The state-backed operator EDF expects to cut nuclear generation by 7.3 gigawatts on Wednesday, representing 12% of the country’s total capacity. This marks the fifth extreme heat event since June, forcing the grid to balance a sharp decline in supply against the rising energy demand typically seen during such spikes in temperature.

France relies on nuclear energy for roughly 70% of its electricity mix, making the grid particularly vulnerable to the low water levels and elevated river temperatures that limit cooling efficiency. Similar constraints are rippling across the continent. In Hungary and Romania, operators recently shuttered reactors after Danube water levels hit 90-year lows. While one turbine at Hungary’s Paks plant resumed production this week following rainfall, Romania resorted to engineering interventions, including blasting rock formations to redirect river flow toward the Cernavoda facility.