Biodiesel (B20) – No significant NOx increase

Posted By on November 10, 2006

NREL B20 Study October 2006
Contrary to a 2002 EPA study, the National Renewable Energy Laboratory published a new study showing that vehicles using B20 fuel —a blend of 20 percent biodiesel and 80 percent petroleum diesel— do not produce an increased level of nitrogen oxide (NOx) emissions in all engines. The previous study by the Environmental Protection Agency (EPA) indicated that although biodiesel (the B20 blend) showed significant reduction in most pollutants, the increase in NOx
Nox Chartwas 2% over petroleum diesel.
According to NREL’s Robert McCormick, this new “study shows that the NOx impact of B20 varies with engine design, such that some engines show a small increase while others show a small decrease. The EPA’s 2002 review was based on a data set made up primarily of data from one engine model that produces a small NOx increase. EPA uses these data to draw a general conclusion for on-highway engines that B20 causes a 2% increase in NOx. The chassis dynamometer testing along with careful review of previously published data suggest that their conclusion is not correct, and that on average B20 has no effect on NOx.”

PM ChartFor renewable fuel advocates, this study is promising since biodiesel is being added to more and more of the nation’s diesel fuel. Production of biodiesel is up a huge 3 fold over 2005 numbers and additional processing facilities are coming online in 2007. Also biodiesel make an excellent lubricity additive to Ultra Low Sulfur Diesel which has been introduced nationwide. This reminds me, a regular reader pointed out that owners of pre-2007 diesel should consider a lubricity additive of some kind, although a couple distributors claim their ULSD fuel is treated with additive packages for cetane boost, winter gelling and lubricity.

Here is the link for a PDF of the NREL’s study.


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