BioDiesel -- a Renewable Fuel
BioDiesel is a renewable fuel that can be used instead of diesel fuel made from petroleum. BioDiesel can be made from vegetable oils, animal fats, or greases. Most BioDiesel today is made from soybean oil. About half of BioDiesel producers are able to make BioDiesel from used vegetable oils or animal fats, including recycled restaurant grease.
BioDiesel is most often blended with petroleum diesel in ratios of 2 percent (B2), 5 percent (B5), or 20 percent (B20). It can also be used as pure BioDiesel (B100). BioDiesel fuels can be used in regular diesel vehicles without making any changes to the engines. It can also be stored and transported using diesel tanks and equipment.
Fueling engines with BioDiesel has just started to catch on, but this isn't a new idea. Before petroleum diesel fuel became popular, Rudolf Diesel, the designer of the diesel engine, experimented with using peanut oil as fuel. In fact, early diesel engines were ran on vegetable oils up until the early 1920's when the oil barons figured out that the waste product they had after making gasoline could be sold to fuel diesel vehicles. Diesel engines eventually were changed to run best on the thinner #2 petroleum diesel and lost the ability to run on the thicker straight vegetable oil. So as a result today's diesel engines can't be ran on straight vegetable oil any more.
Most trucks, buses, and tractors in the United States use #2 diesel fuel. Diesel is a nonrenewable fuel made from petroleum. Using BioDiesel means that we use a little bit less petroleum. BioDiesel results in less pollution than petroleum diesel. Any vehicle that operates on diesel fuel can switch to BioDiesel without changes to its engine.
Because it is so clean burning and easy to use, BioDiesel is the fastest growing and most cost efficient fuel for fleet vehicles. Many school districts are switching to BioDiesel blends for their school buses. BioDiesel is also being used for fleets of snowplows, garbage trucks, mail trucks, and military vehicles. So far, the use of BioDiesel has been limited to fleets of vehicles that have their owner fueling stations. As the number of public fueling stations that offer BioDiesel grows, it may become more popular with individual consumers.
B100 and BioDiesel blends are sensitive to cold weather and may require special anti-freeze, just like petroleum-based diesel fuel does. BioDiesel acts like a detergent additive, loosening and dissolving sediments in storage tanks. Because BioDiesel is a solvent, B100 may cause rubber and other components to fail in older vehicles. This problem does not occur with BioDiesel blends.
BioDiesel is renewable, nontoxic, and biodegradable. Compared to diesel, BioDiesel, is significantly cleaner burning. It produces fewer air pollutants, like particulates, carbon monoxide, hydrocarbons, and air toxics. It does slightly increase emissions of nitrogen oxides, though. BioDiesel produces less black smoke, and smells better, too. Sometimes BioDiesel smells like french fries!
Regular diesel fuel contains sulfur. Sulfur can cause damage to the environment when it is burned in fuels. New environmental laws will require the amount of sulfur in diesel fuel to be dramatically reduced over the next few years. When sulfur is removed from regular diesel fuel, the fuel doesn't work as well. Adding a small amount of BioDiesel can fix the problem. BioDiesel has no sulfur, so it can reduce sulfur levels in the nation's diesel fuel supply while making engines run more smoothly.Last Revised: May 2005
Sources: Energy Information Administration, Annual Energy Review 2003, September 2004.
The National Energy Education Development Project, Alternative Fuels: What Car Will You Drive?, 2004.
U.S. Department of Energy, Energy Efficiency and Renewable Energy, Alternative Fuels Data Center, October 2004.