The electricity system operator NGESO issued a Capacity Margin notice for the GB market for 6pm, when the operating margin is currently expected to fall below the 500MW trigger level.
The notice does not mean that supply does not equal demand – the capacity currently forecast on the transmission system at that time is 43,952MW, while demand is forecast at 43,464MW – but the operating margin is below a 500MW limit set by Capacity Market rules. NGESO will update information at 2pm, 4pm and 5pm.
The market is expected to react to such notices by making capacity available. Previously CM notices were posted by the system operator and cancelled shortly afterwards. One was posted on 3 December 2021, when a CM notice was posted at 1.04pm for 5.30pm and cancelled at 1.36pm. Last winter, notices were posted in September, November, and December, with the final notice of the winter posted on 8 January 2021. On that day a notice was posted at 2.04pm for 6.30pm and cancelled at 2.35pm.

UPDATE: the notice was cancelled at 2pm