Introduction

The name "biodiesel" was introduced in the United States in 1992 by the National SoyDiesel Development Board (now the National Biodiesel Board), which has pioneered the commercialization of biodiesel in the U.S.

Chemically, biodiesel is referred to as the mono alkyl esters of long chain fatty acids derived from renewable lipid sources.

Biodiesel is the name for a variety of ester-based oxygenated fuels from renewable biological sources. It can be used in compression-ignition (diesel) engines with little or no modifications. Pure biodiesel is biodegradable, nontoxic and essentially free of sulfur and aromatics.

Biodiesel is a methyl or ethyl ester of mainly vegetable oils. Since soybean oil is the dominant oil produced in the U.S., the development effort has focused around it as a feedstock for biodiesel. Biodiesel readily blends with diesel fuel in any percent. The blend level is a function of economics, the desired emissions profile, material compatibility, and combustion characteristics. The focus at the moment is on a 20 vol% blend of biodiesel in petrodiesel.

Methyl or ethyl esters can be produced from vegetable and tree oils, animal fats, and/or used oils and fats. These oils are blended with an alcohol (usually methanol, although ethanol can be used as well) and a catalyst such as sodium hydroxide. The resulting chemical reaction (which occurs at moderate temperatures and pressures) produces an ester and glycerine. Glycerine is a valuable material used extensively in the manufacture of soaps and other consumer products.

Biodiesel's performance is similar to diesel. While biodiesel has slightly less energy per gallon than number 2 diesel, it has slightly more energy than number 1 diesel. Tests have shown its performance when used in vehicles to be virtually the same as diesel.

Advantages

Biodiesel has a number of advantages when compared with both petroleum diesel and other alternative fuels. It needs to be emphasized, however, that the goal of the biodiesel industry is not to replace petrodiesel or to supplant the invaluable role of other alternative fuels. Each of these fuels has a place in the development of a balanced energy industry. The compression-ignition engine has certain advantages over spark-ignition engines and role of biodiesel is to contribute to the longevity and cleanliness of diesel engines.

Markets are being developed based on the end users desire to purchase a more costly, premium fuel in either neat, 100% form, or blended with diesel. Consumers have shown that they are willing to purchase biodiesel based upon several factors:

First, biodiesel is produced domestically, which helps reduce the United States' dependence on imported petroleum.

Second, the development of the biodiesel industry would strengthen the domestic, and particularly the rural, agricultural economy.

Third, it is a renewable fuel that can be made from agricultural crops and/or other feedstocks that are considered waste, such as cooking oil and trap grease. This helps conserve resources and makes the best possible use of materials which may be perceived as having little or negative value.

Fourth, the U.S. agricultural sector has, for many years, produced a surplus of soybean oil, and the implementation of the GATT agreement and, to some extent, NAFTA, will affect the U.S. market for this commodity. Use of surplus soybean oil to produce energy domestically and renewably will benefit everyone.

Fifth, the production of soy-based biodiesel has a positive energy balance (as much as 3:1), due to the high energy value of ester-based feedstocks, the low-energy requirements of the conversion process, and the nitrogen-fixing characteristic of soybeans, which reduces the need for fertilizer.

Sixth, biodiesel blends are competitive with other alternative fuels on a life-cycle cost basis, bec