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 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.
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.