Biofuels can be used in all vehicles from buses to boats, and require little or no engine modification. Their use could lead to a cut in carbon dioxide emissions of 50-60% compared with fossil fuels. Biofuels can be either liquids or gases.

Liquid biofuels are divide into replacements for fossil petrol or diesel.

Petrol substitutes are known as 'bioethanol', and are made by fermenting starches and sugars. Diesel substitutes are from oils - derived from either plants or animals. They can either be used directly, in which case vehicle engines need slight modification (often known as 'pure plant oil'), or be chemically altered so as to run in engines without modification. This is known as 'biodiesel'.

Any vehicle that can run on gas can operate on renewable gas - known as 'biomethane'. Although these vehicles are only a small amount of the current fleet, they are more widely used elsewhere, and a number of new models are due to come onto the market in the next few years.

The REA has set up a dedicated website to provide balanced information on sustainable biofuels - www.biofuelsnow.co.uk