UPDATE: the Capacity Market notice below, announced at 14.33, was cancelled at 15.05.

NGESO has published a Capacity Market notice for 7pm this evening – a signal to the market that more power is required to maintain supply margins over demand. Transmission-connected demand is anticipated to be 40,102MW while expected capacity is 40,279MW.
Capacity Market notices are cancelled if more capacity becomes available or expected demand falls.
However this time the notice follows immediately after the use of a new demand response mechanism in which customers are invited to help reduce peak demand in exchange for payment, managed via suppliers. An initial exercise of this mechanism in an hour last week resulted in demand reductions of around 400MW and a second is in effect this evening. But the demand reduction period is 5.30-6.30pm: that may mean demand surges just before 7pm if customers who have reduced their demand – such as by delaying use of electric heating or appliances – rush to use them after the demand response window.