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Biodiesel

Consumer Issues

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Consumers are constantly in search of the best value for each product they purchase. This is especially relevant when prices of products are rising. In recent years, diesel fuel prices have risen, fallen, and risen again. Changing prices have encouraged consumers to examine diesel fuel purchases. Consumers can reduce their petroleum diesel use by driving less, purchasing a more fuel efficient vehicle or by purchasing an alternative fuel such as biodiesel. Each option has advantages and disadvantages. This article will explore the basics of biodiesel.

What is biodiesel?

Biodiesel is a fuel produced in a chemical reaction between a vegetable oil or an animal fat, an alcohol and a catalyst. One of the advantages of biodiesel is that in most cases, biodiesel can be used in a standard diesel engine. Consumers can switch between diesel and biodiesel at any time.

Is vegetable oil the same as biodiesel?

Biodiesel and vegetable oil are not the same product. Although vegetable oil is the main ingredient in most biodiesel, the vegetable oil must undergo a chemical reaction (transesterification) with alcohol and a catalyst before it can be considered biodiesel. Vegetable oil that has not been reacted with an alcohol and a catalyst is commonly referred to as waste vegetable oil (WVO), straight vegetable oil (SVO) or virgin oil.

Are engine modifications required to use biodiesel?

Biodiesel can degrade some natural rubber compounds that are used in fuel lines on older diesel engines (pre-1993). If you intend to use high blends of biodiesel (B20 or above) on a regular basis in an older vehicle then you may need to replace the fuel lines with synthetic fuel lines. Some seals are also made of natural rubber compounds and may need to be replaced. Most newer vehicles utilize synthetic fuel lines and gaskets so modifications are generally not required.

Will biodiesel damage my engine?

Biodiesel that meets the appropriate fuel quality standards is unlikely to cause damage to a diesel engine. The fuel quality standards for biodiesel are defined by the American Society for Testing and Materials (ASTM) in standard “ASTM D6751.” This standard includes acceptable levels for water and sediment, sulfur, free and total glycerin, flashpoint, cetane number and other specifications. Petroleum diesel fuel is also required to meet fuel quality standards. These standards are defined in “ASTM D975-05.” Biodiesel produced for personal use is often not tested
against these fuel standards. The quality of the biodiesel may vary depending on the quality control measures of the biodiesel producer.

Will using biodiesel void my engine manufacturer’s warranty?

Engine manufacturers typically only warranty the engine for defects in “material and workmanship.” Engine manufacturers also recommend the type of fuel the engine is designed to use. Any engine damage caused by fuel (of any type) is generally not the responsibility of the engine manufacturer. Many engine manufacturers have issued statements about their recommendations for biodiesel use. Some of these statements are available at: www.biodiesel.org/resources/oems

What does B2, B5, B20 or B100 mean?

Biodiesel is usually blended with petroleum diesel before it is sold. Biodiesel is commonly sold as 2%, 5%, 20% or 50% blends with petroleum diesel. A fuel sold as B5 will contain 5% biodiesel and 95% petroleum diesel. A fuel sold as B20 will contain 20% biodiesel and 80% petroleum diesel.
Biodiesel that is not blended with petroleum diesel is referred to as B100, neat biodiesel or pure biodiesel.

How much energy does biodiesel contain?

Biodiesel contains 118,296 BTUs per gallon. This is approximately 8% less than the 129,000 BTUs per gallon for Number 2 Petroleum Diesel. More information on energy content is available at: www.biodiesel.org/pdf_files/fuelfactsheets/BTU_Content_Final_Oct2005.pdf

Where can I buy biodiesel?

Biodiesel is not available at most retail fuel locations. The National Biodiesel Board maintains a list of biodiesel retailers across the country. This list is available at: www.biodiesel.org/buyingbiodiesel/retailfuelingsites.

Will biodiesel work in the winter?

Biodiesel has a higher cloud point and pour point than petroleum diesel. This means that biodiesel is more likely to gel in the winter than diesel fuel. Cold weather properties of biodiesel vary depending on the type of oil or animal fat that was used to produce the biodiesel. Most biodiesel is produced from soy oil. Soy oil based biodiesel (B100) has a pour point of approximately 32 degrees Fahrenheit while number 2 diesel fuel has a pour point of approximately negative 16 to
18 degrees Fahrenheit. Biodiesel produced from other feed stocks (such as canola or palm oil) will have different cold weather performance than soy based biodiesel. Additional information on cold flow properties can be found at: www.biodiesel.org/pdf_files/fuelfactsheets/Cold%20Flow.PDF or
www.uidaho.edu/bioenergy/NewsReleases/TechNote3.pdf.

Do fuel taxes apply to biodiesel?

Yes, biodiesel is taxed liked petroleum diesel fuel. Biodiesel purchased at a retail station will have the taxes already included in the price. Biodiesel producers (even small producers) need to register with the state of Montana and pay the applicable fuel taxes. Biodiesel for off road use is eligible for a refund of a portion of the fuel taxes paid, similar to dyed diesel fuel.

Is biodiesel cheaper than diesel?

Commercially produced biodiesel tends be more expensive than diesel fuel. The price premium relative to diesel fuel varies over time but has ranged from $0.11 to $1.17 per gallon in recent years based on data from the Clean Cities Alternative Fuel Price Reports. The average price premium has been $0.58 per gallon. Small scale personal biodiesel producers that have access to free or low cost used vegetable oil can sometimes produce biodiesel for less than the price of
diesel fuel.

Is biodiesel good for the environment?

In general, yes but it depends on a number of factors. Depending on which environmental attributes are measured and how you are measuring these attributes makes a significant difference in calculation of environmental benefits. It also depends on factors like the feed stock (soybean oil, palm oil, animal fat, etc.) that was used in the production of the biodiesel. For more information visit: www.uiweb.uidaho.edu/bioenergy/ALCACLCA.pdf

Where can I find out more information about biodiesel?

Continue reading the factsheets in this series or visit the eXtension Farm Energy Biodiesel webpage at: www.extension.org/pages/28783/farm-energy-biodiesel-table-of-contents