July 2026, latest update
TNUoS and DUoS Charges Explained, Why Your Business Energy Bill Went Up in 2026
TNUoS and DUoS are the two network charges that now account for more than 64% of the average UK business electricity bill and from April 2026, they increased significantly. If your energy bill has risen even though your consumption has not changed, these charges are almost certainly the reason.
This guide explains exactly what these charges are, how much they have increased, why they are rising, and what your business can do to reduce their impact.When you receive a business energy bill, the charges break down into two broad categories. The commodity cost is the wholesale price of the energy itself the gas or electricity your business actually consumes. The non-commodity costs are everything else: network charges, metering costs, environmental levies, policy costs and supplier margins.
In 2026, non-commodity costs account for approximately 64% of the average business electricity bill. This means that for every £1 you spend on business electricity, only 36p relates to the actual energy. The remaining 64p covers infrastructure, policy and administration costs the majority of which are TNUoS and DUoS.
TNUoS Charges- What They Are and How Much They Increased
TNUoS stands for Transmission Network Use of System. These charges are the fees your energy supplier pays to National Grid ESO for access to the high-voltage electricity transmission system; the network of pylons and cables that carries electricity at 400kV and 275kV across the UK from power stations to local distribution networks.
In simple terms: TNUoS funds the national electricity ‘motorway network’. Every business that draws electricity from the grid contributes to this cost.
From April 2026, TNUoS charges for business electricity sites increased by approximately 60%. In practical terms:
- The typical TNUoS rate for an average half-hourly business site rose from approximately £16/MWh to approximately £31/MWh
- For smaller non-half-hourly sites, the impact is felt primarily through higher standing charges rather than per-unit rates
- For energy-intensive industrial sites with high-voltage connections, the annual increase can run to six figures
The reason for this increase is significant investment in the UK electricity transmission network required to connect new offshore wind, solar and other renewable generation. Ofgem has confirmed approximately £80 billion of grid investment over the next five years. The cost of this investment is recovered through TNUoS charges, meaning businesses bear a significant portion of the UK’s energy transition costs.
DUoS Charges- What They Are and How They Vary
DUoS stands for Distribution Use of System. These charges are the fees for using the local electricity distribution network — the lower-voltage cables and infrastructure that carry electricity from the national transmission network into your area and ultimately to your business premises.
Unlike TNUoS which is set nationally, DUoS charges are set by your local Distribution Network Operator (DNO). There are 14 DNO areas across the UK, each setting their own DUoS rates. This means two businesses with identical energy usage can pay very different DUoS charges depending on where they are located.
DUoS charges also vary by time of day, typically structured into three bands:
- Red band– peak demand periods, typically 4-7pm on weekdays. The highest DUoS rate applies during these times.
- Amber band– shoulder periods, typically morning and early afternoon on weekdays. A mid-range DUoS rate applies.
- Green band– off-peak periods, typically overnight and at weekends. The lowest DUoS rate applies.
For businesses on half-hourly meters, DUoS charges are applied based on actual consumption in each time band. For non-half-hourly sites, the charges are typically blended into your unit rate and standing charge.
Why Your Business Bill Went Up Even Though You Used the Same Amount of Energy
This is the most common question we are hearing from clients in 2026. Many businesses have renewed their energy contracts with a fixed unit rate, only to find their bills are higher than expected.
The reason is that TNUoS and DUoS charges are largely outside your fixed-rate contract. A common misconception is that a fixed-rate energy contract locks in all your costs. In reality, a fixed-rate contract locks in the wholesale commodity cost and the supplier’s margin but many of the non-commodity charges, including elements of TNUoS and DUoS, can be passed through at the prevailing rate even during a fixed contract period.
This means that even businesses on a fixed contract signed before April 2026 may have seen their bills increase as the higher TNUoS charges took effect.
What Can Your Business Do?
While TNUoS and DUoS charges cannot be avoided entirely, there are several steps businesses can take to reduce their impact:
Shift consumption away from peak times
If your business operates machinery, industrial equipment or large electrical loads with any flexibility in timing, shifting these away from the DUoS red band (4-7pm on weekdays) can meaningfully reduce your DUoS charges. For half-hourly metered sites, this can result in significant annual savings.
