Before electricity reaches your business, it has a journey to make. It needs to travel across the high-voltage transmission network and then through local distribution networks before it reaches your meter.
Keeping these networks running, maintained, and available comes with costs, and some of these costs are reflected in what you pay for your electricity. TNUoS and DUoS are regulated network costs that form part of the wider cost of supplying electricity. Depending on the customer’s contract and the supplier’s pricing structure, these costs may be incorporated into unit rates, standing charges or shown as separate/pass-through charges.
But what exactly do these charges cover, why do they change, and how can the 2026/27 changes affect the costs behind your business electricity? Let us take a closer look at these charges and where they fit into the bigger picture of your standing charge.
What are TNUoS and DUoS Charges?
TNUoS (Transmission Network Use of System) charges recover the costs of operating, maintaining and developing Great Britain’s electricity transmission system. Suppliers are liable for TNUoS charges, with tariffs varying according to factors including geographical zone and demand.
These network costs contribute towards maintaining and developing the electricity system, including:
- Maintaining and improving existing network infrastructure.
- Supporting the development and connection of new generation and demand, including renewable generation, as the electricity system evolves.
- Keeping the electricity network secure, reliable and resilient.
For energy suppliers, these regulated network charges are part of the wider costs of supplying electricity and can ultimately be reflected in the prices offered to customers.
On the other hand, DUoS, or Distribution Use of System, charges relate to the local distribution networks that carry electricity from the wider network towards your business premises.
This includes:
- Operating the local electricity network
- Maintaining and upgrading distribution infrastructure
- Supporting the network as electricity use changes
- Keeping the network reliable and operational
DUoS (Distribution Use of System) charges recover the costs associated with operating, maintaining and developing the local electricity distribution networks. Charges vary by distribution area and by factors including the customer’s connection, meter configuration and consumption characteristics.
A simple way to understand the difference is to think of TNUoS as the major roads moving electricity across the country, while DUoS is the local road network that helps deliver it to your door.
Where Do These Charges Fit into Your Electricity Costs?
This is where understanding your bills becomes important.
A standing charge for business electricity is a fixed daily amount you pay regardless of how much electricity you use. However, the exact way network costs are reflected in your electricity price depends on your contract and how your energy supplier structures its charges.
Ofgem identifies network costs, including TNUoS and DUoS, as one of the costs involved in supplying energy to businesses. Other costs can include wholesale energy, government schemes, taxes and supplier costs.
So, when you look at your electricity bill, the standing charge is only one part of the wider picture. This is also why comparing business electricity rates purely by their unit price does not always tell you which deal represents the best overall value.
What Changed with TNUoS in 2026?
The 2026/27 TNUoS charging year began on 1 April 2026. NESO published the final tariffs on 30 January 2026, following the annual process used to determine transmission network charges.
TNUoS charges are not simply one national rate. The charging arrangements take account of geographical zones and different categories of electricity demand and generation.
This means the effect of changes to TNUoS can differ depending on the circumstances of the electricity being supplied. Businesses should therefore be cautious about applying a single headline increase or decrease to their own energy costs.
NESO publishes TNUoS tariffs annually. The final 2026/27 tariffs were published on 30 January 2026 and apply from 1 April 2026. NESO has also already published its initial forecast information for 2027/28 during 2026.
Network tariffs are influenced by the costs of operating, maintaining and developing the electricity networks, as well as the methodologies used to allocate those costs across users. The impact therefore varies by charging year, location, connection type and customer characteristics.
So, What’s New with DUoS Charges in 2026?
Great Britain has several electricity distribution network areas, each serving different geographical regions. As a result, DUoS charges can vary depending on where your business is located.
Your charging arrangements can also be influenced by factors such as your connection, meter, and electricity usage. This means two businesses using similar amounts of electricity may still have different distribution network costs.
For 2026/27, Ofgem‘s arrangements for managing excessive surplus residual charges allowed affected DNOs to seek derogations from certain charging requirements when setting their tariffs. The impact varies by distribution area, so there is no single national DUoS increase or decrease applicable to all businesses.
For businesses, the key point is that there is no single DUoS change that applies equally across the country. The impact depends on the relevant distribution area and the specific characteristics of your electricity supply.
So, if you come across a headline saying DUoS charges have risen or fallen, it is worth looking beyond the headline and checking what actually applies to your business.
How Do Network Charges Affect Energy Prices?
When comparing business electricity rates, it is easy to focus on the unit rate because it is the figure most prominently associated with the electricity you consume.
There is more to your energy price than the unit rate alone. Depending on your contract, network costs and other charges may already be built into your quoted rates or listed separately.
This is why it is useful to look at the complete pricing structure rather than comparing one figure in isolation.
Key Details to Check
When reviewing an energy quote, consider:
- The electricity unit rate
- The daily standing charge
- The contract length and pricing structure
- Other applicable charges
- What happens when regulated charges change
Taking this wider view can give you a more realistic idea of what a business electricity contract could cost you.
Can Businesses Manage These Costs?
Businesses cannot determine the regulated network tariffs, but they can understand how those charges are recovered under their contract and how their consumption and connection characteristics affect the overall cost of electricity.
Start by checking your current contract and understanding how network-related costs are reflected in your pricing. If you are renewing or switching, ask your business energy supplier to explain any charges that are unclear.
It is also worth keeping an eye on how and when your business uses electricity. Understanding your consumption patterns can help you identify opportunities to manage demand and improve energy efficiency.
What Does This Mean for Your Business?
The 2026/27 changes to TNUoS charges and DUoS charges are part of the wider costs involved in delivering electricity to businesses across Great Britain.
The impact will not be identical for every business. Your location, connection, meter, consumption and energy contract can all influence the costs that apply to your premises.
Understanding these charges can therefore help you make better sense of your standing charge for business electricity and make more informed comparisons when reviewing business electricity rates.
There can be a lot to consider when looking at your energy bill, but taking the time to perceive what you are paying for can make a real difference. The more familiar you are with the different elements of your energy costs, the easier it becomes to compare options, review your contract, and make decisions that work for your business.
