Biodiesel Production and Distribution

Biodiesel is a legally registered fuel and fuel additive with the U.S. Environmental Protection Agency (EPA). EPA registration includes all biodiesel that meets ASTM D6751 and is feedstock neutral. The federal Renewable Fuel Standard requires at least 1 billion gallons of biomass-based diesel consumption in the U.S. (at this time, biodiesel comprises the vast majority of biomass-based diesel in the US). The RFS requires 1.3 billion gallons of biomass-based diesel in 2013.

Production

Biodiesel is produced from vegetable oils, yellow grease, used cooking oils, and tallow. The production process converts oils and fats into chemicals called long-chain mono alkyl esters, or biodiesel. These chemicals are also referred to as fatty acid methyl esters, and the process is referred to as transesterification. Roughly speaking, 100 pounds of oil or fat are reacted with 10 pounds of a short-chain alcohol (usually methanol) in the presence of a catalyst (usually sodium hydroxide [NaOH] or rarely, potassium hydroxide [KOH]) to form 100 pounds of biodiesel and 10 pounds of glycerin. Glycerin, which is used in pharmaceuticals and cosmetics, among other markets, is a co-product. Although the process is relatively simple, homemade biodiesel is not recommended. Diesel engines are expensive and risking damage, loss of warranty, and operational problems from fuel that does not meet rigorous ASTM D6751 specifications is not wise.

Schematic of Biodiesel
Production Path

Raw or refined plant oil, or recycled greases that have not been processed into biodiesel, are not biodiesel and should be avoided. Fats and oils (triglycerides) are much more viscous than biodiesel, and low-level vegetable oil blends can cause long-term engine deposits, ring sticking, lube-oil gelling, and other maintenance problems that can reduce engine life. (See Straight Vegetable Oil as a Diesel Fuel?).

Research is currently focused on developing algae as a potential biodiesel feedstock, because it's expected to produce high yields from a smaller area of land than vegetable oils.

Distribution

Biodiesel is distributed from the point of production to fuel distributors and wholesalers by truck, train, or barge. Most biodiesel distributors will deliver B20 or B100 depending on the retailer's preference. Find biodiesel distributors. For more information, see the National Biodiesel Board's Guide to Buying Biodiesel.