The relentless heatwaves across Europe this summer have not only tested our resilience but also highlighted the critical role of renewable energy sources, particularly solar power. In a fascinating twist, these extreme weather conditions have become a real-world laboratory, showcasing the strengths and challenges of our energy infrastructure.
The Solar Advantage
Solar energy has emerged as a hero during these challenging times. A recent study by Ember, an energy think tank, revealed that solar output in European countries increased by up to 17% on heatwave days in June and July. This boost in solar generation helped meet the surging electricity demand, which rose by as much as a quarter on hot days. The need for cooling, primarily driven by energy-intensive air conditioning units, has become a major factor in this increased demand.
What makes this particularly fascinating is the global perspective. The International Energy Agency (IEA) estimates that space cooling, largely driven by A/C units and fans, consumed around 7% of the world's electricity in 2022. This trend is not limited to countries with high A/C ownership; even regions with lower usage experience energy spikes during extreme heat.
Heatwaves and Energy Demand
The impact of heatwaves on energy demand is profound. During the early summer heatwaves of 2025, France saw an evening electricity peak that was 25% above the off-season average, largely due to air conditioning. This year's heatwaves have seen similar trends, with daily electricity demand rising by up to 28% in Italy, 23% in Hungary, 14% in France, and 13% in Spain compared to pre-heatwave days.
One thing that immediately stands out is the performance of solar power during these heatwaves. Ember's analysis shows that solar was the only major power source to perform "better than usual" as demand increased. Average daily solar generation during the heatwaves was significantly higher in France, Hungary, Spain, and Italy compared to other days in June and July.
The Evening Challenge
While solar has been a reliable source during the day, the real challenge, as Chris Rosslowe, a senior energy analyst, points out, starts after sundown. In the evening, when cooling demand remains high, the grid becomes more reliant on expensive gas-fired power. This highlights the need for alternative solutions to meet the evening's energy demands.
The Role of Battery Storage
Battery storage systems have been proposed as a potential solution to this evening energy challenge. Experts argue that while solar saves the day, battery storage can save the evening. By storing excess solar energy during the day, these systems can provide a reliable source of electricity in the evening when other power sources may be struggling. This combination of solar and storage has the potential to make Europe's power system more resilient during hotter summers.
A Broader Perspective
The impact of heatwaves on Europe's energy landscape goes beyond solar and storage. Back-to-back heatwaves, exacerbated by climate change, have triggered mass droughts, affecting various energy sources. Low water levels along the Danube River forced nuclear output curtailment in Hungary, while hydropower in the Alpine region neared an all-time low. Even fossil-fuelled energy has suffered, with Poland reducing output at a coal-fired power plant due to critically low water levels in the Vistula River.
In conclusion, the extreme weather events of this summer have served as a stark reminder of the vulnerabilities and strengths of our energy systems. As we navigate the challenges of a changing climate, the role of renewable energy, particularly solar power, in combination with innovative solutions like battery storage, will be crucial in building a more resilient and sustainable energy future. Personally, I believe that these insights should shape our energy policies and investments, guiding us towards a greener and more reliable energy landscape.
