Spain weighs nuclear life extensions as summer gas burn tests Iberian grid
Analysts see Spain's nuclear fleet as a buffer against the 28% surge in gas-fired output that repeated heatwaves have triggered this summer.
ICE Endex TTF front-month gas settled at €61.38/MWh at Friday's (2026-08-14) close, up 1.81% on the session, as summer heat kept pulling on thermal generation across western Europe. [prices]
The price level captures Spain's energy dilemma. Montel Analytics assessed that gas-fired power generation across Italy, Spain, France, Britain and Belgium rose by an average of a third this summer, with the combined increase valued at 6.59 GW compared with average levels in the 2024 and 2025 summers. Italian and Spanish generation levels were each up 28%, roughly 3.1 GW per country, as repeated heatwaves curtailed nuclear output and eroded hydropower resources.6
The Spanish figure sits at the centre of a live policy debate. Wind and solar now account for more than 40% of total electricity supply in Spain, yet the country finds itself drawing harder on gas exactly when the fuel is dearest.3
That is why the decision on Spain's nuclear fleet matters beyond the domestic power mix. The reactors accounted for 19% of generation in 2024. Analysts see them as a brake on the seasonal gas surge that heatwaves have made a recurring feature of the Iberian summer, providing the cheap, constant output that wind and solar cannot guarantee at the evening peak.3
The regulatory backdrop complicates any extension. Spain's energy regulator opened an investigation into nuclear power production earlier this year. Foro Nuclear, the industry lobby, said on Tuesday (2026-05-19) that the probe has no link to the blackout of 28 April 2025 and raises no safety concerns at the facilities.2
That blackout is still politically live. A Reuters report from June 2025 found that grid operator REE's failure to calculate the correct mix of energy was one of the factors hindering the grid's ability to cope with the demand surge that caused the outage.5
The extension question balances supply security against political fallout and the economics of gas. Keeping the reactors running means fewer hours where Spanish demand draws on TTF-linked supply. Retirement on schedule, or curtailed output, forces the country toward more gas-fired capacity — deepening Spain's exposure to European gas price swings each summer.2
Spain's power market has shown it can absorb high renewables penetration. Daily power prices saw fewer negative prints in May this year compared with the same month in 2025, despite higher solar capacity, a trend analysts attributed to stronger demand and changes in trading behaviour. But lower negative-price frequency has not reduced the gas bill when the heat peaks.4
The pattern is not confined to Spain. Montel Analytics' data covers Italy, Spain, France, Britain and Belgium, and the third-on-average increase appears across all five. Spain is the test case: it has the most renewables, the sharpest summer heat exposure, and nuclear plants actively under regulatory review. If the gas surge persists despite the build-out, other west European markets will face the same pressure as they reduce thermal backup.6
At the EU level, the European Commission is working a parallel track. According to a leaked draft seen by Montel, Brussels plans to step up coordination of gas storage filling and consider oil stock releases to curb prices amid the Iran war. Both tracks converge on the same winter gas balance: Spanish nuclear policy and EU storage coordination are moving concurrently, driven by separate political pressures.1
The unresolved risk is summer-to-winter carryover. Even with the reactors running, Spain entered the autumn with depleted hydro reserves and a gas system already under heavy call. If the October-November filling season runs behind schedule, the 28% summer surge in gas-fired output will look like an early read on a much harder winter.6