TNUoS charges set to rise in 2026

The National Energy System Operator (NESO) has forecasted significant increases in Transmission Network Use of System (TNUoS) charges 2026/27.

Set by Ofgem, TNUoS charges are designed to allow transmission network companies to recover their operating costs from suppliers and generators. The majority of supplier costs are recovered via a £/site/day structure included in customer standing charges. In December 2024, transmission network companies published their draft business plans which indicated they are asking Ofgem to permit the recovery of larger sums commencing April 2026.

Following calls for greater clarity, NESO published an initial forecast on 30th April. Outlining that total demand residual revenues, which lead to the majority of TNUoS charges, are forecasted to increase by a further 26% from Apr-25 to Apr-26.

Potential TNUoS increases remain uncertain and depend on a number of factors, yet a significant increase from April 2026 looks highly likely.