The four roles, one analogy
Picture the road network. Someone builds the motorways, someone builds the local streets, someone runs the traffic control, and a haulage firm sells you the delivery. Electricity works the same way.
Transmission owner
National Grid (E&W)
Owns: The high-voltage motorway: 400 kV / 275 kV pylons, lines and big substations.
Job: Move bulk power long distances between regions.
Switch? No
Distribution operator
Your DNO (one of 6)
Owns: The local roads: lower-voltage cables, poles and substations to your street.
Job: Carry power the last stretch to your meter and fix local power cuts.
Switch? No
System operator
NESO
Owns: Nothing physical.
Job: Balance supply and demand every second and plan the future grid.
Switch? No
Supplier
Octopus, British Gas, EDF...
Owns: Nothing physical; it buys power wholesale.
Job: Sell you electricity and send your bill.
Switch? Yes
Side by side
| National Grid | DNO | NESO | |
|---|---|---|---|
| What it is | Transmission owner | Distribution owner | System operator |
| Owns wires? | Yes (high-voltage) | Yes (local) | No |
| Fixes your power cut? | No | Yes (call 105) | No |
| Balances supply and demand? | No (since 2024) | No | Yes |
| Sells you energy / bills you? | No | No | No |
| Can you switch it? | No | No | No |
| Owner | Listed company (E&W) | Regional (6 DNOs) | Publicly owned |
The bottom row of the "sells you energy" question is the punchline: none of these three bills you. Only your supplier does, and the supplier is the only one you can switch.
Who handles your issue?
Pick what is happening and see exactly which of the four is responsible. Calling the wrong one is the single most common time-waster in the UK energy system.
Find the right one in one click
Contact
| Situation | Who to contact |
|---|---|
| My power has gone off | Your DNO — Call 105, free, and it routes to your local Distribution Network Operator, who owns the cables and fixes faults. |
| I want to query a bill or switch | Your supplier — Your energy supplier sells you the power and sends the bill. This is the only company you can switch. |
| I need a new home connection | Your DNO — Your DNO connects homes and small sites to the local network. Very large or transmission-level connections involve National Grid. |
| I read a winter blackout warning | NESO — A capacity or margin notice comes from NESO, the system operator. It is a request for more generation, not a blackout alert. |
| A giant pylon or line near me | Transmission owner — High-voltage pylons belong to National Grid (England and Wales) or the Scottish transmission owners, not your DNO. |
| I want to be paid to shift usage | NESO (via your supplier) — NESO runs the Demand Flexibility Service; you join through a participating supplier or aggregator. |
The supplier is the only one you can switch
National Grid, your DNO and NESO are fixed. Your supplier is not. Compare every live UK tariff, cheapest first, and switch the one part of the bill that is actually in your hands.
Cheapest live rate now: British Gas at 23.85p/kWh, about 3% below the 24.67p cap.
The insight: you spend energy fighting the wrong company
People pour their effort into the part of the system they cannot change. They ring the supplier about a power cut (the DNO's job), or blame the supplier for a "blackout warning" (NESO's call), or think switching supplier will change a network charge (it never does). The single most useful thing to know about the UK grid is which lever each company holds. The wires and the system operator are fixed by where you live and by law. The only lever in your hands is the supplier you choose and the tariff you pick. Spend your effort there, and ignore the rest unless the lights actually go out.
National Grid vs DNO vs NESO: FAQ
National Grid owns the high-voltage transmission network in England and Wales (the motorway). A DNO (Distribution Network Operator) owns the local cables that reach your home (the local roads). NESO is the system operator that balances the grid in real time and owns no wires (the traffic controller). None of them sells you electricity, that is your supplier.
Only your supplier. National Grid, your DNO and NESO are fixed: the network that serves your address and the body that runs the system are not things you choose. Switching supplier changes who bills you and the price of the energy and supplier margin, but never the network owners or the system operator.
Call 105. It is free and routes you to your local DNO, who owns the cables and fixes faults. Not National Grid (it runs the high-voltage system between regions) and not NESO (it has no role in local faults) and not your supplier (it only sells you the energy).
It depends on your postcode, not your supplier. There are six DNOs in Great Britain. You can find yours by postcode, by the first two digits of your MPAN (Supply Number) on your bill, or by calling 105. See our UK distribution networks guide.
Yes. Until 1 October 2024 the system operator was part of National Grid (as National Grid ESO). It was then separated and taken into public ownership as NESO. So the owner of the wires and the operator of the system are now two different organisations.