Biodiesel

 

Biodiesel

Biodiesel is a renewable fuel than can be used as a substitute for fossil fuel derived diesel.  Biodiesel is made by chemically combining vegetable or animal fat with an alcohol and potassium or sodium hydroxide.  This process creates biodiesel as well as other marketable products, including feed quality fat, glycerin, and methanol, that can  generate local income for producers (A Study on the Feasibility of Biodiesel Production in Georgia, University of Georgia, 2003).

Biodiesel is most often blended with petroleum diesel or "petrodiesel" in various amounts, such as B2 (2% biodiesel blend with 98% petrodiesel) or B20 (20% biodiesel blend with 80% petrodiesel).  Biodiesel can also be used in its pure form, B100 (100% biodiesel). 

Sources include:
* Soybeans, Cottonseed, Sunflower, Palm, Canola, Corn, Peanut, Spent (used) restaurant grease/cooking oil
* Animal fat
* Algae

What are the benefits of biodiesel?

• Reduction of Emissions: EPA's analysis demonstrates that the use of biodiesel, in conventional heavy-duty diesel engines, results in much lower emissions than conventional diesel fuel.* with the exception of smog causing nitrogen oxides (NOx).  Use of biodiesel will reduce unhealthy levels of particulates, carbon monoxide, hydrocarbons, and air toxics emitted from diesel engines which threaten to harm ourselves and loved ones.  According to the Department of Energy, the cancer-causing potential of biodiesel (B100) is 94% less than regular diesel and 27% less for B20.  Emissions reduction estimates from the National Biodiesel Board and EPA (2002) are:

B100 (100% biodiesel):
40-50% reduction carbon monoxide
40-70% reduction particulate matter
40-70% reduction hydrocarbons
100% reduction sulfates

B20 (20% biodiesel):
10-12% reduction carbon monoxide
10-15% reduction particulate matter
10-20% reduction hydrocarbons
20% reduction sulfates

*Some studies have shown slight increases in smog forming nitrogen oxide emissions for biodiesel. Additional research is being conducted.

• Biodiesel contains no aromatics or sulfur (it will not contribute to acid rain) and is an excellent lubricant in engines to help make them run smoothly and efficiently. 

• Reduces Global Warming Pollutants:  According to a U.S. Department of Energy and U.S. Department of Agriculture life cycle study, biodiesel reduces net carbon dioxide emissions by 78 percent compared to petroleum diesel.  This is due to biodiesel's closed carbon cycle.  The carbon dioxide released into the atmosphere when biodiesel is burned is recycled by growing plants, which are later processed into fuel. Greater emissions reductions benefits are observed with increasing proportions of biodiesel in conventional fuel.  The global warming benefits will vary depending on what the biodiesel is made from. In general, emissions benefits from animal-based biodiesel are better than for plant-based biodiesel. Feedstocks that require more energy input, such as soybeans, are less favorable sources for producing biodiesel.

• Little to no infrastructure or engine changes are required:  Biodiesel can be used with current existing diesel engines with little to no engine modifications needed and can be incorporated into existing storage tanks and fuel dispensers.  However, because biodiesel is a solvent, when a tank is initially replaced with biodiesel, deposits that have accumulated on tank pipes and walls from petroleum diesel fuel may be released.  The release of deposits may initially impact fuel filters and may require replacement.  Though this should only occur when initially transitioning to biodiesel.
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What is the cost and availability of biodiesel?
Biodiesel is increasingly more competitively priced with regular diesel fuel. Under a law first signed by President Bush in October 2004 and subsequently renewed in 2005, biodiesel manufacturers can receive a one-cent tax incentive for each percent of biodiesel (from virgin sources) used.  A manufacturer can receive a tax credit of twenty cents per gallon of B20 it produces.  A half-cent tax credit is available for biodiesel produced from non-virgin (or used) sources. This new tax incentive is making biodiesel competitive today with regular, more polluting diesel in the marketplace. For more information on the tax incentives, visit http://www.biodiesel.org/news/taxincentive/.  For public refueling stations in the Southeast, go to www.sealtfuels.org and click on "Regional Maps".

What are the obstacles or challenges to production and use of biodiesel?
Unfortunately, reports have shown that using biodiesel may increase smog-forming nitrogen oxides (NOx) between 2%-10% compared to petroleum based diesel.  NOx emissions are dependent on a number of factors including the way a vehicle is driven and maintained and could be offset by tuning the engine specifically for biodiesel use.  New studies are being conducted to better understand the in-use (real-time) emissions profile from using biodiesel.  Previous studies were conducted only under lab conditions.  A 2005 study conducted by North Carolina State University (NCSU) shows a decrease in emissions of nitric oxide (NO) (a precursor to NOx) using soy-based B20. The complete study can be found at: 

http://www.ncdot.org/doh/preconstruct/tpb/research/download/2004-18FinalReport.pdf