Europe Gas-Fired Power Surges a Third Above Recent Summers as Heatwaves Cut Nuclear and Hydro
Repeated heatwaves have driven a 6.59 GW average increase in gas-fired generation across five west European countries, pulling ICE Endex TTF front-month 4.46% higher on Tuesday (2026-09-01).
ICE Endex TTF front-month climbed 4.46% to €69.77/MWh by 08:15 UTC on Tuesday (2026-09-01), extending a summer in which repeated heatwaves have pushed gas-to-power demand across western Europe to levels well above the prior two years. German day-ahead power added 1.15% to €148.08/MWh in the same session.
Gas-fired power generation across Italy, Spain, France, Britain and Belgium averaged 6.59 GW above the 2024 and 2025 summer levels, Montel Analytics assessed. Italy and Spain drove the bulk of the increase, each posting a 28% rise in gas-fired output against prior-year averages. Sustained heat curtailed nuclear plants by raising river temperatures that cool reactors, while drought drew down hydro reservoirs that would otherwise carry shoulder-hour load.4
France has taken the hardest hit in headline price terms. An extreme heatwave that struck western Europe in mid-June, with temperatures reaching up to 42 degrees Celsius, pushed front-week power prices above €100/MWh in both France and Spain, analysts told Montel, with the pressure expected to persist through the week of June 22 (2026-06-22). More heatwaves followed. EDF data showed French nuclear generation cut by 7.3 GW during the week of August 10 (2026-08-10), equal to 12% of total installed capacity, as the country experienced at least its fifth extreme heat episode of the summer. French day-ahead power prices surged 21.8% to €142.5/MWh on Tuesday (2026-08-11), per LSEG data cited by Reuters.2,3
Solar has absorbed some of the load gap. Ember data show Europe's solar panels produced 17% more power during this summer's heat waves than seasonal norms, helping to steady the grid as afternoon cooling demand climbed. Battery systems pushed that output further into the evening, covering hours when air conditioning loads remain high but generation has stopped.5
Yet solar's price impact varies sharply by market. Through May 2026, gas-fired plants set the day-ahead clearing price in 89% of hours in Italy, Ember calculated, meaning Italian power prices track gas closely. Spain's renewable penetration is far higher; gas set the marginal price in only 15% of hours there. That divergence showed in March 2026, when Italy's average power price ran at €142/MWh against Spain's €59/MWh.1
Walburga Hemetsberger, CEO of SolarPower Europe, described the evening demand problem directly: temperatures remain high after sunset and cooling demand stays elevated even as solar output fades. Battery storage is increasingly the tool bridging that gap, she said.5
Storage and battery buildout is accelerating. Across Europe, 36 gigawatt-hours of new solar and battery capacity was commissioned in 2025, a 48% increase over prior-year additions, according to data reported by Canary Media. That growth rate has not prevented gas from bearing the bulk of thermal generation burden during the multi-week heat episodes that have defined this summer.5
France's state utility is planning more than $10 billion in adaptation spending over the next 15 years on its nuclear and hydro fleet, targeting equipment that cools reactor discharge water and manages lower water availability. The adaptation schedule makes clear the fleet will remain climate-sensitive well into the 2030s.5
European gas storage fill as the summer draw period ends is the data point traders will track most closely in the weeks ahead. Gas burn running roughly a third above recent summer averages across five countries has consumed volumes that would otherwise have gone into inventory. Any September extension of above-normal temperatures would keep gas-to-power demand elevated past the seasonal turn, leaving less cushion for winter supply.4