Spain's Gas Fleet Lost 1 GW to Heat Cuts This Summer as Availability Hit Record Low
An unprecedented hot summer forced average curtailments across 4% of Spain's gas-fired capacity, compounding an already strained fleet and pushing day-ahead prices to multi-year highs.
Spain's gas-fired power plants lost an average of 1 GW of output to heat-related curtailments over the summer, equivalent to 4% of the fleet's total capacity, Montel reported on Thursday (2026-09-10). Among plants directly affected, performance fell 15 to 16%, according to Montel calculations. The curtailments hit a fleet already operating at record low availability in 2026, meaning the summer stress landed on a thinner margin of dispatchable capacity than Spain has historically relied upon when renewables fade.5
The consequences showed up in prices. Spain's day-ahead power settled at EUR 150.32/MWh for Wednesday (2026-07-15) delivery, a 3.5-year high, after the market cleared on Tuesday (2026-07-21) amid heatwave demand, reduced renewable output and curtailed nuclear supply, Montel reported. A Spanish trader said demand for Wednesday (2026-07-22) would "remain very high" due to soaring temperatures, coinciding with muted renewable supply and "very high" gas prices. Spanish power day-ahead was trading at EUR 159.10/MWh on Monday (2026-09-14).3
Heat curtailments at thermal plants are a known summer risk across Europe, but Spain's episode this year stands out in scale. Cooling water temperatures rise above safe discharge thresholds, or intake water grows too warm for efficient operation, forcing plant operators to derate or shut down precisely when output is most needed. The 1 GW average figure masks peak curtailment days that would have been sharper still.5
Spain's renewable build provides a partial offset, but an incomplete one. Wind and solar now account for more than 40% of total electricity supply, and a Bank of Spain study found wholesale prices were 40% lower in 2024 than they would have been had the energy matrix remained as it stood in 2019, the Economist reported in May (2026-05-19). Nuclear, accounting for 19% of generation in 2024, provides baseload stability. But that nuclear cushion is not immune to summer heat either.2
France lost 18% of its nuclear capacity to environmental factors in mid-July, Ember found, extending a pattern of summertime nuclear outages that has recurred in recent years, according to Canary Media reporting from August (2026-08-25). Spain avoided comparable nuclear losses this summer, but the French precedent illustrates how heat stress can cascade through generation stacks simultaneously across interconnected grids.4
Solar performed better. Europe's panels produced 17% more power during the summer heat waves than they normally do, as higher irradiance boosted output even as cooling demand climbed in the afternoons, Ember found. For Spain, with its high solar penetration, that uplift was a genuine stabiliser. But solar's afternoon peak does not overlap cleanly with morning ramp-up demand, and evening hours still depend heavily on gas and storage.4
Rising ancillary service costs added a separate burden on the demand side. Costs to balance Spain's grid rose "brutally" in February and March (2026), and were likely to keep climbing, market observers told Montel in May (2026-05-21), with energy-intensive consumers bearing the sharpest impact.1
The pan-European dimension is growing. Only 23% of European households currently have access to or use air conditioning, according to Canary Media, and that share is rising as the continent warms. Italy's power demand jumped 28% in late June compared with the prior week, and France saw a 14% spike over the same stretch, per Ember data. As cooling penetration increases, summer load profiles across Southern Europe will steepen, putting further pressure on dispatchable capacity that is simultaneously being stressed by higher ambient temperatures.4
For Spain specifically, the summer of 2026 sets a benchmark. A 1 GW average curtailment on gas plants during peak demand weeks, on a fleet already at record low availability, narrowed the dispatchable buffer to a degree that left prices exposed when renewable output dipped. ICE Endex TTF front-month gas was trading at EUR 79.51/MWh on Monday (2026-09-14), keeping fuel costs elevated for any gas plant able to run. Whether Spain's grid operator and generators address thermal plant resilience against heat stress through cooling system upgrades, revised dispatch contracts, or expanded storage before next summer's demand season is the question Iberian power traders will need to track through the winter planning cycle.5,3,2