A record-breaking heatwave swept across Europe between late June and early July 2025, daily power demand increased up to 14% causing daily power prices to double. According to an analysis by energy think-tank Ember, while temperature increased, June 2025 saw the highest EU solar generation on record, which kept the grid well-supplied during daytime hours.
Between 28th June and 2nd July, peak daily temperatures averaged over the whole country reached 35°C in Germany and Spain (with local maximums exceeding 40°C), and 34°C in France. As the use of air conditioners soared, daily power demand increased by up to 14% in Spain, 9% in France, and 6% in Germany, compared to a week before.
Multiple thermal power plants had to wind down due to cooling issues. In France, 17 out of 18 nuclear power plants faced capacity reductions during the heatwave. June 2025 saw the highest EU solar generation on record, a 22% increase from the year before. During the hottest hours in early July, solar electricity production reached 50 GW in Germany alone.
Commenting on the trend, Pawel Czyzak, Europe Programme Director, Ember, said, “Heatwaves will not go away, they will only get more severe in the future. Solutions that can help mitigate their impacts, such as battery storage, interconnection, demand flexibility and dynamic tariffs, should become a key part of grid planning and power market design. Perhaps the biggest opportunity is to store solar electricity, to help power air conditioning well into the evening.”
