Restoration Services

Restoration (formerly known as Black Start) is the process used to restore power in the event of a total or partial shutdown of the national electricity transmission system. 

Please be aware we have published our consultation on the Implementation of the ESRS (Electricity System Restoration Standard) . A link to this is below and all responses should be sent to [email protected] by no later than 10 December 2021.

Please also note we have published our consultation on the Assurance Framework as part of the ESO Licence condition. This consultation shall also last for 30 days like the ESRS consultation and closes on the 17 December 2021. Please send all responses to [email protected]

10.11.2021 ESRS Implementation Consultation

19.11.2021 Assurance Framework Consultation

If you are interested in providing this service to us and believe that you can meet the technical requirements, please contact us.

Irrespective of the type of generating plant providing restoration services, providers need the following technical capabilities:

  • The ability to start up the main generating plant (at least one unit/module) of the station from shutdown without the use of external power supplies, and be ready to energise part of the national electricity transmission system or, if appropriate the distribution network, within two hours of receiving our instruction.
  • The capability to accept instantaneous loading of demand blocks, ideally in the range 35 to 50 MW, and control frequency and voltage levels within acceptable limits during the block-loading process. Under these conditions, frequency can be within the range of 47.5 to 52 Hz.
  • The ability to provide at least three sequential starts. This is to allow for possible tripping of the transmission or distribution systems during the re-instatement period, or trips during the station’s own starting sequence.
  • Back-up fuel supplies (e.g. distillate fuel), if appropriate, to enable the power station to run for a minimum duration (ideally in the range of 3 to 7 days) following an instruction.
  • Facilities to ensure that all generating units can be safely shutdown without the need for external supplies, and can be maintained in a state of readiness for subsequent start up.
  • The ability to maintain high service availability on both the main and auxiliary generating plant. We typically require availability of 90 per cent.
  • The reactive capability to charge the immediate transmission and/or distribution systems. This capability will depend on the local system configuration, but generating plant connected at 400kV or 275kV with a capability of at least 100MVAr leading (as measured at the commercial interface) should almost invariably meet this requirement. The generator must also be capable of withstanding the magnetic inrush and transient voltages associated with this charging duty.

If a provider believes that they can partially deliver these requirements, we would also be happy to discuss this further.

Service dispatch

When do providers need to be available to deliver this service?

Providers of the restoration services are expected to achieve high availability levels. When a power station is unavailable to provide the service, it must advise us. Availability payments will then cease until the station re-declares its availability. Settlement periods where the power station is unavailable will be accrued and assessed annually.

How will providers be dispatched?

In the event of a partial or total system shut down, providers of restoration services will be instructed by the control room, with the general guidance of a site specific restoration plan.

How often will providers be dispatched?

Initiating the procedures is considered to be a low likelihood event. However, we may test the delivery of this service at least every three years, as set out in the Grid Code.