If you’ve ever wondered how liquefied natural gas (LNG) gets from distant fields to an industrial site or service station, you’re in the right place. LNG transport combines cryogenic engineering, safety protocols, and a global logistics chain to deliver energy reliably to areas beyond the reach of pipelines. In this clear, fully informative guide, I will explain step by step how LNG is transported by sea, road, and container, along with the relevant regulations and the technologies that make it possible.
What LNG is and why it is liquefied
LNG is natural gas that is cooled to about –162 °C, reducing its volume roughly 600-fold compared with its gaseous state. This reduced volume enables economical long‑distance transport when pipeline infrastructure is unavailable.
The LNG supply chain, end-to-end
Although the final destination of LNG may differ, the supply chain shares common stages:
- Liquefaction plant
After purifying the gas (removing water, CO₂, sulphur compounds, etc.), it is cooled in cryogenic cycles until it liquefies. The product is stored in insulated tanks at low temperature. - Loading at export terminal
It is transferred from the onshore storage tanks to the vessel through rigid loading arms and emergency systems that enable “dry disconnections” when required, thereby minimising risk. - Maritime transport
It is carried in specially designed LNG carriers with membrane or spherical (Moss) tanks and precise management of cold and vapours. - Unloading at import terminal
The vessel is connected to the unloading arms and, following the necessary checks and purges, the LNG is transferred to the onshore tanks. From there, it is either regasified for injection into the grid or assigned to small-scale services (bunkering, tanker trucks, ISO containers).
Maritime transport: the heart of the global LNG trade
Types of tanks and insulation
LNG carriers differ mainly in their containment system: membrane (e.g. GTT), which makes use of the ship’s hull with membrane barriers and insulation, or Moss, with aluminium spheres visible on deck. Both types seek the same goal: to minimise temperature increases and evaporative losses of the cargo (known as BOG or boil-off gas).
Boil-off gas: what it is and how it is managed
A small fraction of the LNG evaporates naturally during the journey. Traditionally this gas was used as fuel for the vessel; today, reliquefaction, use as fuel, and combustion units combine to meet efficiency and environmental goals. BOG management is now a design standard for modern fleets.
Safety during loading and unloading
At terminals and during ship-to-ship (STS) operations, transfer arms, emergency shutdown (ESD) systems, drain systems, and purges are used to ensure controlled disconnections and prevent spills or trapped liquid. SIGTTO (Society of International Gas Tanker and Terminal Operators) procedures are a common reference.
Small-scale LNG: from the quayside to distributed demand
Not all LNG ends up in a regasification terminal. A portion feeds decentralised markets, such as off-grid industries, bunkering for ships, or liquefied natural gas for vehicles (vehicular LNG) stations. This small-scale segment has become well established in the EU, with specialised terminal services (loading of LNG tanker trucks, bunkering, micro-regasification).
Cryogenic road tankers
For medium distances, LNG travels in cryogenic tanker trucks with pressure tanks and multilayer insulation (vacuum/perlite, etc.). In Europe, this transport is regulated by the ADR (Agreement concerning the International Carriage of Dangerous Goods by Road), with periodic updates and national implementation (in Spain via the Ministry of Transport).
T75 ISO containers: intermodality (road-rail-ship)
When intermodal logistics and flexibility are required, T75 cryogenic ISO containers (20‑ or 40‑foot, and some 45‑foot variants) are used. These containers allow LNG transport by rail and container ship, with a typical capacity of up to about 46,000 L and design pressures of around 10 bar, depending on the manufacturer.
How LNG is loaded and unloaded in trucks and ISO containers
- Loading at terminal/plant: LNG is transferred to the tanker or container once the lines have been inerted and cooled, always following ESD procedures and using appropriate emergency‑release couplings.
- Unloading at customer site: normally performed by pumping or by pressure transfer into a stationary cryogenic tank, avoiding water hammer and controlling temperatures to prevent thermal shock in the materials.
- Measurement and safeguarding: the quantity transferred is determined using flow meters or weighbridges, depending on the delivery point and applicable regulations.
Standards, codes, and best practices that make it safe
- ADR (road, Europe): classifies substances, packaging, equipment, personnel training, documentation, and vehicle signage. 2023 revision and 2025 update available.
- Sector guidelines (maritime): SIGTTO recommendations for transfer, purging, draining, and safe disconnection of marine arms.
- ESD systems: the heart of operational safety in LNG transfers, with dry break and coordinated shutdown logic between vessel and shore.