Biodiesel FAQs

Q: What is biodiesel or bioheating oil?
A: Biodiesel is a blend of biofuel blended with traditional diesel or heating oil. It is a clean burning alternative fuel, produced from domestic and renewable resources. Biofuel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biofuel blend. It can be used in compression-ignition (diesel) engines or regular heat equipment with little or no modifications. Biofuel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics.

Q: How does biodiesel differ from ethanol?
A: Biodiesel is made most frequently from high protein feedstocks like soybean oil through the trans-esterificiation process, but can be made from various types of animal fats and vegetable oils as well. New feedstocks like pennycress, castor, jatropha, algae and palm oil are constantly being explored as additional biofuel options for market. Biodiesel is blended with diesel fuel and is used in diesel engines and home heating oil equipment. Ethanol is an alcohol fuel made from sugar-based plant materials such as corn, sugar cane, or grasses. Ethanol is blended with gasoline in gasoline engine vehicles.

Q: How is biofuel made?
A. Virgin soybeans (or another plant based feedstock) are crushed and pressed for oil. There are two byproducts from the pressing – mash and soybean oil. The mash is fed to animals and included in human products (ie. Protein bars). The remaining oil undergoes a chemical process called transesterification – glycerin is separated from the fats and vegetable oils of the feedstock. The glycerin is sold for use in manufacturing of soaps and other household products. The remaining purified methyl esters are in fact Biodiesel that can be blended with diesel or #2 heating oil fuel for a diesel vehicle or heating oil system. Nothing is wasted in the process and everything is used for its’ intended purpose.

Q: Is biofuel cleaner than natural gas?
A: Testing has shown that a biofuel blend of 20% or higher when mixed with ULSD burns cleaner than natural gas. Testing conducted by the National Oilheat Research Alliance (NORA) found that a bioheating oil blend of 80% low-sulfur heating oil and 20% biodiesel (B20) reduced sulfur dioxide emissions by as much as 80% or more. Nitrogen oxide emissions were lowered by about 20%. In addition, carbon dioxide emissions can be lowered by 20%.

Q: Is there any type of quality assurance program for biofuels?
A: BQ-9000 is a voluntary quality assurance program that accredits biodiesel producers and marketers. BQ-9000 warrants that the quality is maintained at proper specifications, and helps monitor quality throughout the distribution system. The EPA has also recognized biodiesel as an Advanced biofuel, making it the only commercial-scale U.S. fuel produced nationwide to meet the agency’s advanced criteria.

In addition, as of December 2014 the ASTM spec for heating oil now includes performance specifications for blends of 6-20% biodiesel in traditional heating oil. This reinforces the confidence in bioheating oil for homeowners and building managers across the U.S.

Q: What are the benefits of biodiesel?
A: Not only does it reduce emissions, displace foreign oil imports, and is grown domestically, it also improves your system’s performance and longevity. You will realize cost per mile savings. If you are using a B5 ULSD blended fuel you will experience:

• Increased cetane rating – shorter ignition delay
• Increased oxygen content improves combustion
• Smoother idling – less vibration and less parts repairs
• Cost savings in fuel efficiency and maintenance
• Increased filter intervals and less maintenance due to vibration
• Less tail pipe emissions and odor
• Older vehicles regain life and gain years in operation

Q: Can I use biodiesel in my existing diesel engine?
A: Yes! Biodiesel can be operated in any diesel engine with little or no modification to the engine or the fuel system. Biodiesel has a solvent effect that may release deposits accumulated on tank walls and pipes from previous diesel fuel storage. The release of deposits may clog filters initially and precautions should be taken. Ensure that only fuel meeting the biodiesel specification is used.

Q: Does biodiesel perform as well as diesel fuel?
A: Biodiesel can be used in existing diesel engines and fuel injection equipment in blends up to 20% with little impact on operating performance. Biodiesel has higher cetane than U.S. diesel fuel. B20 (20% blend of biodiesel with diesel fuel) provides similar fuel economy, horsepower, torque, and haulage rates as diesel fuel. Biodiesel also has superior lubricity, and it has the highest BTU content of any alternative fuel.

Q: Does biodiesel require special storage?
A: No it does not. Biodiesel can be stored wherever petroleum diesel is stored, except in concrete-lined tanks. Acceptable storage tanks include aluminum, steel, fluorinated polyethylene, fluorinated polypropylene and teflon. Use traditional additives as you do for diesel and heating oil treatment in cold months.

