Demand Flexibility Service: a new way to support power system stability

Traditionally, flexibility in the UK power system has come from the supply side. When demand was predicted to reach a given peak level, the extra electricity required would be provided by the ESO instructing generators to match it by providing more power to the grid.

This was relatively simple to achieve when large amounts of thermal generation were dispatchable at short notice. But as we decarbonise the grid – and at a time when we can’t be totally sure of adequate gas supplies going forward – we need a new way to ensure power system stability.

Managing demand rather than supply

This November, ESO launched its new scheme to trial using Demand Side Response (DSR) to provide the stability our power system needs. Called the Demand Flexibility Service (DFS), it enables ESO to instruct electricity users to turn down their power use at peak times in return for a financial incentive.

It’s part of a series of initiatives from ESO designed to ensure system stability in a changing power landscape. Instead of ensuring stability by generating more power as we used to, we’ll now be finding out if we can do it by creating flexible demand to meet generation.

The existing Triads scheme shows that there’s a large potential demand downturn available. But there’s no way of knowing which customers are prepared to do it, and what price would be needed to persuade them to take action. The DFS will give ESO the data they need.

The size of the downturn required by the DFS is high – somewhere between 1 and 2 Gigawatts. And because it’s a last resort service, the prices paid for those taking part are equally high.

But as this is a trial service, the burden on customers in terms of administration is very low (at Drax, we’ll be doing the majority of the heavy lifting for those of our customers who take part.) All that’s required is a smart meter that reports electricity usage on a half-hourly basis.

How the Demand Flexibility Service works for Drax customers

• We tender for a contract with National Grid to offer demand flexibility of between 1MW and 100MW. This’ll be provided by Drax’s own and customers’ assets. It’s likely to include EV charge points, batteries and other DSR assets within areas covered by distribution network operators (DNO).
• 12 test events will take place over the winter of 2022-23. ESO will use these as a replication for a last resort test, where flexibility is required, for a minimum of 30 minutes. We’ll be notified a day ahead and will pay customers a pre-agreed rate to turn down their electricity use at a given time.
• We can turn down power use ourselves on behalf some of our customers. We’ve already done it remotely for selected Electric Assets (EA) customers. For EV charging points, we can support our customers by managing their EV charging scheduling. This will include sending a pre-prepared charging profile to individual charge stations.
• Other customer will be able to turn down their demand for electricity themselves when they receive a notification from us.

Drax is already making the Demand Flexibility Service reality

The DFS is in full swing, with multiple tests having already taken place.

On 15 November, we took part in ESO’s first test event for the Demand Flexibility Service. Our customers – including vehicle manufacturer Ford – reduced their demand on the grid by 17.11 MW (enough to power 34,000 homes), and a revenue of £90,000 was achieved for all participating customers.

Adam Hall, Drax’s Director of Energy Services, said:

“This scheme provides a real opportunity for our supply customers with flexibility in their operations to play their part in strengthening Britain’s energy security this winter, whilst cutting their electricity bills.

“We’re delighted that Drax Energy Solutions has become one of the very first Approved Providers for DFS this winter, enabling our customers to benefit directly from participating in the scheme.

“We’ve been speaking with customers about the benefits the scheme offers their organisations and these conversations have been really positive. Many customers, including Ford, have agreed to be part of the scheme, offering the grid stability but also looking at their operations and how cutting their energy usage can help contribute to their net zero goals.”_

Use the button below if you’d like to find out more about how you can benefit from the Demand Flexibility Service.