Biodiesel Source Comparison
• In the United States, animal fats and oils are as available as the major source of vegetable oil – soybeans.
• Beef tallow tends to cost about $0.03 per pound less than soybean oil, and yellow grease (recovered and rendered cooking oils) tends to cost about $0.05 per pound less than soybean oil. This means that it costs about $0.28 per gallon less to make tallow-based biodiesel, and about $0.47 per gallon less to make yellow grease-based biodiesel.
• Animal-derived biodiesel provides better lubricity than vegetable-based biodiesel because of a larger fraction of saturated fatty acids. This is critical for extending engine life when using low-sulfur diesel fuels.
• Animal-derived biodiesel has a smaller fraction of multiple unsaturated fatty acids than soybean-derived biodiesel, leading to lower nitrogen oxides (NOx) emissions.
• Tallow, lard, and chicken fat have fatty acid compositions similar to palm oil, the largest single source of fatty acid methyl esters (FAME) in the world. Palm-based FAME is used to make biodiesel in a growing number of countries.
• The use of rendered products (animal fats and greases) to make biodiesel is a business based upon recycling. The use of virgin vegetable-based cooking oils directly for fuel, instead of first using them for cooking, denies us the opportunity to use the oils as a valuable commodity twice.
Biodiesel Fuel Facts
• The physical and performance properties of any mixture of mono-alkyl fatty acid esters are determined by the composition of the mixture (fatty acid profile), not the source of the fatty acids.
• A mixture of mono-alkyl fatty acids must meet the specifications of ASTM D 6157-2 before it can be designated biodiesel, or B-100.
• B-100 has been shown to be non-toxic, biodegradable, and B-100 and its blends have demonstrated reductions in all exhaust emissions except for NOx.
• B-100 can be used as a diesel fuel, or it can be blended with petroleum-derived diesel fuel meeting ASTM specification D 975. The blend designations, such as B-20, B-2, or B-5, refer to the percentage biodiesel in the mixture by volume.
• B-20 is a certified alternative fuel under the terms of the Energy Policy Act of 1992.
• B-2 to B-5 blends have demonstrated significant improvement in lubricity when used with low-sulfur diesel fuels. Improved lubricity promotes longer engine life.
• The cost of the fats or oils used to make B-100 is 75 to 85 percent of the finished product cost – less expensive raw materials are better.
August 2002 Render