Biodiesel is a non-petroleum based fuel that can be derived from renewable lipid sources such as vegetable or animal fat. In the scientific jargon, biodiesel consists of long chain mono alkyl esters. Biodiesel is easily degradable and is believed to be completely non-toxic. Therefore the use of biodiesel is growing in popularity. Especially with the alarming rise of the prices of conventional fossil fuels, and a global outcry against the air pollution caused by them, biodiesel seems to offer an excellent alternative. Another convenience of using biodiesel instead of fossil fuels is that, it keeps the engine cleaner and more lubricated.

The first indication that vegetable oil can be used to run automobile engines was probably received as early as 1900, when Rudolf Diesel, the famous inventor of diesel engines, displayed an engine running on vegetable oil. Even in the 1920s and 30s, governments of many nations invested into research programs to find out a commercially viable alternative fuel produced from renewable sources. In 1977, the Brazilian scientist Expedito Parente invented and patented a method of producing biodiesel by transesterification, which has now become an internationally accepted method of producing biodiesel.

Biodiesel is not very widely produced in the US. The reason of this may be that the conventional petroleum or diesel producing companies are reluctant to start making biodiesel as it will mean a complete remodelling of their factories which can be extremely costly. For similar resons, many car companies are not very keen to produce too many cars compatible with alternative fuels including biodiesel. However, the situation is changing.

The government is encouraging and awarding independet biodiesel producers and the use of biodiesel by fuel consumers. Many automobile companies are becoming aware that fuels such as biodiesel are prbably the future of the automobile industry as we are exhausing the fossil fuel resources pretty quickly. The US Navy has made it mandatory to use biodiesel in the vessels where it is possible to store fuel in them. The state of Minnesota has made it mandatory to use biodiesel fuel from the year 2005.

Biodiesel is usually produced by the transesterification process. In this process, a lipid substance (vegetable oil or animal fat) is made to react with methanol in the presence of a catalyst, which can be sodium or potassium hydroxide. The biodiesel that is produced this way is made of methyl esters consisting of long chain fatty acids. This reaction also creates a substantial amount of crude glycerin which needs to be separated from the biodiesel at the final stage of biodiesel production. This is how biodiesel is produced both commercially and domestically in the US.