Three major categories of grid energy storage

Mechanical: Direct storage of potential or kinetic energy. Can involve sensible (temperature change) or latent. . Electrical Energy Storage (EES) systems store electricity and convert it back to electrical energy when needed. The first battery, Volta's cell, was developed in 1800. These systems help balance supply and demand by storing excess electricity from variable renewables such as solar and inflexible sources. . Battery Storage Dominance with Rapid Cost Decline: Lithium-ion batteries have become the dominant energy storage technology, with costs falling over 85% since 2010 to $115/kWh in 2024. . Grid-scale storage refers to technologies connected to the power grid that can store energy and then supply it back to the grid at a more advantageous time – for example, at night, when no solar power is available, or during a weather event that disrupts electricity generation. [pdf]