Compared with other ways to store electricity, FES systems have long lifetimes (lasting decades with little or no maintenance; full-cycle lifetimes quoted for flywheels range from in excess of 10 , up to 10 , cycles of use), high (100–130 W·h/kg, or 360–500 kJ/kg), and large maximum power output. The (ratio of energy out per energy in) of flywheels, also known as round-trip efficiency, can be as high as 90%. Typical capacities range from 3 to 1.
[pdf] A game-changing technology developed by NREL in collaboration with Blue Frontier Inc. offers a solution to lower a building’s electricity bills and help reduce demand on the grid: the Energy Storing and Efficient Air Conditioner (ESEAC).
[pdf] Energy storage systems improve power quality through their ability to regulate voltage and support frequency stability. They act as buffer systems that absorb excess energy during periods of low demand and release it when demand surges, effectively maintaining a stable supply.
[pdf] 
