Transmission Network Use of System charges pay for the high-voltage grid. They are set through regulation rather than by your supplier, they are recalculated every April, and they are among the fastest-moving lines on a business electricity bill.
Verification
- Verified as at:
- Source:
- NESO published TNUoS tariffs; Ofgem RIIO-ET3 price control
- Last reviewed by:
- Omnium
Figures in this sheet were current at the verification date above. Regulated charges reset each April. If you are relying on a figure, check the source or ask us.
A4 board pack. Cover page, then a running head and foot on every page.
What it pays for
TNUoS recovers the cost of building and maintaining the transmission network: the pylons and cables that move power from where it is generated to where it is used.
Status: LawIt is regulated cost recovery applied to every supplier equally. No supplier can tender it away, and one that implies otherwise is describing a product feature rather than a lower cost.
- Charged on consumption, and for half-hourly sites on demand during defined peak periods.
- Recalculated annually and applied from 1 April.
- Published by NESO in final form each January, for the year beginning that April.
Why it moves
The grid is being rebuilt to connect offshore wind and to carry power from where it is now generated to where it is used. That investment is recovered through TNUoS under Ofgem’s RIIO-ET3 price control.
The direction is set by policy over a decade. The sensible planning assumption is that network charges continue to rise in real terms rather than revert.
The question worth asking
Ask whether a quoted rate fixes TNUoS for the term or passes it through. Most fixed-price contracts fix the commodity element only and leave network charges to reset each April, which means a price described as fixed can still move.
Get the answer in writing. We do not treat a supplier as fixing network charges on a verbal assurance, and neither should you. It is a question per supplier, per fuel and per product, because a supplier has one position per product rather than one position overall.
Whether fixing it is worth paying for
A supplier that fixes network charges is selling certainty, and it will be priced in. Whether that is worth paying is arithmetic rather than opinion.
Compare the exposed amount today against the annual premium charged to remove it, and see how far the charge would have to rise before the premium pays for itself. If the answer is several times today’s level, the premium is probably not worth it. The premium is payable every year regardless of what the charge actually does.
Related sheets
- Network charges and agreed capacity
Why regulated network charges rose sharply in April 2026, and why the capacity you reserve is a lever most businesses have never pulled.
- Non-commodity charges
Taxes, levies and regulated network charges now make up a large share of a business electricity bill, and comparing unit rates alone misses where the cost sits.
- Contract types, and how a fixed rate is built
The four business contract types, how a supplier assembles a fixed price, and why the wholesale market is no longer the larger part of an electricity rate.
Take this sheet into a meeting
Transmission charges, TNUoS exports as an A4 board pack: a cover page carrying the title and the verification date, then the sheet itself with a running head and foot on every page.
If this sheet raises a question about your own sites, speak to us.