​Mandatory response services

Mandatory frequency response (MFR) is an automatic change in active power output in response to a frequency change. The service helps us to keep frequency within statutory and operational limits.


Providers of MFR are required to have the following technical capabilities:

  • Have a 3 to 5 per cent governor droop characteristic. Droop is defined in the Grid Code CC6.3.7 (C)(ii)) as: "The ratio of the steady state change in speed in the case of a Generating Unit, or in Frequency in the case of a Power Park Module, to the steady state change in power output of the Generating Unit or Power Park Module.”
  • Be capable of providing continuous modulation power responses via synchronised generation through their automatic governing systems in order to counter frequency changes.