Storage technologies include pumped hydroelectric stations, compressed air energy storage and batteries, each offering different advantages in terms of capacity, speed of deployment and environmental impact. . Energy from fossil or nuclear power plants and renewable sources is stored for use by customers. Grid energy storage, also known as large-scale energy storage, is a set of technologies connected to the electrical power grid that store energy for later use. 1 Batteries are one of the most common forms of electrical energy storage. The first battery, Volta's cell, was developed in 1800. It helps maintain the balance between energy supply and demand, which can vary hourly, seasonally, and by location.