‘The real challenge starts after sundown’: Europe’s heatwave boosted solar by up to 17% on hot days
Published on 14/08/2026 - 7:00 GMT+2 Solar has been doing the “heavy lifting” to help Europe meet its energy needs amid a string of blistering heatwaves. A new analysis...
Published on 14/08/2026 - 7:00 GMT+2
Solar has been doing the “heavy lifting” to help Europe meet its energy needs amid a string of blistering heatwaves.
A new analysis from energy think-tank Ember found that solar output in European countries rose by up to 17 per cent on heatwave days in June and July.
Researchers say that this helped power the grid as electricity demand increased by as much as a quarter on hot days. Heatwaves often trigger a spike in electricity consumption due to the sudden need for cooling, mainly from energy-intensive air conditioning (A/C) units.
The International Energy Agency (IEA) estimates that space cooling, which is mostly A/C units and fans, consumed around seven per cent of the world’s electricity in 2022. Even in countries where A/C ownership is low, countries experience energy demand spikes when scorching temperatures hit.
During the early summer heatwaves of 2025, France, for example, recorded an evening electricity peak that was 25 per cent above the off-season average due to air conditioning.
Solar performing ‘better than usual’ amid heatwave
Ember’s analysis found that during the late-June heatwave this summer, daily electricity demand rose byup 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.
It says as heatwave-driven demand increased, solar was the only major power source to perform “better than usual”. 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.
“Solar is already doing heavy lifting during heatwaves, but the real challenge starts after sundown,” says senior energy analyst Chris Rosslowe.
“In the evening, when cooling demand is still high, the grid is most exposed to expensive gas-fired power.”
How Europe’s blistering summer impacts energy
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 warn that hydropower neared an “all-time low” in the Alpine region.
Fossil-fuelled energy has suffered from the drought too, with Poland forced to reduce output at a coal-fired power plant due to critically low water levels in the Vistula River.
The late-June and early-July heatwaves 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.
Experts say the price surge reiterates the need for battery storage systems, which can prevent excess solar energy from being wasted.
“While solar saves the day, battery storage can save the evening,” Rosslowe says.
“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.”
