At the Terminal, Every Movement Is an Invoice

A terminal is not one custody point; it is many, packed together and moving constantly. Every truck filled, every parcel loaded over a jetty, every unit of gas sent out from a regasification header is a billable transfer with an unforgiving tolerance stack. The pipeline meter tends to get the engineering attention and the proving budget. The terminal, where transfers are frequent and small errors multiply across a year, often does not.

Loading meters drift too — they just rarely see a prover

A truck or rail loading meter is a custody device operating under some of the harshest duty in the system: frequent starts and stops, batch quantities, temperature swings between parcels. It drifts like any meter, but loading skids are proved far less often than mainline meters. API MPMS discipline — Chapter 4 proving, Chapter 7 temperature determination, Chapters 5 and 6 on metering and assemblies — is what keeps gantry throughput reconciling with invoiced volume. Temperature correction alone, done properly to standard volume, accounts for discrepancies that operators often write off as “loading loss”.

LNG send-out lives and dies on conditions

Cryogenic custody is a different discipline. Regasification send-out and boil-off-gas accounting depend on density and flow measured correctly at temperature, and on energy — gross calorific value — not merely volume. A small error in density-at-temperature or in the energy assignment, multiplied by the annual throughput of a receiving terminal, is a large number. Boil-off that is estimated rather than measured is the classic silent loss on an LNG balance.

An imbalance is a station, not a terminal

When a terminal’s receipt-versus-despatch balance will not close, the instinct is to distrust the whole facility. In practice the answer is almost always one or two specific skids — a drifted loading meter, an uncorrected temperature, a sampling point out of position. A structured measurement-assurance pass walks the custody points in sequence and localises the discrepancy instead of arguing about the aggregate. The balance closes when the specific offender is found, not when the terminal is re-litigated.