Liquefied natural gas or LNG is natural gas, predominantly methane, which has been condensed into liquid form for easy storage and transportation. LNG is odourless, colourless, non-toxic and non-corrosive.
Liquefied natural gas takes up about 1/600th the volume of natural gas in its gaseous state. Natural gas is condensed into a liquid at close to atmospheric pressure by cooling it to approximately -162 °C.
Combusted natural gas emits substantially lower levels of carbon dioxide as compared to the emissions from naphtha, coal, oil and LPG. Natural gas also contains no sulphur, particulate matter or heavy metals. It is the most environmentally friendly fossil fuel.
LNG is lighter than air, allowing the leakage of gas to evaporate, to "disappear", in the atmosphere.
Natural gas and biogas have a high proportion of methane, making them mixable. Therefore, LNG technology is excellent back-up for biogas. The difference is that they are formed in different ways and the combustion of biogas gives no net addition of carbon dioxide in the atmosphere. The combustion of natural gas provides 20% less carbon dioxide compared to petrol.
Natural gas is composed of combustible gases stored in the earth's crust. It is used in industrial processes, for heating homes and for vehicles. It is the third most important source of energy in the world after oil and coal. As an energy source natural gas is equivalent to biogas.