Britain’s power system is heading into a summer with a surplus, as renewable generation continues to outpace demand and forces a rethink of how electricity is used in real time.

In its Summer Outlook, NESO says supplies will be secure across 2026 – but the bigger issue will be managing periods where there is simply too much power on the system, driven by strong solar output, growing wind capacity and lower seasonal demand.

This is not a one-off anomaly but a structural shift, with surplus electricity becoming more frequent as the grid decarbonises and becomes more decentralised.

The response is to turn consumers into part of the balancing mechanism.

NESO is expanding its Demand Flexibility Service, allowing households and businesses to be paid to increase electricity use during periods of excess supply, effectively soaking up spare power that would otherwise go to waste.

The idea is simple in theory but significant in practice, shifting the system from one where consumers passively draw power to one where they actively help manage it.

Running appliances, charging electric vehicles or increasing usage at the right time becomes part of how the grid stays stable, rather than something that happens independently of it.

Since 2019, NESO has introduced new tools to manage a system dominated less by large fossil fuel plants and more by variable renewables, with batteries, wind and solar increasingly providing services once delivered by traditional generators.

Voltage support, system stability and balancing are now being handled by a wider mix of technologies, often at lower cost but with greater operational complexity.

The system operator retains backstop measures however, where needed, it can issue market signals such as a Negative Reserve Active Power Margin notice to encourage generators and flexibility providers to respond – but the emphasis is shifting towards pre-emptive balancing through smarter demand.

Dr Deborah Petterson, Director of Resilience and Emergency Management at NESO, said: “The work of our excellent engineering teams at NESO means our energy system is well adapted to support a clean, resilient future.

“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.”

As the UK builds out renewable capacity, the question is no longer whether there is enough power but whether the system can use it efficiently and that increasingly depends on turning millions of consumers into active participants in how the grid runs.