In Electric Power systems, power quality has been one of the issues of increasing interests. Energy storage does not mean just the energy sources but they also provide the added benefits of improving power quality, dynamic and transient stability and also the reliability of the supply. Some of the major disadvantages in electric power supply system have been flickering and deviations in power supply which make some of the electronic equipments and domestic devices highly sensitive to it. To avoid such problems we need to find out devices that can provide a backup during the time of voltage sags and such deviations. The paper concentrates on performance benefits of adding energy storage to power electronic compensators for utility applications. The paper concerns on analysis of various energy storage devices on the basis of different parameters out of which Superconducting magnetic energy storage technology and Super capacitor energy storage has become an alternative for conventional solutions with negligible losses. Flywheel is used for non polluting uninterruptible power supply. For large scale storage, Underground thermal, Compressed air and Pumped hydrogen are preferred but it is difficult to compare all these devices as none of them are optimal for all applications.