Material Insights · Understanding the Material World

LNG chain: How it works

Shrinking gas 600 times so a ship can carry it

What this tab covers How the energy actually moves, step by step: the science that makes it work and the engineering that makes it practical.

Natural gas is chilled to about minus 162 C until it turns liquid and shrinks about 600 times, shipped in insulated tankers, then warmed back into gas at the importing coast.

Step by step

  1. Clean the feed gasCarbon dioxide, water, sulphur, mercury and heavier hydrocarbons are removed, because they would freeze or damage aluminium heat exchangers.
  2. Refrigerate in stagesCompressors drive refrigerant loops (propane, mixed refrigerants or nitrogen) that pull heat from the gas until it condenses.
  3. Store at the export terminalThe liquid waits in double-walled insulated tanks near atmospheric pressure.
  4. Ship by seaCarriers of typically 135,000 cubic metres or more (about 60,000 tonnes, calculated) cross oceans; a little cargo boils off and is burned as fuel or reliquefied.
  5. Unload and regasifyAt an onshore terminal or a floating storage and regasification unit (FSRU), pumps feed vaporisers warmed by seawater or burners, and the gas enters the grid.

The science

Methane boils at about minus 162 C at normal pressure, so below that it is a liquid of about 458 kg per cubic metre, under half the density of water. Liquefying cuts volume about 600 times, which makes ocean shipping worthwhile. Tanks work like a vacuum flask: heat leaks in slowly, and the small amount of liquid that evaporates (boil-off) carries that heat away, keeping the rest cold without refrigeration. Once warmer than about minus 100 C the vapour is lighter than air and rises.

The engineering

A liquefaction train is a chemical plant built around refrigeration compressors of tens of megawatts, driven by gas turbines or electric motors, plus large coil-wound or plate-fin heat exchangers. Tanks use nickel steel or membrane linings that stay tough at cryogenic temperatures. Ships carry membrane tanks (thin stainless steel or invar backed by insulation, mostly GTT designs) or spherical tanks, and modern carriers burn boil-off in dual-fuel engines.

Key numbers

Liquefaction temperature about minus 162 C1 Volume reduction about 600 to 11 World liquefaction capacity, end 2025 524.5 million tonnes per year (Mtpa), about 30 Mtpa added in 2025 (calculated)23 World LNG trade, 2025 437 million tonnes, up 6.3%3 World regasification capacity 1,113.5 Mtpa at end 2025 (IGU); GIIGNL counts 1,188 Mtpa at end 202434 Active LNG fleet, end 2024 742 vessels including 48 FSRUs and 10 FSUs2

Sources

  1. What is LNG GIIGNL, 2025
  2. 2025 World LNG Report International Gas Union, 2025
  3. World LNG Report 2026 (press release) International Gas Union, 2026
  4. GIIGNL Annual Report 2025 GIIGNL, 2025