The University of Tennessee, Knoxville

Tennessee County Municipal Advisory Service

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Municipal Biodiesel Production

Reference Number: MTAS-734
Tennessee Code Annotated
Reviewed Date: September 19, 2017
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Biodiesel is an alternative fuel derived from various feedstocks such as soybean, other oil crops, waste vegetable oil and animal fats that can be used as a renewable fuel alternative to petroleum-based diesel fuel. Other potential next generation feedstocks include algae and jatropha. Biodiesel is biodegradable, nontoxic, and nonvolatile. It is produced through a chemical process called transesterification where methanol and sodium or potassium hydroxide are mixed with the feedstock. The process leaves behind two products: glycerin (a valuable co-product primarily used in soaps and in many cosmetics) and methyl esters (biodiesel). The methyl esters, after carefully washing to remove all remaining catalyst, alcohol and glycerol, are the biodiesel and can be used as a fuel in diesel engines. The esters are good solvents and cleaning gents. In addition to its other attributes, biodiesel reduces greenhouse gases. Used in its pure form, biodiesel reduces emissions of carbon dioxide by 78 percent, carbon monoxide by 40 to 50 percent and particulate matter by 50 percent.

Biodiesel also leads to energy independence by using renewable, American resources and can be a boost to the local economy through job creation and savings in operational costs. Biodiesel offers other services to communities seeking to minimize their energy related costs. It can be used in any diesel public works equipment such as dump trucks, service trucks, mowers and tractors. It can be used to develop heating systems if buildings have oil burners in their furnaces. Government buildings with steam radiators are good candidates to use biodiesel. It is possible to change out the natural gas burner for an oil burner and add an oil storage tank and use biodiesel for heating. Glycerin generated from production of biodiesel can be used to produce car wash soap to clean the vehicle fleet.