We are looking for feedback about our new website.

Frequency response services

We have a licence obligation to control system frequency at 50Hz plus or minus 1%. We make sure there is sufficient generation and demand held in readiness to manage all credible circumstances that might result in frequency variations. On this page you can find out more about the different types of frequency response and 

System frequency is a continuously changing variable that is determined and controlled by the second-by-second (real time) balance between system demand and total generation. If demand is greater than generation, the frequency falls while if generation is greater than demand, the frequency rises.

There are two categories of frequency response.  

Dynamic frequency response is a continuously provided service used to manage the normal second by second changes on the system

Non-dynamic response is usually a discrete service triggered at a defined frequency deviation.

The following make up our frequency response services:

​Mandatory frequency response (MFR)

Mandatory Frequency Response is an automatic change in active power output in response to a frequency change and is a Grid Code requirement.

Find out more

Firm frequency response (FFR)

Firm Frequency Response (FFR) is the firm provision of dynamic or non-dynamic response to changes in frequency. Find out about tendering with us.

Find out more

​Enhanced frequency response (EFR)

EFR is a service, open to both BM and non-BM providers to provide frequency response in one second or less.

Find out more