Stability in Extended Storage

Although biodiesel blends have adequate storage stability for normal use, special precautions must be taken if they are to be stored for extended periods. This might occur in seasonal equipment, like a snow plow or farming equipment, or in the fuel tank of a backup generator. If the fuel will be stored for more than a few months, a stability additive is recommended, and oxidation stability should be measured monthly.

Finally, biodiesel is generally more susceptible than petroleum diesel to microbial degradation. In the case of spills in the environment, this is a positive attribute because it biodegrades more rapidly. However, microbial contamination of fuel storage tanks can plug dispensers and vehicle fuel filters and cause vehicles to stall. This is not unheard of for petroleum diesel, but anecdotal evidence suggests it is a greater problem for biodiesel blends. The best way to deal with this issue (for both petroleum diesel and biodiesel) is adequate fuel storage tank housekeeping and monitoring, especially minimizing water in contact with the fuel. Water bottoms must be removed from tanks, and standing tanks should be sampled and tested for microbial contamination.