Biodiesel is an alternative fuel that provides vast improvements to exhaust emissions and engine performance in compression-ignition (diesel) engines. It is known as neat biodiesel and is designated as B100.

Biodiesel contains no petroleum and is produced through transesterification of vegetable oils or animal fats. It is a fuel comprised of mono-alkyl esters of long chain fatty acids. Biodiesel has physical properties similar to petroleum diesel, yet biodiesel is biodegradable, clean, domestically produced, and meets the requirements of ASTM D 6751.

Biodiesel was used in the first diesel engine. Rudolf Diesel, inventor of the diesel engine, presented his new engine at the World Exhibition in Paris in 1898 and fueled it with peanut oil

• Non-toxic, 10 times less toxic than table salt
• Biodegradable
• Doesn't produce explosive air/fuel vapors because it has a high flash point
• Is safe for marine use
• Diverts used cooking oil from landfills
• Contains only trace amounts of sulfur
• Is "carbon neutral": growing plants absorb CO2 from the atmosphere that is later released during combustion
• B100 reduces CO2 emissions by 78% and B20 by 15% compared to #2 diesel
• Substantial reduction in other exhaust emissions:
  
  

  	PM	Hydrocarbons	CO	SOx
  B100	-30%	-93%	-50%	-100%
  B20	-10%	-21%	-11%	-20%
  ULSD (15 ppm sulfur)	-13%	-13%	-6%	-95%

  
  Compared to highway #2 diesel (500 ppm sulfur)

• Displaces imported petroleum
• Produced domestically
• Reduces pollution-related health problems like asthma and emphysema
• Can be used in conventional diesel engines
• Extends the U.S. petroleum supply
• Convenient to store and dispense
• Supports our agricultural sector, especially our farmers
• Available in all 50 states

• Can be used with little to no modifications to diesel engines
• Is higher in cetane, reducing engine knocking
• Can be blended in any ration with petroleum diesel
• Users can switch back and forth between fueling with a biodiesel blend or petroleum diesel
• Adds lubricity, which is important because ULSD has decreased lubricity properties
• Decreased lubricity results in excessive friction and engine wear
• Many users blend biodiesel with ULSD for biodiesel's lubricity properties
• Older vehicles (typically before 1994) will need to have their natural rubber hoses replaced with a synthetic material to avoid leaking in the fuel lines. This is only an issue with blends of 50% (B50) and above

• Biodiesel is usually more expensive than diesel
• All OEMs have approved B5 as a recommended fuel, and some have approved up to B100. Truck and auto manufacturers are still in the process of approving higher blends of biodiesel
• Depending on engine type and fuel injector adjustments, NOx emissions can be lowered
• Biodiesel is a solvent and will clean accumulated sediment and impurities from the inside of tanks and hoses
• A vehicle's fuel filter may need to be changed after the initial switch to blends of B50 or above. Once the sediments have been removed from the tank, users can use the regular fuel filter maintenance schedule
• Contains less energy per gallon than #2 diesel
• Although #2 diesel also gels in cold weather, biodiesel starts to gel at a higher temperature, this is called Cold Filter Plugging Point (CFPP)
• CFPP is the temperature at which fuel begins to gel, which can plug the fuel filter
• At blends of B50 or below, CFPP is not an issue

Biodiesel can be used in any diesel application, such as in passenger vehicles, industrial vehicles, off-road machinery, marine engines, power generation, and home heating oil.

Europe is the largest producer and user of biodiesel. The main feedstock used is rapeseed oil (similar to canola oil in North America).

The U.S. is the second largest producer and user of biodiesel. In the U.S., most biodiesel is derived from soybean oil (roughly 80%) or used cooking oils. The U.S. biodiesel industry is growing rapidly. Production tripled from 2004 to 2005 and again from 2005 to 2006. Biodiesel production capacity in the U.S. is 1.85 billion gallons with another 1.37 billion gallons under construction.

