Rising TNUoS Charges: What It Means for UK Businesses

When the National Grid released its latest Transmission Network Use of System (TNUoS) forecasts this autumn, the headline figures made headlines for all the wrong reasons. Costs are set to double across many supply types, sending a clear signal: the next few years will bring a steep rise in network charges, and a new era of energy strategy for UK businesses.

But beyond the numbers lies a bigger story. These changes affect not only large industrials and manufacturers, but also charities, local authorities, and community energy projects, all of whom are already grappling with volatile prices, rising demand, and the drive toward net zero.

At VEST Energy, we believe understanding and preparing for these shifts is essential. Here’s what’s driving the rise, what it means in practice, and how businesses can use battery storage and smart energy optimisation to mitigate the impact.

What Are TNUoS Charges (and DUoS Charges)?

Before diving in, let’s get the basics straight.

• TNUoS charges (Transmission Network Use of System) are the fees the National Grid Electricity System Operator (NGESO) collects to recover the cost of operating, maintaining, and reinforcing the high-voltage transmission network.

  
  

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• (Distribution Use of System) are similar, but apply to the lower-voltage distribution network, charged by Distribution Network Operators (DNOs).

Together, these make up a significant portion of your non-commodity energy costs, the part of your bill that can’t be negotiated away through procurement.

For years, these charges have quietly risen in the background. Now, however, they’re front and centre - and climbing faster than ever.

The Numbers: A Steep Climb Ahead

From April 2026, the UK enters the next regulatory period: RIIO-ET3 (RIIO-3), running until 2030/31. This is when the biggest shifts will land.

According to National Grid’s latest forecasts:

• Total TNUoS revenue in 2026/27 is projected at £8.9 billion, up £2.7 billion from initial estimates.

  
  

• By 2030/31, that figure could reach £13.6 billion, a near 50% increase over the period.

These aren’t abstract figures. For many businesses, that will translate to:

• Fixed standing charges (£/site/day) doubling almost overnight.

  
  

• Variable locational tariffs rising, depending on where your site is connected.

In short: there’s no hiding place from higher costs.

Why Are TNUoS Charges Rising So Fast?

Several factors are driving this steep increase:

1. Network Reinforcement for Decarbonisation

The UK is adding renewable generation at record pace. Wind, solar, and battery assets need new grid connections and upgrades to handle variable generation. Those infrastructure costs must be recovered through TNUoS.

2. Targeted Charging Review (TCR) Updates

The Targeted Charging Review has overhauled how fixed charges are calculated. Many organisations are now moving into higher residual bandings, meaning bigger standing charges. regardless of how much electricity they actually use.

3. Rising Transmission Owner (TO) Costs

With inflation, material costs, and labour all higher, Transmission Owners are forecasting greater expenditure during the RIIO-3 period. That’s baked into the new TNUoS rates.

4. Locational Pricing Effects

Variable elements of TNUoS are based on location and sites in the North or Scotland, where much of the new renewable generation sits, may face higher costs to reflect transmission flow constraints.

What This Means for Businesses

The practical implications are significant, especially for large energy users:

1. Higher Operating Costs

Energy is already one of the largest variable costs for manufacturers, data centres, and industrial sites. A doubling of TNUoS or DUoS standing charges will squeeze margins further, particularly for energy-intensive sectors.

2. Budgeting Complexity

When fixed network charges shift dramatically every few years, forecasting becomes a challenge. Finance teams will need to model multiple exposure scenarios across the RIIO-3 period.

3. Strategic Energy Planning

Some businesses may reconsider their agreed capacity, explore load-shifting strategies, or accelerate decarbonisation projects such as on-site solar and storage to offset the impact.

Not Just Big Industry: Charities and Communities Are Affected Too

While the media focus is often on energy-intensive users, charities and third-sector organisations are also exposed.

Community hubs, offices, and warehouses, often operating on tight budgets, may find themselves in higher fixed charge bands. Because these organisations can’t simply pass on increased costs, they’ll face pressure on fundraising, service delivery, and staffing.

Similarly, local authorities and housing associations will need to model new long-term costs carefully. Rising network fees could undermine the financial viability of community solar or microgrid projects unless mitigated by flexibility or on-site generation.

Bridging the Inequality Gap

There’s a deeper issue here, too: energy inequality.

As fixed costs like TNUoS and DUoS rise, the gap widens between organisations that can invest in on-site generation or storage, and those that can’t. Businesses with access to capital or funded solutions will weather the storm; others may struggle.

That’s why accessible, flexible energy solutions matter now more than ever.

How Battery Storage Can Help Mitigate TNUoS and DUoS Costs

While TNUoS residual standing charges are fixed, businesses can influence demand-based components through smarter energy use. That’s where battery storage comes in.

1. Load Shifting

Battery systems allow you to store electricity during off-peak hours and use it when demand (and therefore charges) are highest. This helps reduce demand-based costs.

2. Peak Avoidance

By discharging stored power during peak periods, you can avoid spikes in transmission and distribution charges that are linked to demand peaks.

3. Flexibility Revenue

Through services like Dynamic Containment or demand response, batteries can earn income while improving system flexibility, offsetting higher network costs.

4. Resilience

With network costs rising, the ability to keep operations running during grid events adds both financial and operational resilience.

At VEST Energy, our GreenBattery model offers these benefits with no upfront capital expenditure, making battery storage accessible to more organisations, from industrial sites to community hubs.

What Businesses Should Do Now

The new TNUoS framework isn’t in force until April 2026, but preparation needs to start today.

1. Review Your Banding

Understand your current residual band and where you’ll likely fall after the update. Many organisations will move up one or more categories.

2. Model Exposure

Include both fixed and variable elements in your forecasting. Build models across the RIIO-3 period to identify potential pain points.

3. Explore Demand Flexibility

Even if standing charges can’t be reduced, smart energy management can limit exposure to variable costs.

4. Assess On-Site Solutions

From solar PV to funded battery storage, integrated energy assets can help offset the impact of rising network charges.

5. Stay Informed

Forecasts will be updated in November 2025, with final rates published in January 2026. Keep an eye on Ofgem and NESO updates to stay ahead of the curve.

The Bottom Line

The rise in TNUoS and DUoS charges is unavoidable, they’re baked into the structure of the UK electricity market. But that doesn’t mean businesses are powerless.

By acting early, modelling exposure, and exploring flexibility through technologies like battery storage, organisations can protect margins, support decarbonisation, and build resilience for the decade ahead.

At VEST Energy, we’re already working with businesses, charities, and local authorities to model their exposure and design strategies to offset these rising costs.

If you’d like to understand what TNUoS and DUoS changes mean for your sites, and how GreenBattery can help, get in touch with the team today.