What Car? Q&A - Green special - What other fuels could I use?

Q: Fossil fuels aren't going to last forever. What other fuels can we use, and how green are they?
Mark Evans

A: Fuel-cell vehicles that use hydrogen have been touted as one alternative to fossil fuels - they offer zero carbon dioxide emissions, their only by-product being water.

However, containing and transporting hydrogen is notoriously difficult, and it's all some way off, too - the first production hydrogen fuel-cell cars won't arrive until around 2015.

Other alternatives include hybrid, biofuel and electric cars.

Hybrids use an electric motor to minimise the use of the petrol or diesel engine it is mated to. However, it is really only a temporary 'fix' until more sustainable means of powering a car are found.

The same is true of biofuels - these are made from plants that absorb carbon dioxide as they grow. Although they are an attractive prospect, they're not without their drawbacks.

E85 bioethanol (a mix of 85% ethanol and 15% petrol) is the major biofuel currently available. It is usually made from sugar beet and wheat, which require a lot of land to grow.

Biofuels made from wood chippings and plant waste are being developed to help solve the problem.

Electric cars could provide one solution. GM has developed the Volt concept car, which is powered by an electric motor. However, it uses a small engine to keep the batteries charged, so it's not entirely free of fossil fuels.

Lotus has also developed a 155mph, seven-seat 635bhp electric MPV with a range of 350 miles. It sounds promising, and uses a new type of battery to give it its extraordinary range.

However, any battery needs to be recharged. If such cars were to be available on the mass market tomorrow, we just don't have the means to recharge them sustainably - so inevitably that means emitting carbon dioxide, at least for now.

Green car buyer's guide
Click here to find out how to buy and run a more environmentally friendly car.