European heatwaves push up daily power demand by up to 14%

4 July, Brussels – 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 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. Analysis emphasizes that urgent clean flexibility upgrades are needed to prepare for even more frequent heatwaves.

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.

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Burcu Ünal Kurban
Communications Officer – Europe, Ember
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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, some being shut down completely due to high river temperatures.

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.

Daily electricity prices rose by 175% in Germany

According to Ember’s analysis, the supply-demand imbalance caused average daily power prices to double or even triple. Between June 24 and July 1, average daily electricity prices rose by 175% in Germany, 108% in France, 106% in Poland, and 15% in Spain. During the evening peak on July 1, prices spiked above €470/MWh in Poland and €400/MWh in Germany.

Despite the huge pressure, European grids passed the stress test, and solar electricity played a major role in keeping them running. 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

Pawel Czyzak
‍Europe Programme Director

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.

Pawel Czyzak
‍Europe Programme Director

Interconnectors played a key role in dissipating these price spikes quickly. As the heatwave swept across Europe, peaking in Madrid on Sunday, Paris on Tuesday, and Berlin and Warsaw on Wednesday, interconnectors helped deliver electricity to where it was needed most.

Ember points out that energy systems must rapidly deploy storage and demand flexibility to cope with a warming climate. These tools are essential to balance variable renewable generation and reduce peak stress on the grid. Equally important is investing in distributed energy sources capable of starting the network on their own, such as solar farms with grid forming inverters, and opening new markets that can facilitate the delivery of key grid services.

About Ember

Ember is an independent energy think tank that aims to accelerate the clean energy transition with data and policy. It creates targeted data insights to advance policies that urgently shift the world to a clean, electrified energy future.

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European heatwaves push up daily power demand by up to 14%

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Daily electricity prices rose by 175% in Germany

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