A giant water battery turned on under the Alps

A giant "water battery" that can store as much energy as 400,000 electric car batteries has been switched on in Switzerland. The project worth 2 billion euros is located at a depth of almost 600 meters under the Swiss Alps and was under construction for 14 years.

It was reported by The Independent.

Its 20 million kWh capacity will allow excess energy produced from renewable sources to be stored for future use, thus helping to stabilize the electric network and reduce dependence on fossil fuels. A water battery of 25 million cubic meters capacity has enough resources to power 900,000 homes.

The hydro battery works by using the excess energy to pump water between two separate reservoirs at different altitudes in the Swiss canton of Valais.

Six pump turbines send water from the lower reservoir of Emosson to the upper reservoir of Emosson Vieux during times of overproduction.