Pumped hydro storage is a method of storing energy by using water. It works by pumping water from a lower reservoir to an upper reservoir when there is excess energy, such as from solar or wind sources. When energy demand is high, the stored water is released back down, turning turbines to generate electricity. This process helps balance energy supply and demand. This technology is one of the oldest and most widely used forms of energy storage. It plays a crucial role in integrating renewable energy sources like solar power and wind energy into the grid, ensuring a stable and reliable electricity supply.