As used in: Some Ford and Saab models.
What is it? Biofuels are much like petrols or diesels, but the fuel is derived from organic sources, such as waste vegetable oil (green diesel) or sugar cane (bioethanol).
Where can I buy it? You may already be buying it without realising it, as all fuel now has to contain a certain (albeit very small) proportion of biofuel. However, fuel with a larger proportion of biofuel, such as E85 or B30, is far less widely available. Morrisons became the first supermarket chain to sell bioethanol at some of its stores, but others have yet to follow.
Pros: Biofuels have much lower emissions and no net carbon dioxide emissions (because of the carbon absorbed by the plant when it was alive). They are not dependent on fossil fuel resources and some will run in unmodified engines.
Cons: The fuels are almost impossible to obtain in the UK, and some cars cannot run on them without modification. The amount of land needed to produce the plants to make the fuel in suitable quantities may be prohibitive.
Expert view: Biofuels will conserve fossil fuel stocks, but viability will depend on availability and cost.
Outlook: Biofuels certainly have a future, but it is unlikely we can ever be totally reliant on them.