⚡ Brace for a Step Change: TNUoS Residual Charges to Surge in April 2026

From 1 April 2026, UK businesses face a dramatic shift in electricity network charging: the TNUoS residual (standing-charge) element is set to nearly double in one leap. This isn’t a marginal adjustment — it’s a structural reset of how fixed network costs are recovered.

What’s happening?

• The National Energy System Operator (NESO) projects that demand residual revenue will climb from £3.84 billion in 2025/26 to £7.52 billion in 2026/27.
• These residual charges are fixed per meter, per day — meaning your business pays them regardless of how much power you use.
• This change is tied to the launch of the RIIO-ET3 price control period. Over the next five years, around £80 billion of investment is required to bolster the network: reinforcing lines, enabling new renewables (offshore wind, large-scale solar, etc.), and improving connectivity between regions.

What will the cost impact look like?

• Standing charges will be where most of the pain is felt. Many business energy contracts treat TNUoS residuals as a pass-through cost — meaning even fixed contracts might be adjusted mid-term.
• For example, an HV3 site’s residual charge could rise from ~£85,000 in 2026/27 to over £144,000 by 2030/31.
• Even domestic and LV (low voltage) connections see significant jumps: e.g. LV1 from ~£1,426 → £2,655.
• Importantly: the 2025/26 charging year is unaffected — the step change only begins in 2026/27.

Next steps…

We will continue to keep you updated as Ofgem and National Grid release further detail. In the meantime, we recommend reviewing your electricity contract structures and budget forecasts to ensure you are prepared for the upcoming changes.

If you would like a bespoke analysis of how the new TNUoS charges will affect your organisation, please get in touch with us at hello@gleg.co.uk – we’re here to help.