Having been rather negative about bio-fuels, I’ll be positive and mention The ethanol program in Brazil. And the abstract is: The number of automobiles in the world has been growing fast and today requires one quarter of the global petroleum consumption. This problem requires adequate solutions, one of which Brazil has achieved with the Sugarcane Ethanol Program. This paper presents the history of this program, from its launch in the 1970s to the today’s condition of full competitiveness in a free market. It also shows how it can be replicated to other countries, in order to replace 10 per cent of the world’s gasoline consumption.
It also has some stats on energy output/input ratios, showing sugar cane (10) far ahead of wood, corn or beet (various, centered around 2 ish).
[Apologies – the link I added is obviously some on-the-fly thing designed to stop people doing what i’ve done. So: the journal is http://www.iop.org/EJ/toc/1748-9326/1/1 and the article is down at the bottom – by JosÃ© Goldemberg. I also notice that there is “Learning from the Brazilian biofuel experience” higher up -W]
[Update: since this post I’ve found/had recommended The Ethanol Illusion and http://i-r-squared.blogspot.com, both of which are rather less optimistic. The latter says the return on oil is 6 ish, which makes 10 for sugar seem very high -W]