National Grid: definition and meaning

National Grid has two meanings. In everyday speech, “the national grid” is the network of high-voltage power lines, cables and substations that carries electricity across Great Britain. National Grid plc is a listed company that owns part of that network, plus other energy businesses. The two are often confused, and since October 2024 the company no longer runs the system.

Who owns and runs the grid

Role	Organisation
Transmission owner, England and Wales	National Grid Electricity Transmission (NGET)
Transmission owner, southern and central Scotland	SP Energy Networks (SP Transmission)
Transmission owner, northern Scotland and the islands	SSEN Transmission
System operator for Great Britain	National Energy System Operator (NESO)
Gas transmission	National Gas Transmission
Regulator	Ofgem

The owners build and maintain the equipment. NESO decides minute by minute which generators run, keeps supply and demand in balance and manages new connections, but it does not own the wires. Lower-voltage local networks belong to distribution network operators.

What changed

Until 1 October 2024, the electricity system operator was part of National Grid plc. On that date it became NESO, a publicly owned body, and National Grid sold the business to the government. National Grid has also sold its gas transmission business: the final 20% stake in National Gas Transmission was sold in September 2024, so National Gas is a separate company.

Today National Grid plc’s UK businesses include electricity transmission in England and Wales, and electricity distribution in the Midlands, South West England and South Wales through National Grid Electricity Distribution. It also has regulated networks in New York and New England in the United States.

When a news story says “National Grid is upgrading a line”, it usually means NGET. When it says the grid is being balanced or a connection date has been offered, that is NESO’s job.