Energy storage is a research area focused on developing technologies and systems that can store and release electricity at a later time. This is essential for integrating renewable energy sources, such as solar and wind power, into the electricity grid, as these sources are intermittent and may not always align with energy demand. Energy storage technologies include batteries, pumped hydro storage, flywheels, and thermal energy storage. Research in this area aims to improve the efficiency, capacity, and cost-effectiveness of these storage systems to help create a more reliable and sustainable energy infrastructure.