Ethanol should replace imported fossil fuels and thus reduce the dependence on imported gasoline. Bush wants to reduce fuel usage by 20 % by 2017. This is equivalent to three quarters of the current gasoline import from the Middle East. The president wants to reach this target by making vehicles more fuel efficient and by dramatically increasing ethanol production, to five times the current target level.

Although Bush mentions research into production of ethanol from wood chips and grasses, ethanol in the US is currently produced from corn. Analysts have calculated that Bush's 10-year target would require more corn than the total amount the US currently grows. The reservation of 20 % of US corn for fuel purposes has already quadrupled the price of tortilla (from corn) in Mexico and led to food riots.

In contrast to ethanol from sugar cane, ethanol from corn hardly helps to reduce carbon dioxide emissions, critics say. A report from the Massachusetts Institute of Technology last June showed that emission gains were virtually cancelled out by the energy needed to produce the fertilisers and to convert the crops into ethanol.

Finally, the London based International Institute for Environment and Development (IIED) warns that the hunger for energy crops could be an incentive for farmers and companies to replace forests with corn fields. "Environmental benefits could be lost if the sector's expansion leads to further deforestation," IEDD researcher Annie Dufey says. "It is increasingly urgent to map a path for the global biofuels industry that supports sustainable development."