Specification
SPA/MSA, gas specification, destination terminal and vessel compatibility.
Energy and fuels / Gases
LNG
LNG reviewed through composition, cryogenic chain, energy custody and terminal fit.
Technical identity
LNG as cryogenic liquefied natural gas
LNG is natural gas, mainly methane, converted into liquid by cryogenic cooling for transport and storage. That identity separates it from LPG, which is based on propane/butane under pressure.
An LNG transaction is read through the full chain: gas treatment, liquefaction, cryogenic tank, LNG carrier, receiving terminal, storage, regasification and delivery to grid or industrial user.
Trade is measured by energy and composition, not volume alone. The file should therefore cover heating value, composition, custody transfer measurement and terminal compatibility.
FamilyLiquefied natural gas
TemperatureCryogenic
Key controlComposition / energy
InfrastructureCarrier + terminal
Loading published market reference…Automatic reference data; no estimated value is shown if the source is unavailable.
Treatment, liquefaction, shipping and regasification
1Gas treatment
Water, CO2, sulphur and freeze- or corrosion-forming components are removed.
2Liquefaction
Gas is cooled into liquid form to reduce volume and enable marine transport.
3Cryogenic tank
LNG is stored with insulation and boil-off control.
4LNG carrier
Cargo moves in specialised tanks with custody measurement.
5Regasification
The receiving terminal vaporises LNG and delivers gas to grid or user.
Quality and specification
Composition, energy and custody transfer in LNG
LNG quality is expressed through composition and energy: methane, ethane, nitrogen, heating value, Wobbe index, density and temperature. Custody measurement converts volume and quality into delivered energy.
Nitrogen, heavy components or contaminants can affect pipeline compatibility, regasification and buyer specification. Limits are contractual and terminal-specific.
Review should include measurement methods, calibration, tank, loading/discharge conditions and terminal documents. A standalone COA does not describe the whole transfer.
Cryogenic tanks, boil-off and terminals
LNG requires cryogenic infrastructure: insulated tanks, marine arms, low-temperature lines, safety systems and boil-off gas handling. It is not operated in ordinary LPG pressure vessels.
Boil-off is not a side issue; it affects pressure, safety, energy balance and vessel or terminal management. The contract should allocate measurement, tolerances and responsibility.
Final delivery depends on terminal slot, vessel compatibility, storage capacity, vaporisers, grid connection and permits. Commercial availability without terminal access does not close a real transaction.
Specific controls
| Element | Verification |
|---|---|
| Composition | Methane, ethane, nitrogen and heavier components define quality and compatibility. |
| Heating value / Wobbe | Basis for transferred energy and pipeline acceptance. |
| Temperature and density | Needed for measurement and cryogenic handling. |
| Boil-off gas | Affects pressure, safety and quantity balance. |
| Custody measurement | Combines level, temperature, composition and energy during loading/discharge. |
Liquefaction and regasification geography
The LNG market is best understood through infrastructure: liquefaction plants, carrier routes and regasification terminals. Exporting and importing countries matter only where terminal and contractual capacity exist.
| Market | Role | Context |
|---|---|---|
| United States, Qatar and Australia | LIQUEFACTION / EXPORT | Supply centres with liquefaction infrastructure and marine access. |
| Asia and Europe | IMPORT / REGASIFICATION | Demand linked to energy security, industry and power generation. |
| Receiving terminals and slots | LOGISTICS CAPACITY | Without terminal capacity, an offered volume is not deliverable. |
Sources: U.S. EIA - Liquefied natural gas explained; European Commission - Liquefied natural gas; GIIGNL - LNG Custody Transfer Handbook resources; U.S. EIA - Natural gas explained
Documents for an LNG transaction
Certificate
Quality certificate, custody measurement, energy quantity, tank and loading/discharge report.
Logistics
SDS, permits, terminal nomination, boil-off management, inspection and marine documents.
Buyer questions about LNG
Why is LNG stored cryogenically?
Natural gas liquefies when deeply cooled, reducing volume and making marine transport possible.
How does LNG differ from LPG?
LNG is mainly cold methane; LPG is pressurised propane/butane.
What happens at a regasification terminal?
LNG is discharged, stored in a cryogenic tank, vaporised and delivered as gas to grid or user.
What is boil-off gas?
Gas evaporated by heat ingress; it must be managed for safety, pressure and energy balance.
How is an LNG transaction measured?
Usually by transferred energy, combining volume, temperature, density and composition.
Which documents are reviewed?
SPA/MSA, quality, custody measurement, terminal nomination, vessel documents, SDS and inspection.