Biodiesel is a greener and cleaner source of energy which is far more sustainable than fossil fuel. It is made from compounds derived from animal or vegetable fats which are processed to extract useful oil rather than simply go to waste.

Crucially, it reduces the dependence on fossil fuels such as petroleum and acts as a more sustainable energy source. It is also possible to blend into commercial fuels to enhance their environmental credentials.

In the UK, biodiesel is used widely in transport. For example, London buses use a B20 blend. This allows the network to save over 65,000 tonnes of carbon dioxide annually, which equates to taking 30,000 cars out of circulation.

The fuel is called B20 because it incorporates a 20pc biodiesel with 80pc petroleum. There are other grades too, which are named accordingly, such as 5pc biodiesel - this is called B5.

The B20 blend is one of the modern types that requires no modifications to existing engines. This makes it a great choice for individual and commercial vehicles. Biodiesel also has a special status as the only alternative fuel that has passed the Clean Air Act's Health Effects Test requirements in America.

London's borough of Hackney has taken things even further, however, and its public transport now operates on B100. This has saved the borough 65,000 tonnes of carbon dioxide.

There is even a global Biodiesel Day. It is marked on 10th August in remembrance of the innovator, Rudolf Diesel, who first ran an iron cylinder using peanut oil in 1893. By doing so, he was the first user of biodiesel.

Today there is a range of commercial biodiesel preparations available and various new types in development. Modern products are now so efficient that they are even used within the aviation industry.