With 620 million cars worldwide and fossil fuels running out, are biofuels the green solution to our energy needs? Now there's a revolution going on in the garages of the UK as individuals and companies switch to biofuels. Retired teacher Dick Jones makes his own biofuel, to power his people carrier from the local pub's converted chip fat. Although the chemicals involved are potentially dangerous, the rewards can be worth it. Jones says he likes "the idea of using a waste product to make oil, and I like the idea of being energy independent, but it also saves a lot of money". It costs him some £21 for a tank of home-made bio-diesel, compared with £80 at the garage. Growing phenomenon Businesses including McDonalds and Stagecoach are starting to experiment with biofuels. # UK Biofuel consumption 2004 - 21 million litres # 2005 - 118 million litres # 200 - 264 million litres # 2006 - 264 million litres # 2007 - 500 million litres Source: HM Revenue & Customs They are both trialling fuels made from used cooking oil. But unfortunately there is not enough used chip fat to power our entire economy, which is why biofuels made from food crops like maize, wheat, palm oil and rapeseed, are seen by some as the answer. The justification is when the plant-derived biofuel is burned in an engine, the CO2 released is offset by the amount of the gas that the plants absorbed as they grew. Previously, only Brazil (and at one point Zimbabwe) made fuel from sugar cane, but now the US and Europe see biofuels as the way forward. The UK Government has said that by 2010 5% all UK fuel should come from biofuels. The EU has gone even further, setting a target of 10% by 2020. Food or fuel But how are we going to reach those targets? Critics argue it will mean diverting crops from food to fuels. Will the knock-on effect be a hike in the prices of cereal and grains which hit those already living in poverty hardest? Greenpeace's John Sauven says that "when it comes down to it, you can put food in someone's stomach or you can put fuel in the tank of the car and it's that kind of black and white". And the criticisms don't stop there. Mr Sauven says the demand for biofuels has piled even greater pressure on the world's already fragile rainforests. "It's a disaster to see the rainforests being cleared whole-sale and massive monoculture palm oil plantations put in their place," he says. Traceability Both the UK and the EU have issued guidelines on sourcing biofuels from sustainable sources, but it is hard to enforce. # Average UK unleaded petrol prices Feb 2008 - 104 pence per litre # Feb 2007- 86 pence per litre # Feb 2006 - 90pence per litre # Feb 2005 - 80pence per litre # fact here # Feb 2004 - 81.9pence per litre # Feb 2003 - 80.2pence per litre Fuel giant Shell says it could not guarantee its biofuels do not come from palm oil. Shell's head of Future Fuels, Graeme Sweeney, says "traceability will improve over time". "It won't be possible in the beginning to trace everything, but that doesn't mean to say that we shouldn't do all that we can," he continues. But the bio-fuel industry is not the only one to place demands on palm oil resources. National differences Andrew Owens, of biofuel manufacturer Greenergy, believes the biofuel industry has been unfairly blamed. Although it does not use palm oil, Mr Owens says "you have to look at all the consumers of palm oil, and not just biofuels". "The lion share is the food industry." The car industry has embraced biofuels, investing in designing the so called 'flex-fuel' car, which can run on either unleaded petrol or biofuel. The market leaders are the Ford Focus and the Saab bio-power., but if you do want to run them on the maximum biofuel efficiency, there there's a hitch: the cars take 85% biofuel, known as E85 and it is only available at a handful of UK forecourts. There is a country where things are different: Sweden. There are more than 1,000 biofuel stations there and...

• Jeremy Clarkson