Transportation fuels refer to energy sources used to power various modes of transport, such as cars, trucks, motorcycles, buses, trains, light rail, air planes and watercraft. These fuels are derived from fossil, renewable and synthetic sources, including gasoline, diesel, liquefied petroleum gas, compressed natural gas, jet fuel, marine fuel, propane, electricity, biofuel and hydrogen. Extracting, processing and generating transportation fuels poses implications for both land and water.