Some facts about biodiesel fuels

Biodiesel is a renewable fuel made from oilseed crops, or used cooking oils and unwanted animal fats. Biodiesel proponents claim it can reduce tailpipe emissions, be used in most diesel equipment with little or no modifications, and reduces our dependence on foreign oil.
    As a substitute for petroleum diesel, it is typically blended with petroleum diesel as B20 (20 percent biodiesel, 80 percent petroleum diesel). Soybean, canola, mustard, and palm oils are the most common plant oils that can be turned into biodiesel. The original biodiesel was peanut oil, used by Rudolph Diesel in his engine introduced at the World Exhibition in Paris in 1900.
Because of the many different products (feedstocks) and the chemical reaction that give biodiesel similar properties to petroleum diesel, it must meet an American Society for Testing and Materials (ASTM) standard to be called biodiesel. This is to ensure that the fuel meets certain specifications. This is important because some automobile manufacturers allow biodiesel blended with conventional petroleum diesel, that meets ASTM standards, to be used in their engines. There is also a new certification process for biodiesel that ensures the quality of the fuel. The Web site www.bq-9000.org provides more information about this certification.
Of the three claims identified above, the first is easy to verify. The United States Environmental Protection Agency (EPA) did a detailed study using biodiesel blended with petroleum diesel at a ratio of 20 percent biodiesel and 80 percent petroleum diesel. The results show the biodiesel blend will indeed reduce the chemicals that come out of the tailpipe of an automobile and cause smog. Unfortunately, one smog-producing chemical, nitrogen dioxide, may increase up to 2 percent when the B20 blend is used.
As far as claim number two goes, in the past there have been problems with deterioration of rubber engine components when using pure biodiesel and some biodiesel blends. These have largely been solved by using more resistant materials for seals and gaskets.
The key word in the last claim is “reduce.” Biodiesel cannot eliminate the needs of the United States for petroleum diesel. Our thirst for oil dwarfs the amount of biodiesel that can be produced, even if all the soybean grown in the United States were turned into biodiesel. So biodiesel is only one piece in our nation’s energy puzzle.
For more information about biodiesel see the Maine Department of Environmental Protection web site www.maine.gov/dep/air/mobile/biodiesel.htm.
This column was submitted by Peter Moulton, an environmental engineer with the Maine Department of Environmental Protection.