A surge in solar power helped meet heightened electricity demand across Europe during this summer's blistering heatwaves, with a new analysis from energy think-tank Ember finding that solar output in European countries rose by up to 17 per cent on heatwave days in June and July. The extra generation helped power the grid as electricity demand increased by as much as a quarter on hot days—a critical lifeline as climate-driven extreme weather pushes Europe's energy infrastructure to its limits.
Heatwaves trigger spikes in electricity consumption because of the sudden need for cooling, mainly from energy-intensive air conditioning units. The International Energy Agency estimates that space cooling consumed around seven per cent of the world's electricity in 2022. Even in countries where air conditioning ownership is low, scorching temperatures drive demand upward. During the early summer heatwaves last year, France recorded an evening electricity peak that was 25 per cent above the off-season average because of air conditioning.
Demand Surges Across Southern Europe
Ember's analysis found that during the late-June heatwave this summer, daily electricity demand rose by up to 28 per cent in Italy, 23 per cent in Hungary, 14 per cent in France and 13 per cent in Spain compared with pre-heatwave days. Solar was the only major power source to perform better than usual as heatwave-driven demand increased. Compared with other days in June and July, average daily solar generation during the heatwaves was 17 per cent higher in France and Hungary, five per cent higher in Spain and the same in Italy.
Senior energy analyst Chris Rosslowe said, "Solar is already doing heavy lifting during heatwaves, but the real challenge starts after sundown." He said, "In the evening, when cooling demand is still high, the grid is most exposed to expensive gas-fired power."
Climate Crisis Strains Other Power Sources
Europe's back-to-back heatwaves, which scientists say would have been virtually impossible if it weren't for climate change, have triggered mass droughts across the continent. Low water levels along the Danube River forced nuclear output to be curtailed in Hungary, while experts warned that hydropower neared an all-time low in the Alpine region. Fossil-fuelled energy has also suffered from the drought, with Poland forced to reduce output at a coal-fired power plant because of critically low water levels in the Vistula River.
The late-June and early-July heatwaves this summer also saw average daily electricity prices surge 119 per cent higher in Hungary, 44 per cent in France, 13 per cent in Italy and seven per cent in Spain than on comparable days in the preceding weeks. The price surge underlined the need for battery storage systems, which can prevent excess solar energy from being wasted.
Storage Key to Evening Resilience
Rosslowe said, "While solar saves the day, battery storage can save the evening." He added, "Together, they are one of the clearest ways to make Europe's power system more resilient in the hotter summers. As solar output rises during heatwaves and other power sources struggle, storage can carry that cheap electricity into the evening."
Why This Matters:
This summer's heatwaves demonstrate both the promise and the limits of Europe's renewable energy transition. Solar power proved its worth when demand spiked and traditional sources faltered—but without adequate battery storage, that clean energy can't meet evening demand, leaving households exposed to expensive gas-fired power and price surges. The climate crisis isn't just a distant threat—it's already reshaping Europe's energy landscape, forcing nuclear and coal plants offline while pushing electricity prices beyond what many families can afford. If Europe is serious about energy security and climate justice, it must accelerate investment in storage infrastructure alongside renewables. The technology exists. What's missing is the political will to deploy it at scale before the next heatwave hits.