Every stage exists to solve a problem created by the one before it. Read in order, the chain makes sense; read as a list of facilities, it does not.
Production and gathering
Gas comes out of the ground either on its own or dissolved in oil. Associated gas — produced alongside crude — was historically flared for want of anywhere to send it, and a good deal of LNG capacity exists to monetise gas that would otherwise be burned at the wellhead.
Field gas arrives at the plant wet, sour, and carrying heavier hydrocarbons. Almost nothing about it is ready for liquefaction.
Treatment
This is the part most descriptions skip, and it is frequently the larger half of an export terminal.
Carbon dioxide has to come out to single-digit parts per million, because it freezes solid at liquefaction temperature and blocks the main exchanger. Water has to reach about 0.1 parts per million for the same reason. Hydrogen sulphide is toxic and corrosive. Mercury attacks the aluminium the exchangers are made of. Heavier hydrocarbons freeze, and are worth more sold separately as natural gas liquids anyway.
The size of the treatment section is set entirely by what came out of the ground, which is why two plants with identical liquefaction capacity can look completely different.
Liquefaction
Treated gas is chilled through a refrigeration cycle until it condenses at around minus 162 degrees. This is where the capital and the energy concentrate: 8 to 12 per cent of the feed gas is consumed driving the compressors.
A plant is built from trains, each a complete self-contained line producing roughly 5 to 8 Mtpa at modern scale. Trains are added over time, which is why a terminal’s capacity arrives in steps and why a single site can have trains at three different statuses at once.
Storage and loading
Liquid runs into insulated tanks at close to atmospheric pressure, then to a jetty when a ship arrives. Loading a conventional cargo takes roughly twelve hours at rates around 10,000 to 12,000 cubic metres an hour, plus the time to connect, cool down the arms, and complete the custody transfer measurement that decides what is paid.
Shipping
An LNG carrier is the only part of the chain that moves, and the part with the least slack in it. The world fleet is small, the yards that can build one are few, and freight rates swing by an order of magnitude within a year as a result.
The voyage is a cycle rather than a trip. A laden leg delivers the cargo; a ballast leg returns the ship with only a heel retained to keep the tanks cold. Both legs cost money and only one earns.
Unloading, storage and regasification
At the far end the process reverses, and it is markedly simpler. Liquid is pumped ashore into tanks, then vaporised — with seawater where the sea is warm enough, by burning a little of the gas where it is not, or by ambient air in hot dry climates.
Or none of that happens ashore at all: an FSRU does storage and vaporisation aboard a moored vessel, which is how a country can add import capacity in a year rather than five.
Send-out and distribution
Regasified LNG enters the grid and becomes ordinary gas, indistinguishable from piped or domestic supply. Odorant is added here, downstream, because mercaptan would freeze in the liquid.
For an import terminal, send-out rate is the capacity figure that matters, not storage volume. A terminal exists to push gas into a network at whatever rate the market wants, and in a cold snap that is far above average.
What the chain costs
Roughly a tenth to a fifth of the gas, in energy, from wellhead to grid. Liquefaction takes the largest share, shipping a few per cent more on a long route, regasification one or two.
That total is the number to hold in mind when comparing LNG with a pipeline. A pipeline loses gas to compression too, but far less, which is why LNG only wins where a pipeline is impossible, uneconomic, or politically unavailable. LNG against pipeline gas works through where that line falls.
Who owns what
There is no standard structure. Some chains are integrated end to end by a single company that produces the gas, liquefies it, owns the ships and sells into its own markets. Others are split at every joint: a plant that tolls gas for a customer who owns the molecules throughout, a ship on time charter to a third party, a cargo sold and resold in transit.
That fragmentation is why the ownership data on this site rewards reading carefully. An owner, an operator and a parent are three different relationships, and a terminal page shows all three because conflating them is how analyses go wrong.