BIODIESEL FREQUENTLY ASKED QUESTIONS

What is biodiesel made from?

Biodiesel can be made from a variety of renewable sources such as vegetable oils (soybeans or other crops), recycled cooking grease, or animal fats. These feedstocks are used to manufacture a mixture of chemicals called fatty acid methyl esters (biodiesel).

Which feedstock is best?

Each feedstock can produce a high quality B100 fuel but with slightly different properties, especially cloud point, cetane number, oxidative stability, and nitric oxide [NO] emissions. Cost might also factor into the selection process. Most operational differences seen with B100 are reduced when B20 is produced. Most remaining differences can be managed with additives or diesel fuel blending strategies.

Does biodiesel affect how my engine operates?

Biodiesel blends of 20% or less should not change the engine performance noticeably. Some users of biodiesel blends notice significant reductions in soot, and CO and HC emissions are reduced. Higher blend levels can reduce fuel economy, torque, and power but will also produce lower PM, HC, and CO emissions. NO may also rise with higher blend levels. Less noise and a better exhaust smell have also been noticed with biodiesel fuels.

Does using biodiesel void my warranty?

OEMs provide a material and workmanship warranty on their products. Such warranties do not cover damage caused by external conditions, such as fuel. Thus, if an engine using biodiesel experiences a failure unrelated to the biodiesel use, it must be covered by the OEM's warranty. Federal law prohibits the voiding of a warranty solely because biodiesel was used—it must be the cause of the failure. If an engine experiences a failure caused by biodiesel (or any other external condition, such as bad diesel fuel), it will not be covered by the OEM's warranty.

Who is using biodiesel?

The largest user of B20 is the Department of Defense, which planned to purchase more than 5.2 million gallons of biodiesel during the 2003-2004 contracting year. Many other federal, state, and alternative fuel provider fleets are also using B20, because it allows them to comply with EPAct regulation. B20 is even sold at retail pumps throughout the country.

B2 is sold in many outlets throughout the Midwest. Several states are considering legislation that requires the use of low-level biodiesel blends (B2-B5), and many operators in agricultural areas use biodiesel blends to support their local economies. Some fleets and many private consumers use B100.

Equipment that has been successfully used with biodiesel blends includes on-road vehicles of all types, construction, logging, farming equipment, power generators, boats and barges, heating oil boilers and industrial boilers, and even locomotives.

How much does biodiesel cost?

The wholesale cost of biodiesel is typically higher than diesel fuel by $1 to $2 per gallon. The size of the cost difference depends on the size of the biodiesel producer, their feedstock cost, transportation costs, production incentives, tax incentives, and other local variables. Historically, the cost of B20 has been about 20 cents per gallon higher than diesel fuel. B2 is only a few cents higher than diesel fuel.

How can I tell if the biodiesel I receive is of good quality?

The biodiesel industry has developed a voluntary quality control program for producers and distributors to ensure that biodiesel is produced according to ASTM specifications and that contamination or degradation does not occur during distribution, storage, or blending. That program is called the BQ9000. It is managed by an independent organization: The National Biodiesel Accreditation Commission. There are "Accredited Producers" and "Certified Distributors" depending on the activity in which a firm specializes. The firm receives the accreditation, not the fuel, but the fuel supplied by either an accredited producer or a certified distributor meets all applicable standards for sale and use in the United States.

Just as with conventional fuels, testing each batch of biodiesel is the only way to ensure good quality. The simple tests that consumers may perform, such as inspecting clarity by filling a clear glass container or performing a visual inspection, cannot determine the quality of the fuel. Other fleets conduct more extensive tests, either in-house or by sending the fuel to independent testing laboratories. for more specialized evaluation of fuel properties. The consumer saves money on testing by purchasing biodiesel fuels through certified marketers.

Are there standards or specifications for biodiesel?

ASTM has a biodiesel blend stock standard (ASTM D6751) that describes minimum standards for biodiesel properties. The Department of Defense has specification for B20 blends.

Do I need to modify my vehicle to use biodiesel?

Based on user experience, no vehicle modifications appear to be necessary for blends of biodiesel as high as 20% biodiesel mixed with diesel fuel. Higher blend levels may require minor modification to seals, gaskets, and other parts. Tank and fuel line/fuel filter heaters (arctic packages) are recommended for blends of more than 20% biodiesel.

Detailed long-term engine durability data have not been established for B20 in the United States, so good maintenance practices are recommended.

Do I need to modify my dispensing equipment to use biodiesel?

Dispensing equipment need not be modified for blends of 20% biodiesel or lower blend levels unless there is an issue with specific elastomers incompatible with B20. Occasional fuel filter plugging has been reported and some people filter the biodiesel fuels entering and/or leaving the tank. Some exposed parts of the dispensing systems may need protection from freezing in cold climates. Some people recommend tank cleaning before switching to B20 fuels.

Can I use biodiesel in a cold climate?

User experience with cold weather varies. B20 blends are used in some very cold climates such as northern Minnesota and Wyoming, where temperatures routinely fall below –30°F in the winter. B20 was used in an airport shuttle fleet for four years in Boston with no problems.

Some users have reported using B100 in extremely cold climates such as in Yellowstone National Park. The vehicles were equipped with winterization packages and no other precautions were noted. Since widespread experience with B100 and higher blends in cold climates is lacking in the United States, users should be alert to potential problems and take reasonable steps to prevent them.