The heatwaves that hit Europe in late June and early July led to a 14% surge in daily power demand, according to analysis by energy think tank Ember.
The heatwaves, which saw temperatures reach 35°C in Germany and Spain and 34°C in France, led to increased air conditioner use, driving daily power demand up by as much as 14% in Spain, 9% in France, and 6% in Germany compared to the previous week.
According to Ember, June also saw the highest EU solar generation on record, adding that ‘urgent clean flexibility upgrades are needed to prepare for even more frequent heatwaves’.
Solar power surge
Solar power generation in June was 22% higher than the year before, with solar output during the hottest periods reaching 50 GW in Germany alone. At the same time, several thermal power plants had to wind down during the heatwave, while 17 out of France’s 18 nuclear power plants faced capacity reductions.
“Despite the huge pressure, European grids passed the stress test, and solar electricity played a major role in keeping them running,” commented Pawel Czyzak, Europe programme director at Ember.
“The surplus of solar energy during the day helped prevent blackouts. However, the use of energy storage is still insufficient, leading to reduced energy supply after sunset. This translated into a sharp increase in electricity prices.”
A mismatch between demand and supply led average daily power prices to fluctuate significantly during the period – rising by 175% in Germany, 108% in France, 106% in Poland, and 15% in Spain.
On 1 July alone, evening prices exceeded €470/MWh in Poland and €400/MWh in Germany.
Clean energy flexibility
Ember noted that such heatwaves will only become more frequent and severe, necessitating rapid investments in clean energy flexibility solutions – including battery storage, demand response, dynamic pricing, and renewables equipped with grid-forming inverters.
“Heatwaves will not go away, they will only get more severe in the future,” Czyzak added. “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.” Read more here.
Read more: June 2025 was the third-warmest on record
