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.
National Grid has a licence obligation to control frequency within the limits specified in the 'Electricity Supply Regulations', i.e. ±1% of nominal system frequency (50.00Hz) save in abnormal or exceptional circumstances. National Grid must therefore ensure that sufficient generation and / or demand is held in automatic readiness to manage all credible circumstances that might result in frequency variations.
There are two types of Frequency Response Dynamic and Non Dynamic Response. Dynamic Frequency Response is a continuously provided service used to manage the normal second by second changes on the system. While Non Dynamic Frequency Response is usually a discrete service triggered at a defined frequency deviation.
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Mandatory Frequency Response
Mandatory Frequency Response is an automatic change in active power output in response to a frequency change and is a Grid Code requirement.
Firm Frequency Response (FFR)
Firm Frequency Response (FFR) is the firm provision of Dynamic or Non-Dynamic Response to changes in Frequency.
Frequency Control by Demand Management
FCDM provides frequency response through interruption of demand customers.
FFR Bridging Contract
Enabling smaller parties a route to access the FFR tendered market
Enhanced Frequency Response
A new service aimed predominantly at storage assets to provide frequency response in 1 second or less.
Reactive power services
If you are a returning visitor you may find these areas useful.
Electricity Transmission Operational Data
Monthly Balancing Services Summary