Biofuels have a very important part to play in the future, as we start to derive our energy needs from present day sunshine instead of using the energy that the sun radiated millions of years ago.
However, setting targets for biofuel use with no regard for the way they are produced can be counter productive. The demand for biofuels in Europe is causing the burning and reclaiming of millions of acres of tropical forests. This releases more carbon than will be saved by growing the fuel crop and shows how badly thought out the European targets are.
In the first place, we need to obtain our biofuels from the straw of normal food crops by efficiently harvesting the whole crop intact and then separate the components to use for both food and energy. At this point the straw is a free asset because no extra energy inputs have been used. As methods for producing ethenol from cellulose become well established we will then be able to obtain more and more energy from waste as well as from biomass produces on poor land or from woodland in a sustainable way.