(Bloomberg) -- The French nuclear regulator granted a temporary waiver for five nuclear plants to discharge hot water into rivers that may breach environmental standards as the nation struggles with an energy crisis. 

ASN approved a request to keep the Bugey, Saint Alban, Tricastin, Blayais and Golfech plants in operation, even if the water they emit may exceed the authorized limit, according to a filing on grid operator RTE’s website. The exception brings some relief to the strained European power market, where prices are near record levels as extended heat waves have caused disruption to rivers and waterways used to carry fuel and cool power plants. 

Under the rules, Electricite de France SA must reduce or even halt output when river temperatures reach certain thresholds to ensure that the water used to cool the plants won’t harm the environment when put back into the waterways. 

Sizzling temperatures are expected to hit France, the UK and Germany this week, according to Maxar Technologies LLC. Water levels of the Rhine, Europe’s most important river for commodity trading, are so low the river will soon effectively close. 

Given their locations and cooling systems, the Golfech, Blayais, Bugey, Tricastin and Saint-Alban atomic power stations are the most prone to being affected by environmental limits. The Chooz nuclear plant, not given a waiver, also has to be halted when the flow of the Meuse river falls below a certain threshold.   

The waiver will be in place until September 11.

(Updates with date waiver ends)

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