Liquefied natural gas, or LNG, is simply natural gas (primarily methane) in its liquid state. Natural gas is used in homes for cooking and heating, as fuel for school buses and as fuel for generating electricity. It is an organic fossil fuel found in reservoirs beneath the earth’s surface, often occurring in the same locations as crude oil. When cooled to a temperature of -162°C at atmospheric pressure, natural gas becomes a clear, colorless and odorless liquid. The liquefaction (cooling) process reduces natural gas to 1/600th of its original volume making it possible to transport large amounts of LNG over long distances in specially designed ocean tankers. LNG is non-corrosive, non-toxic and vaporizes when exposed to air.
After natural gas is extracted from reservoirs, it is transported to liquefaction plants where it is liquefied (cooled) and stored. The LNG is stored in double-walled tanks at atmospheric pressure. The space between the walls in the tanks is filled with insulation to keep the LNG cool. These plants are built in association with marine shipping terminals so that the LNG can be loaded into specially designed and insulated double-hulled carriers.