Predicted Changes in TNUoS Charges for 2026

Transmission Network Use of System (TNUoS) charges are a major component of UK electricity costs, covering the maintenance, operation, and development of the national electricity transmission network. These charges are set annually by the National Energy System Operator (NESO) and regulated by Ofgem, the UK’s energy regulator.
Although TNUoS charges are paid by energy suppliers, the costs are ultimately passed on through electricity bills, meaning businesses and households across the UK are affected.
Looking ahead to the 2026/27 charging year, forecasts suggest a significant increase in TNUoS charges. This article explores the predicted changes, the key drivers behind them, who is likely to be most affected, and how organisations can prepare.

How Are TNUoS Charges Expected to Change in 2026?

NESO’s forward-looking forecasts for TNUoS charges in 2026/27 indicate a substantial rise, largely driven by increases in the Transmission Demand Residual (TDR) – the fixed portion of transmission charges recovered from electricity demand.
According to analysis published by D-Energi, the demand residual across Great Britain could increase from around £3.8 billion in 2025/26 to as much as £7.5 billion in 2026/27, with the potential for further increases in future years.
This sharp rise would represent a major shift in transmission charges for UK businesses, particularly those with high electricity demand or large capacity connections.

What Is Driving the Increase in TNUoS Charges?

One of the main drivers behind rising TNUoS electricity charges is increased allowed transmission revenue to fund major grid upgrades.
From April 2026, the RIIO-ET3 framework (Revenues = Incentives + Innovation + Outputs) will come into effect. This price control period is designed to support large-scale investment in the transmission network, including plans to nearly double grid capacity to accommodate growing volumes of renewable electricity.
This investment is critical to supporting the UK’s transition to a low-carbon energy system, improving resilience, and enabling electrification across transport and industry. However, the cost of this infrastructure expansion is reflected in higher transmission network charges.

Changes to Locational Transmission Charges

Another contributing factor is the ongoing shift away from strongly locational charging. Historically, TNUoS charges varied significantly by region, reflecting the cost of using the transmission network in different locations.
While locational charges are changing – with areas such as the Midlands, South Wales, and the South West seeing some of the steepest increases – the Transmission Demand Residual is expected to remain the largest cost driver for most businesses, regardless of location.

Who Will Be Most Affected by Higher TNUoS Charges?

Businesses with high electricity consumption or large agreed capacities are likely to see the greatest increases in TNUoS costs. This includes manufacturers, data centres, logistics operators, and multi-site organisations.
However, rising UK transmission charges will not only affect large energy users. Smaller businesses and domestic consumers are also likely to experience indirect impacts, as higher network costs feed through into overall electricity pricing.

How Can Businesses Prepare for TNUoS Charge Increases?

While increases in TNUoS charges for 2026 cannot be avoided, early preparation can help mitigate their impact.
Key steps include:

• Staying informed about upcoming changes to transmission charging structures
• Understanding how capacity, demand, and location influence costs
• Reviewing energy usage patterns to avoid unnecessary capacity charges
• Improving energy efficiency and demand management where possible

Working with an informed, data-driven energy supplier can also help businesses anticipate cost changes. Suppliers that actively monitor regulatory developments – such as D-energi can provide insight into future risks and help organisations plan more effectively.

Final Thoughts on TNUoS Charges in 2026/27

While forecasts published by D-Energi provide valuable insight into future UK electricity transmission costs, final TNUoS tariffs will not be confirmed until Ofgem approves the proposals, and NESO publishes the official charges.
Nevertheless, preparation remains the best strategy. By staying informed and reviewing energy strategies now, businesses can better manage the impact of rising TNUoS charges and remain resilient throughout the 2026/27 charging period and beyond.