http://www.afdc.energy.gov/fuels/natural_gas_basics.html natural gas Natural Gas Fuel Basics U.S. Department of Energy Alternative Fuels Data Center Visit AFDC to learn more The Basics of CNG U.S. Department of Energy Alternative Fuels Data Center natural gas liquefied natural gas http://www.afdc.energy.gov/fuels/natural_gas_basics.html Natural Gas Compressed natural gas Natural gas Liquefied natural gas Compressed Natural Gas Natural Gas Fuel Basics Natural gas U.S. Department of Energy Alternative Fuels Data Center