What is LNG?

Liquefied Natural Gas, or LNG, is defined as:

“Natural gas in liquefied form as a result of lowering the temperature to below its boiling point of approximately -162° Celsius (about -260° Fahrenheit)”

Natural gas can be either sourced from fossil reserves in the Earth’s crust or produced synthetically or biologically.

LNG consists mainly of methane (CH4), with minor amounts of other hydrocarbons (ethane, propane, butane and pentane). By liquefying the methane gas, LNG takes up only 1/600th of the volume of natural gas in its gaseous state, which means the gas can be distributed around the world more efficiently. By comparison, compressed natural gas (CNG) takes up around 1/100th of the volume of natural gas in its gaseous state, depending on the actual pressure.

The main physical characteristics of natural gas are:

  • it’s colourless,
  • it’s odourless,
  • it boils at -161.48 °C,
  • it has a density of 423 kg/m³ at -161 °C.

During transport the temperature should be below the boiling point. Because LNG is extremely cold it requires special cryogenic equipment, procedures and training of the personnel involved. Due to the relatively low energy density of LNG (in MJ/l) it requires more onboard storage capacity than conventional fuels.

Further reading