A 2-billion-Swiss franc (€2.05 billion/$2.10 billion) project could help stabilize Europe’s increasingly expensive electricity as it shifts to renewable energy.
The so-called water battery, Nant de Drance, located between two reservoirs in a cave 600 meters (nearly 2,000 feet) underground in the Swiss canton of Valais, is being described as a big step in Europe’s transition to green energy. Europe will need to develop 200 gigawatts of energy storage capacity by 2030 — more than fourfold its current capacity, the European Association for Storage of Energy estimates.
The project, which took 14 years to finish, is made up of 17 kilometers (10.5 miles) of underground tunnels, housing six huge turbines powered by water cascading down a steel pipe in a cavern the length of two football fields. At the peak of construction, 650 workers were on-site, working to excavate some 1.5…