Photo by Kevindooley. Licensed under Creative Commons license 2.0.
Anyone who's experimented with running waste veggie oil in their diesel vehicles knows that it doesn't work so well in cold weather. Even using refined biodiesel causes problems because of the higher paraffin content compared to petro-diesel. Unfortunately for school districts in Minnesota, the state requirement to run a minimum of 2 percent biodiesel in school buses and other vehicles is causing problems this winter. Below 10°F, the fuel begins to gel up and causes the engine to not run. Pe