What is biodiesel?

Biodiesel is a renewable, biodegradable fuel that is a cleaner-burning replacement for petroleum diesel fuel by reducing greenhouse gas and particulate matter emissions. (For biodisel in Tennessee check out TN Laws & Incentives for biodiesel here.)

biodiesel in tennessee

Example fleets that use biodiesel in Tennessee:  Great Smoky Mountains National Park, Averitt Express, cities of Crossville & Sevierville, Eastman, Knoxville Utilities Board, Nashville Metro, Performance Food Group, Sullens Transportation, TDOT.

Different blends used by Tennessee fleets  B5, B20 and B99

Best resource for learning about biodiesel in Tennessee and other places – www.biodiesel.orgThe National Biodiesel Board has placed everything from fuel FAQs and production information to the OEM statements on using biodiesel in its vehicles.

How is it produced?

Biodiesel can be produced from anything that contains oil such as soybeans, canola, algae, and animal fats obtained from recycled restaurant grease. The fats and oils are typically filtered and preprocessed to remove contaminants and water. Then, they are blended with an alcohol (usually methanol) and a catalyst (usually sodium hydroxide). Then during a process called transesterification, the fats and oils are transformed into methyl esters and glycerin. Once the two are separated, the methyl esters serve as biodiesel fuel.

How is it used?

Biodiesel can be blended and used in many different concentrations. The most common are:

B100 (pure biodiesel)

B100 and other high-level biodiesel blends are less common than B20 and lower blends due to a lack of regulatory incentives and pricing. B100 can be used in some engines built since 1994 with biodiesel-compatible material for certain parts, such as hoses and gaskets. B100 has a solvent effect, and it can clean a vehicle’s fuel system and release deposits accumulated from petroleum diesel use. The release of these deposits may initially clog filters and require frequent filter replacement in the first few tanks of high-level blends.

B20 (20% biodiesel, 80% petroleum diesel)

B20 is the most common biodiesel blend in the United States. B20 is popular because it represents a good balance of cost, emissions, cold-weather performance, materials compatibility, and ability to act as a solvent. Most biodiesel users purchase B20 or lower blends from their normal fuel distributors or from biodiesel marketers. Regulated fleets that use biodiesel blends of 20% (B20) or higher qualify for biodiesel fuel use credits under the Energy Policy Act of 1992.

B5 (5% biodiesel, 95% petroleum diesel)

Low-level biodiesel blends, such as B5 are ASTM approved for safe operation in any compression-ignition engine designed to be operated on petroleum diesel. This can include light-duty and heavy-duty diesel cars and trucks, tractors, boats, and electrical generators.

B2 (2% biodiesel, 98% petroleum diesel)

Blends like B2 and B5 are popular fuels in the trucking industry because biodiesel has excellent lubricating properties, so usage of the blends can benefit engine performance.

What are the benefits?

Biodiesel growth boosts the U.S. economy, not just by creating jobs but also by reducing our dependence on global oil markets and vulnerability to price spikes. There are currently about 200 biodiesel plants across the country – from Washington state to Iowa to North Carolina – with registered capacity to produce some 3 billion gallons of fuel. The industry is supporting more than 62,000 jobs, generating billions of dollars in GDP, household income and tax revenues. The industry’s economic impact is poised to grow significantly with continued production increases. The industry supports jobs in a variety of sectors, from manufacturing to transportation, agriculture and service.

The EPA has recognized biodiesel’s environmental benefits by classifying it as an Advanced Biofuel, making biodiesel the only commercial-scale U.S. fuel produced nationwide to meet the agency’s advanced criteria. According to the EPA, biodiesel reduces greenhouse gas emissions by at least 57 percent and up to 86 percent when compared to petroleum diesel – making it one of the most practical and cost-effective ways to immediately address climate change. In addition, biodiesel sharply reduces major tailpipe pollutants from petroleum diesel, particularly from older diesel vehicles. This is important because the EPA has consistently cited diesel exhaust – primarily from older trucks, buses and other vehicles – as one of the nation’s most dangerous pollutants.

What are the emissions reductions gained from biodiesel?

Particulate Matter (PM): 12% reduction with B20, 48% reduction with B100
Carbon Monoxide (CO): 12% reduction with B20, 48% reduction with B100
Carbon Dioxide (CO2): 16% reduction with B20, 78% reduction with B100 (life-cycle reduction)
Hydrocarbons (VOCs): 20% reduction with B20, 68% reduction with B100
Nitrogen Oxides (NOx): +/- 1-2% change with B20 or B100
Sulfur Dioxide (SOx): 20% reduction with B20, 100% reduction with B100

biodiesel in tennessee


Discover how Ocean State Clean Cities is helping Rhode Island restaurants cut petroleum use and save money by turning waste oil into renewable biodiesel.

Biodiesel Information & Links

The Biodiesel Basics section on the AFDC Website – Great starting point in learning about biodiesel opportunities and technologies.

The National Biodiesel Board – Everything you ever wanted to know about biodiesel.

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