{"id":26184,"date":"2026-08-19T08:50:33","date_gmt":"2026-08-19T07:50:33","guid":{"rendered":"https:\/\/visegradpost.com\/?p=26184"},"modified":"2026-08-19T08:50:33","modified_gmt":"2026-08-19T07:50:33","slug":"europe-heatwaves-solar-nuclear-fossil-power-disruption","status":"publish","type":"post","link":"https:\/\/visegradpost.com\/en\/2026\/08\/19\/europe-heatwaves-solar-nuclear-fossil-power-disruption\/","title":{"rendered":"Europe\u2019s Heatwaves Reveal Solar Strength as Nuclear and Fossil Power Face Disruption"},"content":{"rendered":"

Europe\u2019s June and July 2026 heatwaves exposed a sharp contrast within the power system: solar generation increased during the sunniest and hottest hours, while higher demand and water stress constrained several conventional sources. An analysis from Ember reported by Renew Economy<\/a> found that solar output rose by as much as 17 per cent in European countries during heatwave days.<\/p>\n

The result was not a uniform success for every technology or every market. Electricity demand rose by up to 28 per cent in Italy, 23 per cent in Hungary, 14 per cent in France and 13 per cent in Spain compared with days before the heatwaves. At the same time, extreme temperatures and drought affected nuclear, gas, coal and hydropower generation. The figures show how the conditions that increase the need for electricity can also make some power plants harder to operate.<\/p>\n

Solar generation increased as cooling demand rose<\/h2>\n

Air conditioning use pushed electricity demand higher during the heatwaves. Solar panels, however, produced more power during daylight hours, when the sun was strongest and cooling demand was already elevated. Ember\u2019s analysis found that average daily solar generation during the heatwaves was 17 per cent higher in both France and Hungary, and 5 per cent higher in Spain.<\/p>\n

Those increases did not eliminate the pressure on power systems. The analysis indicated that supply scarcity and high prices were most pronounced in the evening, after solar generation began to decline while cooling demand remained high. This timing is central to the comparison between technologies: solar performed strongly during the daytime peak, but its output did not continue after sunset.<\/p>\n

\"A
Low river levels can reduce the availability of cooling water for some power plants. Photo: Markus Distelrath \/ Pexels (Pexels License)<\/a><\/figcaption><\/figure>\n

The summer results also fit into a broader change in the European Union\u2019s electricity mix. According to RFI\u2019s report on Ember\u2019s 2025 data<\/a>, solar supplied 22.1 per cent of EU electricity in June 2025, narrowly ahead of nuclear at 21.8 per cent. That earlier monthly result provides context for the latest heatwave figures, but it does not mean that solar production is always higher than nuclear or fossil fuel generation in every country or during every heatwave.<\/p>\n

Heat and drought reduced the availability of thermal power<\/h2>\n

Nuclear, gas and coal plants commonly rely on water drawn from rivers or seas for cooling. When heat raises water temperatures and drought lowers river levels, the amount and effectiveness of available cooling water can fall. Ember linked this combination of heat and drought to disruptions affecting nuclear, gas, coal and hydropower generation during the 2026 heatwaves.<\/p>\n

In Hungary and Romania, historically low levels of the Danube reduced output from the countries\u2019 only nuclear power stations. The situation was particularly significant because those plants normally provide around 40 per cent of Hungary\u2019s electricity generation and around 15 per cent of Romania\u2019s, according to the source material. The figures describe the normal contribution of the facilities, not the amount of generation lost during the heatwaves.<\/p>\n

Switzerland provided another example of the cooling constraint. The Beznau nuclear plant was temporarily shut down in June because the river temperature became too high. Environmental rules can also limit the discharge of cooling water into rivers to protect aquatic life, creating an operational constraint when water temperatures exceed permitted levels.<\/p>\n

France\u2019s nuclear fleet experienced several reductions during the July heatwave. Three of the country\u2019s 57 reactors were shut down, while production at seven others was reduced. On 12 July 2026, as much as 29 gigawatts, equivalent to 23 per cent of French nuclear capacity, was unavailable during the heatwave. The source also notes that nuclear production in France has been reduced during heatwaves in several previous years, including 2003, 2006, 2015, 2018, 2019, 2022 and 2025. These examples show a recurring vulnerability, but they do not establish that heat was the only factor behind every outage or reduction.<\/p>\n

\"Solar
Solar generation is concentrated during daylight hours, while evening demand can remain high. Photo: Ana Morales \/ Pexels (Pexels License)<\/a><\/figcaption><\/figure>\n

Gas and coal generation was reduced or at risk of reduction in the United Kingdom, Italy, France, Poland and Serbia. Hydropower also came under pressure, with droughts across continental Europe bringing output to its lowest July level in a decade, according to Ember.<\/p>\n

The evening remains the critical period<\/h2>\n

The heatwave data point to a timing problem rather than a simple competition between energy sources. Solar helped meet demand while sunlight was available, but the system remained more exposed later in the day, when air conditioning demand could still be high and solar output was falling. Ember senior energy analyst Chris Rosslowe described the evening as the period when the grid was most exposed to expensive gas fired power.<\/p>\n

This pattern helps explain why a rise in solar generation can coexist with pressure on other power stations. Solar output may be particularly well matched to hot daytime conditions, while nuclear and other thermal plants can face cooling restrictions. Yet the same solar output does not automatically cover the evening demand peak. The evidence therefore supports a specific conclusion: during the 2026 heatwaves examined by Ember, solar performed strongly in daylight, while the wider system continued to face operational constraints and a more difficult period after sunset.<\/p>\n

For Europe, hotter summers create a combined challenge. Electricity demand can rise as people seek cooling, while drought and high water temperatures can affect plants that depend on rivers or other water sources. Solar\u2019s performance during the reported heatwaves shows its value during daytime demand, but the figures also underline the limits of treating one source as a complete answer for every hour. The role of nuclear power in this changing system is also being examined through developments such as new nuclear fuel technologies<\/a>, although that separate issue does not alter the heatwave data presented here.<\/p>\n

Photo \u00e0 la une: Tobi &Chris<\/a> sur Pexels<\/a> (Pexels License).<\/small><\/p>\n","protected":false},"excerpt":{"rendered":"

Solar generation rose during Europe\u2019s June and July 2026 heatwaves, just as higher electricity demand and low water levels constrained nuclear, gas, coal and hydropower production in several countries.<\/p>","protected":false},"author":2,"featured_media":26186,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29],"tags":[1118,1117,1114,1115,1116,1113],"class_list":["post-26184","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-climate","tag-electricity","tag-european-energy","tag-heatwaves","tag-nuclear-power","tag-solar-power"],"_links":{"self":[{"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/posts\/26184","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/comments?post=26184"}],"version-history":[{"count":1,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/posts\/26184\/revisions"}],"predecessor-version":[{"id":26185,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/posts\/26184\/revisions\/26185"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/media\/26186"}],"wp:attachment":[{"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/media?parent=26184"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/categories?post=26184"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/visegradpost.com\/en\/wp-json\/wp\/v2\/tags?post=26184"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}