Biodiesel

The Puget Sound Clean Air Agency supports using biodiesel in our fleets because it offers significant health and air quality benefits. 

Biodiesel is produced from renewable resources such as soybeans, mustard seeds, rapeseed (now known as canola) and refined waste vegetable oils.  Biodiesel can be blended at any level with petroleum diesel to create a biodiesel blend.  B100 refers to 100-percent biodiesel.  A mixture of 20-percent biodiesel to 80-percent petroleum diesel, or B20, is the most common blend.

Using a biodiesel mix in a conventional diesel engine substantially reducing emissions compared to regular diesel fuel.

Biodiesel can be used in any diesel engine with little or no modification to the engine or the fuel system.  It is, however, incompatible with natural rubber seals and hoses used in older engines, but newer engines use synthetic materials that are not affected.  Biodiesel is a solvent and will remove deposits from storage tanks and engines; the release of deposits may clog filters initially and precautions should be taken to replace fuel filters until the petroleum build-up is eliminated. This issue is less prevalent with B20 blends, and there is no evidence that lower-blend levels such as B2 (2-percent biodiesel, 98-percent petroleum diesel) have caused filters to plug.

Vehicles using biodiesel emit less air pollution than those using regular diesel

Recent studies conducted by the US Environmental Protection Agency (EPA) and the Department of Energy’s National Renewable Energy Laboratory (NREL) show vehicles using pure or blended biodiesel can reduce emissions of:

• Toxic air pollutants such as diesel particulate matter;

• Hydrocarbons such as volatile organic compounds, one of the ingregients for ozone formation in our region; and

• Carbon dioxide, a pollutant that causes global climate change.

In addition, these fuels do not appear to significantly affect nitrogen oxide (NOx) emissions in the Puget Sound region. As the percentage of biodiesel in the fuel mix increases, so do reductions in particulate matter, hydrocarbons, and carbon monoxide.