Swiss nuclear power plant forced to reduce production due to warmer waters in river Aare

The Mühleberg Nuclear Power Plant in the canton of Bern has announced it is reducing its output due to the rising temperature in the river Aare, which cools the plant's reactor.

Swiss nuclear power plant forced to reduce production due to warmer waters in river Aare
The Mühleberg Nuclear Power Plant. Photo: Fabrice Coffrini/AFP.

The plant this week announced it has reduced its energy production by more than 10 per cent because of the record temperatures in Switzerland. The hottest summer since 1864 has seen water temperatures in many water bodies rise above 23 degrees Celsius, threatening aquatic fauna, and now energy supplies.

“We have reduced the reactors' power to 89 per cent,” Tobias Habegger, a spokesman for the BKW Group, the energy company that manages the plant, told Swiss news portal 20 Minutes.

The Mühleberg Nuclear Power Plant is obliged by law to reduce production once temperatures in the Aare river exceed 20.5 degrees Celsius. This is the second reduction – already on July 5th the power plant was ordered to reduce production as a safety precaution, according to the same report. 

The nuclear power station in Mühleberg is the first to have had to curtail production because of the current heatwave. The nearby power plant in Beznau is functioning normally. That plant only has to take similar safety precautions once temperatures in the Aare river exceed 32 Celsius. 

The Mühleberg Nuclear Power Plant, which has been active since 1972, will be the first in Switzerland to be disconnected as of December 2019, according to a statement by the BKW Group. 

READ MORE: Sizzling temperatures leading to 'catastrophe' for fish in Swiss lakes and rivers 

Correction, July 31st: This article originally stated that the reactor was struggling to cool the plant and has since been amended. The article has also been updated to reflect that The Mühleberg Nuclear Power Plant only has one reactor. The reduction in production is simply in order to comply with the authority‘s requirement to protect the rivers flora and fauna and not further increase the river’s temperature.

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Heatwave: Why is it so hot in Switzerland right now?

Not so long ago we complained about the cold and rainy weather in Switzerland, wishing for sunnier and warmer days. Our wish has come true — but why exactly is it so hot and what can we expect for the coming weeks?

Heatwave: Why is it so hot in Switzerland right now?

The temps have reached high 20s across much of Switzerland in the past days, but the best (or the worst, depending on who you ask) is yet to come: meteorologists forecast the high of 32 degrees for Friday.

“The current heat wave is relatively extreme for a month of May”, meteorologist Joshua Gehring from official weather service MeteoSwiss said in an interview with Watson news platform.

Why is it so unseasonably hot right now?

One reason should come as no surprise to anyone: “What we are currently experiencing, that is to say a relatively early heat wave, is a direct consequence of climate change”, Gehring noted.

READ MORE: EXPLAINED: How the climate crisis is hitting Europe hard

Specifically, a phenomenon called “heat dome” is hovering over Europe. It is, according to Gehring, “a stagnant anticyclone that acts as a lid to accumulate and retain heat”.

This is pretty much what happens when you put a lid over a boiling pot — the heat therein is captured and can’t escape.

What can we expect for next week?

The forecast calls for the heat wave to end from the beginning of next week, with more seasonal, 20-degree-plus temperatures expected throughout the country.

This is what the forecast looks like for Tuesday:

MeteoSwiss screenshot

What can you do in the meantime to cool down?

Indoor air-conditioning is rare in Switzerland, but keeping cool is easier outdoors.

For instance, the abundance of lakes and rivers in Switzerland provides a welcome relief on hot days.

And if you like swimming pools, the good news is (at least during a heat wave) that some are turning off heating to boycott Russian gas, so you could have a nice, cool swim.

READ MORE: Swiss pools go cold in boycott of Russian gas

Also, most public fountains in Switzerland spout cold water you can drink and splash yourself with.

If all else falls, head for the glaciers (while they last).