Not many people look at a farm field and see its potential for powering a bus, but domestic crops can be made into renewable, environmentally friendly fuel. Biodiesel is a nontoxic, biodegradable, renewable fuel produced from agricultural resources like vegetable oils. In the United States, most biodiesel is made from soybean oil; however, canola oil, sunfl ower oil, recycled cooking oils and animal fats are also used.
HOW IT IS MADE
To make biodiesel, the base oil is put through a process called esterification. This refining method uses an industrial alcohol (ethanol or methanol) and a catalyst to convert the oil into the biodiesel.
Biodiesel in its pure form is known as neat biodiesel or B100, but it can also be blended with conventional diesel, most commonly as B5 (5 percent biodiesel and 95 percent diesel) and B20 (20 percent biodiesel and 80 percent diesel). Biodiesel is registered with the EPA and is legal for use at any blend.
Most diesel engines can run on biodiesel without needing any special equipment. If you are interested in using biodiesel in your vehicles, check with the manufacturer for any recommendations and information regarding engine warranties.
In addition, once you have determined the proper blend, make sure to purchase your fuel from a reputable dealer selling commercial grade biodiesel.
BIODIESEL VS. VEGETABLE OIL
There have been stories in the media lately talking about cars, trucks and buses running on used vegetable oil. Though used vegetable oil is a cheap alternative to diesel fuel, it is not biodiesel and also not very good for your engine.
In 1895, Dr. Rudolf Diesel invented the diesel engine with the intention of running it on a variety of fuels, including vegetable oil. In fact, when he demonstrated his engine at the World Exhibition in Paris in 1900, he fueled the vehicle with peanut oil. However, biodiesel and vegetable oil are very different. Cooking oil is thicker, heavier and does not burn as well as regular auto fuel. Because it doesn't burn as well, it is likely to cause more pollution than other types of diesel. Its use may also void manufacturer warranties.
Waste cooking oil that hasn't been processed into esters is not biodiesel, and not registered by the EPA for legal use in vehicles. In addition, vehicles converted to use these oils would likely need to be certified by the EPA; to date the EPA has not certified any conversions.
When running on biodiesel, vehicles have similar horsepower and torque as when run on conventional diesel. Chemically speaking, biodiesel has a higher cetane number, but slightly lower energy content than diesel. To the driver, this means better engine performance and lubrication, but a small decrease in fuel economy (2 to 8 percent). Biodiesel vehicles can also have problems starting at very cold temperatures, but this is more of an issue for higher percentage blends like B100 and easily solved the same way as with conventionally fueled vehicles: by using engine block or fuel filter heaters or storing the vehicles in a building.
In 2004, 25 million gallons of B100 were sold. By 2005, that number had tripled. Today, approximately 600 fleets nationwide use biodiesel blends in their diesel engines, and biodiesel is available in its various blends at approximately 800 locations across the United States.
The price of biodiesel blends varies depending on geographic area, base material (corn, soybeans, etc.) and supplier. Although biodiesel can cost more than traditional diesel, diesel drivers can transition to it and back without purchasing new vehicles. In the case of fleets, managers can transition to biodiesel without acquiring new spare parts inventories or rebuilding refueling stations.
Generally, the use of biodiesel does not cause many maintenance issues. However, when used for the first time, biodiesel can release deposits accumulated on tank walls and pipes, initially causing fuel filter clogs. As a result, vehicle owners should change the fuel filter after their first tank of biodiesel. Also, biodiesel can degrade rubber fuel system components, such as hoses and pump seals. This is especially true with higherpercentage blends and older vehicles. Many newer vehicles feature biodieselcompatible components; contact the manufacturer for specific information.