Biodiesel is a diesel-like fuel derived from vegetable oil or other renewable resources. It can be made from soy or canola oil, waste cooking oil, and even animal fats. Biodiesel is made by combining the vegetable oil with alcohol [usually methanol but occasionally ethanol] in the presence of a catalyst through a process called transesterification.

Biodiesel derived from waste cooking oil is arguably the greenest liquid fuel available because the primary ingredient is a post-consumer waste product. Most biodiesel today, however, is “virgin biodiesel” produced domestically from soy or canola crops. Both recycled and virgin biodiesel are being produced to meet ASTM standard D 6751, approved in December 2001. This new standard, in the works since 1994 by the ASTM Biodiesel Standards Task force, for the first time provides a consistent biodiesel standard.

Some biodiesel today is mixed with petroleum diesel. The most common mixture is B20, a mixture of 20% biodiesel and 80% petroleum diesel. B100, or 100% biodiesel [sometimes called “neat biodiesel”] is being used very successfully by some but is not as widely recommended, due to concerns about cold weather performance, equipment compatibility, and cost.

Passenger vehicles

As an individual consumer, our transportation choices make the single biggest impact on the environment. Bicycling, taking the bus, and carpooling are great choices, but sometimes we need to drive a car. One of the simplest choices that can be made is to buy a diesel-powered automobile and burn biodiesel. By doing this, we can greatly lower the impact that our transportation makes on the environment.In Europe approximately 40 percent of passenger vehicles are diesel, thus the choices are more numerous.
Home/Building Heating

It is also possible to use biodiesel as a home-heating fuel. If your furnace is an oil-burning furnace, then you could be using any biodiesel blend- from B5 to B100. There are currently several customers of Dr. Dan’s Alternative Fuelwerks, in Seattle [see Resources], who have biodiesel delivered for home use.

Fleet [Buses, etc]

Biodiesel use by municipal fleets has the greatest potential to improve air quality in the Puget Sound region, as most fleet vehicles run on diesel. These include most buses (both city and school), garbage trucks, and delivery trucks. In some areas of the US, the US Postal Service has begun using biodiesel in its vehicles.