Biodiesel

Biodiesel is a domestically produced, renewable fuel that can be manufactured from fatty substances. Common feedstocks around the world include soybeans (United States), rapeseed and sunflower oil (Europe), and palm oil (Malaysia). It even can be produced from waste cooking oil. Biodiesel is safe, biodegradable, and reduces serious air pollutants that contribute to global warming. Just like petroleum diesel, biodiesel operates in compression-ignition engines. Thus, blends of 20% biodiesel with 80% petroleum diesel (called B-20) can be used in many unmodified diesel engines, though users should consult their engine warranty statements. Biodiesel can be used in its pure form (B-100), but it may require certain engine modifications to avoid maintenance and performance problems and may not be suitable for use in cold climates. Biodiesel can generally be transported, delivered, and stored using the same equipment as conventional diesel fuel.

Eighty-six biodiesel production plants exist in the United States today. Together, they produce almost 600 million gallons of biodiesel per year. Biodiesel is often blended with petroleum diesel for use in bus and truck fleets. Government biodiesel consumers include the Departments of Defense, Agriculture, Energy, and the U.S. Post Office; countless school districts, transit authorities, national parks, public utility companies, and garbage and recycling companies also use the fuel.

Visual source: http://www.biodiesel.org/resources/fuelfactsheets/

Biodiesel production process: First, fats and oils are chemically reacted with alcohol to make a chemical compound called fatty acid methyl esters. Second, the fats and oils are filtered and washed to remove contaminants. Third, the pretreated fats and oils are mixed with alcohol and a catalyst (usually sodium or potassium hydroxide). The resulting oil molecules are broken apart and formed into two separate products, methyl ester and glycerol. Finally, these products are purified into biodiesel and glycerin (used in soap), respectively.

Further resources on biodiesel:

• The National Biodiesel Board
• The Department of Energy, Energy Efficiency and Renewable Energy Division Biodiesel page
• The Auto Alliance
• Energy Information Association Annual Energy Outlook 2006