Rising TNUoS charges: What UK businesses need to know about electricity network costs

Transmission Network Use of System (TNUoS) charges are set for a sharp rise in April, with expectations they’ll continue increasing year on year. Projections suggest some regional increases of this fixed residual energy charge could double in April compared to current levels. In this blog we take a look at what TNUoS charges are, why they’re increasing, who this will impact and what action businesses across the UK can take.

Transmission Network Use of System (TNUoS) charges are set for a sharp rise in April, with expectations they’ll continue increasing year on year. These network charges are a key part of business electricity costs in the UK. Projections suggest some regional increases in the fixed residual energy charge could double compared to current levels. For many organisations, this could have a serious impact on businesses’ energy bills and is a stark reminder that non-commodity electricity costs, not just wholesale energy prices, influence the total cost of electricity.

Projections suggest some regional increases of this fixed residual charge could double in April compared to current levels. This will have a serious impact on businesses’ energy bills and is a stark reminder that non-commodity costs, not just energy prices, can affect the energy market.

In this blog we take a look at what TNUoS charges are, why they’re increasing, who this will impact and what action businesses across the UK can take.

What are TNUoS charges?
TNUoS charges are one of the main electricity transmission charges in the UK, forming part of the wider network costs that make up a significant portion of business electricity bills.

TNUoS charges are the fees suppliers pay for using Britain’s high-voltage electricity transmission network - the infrastructure that moves electricity from power stations and renewable generation sites across the country to where it is needed.

This national network of pylons, substations and cables is essential to keeping the lights on across the UK. But like any large infrastructure system, it requires constant investment to maintain, upgrade and expand.

TNUoS charges are designed to help fund:
•    Maintenance of the high-voltage transmission network
•    Upgrades to ageing infrastructure
•    Connecting new renewable generation to the grid
•    Ensuring the electricity system remains reliable and resilient

The tariffs are calculated and published annually by the National Energy System Operator (NESO), which forecasts network costs and allocates charges across the market. The revenues collected ultimately go to the companies that own and operate the transmission network infrastructure.

These charges form part of the non-commodity portion of electricity bills - the elements of energy costs for UK businesses that sit alongside the wholesale price of electricity itself.

This distinction is important. Even if wholesale electricity prices fall, businesses can still see their energy bills rise if network and policy costs increase.

How are TNUoS charges calculated for businesses?
TNUoS tariffs are not a simple flat fee. They are calculated using several factors that reflect how and where electricity is used.

The main elements include:

Residual charge
The residual charge is a fixed daily cost applied to electricity consumers. It is usually based on a site’s voltage level and agreed supply capacity. This charge recovers the majority of the cost of maintaining the transmission network.

Locational demand charge
Electricity costs more to transport to some regions than others. As a result, the UK transmission network is divided into 14 demand zones, each with different tariffs depending on local network constraints and infrastructure requirements.

Businesses located further from major generation hubs can therefore face higher transmission costs.

Triad charges (for half-hourly metered sites)
For larger businesses with half-hourly electricity meters, an additional cost element is linked to demand during the three peak periods of electricity usage on the national grid, known as the Triads.

These are the three highest demand half-hour periods between November and February, each separated by at least ten days.

If a site consumes a lot of electricity during these peak periods, it can face significantly higher transmission charges. The structure is designed to encourage businesses to reduce demand during times when the grid is under the most stress.

Why are TNUoS charges increasing?
The short answer: Britain’s electricity network is undergoing one of the largest upgrades in its history.

As the UK transitions towards a low-carbon energy system, the electricity grid must evolve to support:
•    Rapid growth in renewable generation such as wind and solar
•    Electrification of transport and heating
•    Increased electricity demand from businesses and households
•    New storage technologies and smart grid infrastructure

Much of the current transmission network was built decades ago, at a time when electricity flowed largely from a small number of large fossil fuel power stations.

Today’s energy system is, of course, very different.

Power is increasingly generated from multiple renewable sources located across the country, from offshore wind farms in the North Sea to solar farms and rooftop solar installations across Britain.

To support this shift, substantial investment is required in new transmission infrastructure.

In December 2025, Ofgem approved £28.1 billion of investment in electricity transmission networks, enabling more than 80 major infrastructure projects across Great Britain. These upgrades are essential to meet the UK’s Net Zero targets and ensure long-term energy security. However, the cost of building and maintaining this infrastructure ultimately feeds into the network charges paid by electricity users.

