Odds are probably none of this stuff is 100% good for environment, but that doesn't mean it won't be better. These fuels are being studied with what they produce being one of the concerns of researchers, at the time that gasoline started getting realized people were just trying to push it out as the revolutionary thing it was with zero concern to its long term repercussions. Biofuels won't be perfect but they should be safer.
The development of Biofuels like Ethanol will reduce Greenhouse Gas Emissions greatly. These types of fuels are much safer for the environment. Millions of people are waiting to have access to them and would use them if they could. This would cut down on emissions from standard fuel vehicles and help the environment.