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.

6 March 2020 - Please be advised that the Frequency Response Price Submission (FRPS) portal is currently unavailable. Should you wish to submit new or revised prices – please use the offline template until further notice. Please note – previous submitted prices will be used in Response Delivery Month unless new/revised prices are submitted.

The ‘window’ for the submission of prices remains unchanged as indicated within the FRPS calendar for your information.

Providers can offer one of these or a combination of different response times.

Primary response

Response provided within 10 seconds of an event, which can be sustained for a further 20 seconds.

Secondary response

Response provided within 30 seconds of an event, which can be sustained for a further 30 minutes.

High frequency response

Response provided within 10 seconds of an event, which can be sustained indefinitely.

Providing MFR

Depending on their size and location, a power station may be obliged to have the capability to provide MFR. This requirement will be set out in their connection agreement and is summarised in the table below.

Summary of connection agreement capability for MFR
	National Grid	Scottish Power	Scottish Hydro Electricity Transmission
Small	< 50 MW	< 30 MW	< 10 MW
Medium	50 MW =< 100 MW	N/A	N/A
Large	=> 100 MW	=> 30 MW	=> 10 MW

Offering MFR alongside other balancing services

You may provide other balancing services, as long as doing so does not interfere with your ability to deliver MFR.