A new wave of network cost increases
Businesses could soon face a sharp rise in network charges as Ofgem and the National Energy System Operator (NESO) move ahead with new transmission cost frameworks under RIIO-3, due to take effect in April 2026.
The latest forecasts point to significant increases across standing charge elements, part of the non-commodity costs that make up every electricity bill.
Transmission Network Use of System (TNUoS) charges - the fees paid to maintain and operate the UK’s high-voltage electricity grid are expected to rise sharply from April 2026, following Ofgem’s October 2025 update and fresh forecasts from the National Energy System Operator (NESO).
These charges form part of your standing charge and are one of several non-commodity costs that make up business electricity bills.
Why are TNUoS costs increasing?
The rise coincides with the launch of RIIO-3, Ofgem’s next five-year regulatory framework for the transmission network.
Under RIIO-3, transmission operators (TOs) including National Grid Electricity Transmission, Scottish Power Transmission, and Scottish & Southern Electricity Networks are submitting business plans for approval. These plans include billions in infrastructure upgrades to meet the UK’s Net Zero targets and ensure long-term energy security.
Ofgem will review and approve these plans by December 2025, setting the final cost base for TNUoS rates from April 2026.
What the latest forecasts show
- NESO has forecast that industry-wide TNUoS costs may rise by around 90% in 2026/27 compared to 2025/26.
- This could lead to similar percentage increases for end users, though the actual figure depends on a site’s region, voltage level, and specific banding.
- The final determination will be published January 2026.
While the figures are not yet confirmed, these early signals suggest significant upward pressure on standing charges in the next 18 months.
What businesses should do now
Even though these changes won’t take effect until April 2026, they highlight why forward planning and fixed-rate contracts matter.
Energy costs are no longer driven purely by commodity markets network and policy costs now account for more than 30% of a typical business electricity bill.
Here’s what to consider:
- Review current contracts: locking in competitive rates before April 2026 could shield your business from future cost rises.
- Audit your bills: ensure pass-through costs are being applied correctly.
- Stay informed: Ofgem and NESO updates will continue throughout 2025.
The Resolve View
The upcoming TNUoS changes are another reminder that non-commodity costs, not just energy prices can move markets.
By staying proactive, businesses can avoid exposure to volatility and make strategic procurement decisions ahead of the next price reset.
Get ahead of April 2026.
If you're looking to save money on your business gas bills then why not get in touch today? The close relationships Resolve Energy has developed with over 24 of the UK’s biggest business energy suppliers allows our energy experts to source the best business gas rates available for your company right when you need them. Request a free quote today and start saving money on your energy.
