Calculate how the incoming TNUoS charges will impact your bill

In September 2025, The National Energy System Operator (NESO) released its forecast for upcoming changes to Transmission Network Use of System (TNUoS) charges, to be implemented between the financial years 2026 – 2030. NESO seeks to raise ~£3.5bn in charges through customer bills to cover the costs of upgrading and expanding the existing transmission network. This will mean a significant increase in cost to customers on their standing charges. 

This tool has been developed in partnership with the NFU to help you quickly understand how the proposed changes could affect your business’ energy costs, using a few simple details from your bill to give you a personalised estimate. The information gathered through you completion of the calculator will support the NFU’s efforts lobbying the government.

Important notice

To ensure the calculator continues to provide the most accurate estimate for how TNUoS charges will impact you, we will update it in line with the latest figures from National Energy System Operator (NESO). This means you may see different results over time if you re-visit the tool. The below dates confirm NESO's timeline of future TNUoS updates.

The following updates have been made to the calculator:

Version 1 published 02 December 2025 - Calculator first published on the website

Version 2 published 19 December 2025 - Calculator updated to incorporate the revised TNUoS charges proposed by NESO 19 December 2025

Version 3 published 30 January 2026 - Calculator updated to incorporate the final charges for the 2026-27 charging period, announced 30 January 2026