liquefied natural gas Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4) that has been converted to liquid form for ease of storage or transport. It takes up about 1/600th the volume of natural gas in the gaseous state. It is odorless, colorless, non-toxic and non-corrosive. LNG achieves a higher reduction in volume than compressed natural gas (CNG) so that the (volumetric) energy density of LNG is 2.4 times greater than that of CNG or 60 percent of that of diesel fuel. liquified natural gas LNG liquefied hydrocarbon gas