What is biodiesel?
Safety and Performance
Government Programs and Regulations

What is biodiesel?

Biodiesel is a diesel fuel substitute used in diesel engines made from renewable materials such as:

  • Plant oils: canola, camelina, soy, flax, jatropha, mahua, pongamia pinnata, mustard, coconut, palm, hemp and sunflower;
  • Waste cooking oil:yellow or tap grease;
  • Other oils: tall, fish, and algae;
  • Animal fats:beef or sheep tallow, pork lard, or poultry fat; and
  • Potentially from cellulosic feedstock consisting of agriculture and forest biomass.

How is it made?

The feedstock goes through a process called transesterificationand consists of fatty acid methyl esters (FAME). Transesterification is a reaction between the oil or animal fat with an alcohol and a catalyst. The chemical reaction of transesterification produces two products - glycerol and an ester called biodiesel. Raw vegetable oil or animal fats which have not undergone a chemical/refining process is not considered biodiesel and is not recommended for use in diesel engines.

Biodiesel is one common example of a renewable diesel. Hydrogenation-derived renewable diesel (HDRD) is another type of renewable diesel produced by hydrotreating of similar fat or oil based biodiesel feedstock. Other technologies to turn biomass into renewable diesel are being developed.

Feedstock use in renewable diesel

Biodiesel: vegetable oil, waste cooking oil, animal fats, fish oil, and algae oil.

Hydrogenation-derived renewable diesel (HDRD): vegetable oil, waste cooking oil, animal fats, fish oil, and algae oil

Emerging Fuels Technologies, Fischer-Tropsch, Biomass to Liquid: cellulosic feedstock

Biodiesel Blends

Biodiesel is mixed with diesel to create a blend. This blend is comprised of pure biodiesel, also referred to as B100, blended with petroleum diesel at varying concentrations (Bn). The n refers to the percentage of biodiesel in the blend. Common blends are:

Blend Pure Biodiesel (B100) Petroleum Diesel
B2 2% 98%
B5 5% 95%
B10 10% 90 %
B20 20% 80%