The story
- Renewables produced 44% of UK electricity in 2025, up from 3% in 2000. Rooftop solar has more than doubled in the last decade — about 22 GW of installed capacity, equivalent to roughly thirty large coal plants.
- On a sunny, windy summer weekend — when factories are quiet and most people are outside — the grid can find itself with more electricity coming in than there is demand to absorb.
- The current solution is to pay wind and solar farms to switch off. Britain spent £363 million on those payments in 2025 alone, plus another £1 billion replacing the curtailed clean power with gas. The bill ends up in everyone's monthly statement.
- Now the National Energy System Operator is flipping the script. Through an updated Demand Flexibility Service, suppliers will reward customers who shift their usage into the surplus windows — discounted rates, points, or in some cases free electricity for a few hours. It requires a smart meter and a participating supplier.
- The new piece is that NESO will now signal these surplus windows nationally, rather than each supplier figuring it out alone. Peak summer demand is forecast at 29.7 GW, similar to 2025; the agency expects sufficient supply across the April–October period.
- For decades the engineering question was: how do we make sure there's enough? The question, increasingly, is the opposite.
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Tools such as the Demand Flexibility Service not only reward consumers and businesses for flexible electricity use but also strengthen the resilience and efficiency of Great Britain's electricity network.
— Dr Deborah Petterson, Director of Resilience and Emergency Management, NESO
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