Energy storage technologies are crucial for stabilizing electricity supply and integrating renewable energy sources. Pumped-storage hydropower, compressed air storage, and batteries are key options. To ensure grid stability, 15% of capacity should be based on energy storage. Pumped-storage hydropower is the most common form of large-scale storage. Small-scale options like supercapacitors and flywheels are also used. Energy storage can help balance energy supply and demand, especially with the rise of renewable energy sources.