Biofuel: a tankful of weed juice

Before we give up on alternative fuels and dive back into an ever-shallower pool of crude oil, though, let’s spare a thought for a new batch of biofuels being cooked up in laboratories worldwide. They hold the promise of more efficient, cleaner energy sources that don’t compete with forests or food crops for growing space. Airbus, the maker of the A380, the largest passenger aircraft in the world, announced last week that it expects these second-generation biofuels to make up (eventually) a third of all aviation fuel.
Getting new biofuels off the ground is taking some doing. Starchy and sugary crops such as wheat and sugar cane make good biofuels because they are easily converted to ethanol, while oily sunflower and palm plants can readily be made into biodiesel. It would make much more sense, however, to produce biofuels from weeds growing on land that can’t be farmed, or from agricultural waste, old wood chips or even secondhand paper.

While the new fuels do not threaten rainforests or food supplies, they are not without problems. Scientists at the Global Invasive Species Programme, an international group dedicated to monitoring and tackling invasive plants and animals introduced from one region to another, warned last week that countries importing plants for biofuels could also be importing a host of problems. It estimates that alien species cost the world economy