Beznau nuclear power plant limits power output to reduce Aare warming

Switzerland, like many other European countries, has to cope with a heat wave today. Temperatures are rising so high that a Swiss nuclear power plant has reduced energy production to prevent the temperature of the river whose water is used to cool the reactors from rising too quickly. This could be dangerous for aquatic life.

In Switzerland, the temperature today fluctuates around 35 degrees. Beznau nuclear power plant has temporarily reduced its activities in order to prevent the temperature of the River Aare from rising “to a level that is dangerous for the fish”.

The Beznau power plant consists of two light water reactors that together produce roughly 6,000 gigawatt hours of electricity annually. According to Axpo, the operator of the power plant, this corresponds to around twice the electricity consumption of the city of Zurich.

Instead of using a cooling tower to control the temperature, the plant in Beznau uses the Aare river. Through its activities, the plant heats this water, which is eventually returned to the river. According to the operator, the power plant heats the water by 0.7 to 1 degree Celsius when running “at full power”. Axpo adds that this depends on the water conditions.

A spokesman for Axpo told CNBC in a response that there are regulations regarding water protection, which limit the operation of the Beznau nuclear power plant when the water temperatures in the Aare rise sharply.

“We are monitoring the situation closely and have already taken the first measures,” he said. “This is a routine procedure that is needed from time to time during the hot days of summer. We assume that we will have to further reduce production due to the heat in the coming days.”