Heatwave Hits European Rivers, Affecting Nuclear Power Output

Impact of Heatwave on River Levels

A combination of above-average temperatures combined with below average rainfall across much of western and central Europe during June and the first half of July has placed increasing pressure on rivers, ecosystems, and energy infrastructure. Persistent high-pressure systems brought prolonged sunshine, suppressed rainfall, and enhanced evaporation, causing river levels to fall and water temperatures to increase. These unusually warm rivers are affecting electricity generation in France, as several nuclear power stations rely on river water for cooling.

Under French environmental regulations, operators must limit the amount of heat discharged back into rivers, meaning electricity output may need to be reduced when water temperatures become too high. Earlier this month, EDF temporarily shut down a reactor at the Golfech nuclear power station after the Garonne River approached its environmental discharge threshold, while production restrictions are expected at the Nogent nuclear power station from 14 July if the river reaches its forecast temperature. The prolonged heat has also increased electricity demand as air conditioning use has risen in urban areas.

Effects on Electricity Generation

The prolonged heatwave in France is not only affecting power generation but also increasing electricity demand due to higher usage of air conditioning, particularly in urban areas where population density is high. The national grid company, RTE, reported that the country's electricity consumption reached record highs during the heatwave, peaking at 37 gigawatts on a single day.

Similar issues are also being faced across Spain and Portugal, with increased demand leading to higher prices for consumers. In Madrid alone, the city government has issued advisories urging residents to reduce energy use during peak hours to avoid blackouts. The situation is further compounded by the fact that these countries have a higher proportion of renewable energy sources in their mix, making it more challenging to balance supply and demand.

Outlook for Europe

While temperatures are expected to ease slightly in some areas over the coming days, weather models indicate warmer-than-average conditions will persist across much of southern Europe. Vegetation remains dry, so the wildfire risk is likely to remain high. Rivers are projected to continue experiencing unusually warm conditions, further impacting water availability and energy production.

In Portugal, for instance, the national forest authority has issued an orange warning for wildfires in several regions, citing prolonged heat as a key factor. In Spain, the situation is even more severe, with the Almería province having experienced one of the largest fires in recent years. The fire was so intense that it prompted evacuations and extensive firefighting efforts.

Impact of Typhoon Bavi

In Asia, Typhoon Bavi has weakened to a severe tropical storm after making two landfalls along China’s eastern coast. Despite this, it continues to pose a significant flooding threat as it moves inland. Before reaching China, Bavi rapidly intensified over exceptionally warm waters in the western Pacific, attaining Category 5 strength and becoming one of the strongest tropical cyclones of the 2026 north-west Pacific season. More than 2 million residents were evacuated before the storm reached China, while hundreds of flights, rail services, and ferry operations were suspended. Earlier in its track, Bavi brushed the northern tip of Taiwan and passed through Japan’s Sakishima Islands, bringing damaging winds, torrential rainfall, and widespread transport disruption. Though the wind strength has eased since landfall, the storm contains a vast reservoir of tropical moisture, with its slow inland progression expected to prolong heavy rainfall across eastern China during the coming week, increasing the risk of flash flooding, river flooding, and landslides.

Source: The Guardian