In The Media - Biodiesel May Not Increase Nitrogen Oxides Emissions,

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Posted by: Community Fuels

5/11/2005

Extensive testing at an energy department laboratory contradicts the widely held belief that burning biodiesel produces more nitrogen oxide (NOx) emissions than traditional diesel, a top lab official reported

May 9 at a Society of Automotive Engineers (SAE) conference in

Washington, D.C.

Air regulators and environmental groups have been slow to embrace biodiesel, a renewable fuel that substantially lowers hydrocarbon and particulate matter emissions, because of concern over increases in NOx emissions, a major contributor to ground-level ozone. Indeed, an emissions fact sheet on the website for the national voice of the U.S. biodiesel industry, the National Biodiesel Board (NBB), states that NOx emissions increase by 2 percent for B-20 (a blend of 20 percent biodiesel and 80 percent diesel). But the National Renewable Energy

Laboratory's (NREL) fuels performance manager, Wendy Clark, said that after exhaustive testing of biodiesel emissions on two 40-foot urban transit buses, NOx emissions were comparable to the buses' diesel-fuel emissions. In other words, they found no increase in NOx emissions.

The dynamometer testing was carried out at NREL's facilities in Golden, CO. The tests on two different buses burning B-20 were repeated because the initial results were so surprising, Clark told the SAE conference participants.

Clark also suggested the biodiesel market could grow to 125 million gallons in 2006, from the less than 30 million gallons used in 2004.

The number could rise to 1.7 billion gallons by 2015 if the current, high diesel prices are sustained, Clark added. In addition to lowering PM and hydrocarbon emissions, biodiesel, which is made from vegetable oils, also has superior lubricity properties.

If oil companies embrace biodiesel as a lubricity additive and blend it at a 1 percent concentration in ultra-low-sulfur diesel, it could mean a 450 million-gallon market. If an energy bill containing a so-called renewable fuels mandate becomes law, Clark predicts it would mean as much as a 900 million-gallon market. Refiners would be looking for ways to meet the renewable fuels mandate without having to invest in new and expensive refinery capacity needed to blend ethanol, the only other viable renewable fuel. Current fuel ethanol production is approximately

3.7 billion gallons annually.

While less than 30 million gallons of biodiesel were consumed last year in the U.S., there is production capacity for another 140 million gallons. Also, Clark said, there is another 100 million gallons of new plant capacity in the development stage, and agricultural processing giant and leading U.S. ethanol producer Archer Daniels Midland is poised to enter the market. They already have two 30 million-gallon biodiesel plants in Germany.

Biodiesel, which can be made from most vegetable oils as well as waste cooking oils, is sulfur free and, according to the NBB website, a B-20 blend reduces hydrocarbon emissions by 20 percent, carbon monoxide emissions by 12 percent, and particulate matter emissions by 12 percent.

Clark said the cost is about 15 cents per gallon more than traditional diesel fuel. Biodiesel is not without its own set of problems. Engine manufacturers are reluctant to allow warranty coverage for anything more than a 5-percent blend of the renewable fuel. They are concerned biodiesel will degrade engine fuel system components. German automaker Volkswagen recently announced that its warranties would cover B-5, and officials said it was likely the company would extend this to B-20 in the future.

There have also been challenges in establishing biodiesel specifications, and even problems with blending proportions. A recent survey by NREL found a significant amount of improper blending, Clark said. In many of the samples of B-20 taken from around the U.S., the amount of biodiesel was far outside the 18 percent to 22 percent acceptable range.

There are no established scientific tests used by biodiesel distributors to determine biodiesel purity. They "use only visual testing, if it looks clear and bright they accept the sample," Clark reported.

Finally, the energy content of biodiesel is less than that of diesel about 10 percent for neat biodiesel and 2 to 3 percent for B-20.

Robb Barnitt

National Renewable Energy Laboratory

Golden, CO

303-275-4489

robb_barnitt@nrel.gov

Robb Barnitt - NREL

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