Great Britain's electricity grid operator has taken emergency measures to secure additional power supplies as a heatwave sweeps across the country, driving up demand for cooling. The National Energy System Operator (NESO) instructed several power plants to remain online or ramp up output to prevent blackouts, according to officials.
Extra capacity activated
NESO issued a notification to the market on Wednesday, calling for extra generation capacity to meet peak demand expected to hit 35 gigawatts (GW). The move comes as temperatures exceeded 30°C in parts of southern England, with the Met Office issuing a level 2 heat-health alert for much of the country. The grid operator typically relies on a mix of gas, renewables, and interconnectors, but the heatwave has reduced the output of some solar farms due to cloud cover and limited wind generation.
“We have taken pre-emptive action to ensure sufficient generation is available to meet demand,” a NESO spokesperson said. “This is a routine procedure during periods of high demand or low generation.”
Demand surge and market response
The extra capacity is being sourced from existing power plants that would otherwise have been offline for maintenance or economic reasons. In total, NESO has secured approximately 2GW of additional capacity through its balancing mechanism, which pays generators to increase output or consumers to reduce usage. The cost of these measures will be passed on to energy suppliers and ultimately to consumers, though the impact on bills is expected to be minimal.
Energy analysts noted that the heatwave’s impact on the grid is less severe than during the 2022 record-breaking temperatures, when demand briefly exceeded 40GW. However, the combination of low wind and reduced solar output has heightened the need for fossil fuel backup. Gas-fired power plants are providing the bulk of the extra supply, accounting for about 60% of the additional generation, with biomass and hydro contributing the rest.
Grid resilience under scrutiny
The incident has reignited debate about the resilience of Britain’s energy system amid more frequent extreme weather events linked to climate change. Critics argue that the government’s push for net-zero emissions has not been matched by sufficient investment in storage and demand-side flexibility. “We are still too reliant on gas to fill the gaps when renewables falter,” said a spokesperson for the Energy and Climate Intelligence Unit. “The heatwave shows we need faster deployment of batteries and better interconnections.”
NESO has defended its approach, stating that the system is designed to handle such events. “The grid is operating securely, and we have a range of tools to balance supply and demand,” the NESO spokesperson added. The heatwave is expected to persist until the weekend, with temperatures forecast to reach 32°C in some areas, which could prompt further action by NESO.
