31 Aug 06
None, really, provided your diesel engine is compatible. Pure vegetable oil used as biodiesel has a tendency to gum up injectors, so they might need overhauling more often. Many people use a mixture of biodiesel and conventional derv to mitigate these factors, but plenty of dedicated users are now reporting years of trouble-free motoring aside from the smell of frying from the exhaust pipe when running on biodiesel sourced from waste cooking oils...
There's a chap in the States called Joshua Tickell, who drives what's called The Veggievan - a camper that runs exclusively on reclaimed fast-food cooking oil. The only problem he has encountered is being chased by bears in Yellowstone National Park: they found the smell of Chicken McNuggets overwhelming. Other disadvantages? If you make your own biodiesel, you have to declare the fact and take the full hit of road fuel duty on it. Try to avoid it and HM Customs and Excise will come down very, very hard.
Right now, supply is still limited - and the quality of the fuels on offer varied - but there are a number of small companied now offering both recycled vegetable oil-derived fuels and synthesized RME. It's easier to get hold of it if you're a fleet user buying in bulk, but some outlets do now sell to individual private motorists, and availability is increasing.
