Safety and performance
Safety
Biodiesel is considerably less flammable than petroleum diesel, which burns at 50°C (120°F). Pure biodiesel (B-100) does not ignite until 150°C (300°F). The flashpoint (the temperature at which it will ignite when exposed to a spark or flame) of a biodiesel blend falls somewhere between these temperatures, depending on the mixture.
Because biodiesel is a mild solvent it is important to wipe up spills and dispose of rags safely. Biodiesel may deface some paints if left on painted surfaces for a long time.
Vehicle performance
Biodiesel-powered engines have been shown to deliver similar torque and horsepower as diesel-powered engines. Biodiesel has a higher cetane rating, which can improve starting and reduce smoke emissions. Biodiesel has slightly more energy per litre than No. 1 diesel and slightly less energy than No. 2 diesel.
Major engine companies have confirmed that the use of blends of up to 20 percent biodiesel will not void their parts warranties. As biodiesel is more widely tested and used, manufacturers will be in a better position to support the use of higher blends, including pure biodiesel.
Like petroleum diesel, biodiesel can gel in cold weather. Laboratory tests show that the biodiesel blend gels at a higher temperature than petroleum diesel would otherwise. Actual experience with cold weather has varied. B-20 blends are used in some very cold climates, such as in northern Minnesota and Wyoming, where temperatures can fall below –40°C (–40°F) in the winter. B-20 has been tested in buses in Montréal to determine how well it works in cold weather. Toronto Hydro has used B-20 with no adverse affect on its fleet vehicles.
Some types of biodiesel freeze at lower temperatures than others, depending on the level of saturated source contents in the fuel. Solutions to cold weather problems are the same as those for petroleum diesel. They include using fuel additives and engine block or fuel filter heaters and storing vehicles near or in a building.
It is important to clean storage tanks before using biodiesel blends of 30 percent or higher because biodiesel is a mild solvent. This characteristic makes it "clean out" fuel tanks and storage systems. If high blends are put into aged and dirty systems that previously held No. 2 diesel, biodiesel will dissolve the sediments and carry them into vehicle fuel systems. In severe cases, the dissolved sediments can cause fuel injector failure.
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