National Transmission System
The United Kingdom's National Transmission System (NTS) is the network of gas pipelines that supply gas to forty power stations from natural gas terminals situated on the coast and to gas distribution companies that supply homes and other users.
North Sea Gas was first brought ashore in the UK in 1967, after which NTS was built by British Gas. Before this, gas came locally from municipal gasworks. Most of the system was built in the 1970s and early 1980s. In February 1997, British Gas split into two units. The NTS became owned by BG plc. In October 2000 ownership moved to the de-merged Lattice Group. In October 2002, the Lattice Group merged with National Grid.
NTS is the starting point for UK gas distribution. The pipeline system for houses is not part of the NTS, but the two systems combine to form the UKs gas distribution network.
The two types of gas pipelines in the UK are: large diameter high-pressure (up to 85 bar and 600mm diameter) pipelines - the type that the NTS uses, and smaller diameter lower pressure pipelines that connect to users who burn gas for heat.
The NTS has over 7,600km of welded steel gas pipeline with twenty five (mostly gas turbine driven) compressor stations and over 25 pressure regulators. Gas moves through the system at speeds up to 25 mph depending on pressures and pipeline diameters.
Compressor stations include:
- England - Wooler, Bishop Auckland, Carnforth, Nether Kellett, Warrington, Hatton, Alrewas, Wisbech, King's Lynn, Peterborough, Churchover, Huntingdon, Cambridge, Diss, Chelmsford, Aylesbury, Lockerley and Wormington.
- Scotland - Aberdeen, Avonbridge, Kirriemuir, Moffat and St Fergus
Gas enters the system via the seven UK gas terminals (six in England and one in Scotland) and various storage facilities. These include a mixture of salt cavity and LNG storage sites (onshore) and the depleted oil field at Rough (offshore).
Gas distribution network
Companies that own part of this gas network, also known as the Local Transmission System (LTS), are known officially as Gas Transporters. Gas enters this network via the NTS through a pressure reduction station to the twelve gas distribution zones in England, Scotland and Wales within eight distribution networks. The network covers 275,000 km (171,000 mi). The LTS is managed from Hinckley, Leicestershire (former headquarters of the NTS). Financial transactions between gas transporters are managed by Xoserve, based in Solihull. It was formerly an internal department of National Grid and then became an independent company.
For retail distribution, National Grid plc (this division is based in Northampton) owns the network in North West England, the West Midlands, the East Midlands, the East of England and North London. In the North of England, local distribution is owned by Northern Gas Networks; in the Wales and West by Wales and West Utilities; and in Southern England and Scotland by SGN.
National Grid plc
NTS is managed by National Grid plc (NG), the same company that manages the country's National Grid for electricity transmission. NG is administratively based in Warwick. While NG owns the gas transmission system in England, Wales and Scotland, electrical distribution in Scotland is owned by two Scottish companies.
Northern Ireland is not part of the NTS per se and gets its gas via the Scotland-Northern Ireland pipeline (SNIP) owned by Premier Transmission and built between 1994 and 1996. The gas network in Northern Ireland is split, with one area owned by Phoenix Natural Gas and the other by Firmus Energy.
- Gas Transmission System Operations
- Map of the NTS at National Grid
- Detailed Map of the NTS
- Pipeline projects at National Grid plc
- Ownership of the gas distribution network
- Society of British Gas Industries (slow loading)
- Energy Networks Association
- GCSE PDF factsheet about the NTS