Chris Rhodes’ Energy Balance blog has an interesting insight into how bioethanol could feature in the UK's future fuel mix. Rhodes examines some of the UK's Royal Society of Chemistry’s Policy Bulletin on Energy Policy (published October 2006).
I think he sums up the current situation quite nicely when he says:
There is no way we can produce enough ethanol to match our current level of fuel use, either using biomass waste or without compromising our food production. There is no way we can produce enough ethanol to match our current level of fuel use, either using biomass waste or without compromising our food production.
His calculations are worth a look.