Katkuri Rajendar,Dr. B. Sathyavani,Dr. Ch Hussaian Basha 02 12 This paper reviews the growing importance of energy storage technologies in modern power systems driven by the rapid expansion of renewable energy sources such as solar PV and wind The inherent variability and intermittency of renewables create challenges in maintaining grid stability power quality and reliability To address these issues several energy storage elementsbatteries ultracapacitors flywheels and fuel cellsare increasingly integrated into gridconnected and islanded systems The review covers their operating principles performance characteristics and suitability for AC and DC microgrid environments Special attention is given to battery charging and discharging strategies as they significantly influence system efficiency and lifetime The survey further examines the impacts of renewable energy integration on the main grid and highlights how microgrids and BuildingtoGrid B2G concepts enhance flexibility controllability and energy management Key findings indicate that hybrid storage systems and coordinated control methods are critical for future smart grids while gaps remain in multistorage optimization and standardized frameworks for ACDC microgrids and B2G interaction Copyright (c) Journal of Science Engineering Technology and Management Science. All rights reserved 2026