Pumped Hydro Storage (PHS)

About

Pumped Hydro Storage (PHS) is a widely used method for large-scale energy storage, leveraging the gravitational potential energy of water between two reservoirs at different elevations. During periods of low electricity demand, excess power is used to pump water from the lower reservoir to the upper one. Conversely, when demand is high, water is released back to the lower reservoir, generating electricity through turbines. This process allows PHS to effectively balance supply and demand on the grid, especially with the integration of intermittent renewable energy sources like solar and wind. PHS facilities are crucial for grid stability, offering long-duration energy storage capabilities. They can provide ancillary services such as frequency regulation and inertia. Despite high upfront costs, PHS systems are cost-effective in the long term due to their durability and efficiency, typically achieving round-trip efficiencies of 70-80%. The technology has been in use for over a century and remains the largest form of grid energy storage globally, with significant installations worldwide. Its role in supporting renewable energy integration makes it a vital component in the transition towards cleaner energy systems.