Q: Will biodiesel perform well in cold weather?
A: Just like common #2 diesel, certain high-freezing-point compounds in biodiesel will crystallize in very cold temperatures. As temperatures get colder, proper blending for B20 becomes more critical, and the fuel’s sensitivity to process variations increases. Blends of 5% biodiesel and below have a small impact on cold-flow properties (measures of low temperature operability).

Q: Will biodiesel plug the filters?
A: Biodiesel has a solvent effect proportionate to the amount of biodiesel in the fuel. For example, B100 has a higher solvent effect than B20. This will clean your vehicle’s fuel system and could release deposits accumulated on tank walls and in pipes from previous diesel fuel usage. The release of deposits in higher biodiesel blends may initially clog filters, so you should be proactive in checking for and replacing clogged fuel filters. Once the build-up is eliminated, return to your regular replacement schedule. This issue is prevalent with B20 and lower blends. There is no evidence that lower blends plug filters.

Q: What is the BTU of various blends of biodiesel compared to diesel?
A: The efficiency is the same whether using biodiesel, diesel, or biodiesel blends so differences in horsepower, torque or fuel economy are due entirely to volumetric energy content1. The energy content of biodiesel is much less variable than that of petrodiesel, and with biodiesel meeting D 6751 standards the energy content is more dependent upon the feedstocks used than the particular process. Blends of biodiesel and diesel fuel fall between the parent fuels.

The values below represent those of energy content of average No. 2 diesel fuel and average biodiesel in the US.2 While BTU changes of 1-2% can be picked up in lab tests for horsepower, torque, and fuel economy, in practice it is difficult to detect any differences with a 1-2% change in fuel BTU content outside normal variability experienced from day to day operations, even in closely monitored fleets.

Average Density and Heating Value of Biodiesel and Diesel Fuel

Fuel Density, g/cm3 Net Heating Value Avg., BTU/Gal. % Difference vs. No.2 Diesel Avg.
No. 2 Diesel 0.850 129,500
 Biodiesel (B100)  0.880  118,296 8.65%
 20% Biodiesel Blend (B20)  0.856*  127,259 1.73%*
 2% Biodiesel Blend (B2)  0.851*  129,276 0.17%*

*Calculated Values from those of No. 2 disesel and biodiesel (B100)

1 “2004 Biodiesel Handling and Use Guidelines”, US Department of Energy, US Department of Energy, DOE/GO-102004-1999 Revised 2004.
2 “A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions”, US Environmental Protection Agency, EPA420-P-02-001, October 2002.
3 “Energy Content”, National Biodiesel Board

Q: How do biodiesel emissions compare to petroleum diesel?
A: Biodiesel is the only alternative fuel to have fully completed the health effects testing requirements of the Clean Air Act. The use of biodiesel in a conventional diesel engine results in substantial reduction of unburned hydrocarbons, carbon monoxide, and particulate matter compared to emissions from diesel fuel. In addition, the exhaust emissions of sulfur oxides and sulfates (major components of acid rain) from biodiesel are essentially eliminated compared to diesel.

Of the major exhaust pollutants, both unburned hydrocarbons and nitrogen oxides are ozone or smog forming precursors. The use of biodiesel results in a substantial reduction of unburned hydrocarbons. Emissions of nitrogen oxides are either slightly reduced or slightly increased depending on the duty cycle of the engine and testing methods used. Based on engine testing, using the most stringent emissions testing protocols required by EPA for certification of fuels or fuel additives in the US, the overall ozone forming potential of the speciated hydrocarbon emissions from biodiesel was nearly 50% less than that measured for diesel fuel.

Q: How much biodiesel is being produced?
A: Biodiesel production has been on the rise each year. In 2012 a billion gallons were produced in the U.S., followed by 1.28 billion in 2013. The industry has established a goal of producing about 10% of the diesel transportation market by 2022.

Q: Can biodiesel help mitigate “global climate change”?
A: A 1998 biodiesel lifecycle study, jointly sponsored by the US Department of Energy and the US De-partment of Agriculture, concluded biodiesel reduces net CO² emissions by 78% compared to petroleum diesel. This is due to biodiesel’s closed carbon cycle. The CO² released into the atmosphere when biodiesel is burned is recycled by growing plants, which are later processed into fuel.

You can measure your emissions reductions using biofuel by using the National Biodiesel Board biodiesel emissions reduction calculator:


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