Energy storage refers to the capture and holding of energy produced at one time for use at a later time. It plays a crucial role in balancing supply and demand in energy systems, enhancing grid reliability, and integrating renewable energy sources like solar and wind into the power grid. Energy storage technologies can take various forms, including batteries, pumped hydro storage, flywheels, compressed air energy storage, and thermal storage. By storing excess energy generated during low-demand periods and releasing it during high-demand periods, energy storage helps to optimize energy usage, reduce costs, and improve overall efficiency in energy systems.