Europe’s heat wave is intensifying, fueling wildfires across the Mediterranean and threatening to curb
electricity generation from both nuclear and hydropower plants.
Temperatures in Spain are forecast to hit 39C (102F) on Wednesday, but could climb further to 42C next week a
s hot air streams in from North Africa, according to Rubén del Campo, a spokesperson for Spanish forecaster Aemet.
Heat alerts have been issued across southern regions, including more than half of France, with water sprays and fans being distributed to cool students in Ma
rseille schools. That could also hit several of Electricite de France SA
’s reactors along the Garonne and Rhone rivers as rising water temperatures compromise cooling operations.
Read more: Wildfire Alerts Issued Across Mediterranean as Heat Wave Builds
Global warming is boosting the intensity and frequency of heat waves, disrupting power grids just as demand for summer cooling increases. At the same time, t
he heat is generating violent storms, which on Wednesday shut roads and cut power to 8,000 customers in France’s Bassin d’Arcachon region.
Descenso de temperaturas mañana y nuevo ascenso previsto el viernes, con temperaturas muy altas a pa
rtir del fin de semana que se prolongarán durante varios días. Los valores
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más altos se registrarán en el interior, con régimen de brisas y sensación de bochorno en el litoral. pic.twitter.com/6jOkIHGFoD
— AEMET Comunitat Valenciana (@AEMET_CValencia) June 25, 2025
While firefighters on the Greek island of Chios brought a number
of blazes under control, wildfire warnings were issued for central and southern France.
The next blast of heat — peaking at the end of next week — could bring even hotter conditions, according to data fro
m Atmospheric G2 and analysis from weather analytics firm MetDesk.
Europe’s power markets remain sensitive to any issues affecting the French nuclear fleet, the region’s largest. Int
erruptions to that supply could push countries to increase their reliance on fossil fuels.
France’s day-ahead power price surged to €81.8 per megawatt-hour, the highest level since March. Prices for July climbed as much as 8.3%. Nuclear output may be restricted at EDF’s Blayais site from June 30, St. Alban from July 1, and Golfech from July 2.
“The river temperatures of the Garonne and Rhone are very likely to lead to production restrictions until next week,” said Nathalie Gerl, lead power analyst at LSEG. “In the case of the Garonne, we see a higher risk of this happening again this summer.”