French nuclear output constrained, German wind power down, European spot power prices rise over 20%

en.Wedoany.com Reported - Day-ahead power prices for delivery on August 12 rose 21.8% in France to €142.5/MWh, while German day-ahead prices for the same period climbed 22.8% to €138.50/MWh. Limited French nuclear output, lower German wind generation, and high temperatures boosting electricity demand have jointly tightened short-term supply-demand conditions in both power markets.

Scheduling data from EDF show that French nuclear output is expected to be constrained by 7.3 GW during the midday peak demand period on August 12, accounting for approximately 12% of the country's total nuclear fleet capacity. Due to rising river water temperatures, two reactors are expected to be fully shut down, while four units are planned to reduce output; one reactor may also cease operation due to low river water levels.

French nuclear plants use river water for unit cooling, and discharge temperatures along with their impact on river water temperatures are subject to environmental regulations. When river water temperatures approach prescribed limits, operators must reduce unit output or suspend operations to control thermal discharge.

German wind output is expected to decline by 8.1 GW to 4.7 GW, approximately 60% below the seasonal average. With wind speeds falling during the heatwave, gas-fired units are required to take on more peaking generation duties, and rising natural gas prices have further pushed up marginal generation costs.

Météo-France recorded maximum temperatures of 40.6°C in parts of Corsica on August 11. On August 12, maximum temperatures across most of France are expected to range between 36 and 38°C; on August 13, they are forecast to broadly rise to 35–39°C, with localized peaks of 40°C. Temperatures in western regions are expected to gradually ease from August 14 onward, while most eastern areas will remain at 35–40°C.

Data from French transmission system operator RTE show that French nuclear generation in the first half of 2026 reached 189.8 TWh, up 7.9 TWh year-on-year. Net electricity exports over the same period totaled 51 TWh, including 13.9 TWh of net exports to Germany and Belgium and 12.4 TWh of net exports to the UK.