Heatwave Britain forced to rely on EU to avoid power cuts

By the Editorial Team · Thursday, June 25, 2026

Britain's National Energy System Operator issued an emergency power supply warning and increased electricity imports from the EU after a heatwave caused a sharp decline in solar energy output. This marked the first summer alert of its kind and led to the relaxation of import limits, ensuring grid stability despite soaring demand and reduced renewable generation.

Britain faced an urgent need to increase electricity imports from the European Union amid a record-breaking heatwave in order to prevent power shortages, according to industry sources. The National Energy System Operator (Neso), responsible for managing the national grid, issued a rare emergency power supply warning on Tuesday as soaring temperatures caused a significant drop in solar energy output.

The warning was prompted by the heatwave pushing temperatures as high as 36 degrees Celsius, which reduced the efficiency of solar panels. Solar farm performance declines by approximately 0.3 to 0.5 percent for each degree above 25 degrees Celsius, impacting Britain’s renewable energy generation during a period of heightened demand. The warning marked the first time Neso issued such an alert during the summer months.

In response to the strain on domestic power resources, Neso secured emergency electricity imports from the Continent via interconnectors linking the UK grid to neighbouring European networks. Initially, Britain had been scheduled to export electricity, but the heatwave forced an abrupt reversal of that plan.

Industry consultant Kathryn Porter indicated that Neso had requested the EU to relax trading limits on electricity imports, which had previously capped imports at 1.5 gigawatts (GW) since May. Following the easing of these restrictions, imports increased to 2.3 GW, providing a critical boost to meet demand and avert shortages. Porter noted that the grid operator had not anticipated the sudden shortfall in supply, prompting the urgent appeal for imported power.

Fintan Devenney of energy consultancy Montel described the situation as severe enough to justify overriding the existing trading limits. When these limits were initially announced, Neso had assured the market there were no concerns about electricity system security.

To supplement supply, gas-fired power stations were also urged to ramp up production as residential and commercial air conditioning use surged. Despite the challenges, a Neso spokesperson confirmed that Great Britain’s electricity system remained secure and reliable throughout the extreme weather event. The operator utilized established arrangements with neighbouring grid operators alongside standard operational measures to maintain system stability during the heatwave.

This article was reported by synthesizing coverage from multiple independent news outlets to present a balanced, unbiased account. Read about our editorial standards. Spotted an error? Let us know.