Third Demand Flexibility Service test unveiled amid tight capacity

National Grid ESO is to run the third test of its Demand Flexibility Service (DFS) tomorrow (30 November) from 17:30-18:30.

This comes as conditions on the grid are particularly tight due to low wind generation and constrained interconnector capacity, which has led to power prices spiking.

The ESO has now run a test of the DFS on 15 and 22 November, calling on participants up and down the country to turn down demand by 200MW.

During the first test, Octopus Energy customer contributed 108MW and during the second they contributed 112MW as part of the company’s Saving Sessions scheme for example.

There are an increasing number of providers of DFS, including OVO – the UK’s third largest domestic supplier – which announced its customers would now be able to participate in DFS today.

National Grid ESO is calling on providers to reduce demand by 250MW per half an hour between 17:30 and 18:30 tomorrow, making this the largest DFS trial at 500MW since it went live at the beginning of November.

It comes as EPEX Day Ahead prices for 29 November have surged to over £1,200/MWh according to LCP Enact. With the colder weather setting in, a significant reduction in wind generation this week, and the French nuclear fleet remaining constrained hampering interconnector availability, power prices are beginning to jump.

The tighter conditions on the grid over the last week has led to the first two Capacity Market Notifications of the winter being issued, first on 22 November and the second on 28 November.

Along with the notification yesterday, the ESO did initially suggest it would utilise DFS over the evening of 29 November amid the tight conditions, but subsequently cancelled this.

DFS was initially set out in the ESO’s Winter Outlook report in October, and is one of a number of key tools the operators is set to use to keep the grid balanced over the coming months.

Despite the difficult conditions, created largely by the international gas crisis and the impact of the Russian invasion of Ukraine, National Grid ESO remains “cautiously confident” that it has the tools to manage the constraints.