Vegetable oil fuel States was producing in excess of 11 billion liters (2.9 billion U.S. gallons) of recycled vegetable oil annually, mainly from industrial deep fryers in potato processing plants, snack food factories and fast food restaurants. If all those 11 billion liters could be recycled and used to replace the energy equivalent amount of petroleum (an ideal case), almost 1% of US oil consumption could be offset. Utilizing recycled vegetable oil as a replacement for standard petroleum-derived fuels like gasoline would reduce the price of gasoline by preserving the supply of petroleum. Virgin vegetable oil, also termed pure plant oil or straight
Butter sauce with meat and vegetables. In antiquity, butter was used for fuel in lamps as a substitute for oil. The "Butter Tower" of Rouen Cathedral was erected in the early 16th century when Archbishop Georges d'Amboise authorized the burning of butter instead of oil, which was scarce at the time, during Lent. Across northern Europe, butter was sometimes treated in a manner unheard-of today: it was packed into barrels (firkins) and buried in peat bogs, perhaps for years. Such "bog butter" would develop a strong flavor as it aged, but remain edible, in large part because of the unique cool,