What are Balancing Services Use of System (BSUoS) charges? Balancing Services Use of System ( BSUoS ) charges recover the cost of keeping the electricity system in balance in real time. Electricity must be generated and consumed at the same moment, and BSUoS funds the actions National Grid Electricity System Operator (NESO) takes to achieve this. These actions include: Instructing generators to increase or decrease output Paying for reserve and response services Managing system constraints and frequency control BSUoS is therefore not about building networks (like TNUoS or DUoS ), but about operating the system safely and securely second-by-second. Who pays BSUoS charges? Since April 2023, BSUoS costs have been recovered entirely from electricity demand rather than split between generators and suppliers. In practice: Suppliers pay BSUoS charges to the system operator These costs are then passed through to all electricity consumers, including business customers Most businesses see BSUoS as a pass-through charge in their supply contracts Domestic customers also contribute, although the charge is typically embedded rather than itemised. How do BSUoS charges work in practice? BSUoS is charged on a per kWh basis, based on actual electricity consumption during each settlement period. The BSUoS rate reflects the real-time cost of balancing the system, which can vary significantly depending on: Weather conditions Generator availability Network constraints Levels of intermittent renewable generation Unlike DUoS or TNUoS, BSUoS is not location-specific. The same rate applies across Great Britain for each settlement period. How much is BSUoS (and when are charges set)? BSUoS charges are not fixed in advance. Instead, they are calculated using a forecast-and-reconciliation model. This means the amount originally charged can be reconciled after the fact once actual consumption data is available. In p/kWh terms, BSUoS charges have varied widely in recent years, but for business customers they have typically fallen in the range of 0.6–1.6 p/kWh, with occasional spikes during periods of market volatility. Because of this variability, BSUoS can be a driver of bill uncertainty for large and flexible users. Why BSUoS matters for businesses As the electricity system becomes more reliant on intermittent renewables, balancing actions are expected to increase. This means BSUoS is likely to remain a material and structurally important cost. For sites with half-hourly metering, reducing consumption during system stress periods -- or using on-site generation and storage -- can help limit exposure, although BSUoS is generally less controllable than DUoS or TNUoS. If you would like to ensure that your BSUoS 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.

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.