Review: The current problems with oil supply and the change in costing is raising yet again the debate about alternatives. The difference now is that the issues are that much greater and cover a wider area. The first idea for biofuels in modern times was following the "oil shock" of the early 1970s. When prices stabilised the demand reduced only to return again periodically. Now, with the threat of global warming along with an increase in international tension it seems more appropriate to return to the biofuel issue. Unlike the other times we now have this guide written by the researchers at Worldwatch and commissioned by a range of German government organisations.

The book is divided into eight parts. The first reviews the status of biofuel and the general global trends. We start with a history of the product (far longer than one might imagine, going back to 1820!) and then coming up to date with some of the more recent changes. Everyone needs to appreciate the potential of biofuels but not everyone is a chemist so a chapter outlining the basic production system is welcomed. A further chapter explores the raw materials side. Next we move to a section dealing with the advances in the product. History is useful and the development of the Brazilian ethanol production is well known and appreciated but if this system is to get anywhere near useful global production then we need to increase our base. There are really three questions we need to answer here: what crops can we use, how do we "refine" them and what is the potential. Each of these is answered here setting the scene for a consideration of implications. The conclusion is that there is considerable potential for biofuels which might lead one to assume that the debate is over. However, that is only part of the picture. Biofuels are not environment-neutral, neither are they a resource on their own. Biofuels interact with all elements of environment and economics. Part three chooses to focus on the economic and social issues. Economic issues take first place with an examination of the cost effectiveness of the fuel and the degree of energy security it could produce. The answers are surprising with tropical nations standing to gain and the final benefit depending on uptake and production so although we have a viable source, there is still much left to get right. Biofuels take land and this land could grow other crops. Given that biofuels will need a huge amount of land it does mean that other systems will lose out and so a discussion on this aspect is vital. Also, some businesses will profit e.g. agribusiness and so there is no obvious equity in this issue. Currently, trade is not an issue but this will change and it is useful to see what might happen. Part four looks at the environmental side of the equation. Energy balance starts the debate with a discussion on the effect of biofuel in terms of efficiency and global warming contribution. The global aspect is given more prominence with a chapter devoted to the trade-offs associated with global warming and biofuel proportion. These are end-user issues - there's also the production and processing side to consider. Part five looks at a key component so far neglected - markets and technology. It's one thing to produce a fuel but you need a market to sell it to and a technology to run it. Given the debate over running ethanol in "conventional" engines this is one section that is definitely needed. Once produced we need to distribute the product. Luckily, in liquid form this is much like current petroleum models and so there is already of model to draw upon. Next, vehicles have to be made to run biofuel and expertise needs to be developed to continue innovation. Part six takes on the vital aspect of regulation and policy. Like oil, there needs to be a set of standards which can deliver a globally-acceptable product. Part seven is just one chapter - a summary of the key points and part 8 comprises five brief biofuel studies in a range of nations. Appendices provide some useful data and flow charts.

Biofuel is not the first energy system to be put forward as a/the solution to energy needs. What alternatives have lacked is a book like this, much at the beginning of the debate, to guide thinking in its development. This is an excellent overview prepared by members of the Worldwatch Institute - many of the same people who bring us the renowned annual State of the World publications. They've kept up their standards of research and the single focus has allowed them a much more authoritative overview. That said, it's a dense read packed with technical details and information - excellent material for the educator taking up this topic (in a range of fields not just environmental/ecological science). Overall, one of the best texts on energy and energy futures. It deserves the widest readership.