Review your agreed supply capacity
Your agreed supply capacity (measured in kVA) determines part of your TNUoS residual charge. If your business has reduced operations, downsized equipment or improved efficiency since your supply capacity was last set, you may be paying TNUoS charges based on a capacity level you no longer need. A capacity reduction with your DNO can permanently reduce these charges.
Commission a forensic energy audit
TNUoS and DUoS errors are among the most common billing mistakes we identify in forensic audits. Businesses are sometimes charged at the wrong capacity band, the wrong DUoS zone, or with incorrect metering classifications. These errors can be running for months or years before they are spotted. Our forensic audit service reviews every line of your bills to identify recoverable errors at no upfront cost.
Compare your current contract against the market
If your contract is due for renewal, now is the time to compare the market with full awareness of the higher non-commodity charge environment in 2026. A broker who understands how TNUoS and DUoS are structured across different contract types can help you find the most cost-effective arrangement for your specific situation.
The Outlook for 2027 and Beyond
The increases seen in April 2026 are not a one-off. National Grid ESO and Ofgem have confirmed that significant grid investment will continue through the rest of this decade. Businesses should expect TNUoS and DUoS charges to remain elevated and potentially continue rising as the UK’s energy infrastructure is upgraded for the renewable transition.
Understanding and actively managing your non-commodity costs is no longer optional for businesses that want to control their energy expenditure. The days when energy management meant simply comparing unit rates are over — in 2026, the unit rate is only one third of your bill.
If you would like a free review of your current energy bills to identify whether you are paying the right TNUoS and DUoS charges, contact Kilowatt Energy today.
FAQs
What are TNUoS charges?
TNUoS (Transmission Network Use of System) charges are fees your energy supplier pays to use the national electricity transmission network the high-voltage ‘motorways’ that carry power across the UK. These costs are passed directly to you as a business customer. From April 2026, TNUoS charges rose by approximately 60%, from around £16/MWh to £31/MWh for the average half-hourly business site.
What are DUoS charges?
DUoS (Distribution Use of System) charges are fees for using the local distribution network the ‘A-roads’ that carry power from the national grid into your area. Unlike TNUoS which is set nationally, DUoS varies by region and is set by your local Distribution Network Operator (DNO). DUoS charges are typically higher at peak times known as red, amber and green band charging.
Why did my business energy bill go up even though I didn't use more energy?
This is the most common question we are hearing in 2026. Your bill can increase even if consumption stays flat because TNUoS and DUoS charges sit outside the wholesale energy price. They are regulated network costs that rise independently of what you agreed with your supplier. From April 2026, these non-commodity costs now account for over 64% of the average business electricity bill more than the wholesale energy cost itself.
Can I avoid TNUoS and DUoS charges?
You cannot avoid these charges entirely, but you can reduce their impact. Shifting consumption away from peak DUoS red band times (typically 4-7pm on weekdays) can reduce DUoS costs. Reducing your agreed supply capacity can lower TNUoS residual charges. Installing on-site generation such as solar reduces the amount of electricity you draw from the grid. A forensic energy audit can also identify whether your business is being charged correctly for these costs.
Will TNUoS and DUoS charges continue to rise?
Yes, Ofgem has confirmed that approximately £80 billion will be spent on upgrading the UK national grid over the next five years, primarily to connect offshore wind and other renewable generation. The majority of this cost is recovered through TNUoS and DUoS charges. Businesses should expect these costs to continue rising through 2027 and beyond.
What is a pass-through contract and should I consider one?
A pass-through contract separates the wholesale energy cost from the non-commodity charges, billing each element separately as the actual costs occur. This gives businesses greater transparency over what they are paying for but also exposes them to fluctuations in network charges. For most SMEs, a fixed-rate contract that bundles all charges remains simpler but larger businesses may benefit from the transparency and potential savings of a pass-through arrangement
Get in touch today to know more!