Understanding Nuclear RAB Charges and TNUoS Tariff Rises (2025–2030)

From nuclear financing to grid infrastructure, the cost of powering the UK is shifting and the burden is increasingly falling on commercial and industrial energy users.

At True Group, we believe knowledge is power. That’s why we’re here to help you navigate two major regulatory developments that could significantly impact your long-term energy costs: the upcoming Nuclear Regulated Asset Base (RAB) charge and sharp increases to Transmission Network Use of System (TNUoS) tariffs.

RAB Charges: Nuclear Costs Coming to Your Bill

The government is introducing a new Nuclear RAB charge to fund the construction of new nuclear power stations through a regulated income stream for investors, paid for by energy users.

Here’s What You Need to Know:

• Supplier Obligation Levy: £3.455/MWh (0.3455p/kWh), effective 1 November 2025
• Operational Levy: £0.0028/MWh, effective 1 October 2025.

These will appear as line items on your electricity bill. While the rates are confirmed, they may vary over time and are subject to reconciliation by government.

How This Affects You:

• Pass-through contracts: The charges will be automatically applied. (No need to worry, True Group will track these for you.)
• Fixed contracts: Some suppliers may absorb the costs initially, but many reserve the right to adjust prices due to regulatory changes. (We’ll review your contract terms for you and let you know exactly where you stand.)

Exemptions apply to businesses qualifying under the Energy Intensive Industries (EII) scheme.

TNUoS Tariffs: Forecasted to Surge Through 2030

The National Energy System Operator’s (NESO) Five-Year View reveals a steep trajectory for TNUoS charges, critical costs that fund the UK’s electricity transmission network.

From 2026/27 onwards, businesses will see significant uplifts:

• Demand Residual Revenue: £7.52bn (↑ from £3.84bn in 2025/26)
• HH demand tariff: £3.18/kW (↑ £0.18/kW)
• NHH demand tariff: 0.43p/kWh (↑ 0.05p/kWh)
• Embedded Export Tariff: £3.45/kW (↑ £0.45/kW).

What’s Driving This?

• The transition into RIIO-3, requiring higher revenue for grid upgrades
• Large-scale investment to support the net zero transition
• Refined transport models that redistribute charges in new, complex ways.

With additional reforms expected under the government’s Review of Electricity Market Arrangements (REMA), this volatility could persist into the next decade.

How True Helps You Stay Ahead

We don’t just flag these changes, we help you prepare for them.

At True Group, our team delivers:

• Tailored analysis of site-specific TNUoS exposure
• Accurate cost forecasting for future budget planning
• Clear strategies to reduce and manage non-commodity costs.

Whether you’re managing a complex portfolio or a single large site, our experts and technology will ensure you stay on the front foot. From nuclear levies to grid fees, we turn energy market complexity into commercially sound decisions.

Let’s Talk About Your Exposure

Need clarity on how these changes affect your contracts, forecasts or budgets?

We’ll do the heavy lifting - reviewing your terms, checking your bills, and modelling the impact. Because at True Group, we believe making better energy decisions shouldn’t be complicated.

Get in touch today to find out how we can help you navigate the next wave of cost and complexity and protect your bottom line while building toward net zero.