U.S. Department of Energy - Energy Efficiency and Renewable Energy
Vehicle Technologies Office
Fact #449: December 25, 2006
Biodiesel to Conventional Diesel: An Emissions Comparison
Biodiesel is a clean-burning substitute for conventional diesel fuel that can be used in today's diesel engines. An Environmental Protection Agency study shows that emissions from B100 (100% biodiesel) and B20 (20% biodiesel/80% conventional diesel) are significantly lower than from conventional petroleum-based diesel, with the exception of nitrogen oxides (NOx).
Difference in Emissions from B100 and B20 to Conventional Diesel
Average Biodiesel (B100 and B20) Emissions Compared to Conventional Diesel
||Emissions in relation to conventional diesel|
|Total Unburned Hydrocarbons (HC)
|Carbon Monoxide (CO)
|Nitrogen Oxides (NOx)
|PAH (Polycyclic Aromatic Hydrocarbons)b
|nPAH (Nitrated PAH's)b
|Ozone potential of speciated HC
Source: Oak Ridge National Laboratory, Biomass Energy Data Book: Edition 1, ORNL/TM-2006/571, September 2006, p. 55. Original source: "A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions."
a Estimated from B100 result.
b Average reduction across all compounds measured.
c 2-nitroflourine results were within test method variability.
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