The Nant de Drance pumped storage power plant in Valais, Switzerland. Image: Alpiq.
A pumped hydro energy storage (PHES) plant with a capacity of 20GWh in Valais, Switzerland will begin operations on Friday 1 July.
The launch of the Nant de Drance plant, which sits 600m below ground in a cavern between the Emosson and Vieux Emosson reservoirs, marks the conclusion of 14 years of construction. It will be officially inaugurated in September and its shareholders have invested CHF2.2 billion (US$2.3 billion) in the project.
It features six turbines with a nameplate capacity of 150MW each meaning a maximum power of 900MW. The upper Vieux Emosson reservoir, which sits at an altitude of 2,200m, holds 25 million cubic meters of water which represents an energy storage capacity of 20GWh. That means a maximum duration of dispatch of 20 hours.
Utility Alpiq, the main…