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.

​Enhanced frequency response (EFR)

​Enhanced frequency response (EFR) is a dynamic service where the active power changes proportionally in response to changes in system frequency. This service is aimed at improving the management of system frequency pre-fault to maintain system frequency closer to 50Hz.

EFR is open to both Balancing Mechanism (BM) and non-BM providers who could meet the technical requirements

This service was developed to improve management of the system frequency before a fault occurs, maintaining system frequency closer to 50Hz under normal operation.

System frequency is a continuously changing variable that is determined and controlled by the second-by-second balance between demand and generation.

We must maintain system frequency within one per cent of 50 Hz at all times, except in abnormal or exceptional circumstances.