Abstract: New-type power system, characterized by high penetration of renewable energy and power electronic equipment, is undergoing rapid development. Its significantly changed dynamic behavior and operating characteristics are bringing serious concerns to the balance of power and energy in different time scales. Energy storage is of great potential to improve operating performance and to balance power and energy in broad time scales. This paper first reviews the challenges in achieving multi-time-scale balance of power and energy in a new-type power system. Next, the key technical features of different energy storage technologies are summarized and their potential applications are explored. Then, the status quo of research on energy storage's functions is investigated. Finally, a multi-objective coordinated control scheme is proposed to achieve prospective and comprehensive functions of energy storage. Hopefully, the scheme can balance power and energy well in different time scales, and make energy storage the key to addressing the various challenges faced by a new-type power system.