Energy storage refers to the capture of energy produced at one time for use at a later time. It allows for the storing of excess energy generated, typically from renewable sources like solar or wind, so that it can be utilized during periods when production is low or demand is high. Energy storage systems can take various forms, including batteries, pumped hydroelectric storage, compressed air energy storage, and flywheels. These systems improve the reliability and efficiency of energy supply, help balance supply and demand, enhance grid stability, and facilitate the integration of renewable energy sources into the power grid. By storing energy, it can also support a more resilient energy infrastructure and reduce the reliance on fossil fuels.