Business Energy Glossary
What is the National Transmission System (NTS)?
The National Transmission System, almost always shortened to NTS, is the high-pressure gas pipework operated by National Gas Transmission across Great Britain. The NTS moves gas from coastal entry points (where it arrives from the North Sea, Norway, LNG terminals, and interconnectors with the European mainland) and from storage facilities, to the regional Local Distribution Zones (LDZs) where the Gas Distribution Networks (GDNs) take over for the final distribution to customers. The NTS is one of the largest engineering systems in the UK.
The NTS is the backbone of UK gas supply. Almost every kWh of gas consumed in Great Britain passes through the NTS at some point. Understanding the NTS helps explain wholesale gas pricing dynamics, regional supply differences, and security of supply considerations.
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What the NTS is
The National Transmission System (NTS) is Great Britain’s high-pressure gas pipeline network, owned and operated by National Gas Transmission. Its costs are passed through suppliers into the unit rates and standing charges on business gas bills.
For the full explanation, see How Business Gas SupplyWorks in the UK.
The NTS is the high-pressure gas pipework that connects gas entry points (where gas enters Great Britain from offshore and from continental Europe) to the offtake points where it transfers to the regional distribution networks. Key characteristics:
- Around 7,600 km of high-pressure pipeline across Great Britain.
- Operates at pressures of up to 94 bar (compared to 30 to 60 millibar for the customer-facing distribution networks).
- 26 compressor stations to maintain pressure.
- Around 90 transit pipelines feeding 13 Local Distribution Zones.
The NTS is owned and operated by National Gas Transmission (formerly known as National Grid Gas), now part of National Gas plc following the 2023 demerger from National Grid plc.
How gas flows through the NTS
The daily gas system runs on a 05:00 to 05:00 gas day cycle. The basic flow:
- Entry points. Gas enters the NTS from coastal terminals, gas storage facilities, and interconnectors.
- NTS transport. The high-pressure system moves gas across the country, balanced second-by-second through compressor station operation.
- Offtakes. Pressure-reducing stations transfer gas from NTS to the LDZs at lower pressures.
- LDZ distribution. The Gas Distribution Networks deliver gas through medium and low pressure pipework to customers.
NTS entry points
The major UK gas entry points:
- St Fergus (Scotland). Receives gas from the UK North Sea fields.
- Easington (Yorkshire). Receives Norwegian and UK North Sea gas.
- Bacton (Norfolk). Receives gas via interconnectors from Belgium and the Netherlands.
- Isle of Grain (Kent), Milford Haven (Wales). LNG import terminals.
- Storage facilities. Several large storage facilities (Rough was the largest until decommissioned, partial reopening from 2022) feed into the NTS.
The mix of supply sources at each entry point varies daily based on market prices and operational availability.
NTS offtakes to LDZs
The NTS feeds 13 LDZs at around 90 offtake points. Each offtake is a pressure-reducing station that drops gas pressure from NTS levels (up to 94 bar) to LDZ operating pressure (typically 7 bar at the LDZ entry).
Large industrial users with very high consumption can also take gas directly from the NTS, bypassing the LDZ. These are known as NTS-connected sites and are relatively rare in the UK.
National Gas Transmission
National Gas Transmission (NGT) operates the NTS under licence from Ofgem. National Grid sold the business to a consortium from 2023, and it now operates as National Gas Transmission, owned by a consortium led by Macquarie Asset Management.
NGT responsibilities include:
- Day-to-day NTS operation and balancing.
- Maintenance and reinforcement of the high-pressure network.
- Connection of new entry points and offtakes.
- Operation of the gas balancing market for shippers.
NGT is regulated by Ofgem under the RIIO-3 price control.
NTS charges and customer bills
NTS costs are recovered through transportation charges levied on gas shippers, who recover them from suppliers, who recover from customers. The charges appear bundled into supplier unit rates and standing charges.
Two main NTS charge components:
- Capacity charges. Recover the cost of maintaining the network.
- Commodity charges. Recover the cost of operating the network (compression, balancing actions).
For a typical UK business gas bill, NTS-related charges account for around 5 to 10 per cent of the total. The customer sees them as part of the unit rate, not as a separate line.
the National Transmission System (NTS) FAQs
What is the National Transmission System (NTS)?
The high-pressure gas pipework operated by National Gas Transmission across Great Britain, moving gas from coastal entry points and storage facilities to the regional Local Distribution Zones (LDZs).
Who operates the NTS?
National Gas Transmission, part of National Gas plc. Demerged from National Grid plc in 2023. Operates the NTS under licence from Ofgem under the RIIO-T2 price control.
How does gas enter the NTS?
Through coastal entry points: St Fergus (Scotland), Easington (Yorkshire), Bacton (Norfolk), and LNG terminals at Isle of Grain and Milford Haven. Gas also enters from storage facilities and via interconnectors with the European mainland.
What pressure does the NTS operate at?
Up to 94 bar (compared to 30 to 60 millibar for customer-facing distribution networks). The high pressure allows large volumes of gas to be moved across the country efficiently.
What is the difference between NTS and LDZ?
The NTS is the high-pressure national transmission system. The LDZ is the regional distribution network that takes gas from the NTS and delivers it to customers at lower pressures.
How long is the NTS?
Around 7,600 km of high-pressure pipeline across Great Britain, supported by 26 compressor stations to maintain pressure as gas flows across the country.
Does NTS appear on my gas bill?
Not as a separate line for most customers. NTS charges are bundled into supplier unit rates and standing charges. For larger pass-through contracts, NTS charges can be itemised.
Can businesses connect directly to the NTS?
Yes, for very large industrial users with high consumption. NTS-connected sites bypass the LDZ entirely. These are uncommon in the UK and typically reserved for major manufacturing, power stations, or industrial chemical sites.