Nearly 2 million households and businesses registered for Demand Flexibility Service (DFS) last winter

The Demand Flexibility Service (DFS) was used 44 times last winter at a cost of £1.2 million, proving itself as a competitive balancing tool for Britain’s electricity network, new figures from the National Energy System Operator (NESO) show today.

DFS successfully reduced or shifted power consumption by 3,917.7 MWh, the equivalent of powering 12.7 million British homes for an hour. That’s up from 3,759 MWh saved the previous winter (2023/4).

Great Britain is the first country in the world to have introduced a national Demand Flexibility Service, rewarding households and businesses for reducing or shifting their electricity consumption at peak hours. Other countries have since begun trialling their own national schemes.

Britain’s DFS succeeded in saving more energy last year at a fraction of the cost of previous years, having stood at £11.9 million the year before for 16 events. This shows consumer-led flexibility has become a successful and cost-effective way of balancing Britain’s energy network compared to alternative actions available to NESO, such as asking gas power stations to turn on or buying more power via interconnectors.

Rebecca Beresford, Director of Markets at NESO, said:

“Accessing more flexibility in our electricity system is vital for running a clean, green, and fair system of the future. NESO’s world-leading Demand Flexibility Service has been a real breakthrough, which has this year proven itself effective not only at times when margins have been tight during periods of high demand, but as an efficient everyday tool for balancing the network when needed.

“If we can reduce electricity demand by rewarding participating customers to turn down when we need them to, it means we can avoid using expensive and polluting fossil fuel generators. Indeed, the DFS reduced carbon emissions by more than 620 tonnes last winter.”

The DFS was a pioneering mechanism introduced by NESO in 2022 to support flexibility for consumers, with the registered service providers - typically electricity suppliers and aggregators - who have voluntarily joined the program, offering those who have a smart meter the option to reduce their energy use at busy times for payment or other rewards.

Consumers who sign up for the DFS receive notifications from their electricity supplier/aggregator on days when NESO enact the service, when energy demand across the country is expected to be high. They let households and businesses know the peak time, usually between 4 and 7 pm, and ask if they can reduce their energy use during this period. 28 registered service providers have participated in the service since its original launch.

Participation is voluntary, so consumers only take part if it works for them. For example, people could save energy by opting to use the microwave instead of the oven, not using the washing machine until later, or charging their electric car overnight. 

For the first time last winter, consumers could also enter into DFS via a registered service provider at the same time as securing revenue from other markets for changing the time they used energy-intensive appliances like an oven or washing machine.

During the last winter period (27 November 2024 to 28 March 2025), NESO received 10,838 MWh worth of bids from registered service providers, with 5,421 MWh accepted. A total of £1,233,311 tenders were accepted, with £943,983 paid out to registered service providers, with the forecasted savings to the end consumer in balancing costs reaching £483,000.