Jellyfish and heat knock out French nuclear capacity

In August 2026, France's nuclear power generation suffered a record shortfall of over 20% of capacity due to a combination of extreme heat, drought, and a jellyfish invasion. A swarm of jellyfish clogged the cooling water intake pumps at the Gravelines Nuclear Power Station, the largest in Western Europe, forcing the shutdown of three reactors (units 2, 3, and 4) and reducing output at unit 1. Unit 5 was already offline for maintenance, leaving only unit 6 operational. Électricité de France, the state-owned utility, deployed fishing boats and vacuum trucks to remove the jellyfish, and by Wednesday morning units 1 and 6 had returned to full power, with unit 2 expected to reconnect later that day. In total, 13 of Électricité de France's 57 reactors were affected, with eight fully shut down and five operating at reduced power due to environmental constraints. The outages were driven by jellyfish at Gravelines and by heat and drought limiting cooling water availability at other plants. Experts attribute the jellyfish proliferation to overfishing, plastic pollution, and warming seas linked to climate change. Électricité de France stated the incidents had no impact on safety, and analysts noted that France remained a net electricity exporter in the short term, though longer-term climate adaptation poses challenges.