Transmission Network Use of System (TNUoS) charges. October 2025

In September 2025 the National Energy System Operator (NESO) announced a five-year view of Electricity’s Transmission Network Use of System (TNUoS) charges.

The scale of the annual increases and the short notice before they will start to be implemented has caused concern throughout the industry due to the impact these will have on businesses, who are already heavily burdened with costs other than the price of the energy itself.

There is little question that the work involved in upgrading the Transmission network is significant and vital in order for us to achieve Net Zero. Without the additional funding then new generation, specifically Renewables, will not be connected to the network and delivered the long distances across the country to where it is needed.

An example of the current problems are the well-publicised long waiting times for connections to the network. Also, with increasing frequency, payments are being made to Renewable generators to stop supplying, whilst at the same time, burning Gas. These payments are then passed onto customers through bills in the form of Balancing charges.

Now for the detail:

• The current budget from April 2025 is £5.1bn.
• The estimated budget from April 2026 is £8.9bn.
• The estimated budget from April 2027 is £10.3bn.

It is expected that by 2030 this will be in the region of £13.6bn.

These costs will likely be included within the Electricity bill’s Standing Charge, although some suppliers may show as separate items. When tendering Electricity contracts including the period from April 2026, we have been seeing a range of approaches from energy suppliers in terms of how they price these currently estimated costs. They are likely to be confirmed in January 2026. For this reason, it is worth clarification before entering a new contract.

Most of the Transmission and Distribution charges that the customer pays are determined by their meter’s Band, which is a relatively new concept that looks to be fair and transparent. The Band depends on how much energy the meter requires. For Half Hourly metering, Indigo Swan encourages customers to review and consider their levels of Available Capacity, as savings can be made to this Distribution cost.

A review of the Available Capacity could potentially see a meter moved into a lower Band and reduce the Transmission and Distribution charges further. However, it is worth being aware that despite some claims, this is not always the case, and the impact can be modest, with some exceptions for larger supplies.

If you would like to discuss the above in more detail or would like Indigo Swan to carry out a review of your Half Hourly meter’s Available Capacity, please contact us.

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