A heatwave sweeping across Europe has forced France to reduce nuclear power output due to high river temperatures, while in Poland the last time such emergency measures were introduced was over a decade ago. However, Polish authorities assure that the system is better prepared this time, thanks to investments and growing renewable capacity.
According to data from French operator EDF, cited by Reuters, production fell by 4.1 GW at midday Wednesday, or 7 percent of total demand. In some parts of France temperatures exceeded 40 degrees Celsius, which combined with weaker wind pushed up wholesale electricity prices. On Tuesday, spot prices in France and Germany hit their highest since mid-January 2025. Power systems, grappling with the heatwave, relied on gas-fired generation.
France is typically a large net exporter of cheap electricity to neighboring countries, but as temperatures rose, exports dropped to around 3 GW on Wednesday afternoon from 10–12 GW a week earlier, reducing cheap supplies for neighbors and cutting transmission revenues.
French nuclear fleet struggles with heat
Climate change shows how extreme heat can be as disruptive as price spikes caused by low temperatures and low renewable output seen in winter, said Alessandro Armenia, an analyst at Kpler. – We should expect similar dynamics next summer as climate change is undeniable – he added. The heatwave has reduced output at units Saint-Alban 2, Bugey 3, and Nogent 2, while the Golfech 2 reactor was shut down Monday evening. French environmental regulations force EDF to cut production when river temperatures reach a certain threshold to protect local ecosystems.
The heatwave, driven by an Omega blocking pattern, is now entering Poland. According to the Institute of Meteorology and Water Management, temperatures are expected to rise rapidly to 35–38 degrees Celsius, locally above 40°C. High temperatures increase electricity demand, mainly from air conditioning and cooling devices.
Poland’s power grid better prepared than a decade ago
– Currently, there are no restrictions on the operation of system power plants resulting from water level or temperature – said Maciej Wapiński, spokesperson for Polskie Sieci Elektroenergetyczne (PSE), the Polish transmission system operator. – Even if some coal and gas plants were to reduce output, this would not threaten the security of the system – he added. According to PSE, there is no risk of introducing power rationing steps, which were last imposed in August 2015 during a drought and high river temperatures. Since then, conventional plant owners have carried out investments to mitigate such risks.
Poland has also significantly expanded its renewable energy capacity, especially solar photovoltaics, which is particularly valuable during heatwaves. According to the latest PSE data, the total installed PV capacity reached nearly 27 GW in May 2026. – In previous years we passed heatwaves without problems. To maintain this, it is necessary to ensure adequate dispatchable capacity, i.e. sources that work regardless of weather conditions – Wapiński pointed out.
Renewables and gas fill the gap
According to the World Meteorological Organization, Europe is warming more than twice as fast as the global average, increasing the likelihood of prolonged heatwaves. The European energy system is becoming more dependent on renewables. Evening drops in solar production are replaced by wind and conventional sources: nuclear, coal and gas, pushing up electricity prices after sunset. Data from Kpler shows that almost all European countries recorded an increase in conventional power generation in the evenings.
– This week the situation is worsened by higher cooling demand and lower than usual wind generation, requiring more gas-fired power. The wholesale price is set by the most expensive plants, which are gas-fired – said Nathalie Gerl, an analyst at LSEG. – This week is an exception because in summer the electricity market usually has a surplus – she added.
Źródło: WNP.PL, Fot. EPA/TERESA SUAREZ / PAP
