Distribution Use of System (DUOS) charges
What are Distribution Use of System (DUoS) charges?
Distribution Use of System (DUoS) charges are fees paid for the operation, maintenance and reinforcement of Great Britain’s electricity distribution networks. These networks deliver electricity from the high-voltage transmission system to homes and businesses via lower-voltage local infrastructure.
DUoS charges are set and recovered by the Distribution Network Operators (DNOs), which include companies such as UK Power Networks, National Grid Electricity Distribution, and SSE Networks.
Who pays DUoS charges?
DUoS charges apply to all electricity customers, including domestic and business users. For most businesses, DUoS charges are recovered by the electricity supplier and passed through as a non-commodity network charge.
Larger sites connected at higher voltages (HV or EHV) face more complex DUoS tariffs, while smaller sites at low voltage (LV) typically pay lower rates that are embedded in their standing charges.
How do DUoS charges work in practice?
There are multiple types of DUoS charge:
- DUoS Standing charge - charged as p/day similar to the traditional standing charge
- DUoS Capacity charge - charged as p/kVA/month
- Red/Amber/Green Unit charges - charges depending on when electricity is used.
With the Red, Amber, and Green charges, these are based on whether a unit of electricity is consumed during peak or off-peak network hours:
- Red – the highest of the three charges occurs during peak network demand periods
- Amber – is applied during intermediate demand periods
- Green – the lowest of the three charges is for off-peak periods
With the capacity charge, this is based on the kVA capacity assigned by the DNO. This charge can be reduced by agreeing with the DNO to lower your kVA capacity. We recommend conducting regular kVA reviews to ensure you are not paying for capacity that you don't use. Contact us today if you would like assistance in conducting a kVA review and potentially saving £10,000s each year on your capacity charges.
How much is DUoS (and when are charges set)?
DUoS tariffs are set annually by each DNO and apply for the charging year from 1 April to 31 March. Rates vary significantly by region, voltage level and time of use.
For non-domestic customers, DUoS can range from 1–2 p/kWh at Low Voltage sites with limited exposure to red periods, or 3–6+ p/kWh (or higher) for High Voltage customers with heavy peak-time usage.
As a result of this variability, DUoS is often one of the largest and most volatile network charges on a business electricity bill.
Why DUoS matters for businesses
DUoS is one of the few bill components that businesses can actively influence. Shifting consumption away from red periods, optimising agreed capacity, or investing in on-site generation or storage can materially reduce costs.
DUoS optimisation can deliver immediate and recurring savings, making it a critical focus area in energy cost management.
If you would like to check if your capacity charges can be reduced, or that your DUoS charges are being invoiced correctly. Contact us today and we can review your recent invoices to make sure you aren't paying more than necessary.
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