UN 
With temperatures soaring across Southern Europe this week, grid operators from Spain’s Red Eléctrica to France’s RTE are wrestling with the immediate impacts of persistent heatwaves on electricity generation. The European Centre for Medium-Range Weather Forecasts reported peak temperatures above 42°C in several Mediterranean cities by Tuesday, triggering concerns over grid reliability as air conditioning demand spikes.
Nuclear plants in France and Hungary have already reduced output in response to overheated river water, which is required for reactor cooling. According to the International Atomic Energy Agency, at least 3% of French nuclear capacity was curtailed on Monday morning due to elevated Rhône and Garonne river temperatures, a move permitted under emergency regulatory waivers but not sustainable as a long-term adaptation.
Gas-fired power stations, which account for more than 20% of electricity generation in Italy and Greece, are also feeling the strain. Operators report lower efficiency and occasional shutdowns as turbines overheat, compounding the risk of blackouts during peak demand. Enel, Italy’s largest utility, confirmed that several plants in Sicily are on stand-by status until ambient temperatures drop below 35°C.
Meanwhile, wind generation has fallen sharply in Portugal and southern Spain since the weekend, with Iberdrola citing a 25% decrease in average output compared to the previous month. The lull is attributed to stagnant high-pressure systems typical of summer heatwaves. Solar output remains high, but panel efficiency has dipped by up to 8% during midday peaks, according to data from PV monitoring firm SolarPower Europe.
With forecasts indicating sustained high temperatures well into August, grid operators across the region are urging both businesses and households to reduce consumption during evening hours. The European Commission’s Joint Research Centre is expected to issue updated resilience guidelines for member states later this month, aiming to address these vulnerabilities ahead of further climate-driven extremes in 2026.
Frequently Asked Questions
How is the heatwave affecting nuclear power plants in Europe?
Nuclear plants in France and Hungary have reduced output due to overheated river water needed for reactor cooling, with at least 3% of French nuclear capacity curtailed on Monday.
Why are gas-fired power stations in Italy and Greece struggling during the heatwave?
Gas-fired power stations in Italy and Greece are experiencing lower efficiency and occasional shutdowns as turbines overheat, especially when ambient temperatures exceed 35°C.
How has the heatwave impacted wind and solar power generation in Southern Europe?
Wind generation in Portugal and southern Spain dropped by 25% due to stagnant high-pressure systems, and solar panel efficiency has fallen by up to 8% during midday peaks.
What measures are grid operators taking in response to the heatwave?
Grid operators are urging businesses and households to reduce electricity consumption during evening hours to help manage the strain on the power grid.
What guidance is expected from the European Commission regarding power grid resilience?
The European Commission’s Joint Research Centre is expected to issue updated resilience guidelines for member states later this month to address vulnerabilities exposed by the heatwave.
