Sixth Demand Flexibility Service test set for 21 December

The sixth Demand Flexibility Service (DFS) test will take place tomorrow evening (21 December).

National Grid ESO has put out a call for 100MW per half an hour from 17:30 to 18:30, the smallest yet as warmer weather eases grid constraints.

Over 780MWh of real and projected demand reduction has been provided over the first five DFS tests, which have run on 15 November, 22 Novembe, 30 November,1 December and 12 December.

According to National Grid ESO’s findings, the first two DFS tests saw customers overdeliver by at least over 35%.

This was a result lauded by Craig Dyke, head of National Control, who said: “This service successfully proves that consumers up and down the country are standing by to get involved in flexibility solutions. These test results show that if called upon this service will help the ESO balance the national electricity network this winter and is a valuable addition to the ESO’s operational tools.”

While the tests have generally been welcomed, the fifth drew some criticism given the tight margins on the grid at the time, which led the ESO also issue a call for two coal units to warm. Ultimately it did not use the contingency coal units, but record high prices were seen in both the Day Ahead and Balancing Mechanism.

Some felt that given the extremes of the situation, that last Monday (12 December) should have represented the first DFS event as opposed to test.

There are now 26 providers of DFS, up from just four during the first test back in November.

This includes Octopus Energy, which was one of the most visible companies involved in the development of the service. Over the first test its customers provided 108MW of flexibility and 112MW over the second.

Over the first four tests, Octopus customers moved almost 450MWh of energy consumption out of peak times resulting in each customer saving an average of over £4 across the sessions. Collectively, they have saved over £1 million, according to the company.

The providers signed up to DFS currently are: