We are a separate company

On 1 April the Electricity System Operator became a legally separate company within the National Grid Group. Find out more about what this change means.

System security services

We use a number of techniques and services to help maintain the security and quality of electricity supply across Britain's transmission system. In these pages, you will find out more about these services and how you can participate.

The techniques we use are:

  • buying or selling electricity in the balancing mechanism;
  • buying or selling electricity through trading; and
  • entering into contracts for balancing services.


Intertrip services are required as an automatic control arrangement, where generation may be reduced or disconnected following a system fault event.

Find out more

​System operator to system operator (SO to SO)

SO to SO services are provided mutually with other transmission system operators connected to Britain's transmission system via interconnectors.

Find out more

Black Start

Find out about providing a black start service to us. Black start is the procedure to recover from a total or partial shutdown of the transmission system.

Find out more

Transmission constraint management

Required where the electricity transmission system is unable to transmit power to the location of demand due to congestion at one or more parts of the transmission network.

Find out more

Previous services

We will no longer use or contract contingency balancing reserve (CBR). CBR services were designed as a transitional product to provide additional reserve in the mid-decade period. As we transition to the Capacity Market, 2016/17 was the last year that we procured these services.

We are no longer procuring demand side balancing reserve (DSBR) and supplemental balancing reserve (SBR).