Record solar generation helped Europe’s power grids manage higher electricity demand during the June and July 2026 heatwaves, says Ember in a new report
Extreme heat and drought constrained nuclear, thermal, and hydropower generation, while pushing electricity prices sharply higher in several European markets
Ember says more battery storage, demand response and stronger interconnections are needed to cover evening demand and improve grid resilience during future heatwaves
Record solar generation helped Europe’s electricity grids withstand the June and July 2026 heatwaves, with solar accounting for 25% of EU electricity in both months, according to Ember.
Solar was the ‘only major power source’ to perform better than usual during the heatwaves. Average daily solar generation was 17% higher in France and Hungary and 5% higher in Spain on heatwave days compared with other days in June and July.
In a new analysis, Ember says that across the EU, solar generation reached record levels of 52 TWh in June and 55 TWh in July, helping meet higher daytime electricity demand as air-conditioning use increased.
With local temperatures exceeding 40°C on consecutive days in parts of Central and Eastern Europe, daily power demand increased by up to 28% in Italy, 23% in Hungary, 14% in France, and 13% in Spain. The heatwaves coincided with prolonged drought across much of Europe, putting further pressure on power systems. Reduced nuclear, gas, coal, and hydropower generation also constrained electricity supplies as demand increased. EU hydropower production, says Ember, was at its lowest level in at least a decade in May, June, and July, with seven of the EU’s eight largest producers recording output below their 5-year averages in July.
Grid equipment also faces thermal limits during extreme heat. Overhead power lines can transmit less electricity at high ambient temperatures, while equipment such as grid transformers can overheat.
The combination of high demand, supply constraints, and elevated gas prices pushed electricity prices higher during the heatwaves. Average daily prices were 119% higher in Hungary, 44% higher in France, 13% higher in Italy, and 7% higher in Spain than on comparable days in the preceding week, according to Ember. The report says elevated gas prices have persisted since the start of the US-Israel war with Iran.
On June 24, day-ahead electricity prices reached €313/MWh in France and €285/MWh in Italy, while on June 30, prices in Hungary exceeded €900/MWh.
At the same time, the weather systems that bring heatwaves to Europe typically also bring clear, sunny conditions, boosting solar generation. Solar supplied 25% of EU electricity in both June and July 2026, the first months on record to reach that share. In June, Ember estimated that a typical UK rooftop solar system generated enough electricity to power a household air conditioner for 5 hours.
The increased solar output helped limit price increases during daylight hours, although prices rose more sharply in the early evening.
“Solar is already doing heavy lifting during heatwaves, but the real challenge starts after sundown. Battery storage is one of the clearest ways to make Europe’s power system more resilient in hotter summers,” says Ember’s Senior Energy Analyst Dr. Chris Rosslowe.
Ember says Europe will need more power system flexibility to manage price spikes, including through battery storage, demand response, and stronger interconnections. More battery storage could shift low-cost solar power into the evening, when cooling demand remains high, reducing reliance on expensive thermal generation.
Titled Solar helps Europe’s grid withstand extreme heat, the analysis is available for free download on Ember’s website.
