Clean Energy Fuels Corp. specializes in providing natural gas as an alternative fuel for vehicle fleets in the U.S. and Canada, focusing on renewable natural gas (RNG), compressed natural gas (CNG), and liquefied natural gas (LNG). They not only supply fuel but also design, build, operate, and maintain fueling stations. Additionally, they sell equipment for RNG production and fueling stations, and manage virtual natural gas pipelines. The company also earns credits for using RNG as a vehicle fuel and is involved in developing RNG projects from dairy and livestock waste. Their services cater to a wide range of sectors including trucking, public transit, and government fleets.