Biodiesel Basics


The concept of biofuels dates back to Rudolf Diesel who envisioned vegetable oil as a fuel source for his newly invented engine. The process the Initiative uses to produce biodiesel was discovered in 1937 by G. Chavanne of the University of Brussels in Belgium who was granted a patent for a paper entitled "Procedure for the transformation of vegetable oils for their uses as fuels", a process now called transesterification.

For more information about the history behind biodiesel, please visit Biodiesel at Home

Biodiesel can be blended and used in many different concentrations with petroleum diesel depending upon the desired application.

Low Level Blends

  • B5: 5% biodiesel, 95% petroleum diesel
  • ASTM approved for safe operation in any compression-ignition engine designed to be operated on petroleum diesel
  • Can be used in light and heavy-duty diesel cars/trucks, tractors, boats, and electrical generators


  • 20% biodiesel, 80% petroleum diesel
  • Most common biodiesel blend in the US
  • Good balance of cost, emissions, cold-weather performance, and materials compatibility
  • Blends at or above B20 qualify for biodiesel fuel use credits under the Energy Policy Act of 1992


  • 100% biodiesel
  • Can gel in cold temperatures, impact engine warranties, and suffer from microbial contamination in tanks
  • Less common than B5 or B20 due to a lack of regulatory incentives and pricing
  • Contains about 8% less energy per gallon than petroleum diesel


Source: US Department of Energy


Biodiesel is energy derived from natural resources such as plants. Incorporating biodiesel provides a cleaner burning fuel which improves air quality by reducing carbon emissions. For more information about the advantages of biodiesel, please visit the following sites:

Transesterification is the process of converting used cooking oil, or triglycerides, to fuel. Methanol (CH3OH) is used as a catalyst to break down the triglycerides into a mix of fatty esters, known as biodiesel. In order to utilize the methanol, it needs to be broken down by a strong base. In our lab, we use potassium hydroxide (KOH) where methanol splits into two ions: methyl ions (CH3+) and hydroxide ions (OH-). The hydroxide ion will form water with the free hydrogens, creating glycerin which is used in soap production. While the methyl ions react with the triglycerides in a 3 to 1 stoichiometric ratio forming biodiesel. For more information on the chemistry behind biodiesel production, please visit the following site: