EDF Confirms Nuclear Restrictions Hold at 9.5% as French Heatwave Extends Into Fourth Week
France's heat-driven curtailments remain near their July record, sustaining pressure on the export surplus that neighbours depend on to balance peak summer demand.
EDF's heat-related nuclear output restrictions were confirmed at 9.5% of installed capacity for Tuesday (2026-07-22), Montel reported on Monday (2026-07-21), with no sign of the heatwave relenting in time to ease the burden before late July. The curtailment keeps France close to the record levels set three weeks earlier and extends the most severe episode this summer by another full week.5
France generates roughly 70% of its electricity from nuclear power and, when the fleet runs without constraint, exports surplus generation to Germany, Switzerland and Iberia through interconnectors, Oilprice.com noted. Restrictions at 9.5% reduce that export margin and force neighbours to cover their shortfalls from other sources.3
The episode began modestly. EDF's restrictions stood at 1.6 GW at 09:00 CET on Wednesday (2026-07-08) and climbed to 3 GW by noon, Montel reported, when EDF disconnected the 1.3 GW Golfech 2 reactor on the Garonne River in southwestern France as temperatures hit 42C. That 3 GW amounted to 4.6% of total installed capacity.1
Four days later the constraint broke into record territory. France's heat-related nuclear cuts reached 9.2 GW on Sunday (2026-07-13), Montel said. Swiss utility Axpo closed a reactor the same day because river temperatures had climbed past cooling thresholds, tightening supply across France and the Alpine corridor simultaneously.2
EDF was still curtailing 8.8 GW on Monday (2026-07-14), Montel data showed. Oilprice.com put the figure at 6.4 GW that day, which it described as equivalent to 14% of France's overall power demand that morning. The two figures likely reflect different measurement points across the day rather than a straightforward contradiction.2,3
France held its net exporter status despite the outage volume. RTE data showed more than 10 GW crossing French borders to neighbouring countries on Monday (2026-07-14), Oilprice.com reported. That surplus kept the region out of deficit through mid-July, but it narrows if curtailments at the 9.5% level confirmed for Tuesday (2026-07-22) persist without stepping back as peak summer demand draws more heavily on interconnector capacity.3,5
The current episode is not unprecedented in its origins. EDF temporarily shut two nuclear reactors in late June (2026-06-25) as a precautionary environmental measure after river temperatures rose during a heatwave that had already turned deadly, Yahoo News UK reported. Those closures were partial and brief; the July wave started at lower curtailment levels before accelerating to record volumes within four days.4
ICE Endex TTF front-month was flat at €61.90/MWh on Friday (2026-07-25), giving no clear signal that the market has revised its late-summer supply view in response to the sustained French outage. German power also sat unchanged at €132.45/MWh. Both markets are exposed to French nuclear availability through interconnector flows: less baseload from France tightens the continental generation stack and, where gas-fired capacity fills the gap, supports gas demand and TTF prices.
The gap between the market's current calm and the physical picture in France is the thing to track over coming sessions. River temperature data on the Loire, Rhône and Garonne, which determine when EDF can bring curtailed units back online, is not covered in available source material beyond Monday (2026-07-21). Updated Remit notifications from EDF will show whether the export margin France held on Monday (2026-07-14) has been maintained or has eroded as the heatwave pushes past its third week. If restrictions stay near 9.5% into early August, the 10 GW export buffer that kept neighbours in balance during mid-July may not hold.5,3