Europe's heat wave forces nuclear plant shutdown, threatens grid stability

Europe's ongoing heat wave is breaking temperature records across the continent, forcing school closures, threatening lives, and even canceling a London Climate Action Week event about extreme heat. Most notably, the Golfech nuclear power plant near Toulouse in southern France had to shut down its unit two because the river water used for cooling became too warm. Unit one was already offline for planned maintenance and refueling, according to operator EDF. Simone Tagliapietra, senior fellow at Bruegel, describes a 'triple squeeze' on the grid: cooling demand from air conditioners rises sharply, power plants and transmission lines become less efficient in high heat, and thermal and nuclear plants must cut output when cooling water is too warm or scarce.

Unlike the US, where nearly 90% of homes have air-conditioning and summer is the peak season, Europe has historically seen winter peaks due to electric heating. Only about 20% of European homes have AC—the UK sits at 5%, Germany at 3%. But as brutal summers become more common, AC adoption is ticking up, shifting seasonal demand patterns. This forces utilities to look across borders for extra power, driving up prices for everyone. Grid operators must now replan maintenance outages that historically fell in summer months. With El Niño looming, 2027 could bring even worse heat waves. Adapting the grid—adding more supply quickly and managing shifting seasonal loads—is becoming an urgent priority for European utilities and policymakers.