This lecture discusses the infrastructure and operation of pumped storage facilities for hydropower, focusing on the Swiss context. It covers the importance of water storage for energy purposes, different types of turbines, high-head mixed storage schemes, and the challenges of flexibility versus fatigue in energy production. The instructor explains the concept of water storage, the energy produced in a hydrological year, and the balance of greenhouse gases. The lecture also explores the current energy equivalent of Swiss storage reservoirs, the outlook for Swiss hydropower, and the challenges and future developments in the field.