Biodiesel is widely available in the Northwest and production plants are operating in Oregon, Washington, Idaho, and Montana (see a few of the facilities below).

Biodiesel (B100) has 103% the energy of gasoline or 93% of diesel. B20 has 109% the energy of gasoline or 99% of diesel, and minimally affects power and torque. Most B20 users report no noticeable difference in performance or fuel economy.

To determine the net energy balance, lifecycle analyses are performed by comparing energy inputs to energy outputs throughout the entire fuel's production process. When comparing the energy balances of two fuels, such as biodiesel versus diesel, it is important to consider the entire production cycle and not just the energy content in the end product.

Biodiesel has a positive energy balance. By using a biodiesel lifecycle assessment, it was determined that 3.2 units of energy are produced for every 1 unit of energy consumed for production. Diesel has a negative energy balance, 0.83 units of energy is produced for every 1 unit consumed.

Biodiesel is produced through a chemical process called transesterification. Triglyceride oils in vegetable oils, animal fats, or recycled cooking oils are chemically reacted with an alcohol (commonly methanol) in the presence of a catalyst (such as sodium hydroxide) to produce fatty acid methyl esters (biodiesel) and glycerin.

Glycerin is a byproduct and can be burned as a fuel, made into soap, or used as livestock feed. The methanol is removed, cleaned, and recycled back into the process.


Image courtesy of the Department of Energy

Biodiesel quality is ensured throughout the distribution chain through rigorous standards and testing programs. All commercially sold biodiesel must meet ASTM D 6751 specifications.

• B99 (99% biodiesel) is the highest blend of biodiesel available on the market and provides the maximum engine, health, and environmental benefits. B99 requires an initial change of fuel filter, possible switching out of natural rubber materials, and will need to be blended with diesel in cold weather.
• B50 (50% biodiesel) is a common blend for cold weather operation and still provides a high level of biodiesel benefits.
• B20 (20% biodiesel) is the most common blend of biodiesel in the U.S. Materials compatibility and fuel filters are normally not of concern when using B20.
• B2 (2% biodiesel) and B5 (5% biodiesel) are blends mainly used to increase lubricity, especially when using Ultra Low Sulfur Diesel.

For specific procedures to follow when switching to any biodiesel blend, visit Biofuels4Business.

Original Equipment Manufacturers (OEMs) recommend biodiesel blends ranging from B5 to B100. Although an OEM may only recommend a lower blend of biodiesel, it does not void the vehicle's warranty to use a higher blend of biodiesel. However, if a problem occurs that is the fault of the fuel, it will not be covered by the warranty. If the problem is unrelated to the fuel and is a result of faulty workmanship or parts, it must be covered by the warranty. For more information, visit Biofuels4Business.

B20 is compatible with most diesel vehicles and storage and distribution equipment. It may be stored in tanks previously used for petroleum diesel.

B99 may degrade some hoses, gaskets, seals elastomers, glues and plastics with prolonged exposure. To provide fuel integrity, suppliers recommend that B99 be stored in existing tanks that have been steam cleaned or new B99 dedicated tanks. Teflon® , Viton® , and Nylon can be used to upgrade biodiesel incompatible equipment.

Homes or businesses heating with oil can use biodiesel in their furnaces and boilers with little to no modifications. Various blends of biodiesel can be used, including B20, B99, and other blends.

B20 blended with regular #2 heating oil reduces carbon monoxide emissions by 12.6% and particulate matter emissions by 12%. Using B20 is especially beneficial to human health because #2 heating oil contains sulfur. By switching to B20, those sulfur emissions are greatly reduced.

The solvent properties of B20 will clean out heating systems and fuel filters should be changed more frequently when first using the blend.

• www.biodiesel.org
• www.energy.gov/energysources/bioenergy.htm
• biodieselmagazine.com/index.jsp
• www.eere.energy.gov/afdc/fuels/biodiesel.html
• www.biodiesel.org/askben/basics
• www.fueleconomy.gov/feg/biodiesel.shtml
• www.biofuels4business.com