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.
