What is Biodiesel?
Biodiesel is a clean-burning alternative to petroleum diesel made from domestic, renewable resources such as vegetable oils, recycled cooking oil and animal fats. For vehicle use, biodiesel must pass the specifications of ASTM D6751, which is a number of chemical parameters that ensure fuel reliability and quality. If it doesn't pass the ASTM specs, it's technically considered a methyl ester.
Biodiesel can only be used to power diesel engines. Sometimes people confuse biodiesel with ethanol. Ethanol is typically made from corn in the US and is an alcohol, while biodiesel is simply a modified vegetable oil.
How is Biodiesel made?
Making biodiesel is a simple chemical process. The heated vegetable oil or animal fat is reacted with methanol and a catalyst, such as sodium hydroxide, to produce a methyl ester - the biodiesel. The reaction creates two layers, biodiesel on top and glycerin on the bottom. After separation the biodiesel goes through further processing to remove excess methanol, soaps and residual catalyst. This is required to meet ASTM specifications as a road fuel. The glycerin can be used to make many other products including soap and non-toxic antifreeze. Learn more about making biodiesel here
Most biodiesel in the US is produced from soybean oil. We favor used vegetable oil from restaurants because it is plentiful in urban environments. Other local feedstock that could be utilized to make biodiesel are:
- Oil from used coffee grounds
- Fish oil from Asian Carp
- Oil from phytoremediation crops grown on contaminated land
How is Biodiesel used?
Biodiesel can be used in virtually any diesel engine without modification. It can be used in its pure form (called B100) or as a blend with diesel fuel at any ratio. The most commonly used form of biodiesel is a 20% blend of biodiesel with 80% petroleum diesel, known as B20. This has become a common practice as a balancing of benefits with costs, cold weather and solvency considerations associated with biodiesel. (More on these below.) Biodiesel provides similar horsepower and fuel economy as petroleum diesel with superior lubricity to reduce wear and tear on the engine.
Blended biodiesel can also be used to heat homes in oil burning boilers. Most of the oil burning furnaces in the Chicago area were replaced or retrofitted to use natural gas, but the home heating oil is still big on the East Coast. The biodiesel blend is call Bioheat. Learn more here
Benefits of Biodiesel
Biodiesel provides numerous environmental and economic benefits:
- Biodiesel reduces nearly all forms of air pollution compared to petroleum diesel. In particular, biodiesel reduces toxic contaminants and cancer-causing compounds, along with the soot associated with diesel exhaust.
- Biodiesel also reduces greenhouse gases, which contribute to global warming. Lifecycle analyses of biodiesel production, distribution and use show that biodiesel produces 78% less CO2 than petroleum diesel fuel.
- Biodiesel has a positive energy balance, producing 3.2 units of energy for every unit of energy used in production. In contrast, diesel fuel produces on .89 units of energy for every unit of energy used in production.
- Biodiesel is non-toxic and biodegradable.
- The use of domestic, renewable sources of energy reduces our dependence on imported oil, thereby improving our nation’s energy security.
- The domestic biodiesel industry provides jobs and economic development.
- Biodiesel is easy to use and can be used in existing diesel vehicles and fueling infrastructure.
In Illinois we have a state sales tax exemption on any biodiesel blend of B11 or higher. This 6.25% tax savings means that B11 is cheaper than straight petroleum diesel. For this reason, almost all fuel pumps in IL sell B11 and Illinois state sells more biodiesel than any other state in the US. It also makes it difficult to purchases higher blends of biodiesel because there is not a direct economic advantage. There are 2 public stations that sell higher blends withing 36 miles of Chicago. You can also purchase B100 from the Loyola Biodiesel Program by appointment only. Chicago Biofuels is proud to supply the vegetable oil for the Loyola Biodiesel program.
- The closest biodiesel pumps to Chicago:
- B100 - Loyola University in Chicago. *map*
- B100 - Feece Oil Co. in Batavia. *map*
- B20 - Petroliance in Elgin. *map*
To see more stations outside of the Chicago area as well as locations for other types of renewable fuels, use the Department of Energy Alternative Fueling Station Locator
In general, the standard storage and handling procedures used for petroleum diesel can be used for biodiesel. There are differences, however, in the requirements for pure biodiesel and biodiesel blends.
- Flash Point: Biodiesel has a significantly higher flash point than that of diesel fuel, making pure biodiesel one of the safest fuel to use, handle and store.
- Cold Weather: As with any diesel fuel, biodiesel can gel at low temperatures. Pure biodiesel (B100 or 100% biodiesel) requires some special handling, such as a heated or insulated storage tank. For biodiesel blends, precautions beyond those employed for diesel are generally not needed.
- Solvency: Biodiesel can loosen or dissolve sediments in fuel tanks and fueling systems. Cleaning tanks prior to biodiesel use may be warranted. At a minimum, fine gauge filters should be used on fuel lines going into and out of storage tanks, as well as in the vehicle. Check these filters often during the initial phase of biodiesel use and change as needed. The solvency effect is reduced when using biodiesel blends. The solvency property of biodiesel makes it an excellent parts cleaner, but avoid contact with painted surfaces.
- Material Compatibility: Biodiesel can soften or degrade natural rubber hoses and gaskets, leading to fuel leaks and spills. Most newer engines contain synthetic parts. However, older engines should be checked and any natural rubber parts replaced. Biodiesel is also not compatible with some metals and other materials. Aluminum, steel, fluorinated polyethylene, fluorinated polypropylene, and most fiberglass make acceptable storage tanks. Brass, bronze, copper, lead, tin and zinc should be avoided.
- Spills: Spills of biodiesel blends should be treated as a petroleum diesel spill. Spills involving pure biodiesel require much less intensive clean-up. Consult with your local department of ecology or fire department for details.
Who else uses Biodiesel?
Fleets have logged millions of miles using biodiesel and biodiesel blends. Some market segments are pushing higher blends for safety reasons.
- ComEd Commonwealth Edison, based in Chicago, has used a B20 blend in all of their diesel equipment all year around for over 6 years.
- The Mining Industry The cleaner burning biodiesel is a lifesaver in underground mines where air quality standards are very strict for heavy equipment. Even though B100 may at times cost more than petroleum diesel, it is cheaper than purchasing all new equipment with expensive exhaust management technologies. More info here: here
- Marine applications Diesel boat engines are perfect for biodiesel because in the event of a spill, biodiesel is non-toxic and biodegrades rapidly. In environmentally sensitive areas, the cleaner exhaust will not damage wildlife
- Aircraft The airline industry is making an effort to decrease their carbon footprint and have made many successful test flights with biodiesel blends at high altitudes
- Military The US military has made a comitment to using domestically produced renewable fuels.