What Is Biodiesel?

Biodiesel is a nontoxic, biodegradable replacement for petroleum diesel. Biodiesel is made from vegetable oil, recycled cooking oil and tallow. Chemically biodiesel is described as a mono alkyl ester. Through a process called esterification, oils and fats are reacted with methanol and a sodium hydroxide catalyst to produce fatty acids along with the co-products: glycerin, glycerin bottoms, soluble potash and soaps. Biodiesel belongs to a family of fatty acids called methyl esters which are defined by the medium length, C16-18 fatty acid linked chains. These linked chains help differentiate biodiesel from regular petroleum diesel.
Although biodiesel contains a similar number of BTUs as petroleum diesel (118,000 vs. 130,500 BTUs per equivalent translating to similar engine performance in torque and horsepower), the chains are oxygenated and have a higher flash point. This makes biodiesel a much cleaner burning fuel while being safer to handle and store than petroleum diesel. In tests conducted at the Colorado Institute for Fuels and High Altitude Engine Research, a 20% blend was found to reduce particulate discharge by 14%, total hydrocarbons by 13%, and carbon monoxide by more than 7%.
Biodiesel (including a B20 blend) is now recognized by both the Environmental Protection Agency and Department of Energy as an alternative fuel, and it qualifies for mandated programs under the Clean Air Act Amendments (CAAA 90) and the Environmental Protection Act of 1992 (EPACT). In addition, biodiesel is:

• non-toxic (its toxicity is less than 10% of that for ordinary table salt)
• biodegradable (degrades in about the same time as sugar)
• essentially free of sulfur and carcinogenic benzene
• derived from renewable, recycled resources, which don't add significantly to the greenhouse gas accumulation associated with petroleum-derived fuels.
 
Direct benefits associated with the use of biodiesel in a 20% blend with petroleum diesel as opposed to using "straight" petroleum diesel include:
• increasing the fuel's cetane and lubricity for improved engine life
• reducing substantially the emissions profile including CO, CO2, SO2
particulate matter (PM) and volatile organic compounds (VOCs)
• helping to clean injectors, fuel pumps and fuel lines.

These benefits occur while requiring virtually no engine modifications or costly infrastructural additions. In fact, with the addition of a catalytic converter, nitrous oxides (NOX) can be reduced as well, allowing B20 fleets the flexibility to meet various air quality compliance criteria.
Ultimately, biodiesel provides the diesel fleet operators and vehicle/equipment owners (including both on and off-road use, stationary generation, and marine environments) the opportunity to comply seamlessly with federal Clean Air and EPACT mandates without the burden of many of the high costs in capitalization associated with other alternative fuels. A number of independent studies have been conducted comparing the various alternative fuels, including studies conducted by the US Department of Agriculture and the US Department of Energy's National Renewable Energy Lab. In these, the life cycle costs and the projected cost per mile traveled were compared and biodiesel was substantially the most cost competitive of the alternative fuels.