In recent months biofuels have earned a reputation blacker than the crude oil they are meant to be replacing. No sooner do we learn that rainforests from Indonesia to Brazil are being razed to farm “green” fuels for the West than intensive production of biofuels is blamed for the current crisis in world food prices. And apparently some biofuels create more potentially harmful ozone than petrol does.

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.

The world’s biggest second-generation biofuel factory is due to open in Georgia, USA, next year. Range Fuels’ Soperton plant is expected to produce 16m gallons of ethanol biofuel annually from logging waste and grasses. This may not sound a lot in global terms but it is the start of something much bigger: a 13 billion-gallon ocean of second-generation biofuels that the USA is aiming to produce by 2022.

Meanwhile, Warwick HRI, the horticultural research division of Warwick University, is doing its bit in Britain. It is working on ways to turn worthless material such as straw into valuable fuel right on the farm, using a combination of bacteria and fungi.

Guy Barker, the research leader, says, “If we could break down straw into a liquid form on the farm, it could then be shipped straight to a refinery, like crude oil. Any leftover material on the farm could be worked back into the ground to sustain future crops.”

The Warwick process, which is still some way from commercial viability, will be slower than the enzyme system preferred by the Americans. “But do you want speed or do you want efficiency?” Barker asks. “Transporting large amounts of waste biomass to factories becomes a real problem, and the cost is high.”

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 £700 billion every year. It instances plants such as the giant reed, Chinese silvergrass and the sawtooth oak as species that are being cultivated in Europe despite being highly invasive.

We have recently learnt that every environmental solution brings its own set of problems. Fair trade or transport miles? Fossil-fuel power stations or carbon-free nuclear ones? Genetic crop engineering or pesticides? Biofuels or food riots?

You can’t win ’em all, so it’s a matter of choosing the least worst option. Right now that looks like second-generation biofuels.

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