FAQs

A Capacity Market Notice is a signal four hours in advance that, when taking into account additional operational reserve requirements, there may be less generation available than National Grid Electricity System Operator (ESO) expects to need to meet national electricity demand on the transmission system. The notices are intended to be a signal that the risk of a System Stress Event in the GB electricity network is higher than under normal circumstances.

Capacity Market Notices are communicated automatically by National Grid ESO systems to this website and will be issued at least four hours ahead of the stated commencement time. The primary trigger set by the UK Government for a Capacity Market Notice to be issued to the industry is where the level of available generation is within a 500MW threshold of National Grid ESO's requirement.

However, in certain situations, Capacity Market Notices can also be triggered in response to a Demand Control event. Where such events take place and a Capacity Market Notice is not already active, a discrete Capacity Market Notice shall be issued. The exception to this is when the event has been determined as occurring for system management reasons, in such circumstances a Capacity Market Notice will not be issued.