| Biodiesel makes no sense in the context of home heating. Non-transesterized oils can simply be heated until their viscosity is low enough that they can flow through the fuel lines. Making biodiesel is a rather involved process but attractive for several reasons. The following are no-brainers. 1.) it can be used without preheating 2.) continuous production of biodiesel is more lucrative than one time engine modifications. 3.) ethanol is required for transesterication. Chalk up another victory for corn subsidies. 4.) the byproducts of transesterication are also useful for industry. In a car engine, biodiesel might make more sense than straight vegetable oil because of the cold temperatures experienced and the relatively short trips taken in personal vehicles. On the other hand, furnaces run continuously for several months, you could start the furnace on heating oil and then supply vegetable oil the rest of the time. Both vegetable oil and biodiesel require stabilizers if they are to be stored for long periods so neither one has a clear advantage in that regard. Ryan | 
