Heatwaves push western Europe's gas burn up a third as renewables falter
Repeated extreme weather has lifted gas-fired generation across five EU countries by 6.59 GW this summer, complicating the region's emissions math despite record renewable additions.
Gas-fired power generation across Italy, Spain, France, Britain and Belgium has climbed by an average of 6.59 GW this summer, a third higher than average levels recorded across the 2024 and 2025 summers, according to Montel Analytics.8 Italy and Spain each posted a 28% increase in their gas burn. The driver is straightforward: repeated heatwaves have curtailed nuclear output and drained hydropower reservoirs, leaving gas to fill the gap.8
The volume matters for the European carbon chain. When hydro and nuclear underperform together, gas-fired plant becomes the marginal source of supply, pushing power-sector emissions higher even as renewable capacity grows. ICE Endex TTF front-month eased 3.45% to €80.08/MWh in the session ending 2026-09-15, and German baseload fell 4.11% to €165.36/MWh. The moves suggest the market is not pricing a summer-style supply squeeze into September, but the gas-burn data make dismissing further weather risk harder than those prices imply.8,2
The renewables buildout has been substantial. More than 70 GW of new renewable capacity was added across Europe in 2025, led by Germany, Spain and France, according to a study by Montel's EnAppSys, EQ and Energy Brainpool analysts.2 Yet that deployment has not consistently translated into lower emissions, with structural challenges persisting across the transition.2
The mechanism is simple. Variable renewables need firm backup, and when weather simultaneously suppresses hydro, nuclear and wind output, the backup is gas. Germany is forecast to see record commercial green curtailment this year, jumping 10% from 2025 to 2 TWh, according to a Montel Analytics report.6 That curtailment creates a pull for battery storage, but batteries at current build rates cannot cover the kind of multi-day shortfall that heatwaves produce.6
The economic exposure is not confined to power bills. This summer's heatwaves and the productivity losses and agricultural damage they cause could erase as much as 1% of EU gross domestic product, wiping out most of the bloc's expected 2026 growth, according to a Dutch bank estimate.7 By 2030, Europe's largest economies could lose more than $600 billion due to heat-related expenses and shortfalls, with projected losses of $240 billion for France, $147 billion for Italy, $131 billion for Germany and $120 billion for Spain.5
The political pressure compounds the economic one. Europe's hard right has been pushing the continent's climate consensus hard, with opposition to emissions-cutting measures gaining traction across several member states.4 Sustained gas burn during extreme weather hands ammunition to those arguing that the green transition is both expensive and ineffective at reducing emissions. The analytical point is narrower: the buildout is working on capacity terms, but the emissions arithmetic is failing because the system is not yet flexible enough to run on renewables alone.4,2
Not everything points in the same direction. Analysts said growth in green generation has made European and Nordic power systems more capable of weathering a gas supply shortage now than during the 2022 energy crisis.1 That is genuine progress in energy security. But resilience to a sudden gas cut-off and resilience to a sustained heatwave that eats into hydro and nuclear output while simultaneously spiking cooling demand are different problems requiring different solutions.1
The comparison with China is illustrative rather than consoling. China's mostly coal-powered thermal generation rose 1.5% in 2024 to 6.34 trillion kWh, defying expectations that coal output was peaking, according to National Bureau of Statistics data published on Friday (2026-05-15).3 Overall Chinese power demand grew 4.6% that year. Every major grid is finding that decarbonisation does not follow a straight line.3
For gas traders, the summer data point to a European gas-fired generation floor that sits higher than pre-heatwave consensus assumed. The 6.59 GW average increase across Italy, Spain, France, Britain and Belgium is not a one-off; it is the product of multiple summers of extreme heat.8 As long as nuclear maintenance schedules and hydro reservoir levels remain weather-dependent, gas-fired plant holds a larger role in the European power stack than installed renewable capacity alone would suggest.
The signal to watch over autumn is reservoir recovery. If hydro levels do not refill adequately, the gas burn that covered summer demand could extend into the heating season, tightening the European gas balance when seasonal demand peaks. ICE EUA Dec-rolling prices and their response to any revision in power-sector emissions expectations are the second read on how seriously the market is taking that risk.8,2