ESO orders demand flexibility service to go live for first time

The National Grid Electricity System Operator (ESO) is to use its demand flexibility service (DFS) live for the first time amid tight supply margins for Monday (23 January) evening.

The ESO has also ordered Drax to ready two coal-fired units although stressed this did not necessarily mean they would be used.

After a series of tests over the winter, the ESO is now planning to use the DFS “in anger” for the first time between 5pm and 6pm. It has set a requirement of 659MW of demand to be reduced.

The service sees customers of participating suppliers / aggregators paid £3 per kilowatt hour saved. The first five tests saw almost 800MW of demand avoided.

An ESO spokesperson said: “Our forecasts show electricity supply margins are expected to be tighter than normal on Monday evening. We have instructed coal-fired power units to be available to increase electricity supplies should it be needed tomorrow evening. We are also activating a Live Demand Flexibility Service event between 5-6pm tomorrow. This does not mean electricity supplies are at risk and people should not be worried. These are precautionary measures to maintain the buffer of spare capacity we need.”

The ESO considered a live DFS event in November, when tests were still in their infancy. Claire Dykta, ESO’s head of markets told Utility Week for a recent feature that while a live event was considered unnecessary at that point, “it was a really good test of our processes and procedures and running through that thought process was very useful”.

The request for the coal plants to be warmed up falls under the winter contingency plans announced last year. However, EnAppSys director Phil Hewitt questioned why they were being deployed now, saying that while power prices for Monday evening did indicate tight margins they were no worse than other points this winter when ESO had not taken similar action.

To read analysis on early learnings from the DFS, including from ESO, Eon, Flexitricity and Octopus, as well as customers taking part, click here.