Black start

Black start is the procedure we use to restore power in the event of a total or partial shutdown of the national electricity transmission system. On this page, you will find out about providing a black start service.

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 black start 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 black 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 a black start 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 black start service are expected to achieve high availability levels. When a power station is unavailable to provide black start, 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 black start 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 black start procedure is considered to be a low likelihood event. However, we may test the delivery of this service every two years, as set out in the Grid Code.