From April 2026, the way businesses are charged for using the electricity transmission network will change significantly. These charges, known as Transmission Network Use of System (TNUoS) charges, are set nationally and passed through by suppliers. They cover the cost of maintaining and upgrading the high-voltage transmission system that moves electricity around Great Britain.

The latest forecasts show a sharp increase in TNUoS charges for 2026/27. In fact, the revenue National Energy System Operator (NESO) needs to recover is set to rise by nearly 75% compared to this year. That means:

  • Standing charges (the fixed daily element of your bill) are expected to almost double for many meter bands.
  • Demand tariffs (the charges linked to your site’s capacity and usage) will also increase, particularly for half-hourly customers with higher demand.
  • The impact will vary by location and meter type, but many medium-to-large businesses could see five-figure increases per site, per year.

Final tariffs will be confirmed in January 2026, but we already know the direction of travel: costs are going up.

What this means for you

  • Check the detail on supplier offers carefully. If TNUoS is “pass-through” in your contract, you’ll need to budget for these uplifts when they land.
  • Understand your exposure. Your meter type, capacity, and region all affect how the new charges flow through to you.
  • Plan ahead. For larger energy users, these increases could have a material impact on budgets from April 2026 onwards.
  • Consider fixing: If your non-commodity costs currently pass through, whilst things are volatile.

At Equity Energies, we are monitoring the draft tariffs closely and will keep you updated as more detail emerges this autumn. Our role is to help you interpret these changes, forecast the impact on your sites, and ensure your procurement strategy takes them into account.

We are in the process of putting together resources for clients to help you understand the cost implications of the changes to your business –  but if need to speak to us about this, please let your client manager know or speak to the team.

By Stephanie Palmer, Head of Pricing