largest producers and exporters of ethanol, there is pressure to flatten rainforests to make more room for sugar production. One green objective (reducing dependency on fossil fuels) thus conflicts with another (preserving the environment)." From The Economist.