In other words, the increases in TNUoS charges reflect the investment required to build a cleaner, more resilient electricity system.

How much are TNUoS charges increasing by?
Recent forecasts from the National Energy System Operator suggest that the increases could be substantial over the coming years.

Across the industry:
•    Total TNUoS revenue is forecast to rise from around £8.9 billion in 2026/27 to £13.6 billion by 2030/31. 
•    Some forecasts suggest the fixed residual charge could rise by more than 90% between 2025 and 2026.
•    In certain regions, transmission costs for half-hourly metered sites could increase by over 50%.
•    Overall, the impact could add roughly 5% to electricity bills for many businesses.1

While Ofgem has taken steps to smooth the increases, the overall trend remains clear: network costs are rising and are expected to continue rising in the coming years.

For businesses planning their energy budgets, these changes are becoming an increasingly important consideration.

Which businesses are most affected by rising TNUoS charges?
While TNUoS charges affect all electricity consumers, some organisations are more exposed than others.

Energy-intensive industries

Sectors such as:
•    Manufacturing
•    Logistics and warehousing
•    Data centres
•    Agriculture and food production

These industries tend to have large electricity demands, which means transmission costs can make up a significant portion of their overall energy spend.

Multi-site organisations
Businesses operating across multiple locations may experience varying cost impacts depending on where each site sits within the transmission network.

Regions with higher locational charges
Because TNUoS tariffs are location-dependent, organisations in some parts of the country, particularly areas further from major generation centres, may see larger increases. Businesses in South Wales, South West England and South East England are expected to face the steepest increases due to their distance from major generation hubs. 

Businesses with high peak demand
Companies with significant electricity usage during winter peak periods may face higher demand-related transmission charges.

Even organisations with relatively modest electricity consumption should take note. While the absolute costs may be smaller, the proportional impact on operating budgets can still be significant.

What can businesses do?
Businesses cannot avoid TNUoS charges entirely, but as electricity network costs continue to rise, many organisations are looking for practical ways to reduce business electricity costs and reliance on the grid. Here are several steps organisations can take to manage their exposure:

Review electricity contracts carefully
Network charges are often included within electricity contracts as pass-through costs. Understanding how these are applied and forecast within your contract can help avoid unexpected price changes.

Check capacity and banding
Ensuring your site is placed within the correct capacity band can prevent unnecessary over-charging.

Improve energy efficiency
Reducing overall electricity demand remains one of the most effective ways to lower energy costs across both commodity and non-commodity charges.

Manage peak demand
Businesses with half-hourly meters may benefit from monitoring grid peak warnings and reducing consumption during likely Triad periods.

Consider on-site energy generation
Generating electricity on-site can significantly reduce reliance on grid electricity, particularly during periods when network charges are highest.

Why solar PV and battery storage are a strong solution
For many organisations, on-site solar generation combined with battery storage is becoming one of the most effective ways to manage rising electricity costs.

Commercial solar panels allow businesses to generate electricity directly from their rooftops or land, reducing the amount of power they need to import from the grid.

This can deliver several advantages:

Lower electricity imports
Every unit of electricity generated on-site is one less unit that needs to be purchased from the grid - helping reduce exposure to both wholesale prices and network charges.

Reduced peak demand
Solar generation can lower demand during daylight hours, while battery storage can help shift energy use away from peak grid periods. This can help businesses reduce exposure to demand-related transmission charges.

Greater energy resilience
On-site generation and storage provide businesses with greater control over their energy supply and costs.

Greater control of consumption
Battery storage can also play a valuable role. By storing excess solar energy generated during the day, batteries allow businesses to use that power later when demand is higher or when electricity from the grid is more expensive. This helps reduce reliance on grid electricity during peak periods, particularly the winter demand windows that influence transmission charges. In effect, battery storage gives businesses greater control over when they draw power from the grid, helping to reduce business electricity costs and exposure to rising network charges.

Start taking control of your energy costs
TNUoS charge increases are a reminder that energy bills are influenced by far more than wholesale electricity prices.

By generating and managing more of their own energy on-site, businesses can reduce exposure to rising network costs and gain greater control over their electricity spend.

At Plug me in, we’ve helped businesses across the UK install solar and battery systems that reduce reliance on the grid and bring greater control over energy costs. You can see how this works in practice in our solar and battery case studies.

If you’d like to explore whether solar PV and battery storage could work for your organisation, the Plug me in team would be happy to help.

Source ref
1 https://www.neso.energy/industry-information/charging/tnuos-charges