Biofuels are already quietly gaining acceptance into everyday life.
Tesco blends five per cent of ethanol, made with fermented Brazilian sugar cane, with petrol on 40 per cent of its forecourts.
A fuel dubbed E85 - 15 per cent petrol to 85 per cent ethanol - is being sold at Morrisons forecourts around the West country, for use in so-called flexible fuel cars, such as Ford's flexi-fuel Ford Focuses. Avon and Somerset Police have commissioned 40 such vehicles.
But biodiesel has also been creeping into use on a more homespun level.
Although rapeseed oil is the best vegetable-based alternative to mineral oil, cheap waste cooking oil is the secret ingredient in many tanks.
James Allison, a 36-year-old electronic engineer from Staffordshire, first turned to it when finances were tight two years ago.
He could not afford the fuel for a 100-mile round trip to the premises of his new job and started filling up with waste cooking oil collected from nearby Chinese restaurants and takeaways, which he would keep and filter in containers in his kitchen.
He got it for free and the restaurants relished the opportunity to get rid of it without having to pay for its disposal.
Now he sells it as a sideline at Allison Racing in Newcastle under Lyme, one of five biodiesel suppliers in the West Midlands.
Is there a market for biodiesel? "God yes, there's a huge market for it," he said. "I collect 1,000 litres every week. I'm limited because of the supplies and because I filter and heat it at home. It sells at 87p per litre and it costs close to £1 per litre in garages.
"Some people want it for environmental reasons and others for the cost. I'm deliberately not marketing the company because it sells so quickly."
Birmingham MP John Hemming decided to have his Land Rover Discovery converted to run on vegetable oil. Mr Hemming (Lib Dem Yardley) now visits his local Somerfield store rather than a garage when he needs to top up his tank.
At £8 for a large can, or 53p a litre, he is making a saving on the cost of a tank of diesel. He is also promoting his party's green credentials by cutting down on fossil fuel emissions.
Mr Hemming paid £1,000 to have twin fuel tanks installed on his Discovery. He still has to start the engine using diesel, but switches once the vegetable oil has reached 80 degrees Celsius. The practice is perfectly legal, although the MP does have to pay 27p a litre in tax to the Government for the privilege of using oil rather than diesel.