Pumped-storage hydropower (PSH) is a form of long-duration energy storage that utilizes the gravitational potential energy of water. During periods of low electricity demand, excess energy (often from renewable sources like wind and solar) is used to pump water from a lower reservoir to a higher one. When electricity demand increases, the stored water is released to generate hydroelectric power, thereby providing a reliable method to balance intermittencies in renewable energy generation and ensure grid stability, which is crucial for sustainable energy management.