Firm Frequency Response (FFR) is one of the most valuable balancing services to National Grid on a £/MW hour basis and relies on the customer being able to respond fully within 30 seconds to movements in system frequency. Data from National Grid suggests static FFR providers can be expected to be called upon roughly 10 times a year at the pre- set frequency trigger point of 49.7Hz.
There are two types of Firm Frequency Response: