Biodiesel, an alternative to running 100% petroleum- based diesel (petrodiesel), is a renewable resource made from animal fats, vegetable oils, or recycled cooking grease through a refining process called transesterification. Straight vegetable oil (SVO) and waste vegetable oil (WVO) are not considered biodiesel until they have been transesterified. Soybean oil and WVO from restaurants are the most common sources of biodiesel in the United States. Biodiesel requires less energy to produce than ethanol, petrodiesel, or gasoline. Biodiesel can be burned at 100% or it can be blended with traditional petrodiesel. Biodiesel blends are given “B” designations. For example, B20 fuel is blended with 20% biodiesel/80% petrodiesel. Pure biodiesel (B100) is non-toxic and biodegradable. Using biodiesel is more environmentally friendly than petrodiesel, reducing pollution emissions and recycling carbon dioxide. It also has an increased lubricating ability, reducing friction in the engine.