Power systems are going through a period of huge change as there are many revolutionary changes occurring simultaneously. The global market is moving towards renewable energy based generation and we are transitioning from more fossil-fuel based transportation system to a more ecological one. Despite these changes, some new paradigms are evolving in the operation of power systems. As a result of all of these challenges, solutions will require some sort of storage system. Energy storage systems (ESS) provide a way for improving the efficiency of electrical systems when there are imbalances between supply and demand. Additionally, they’re a key element for improving the steadiness and quality of electrical networks. They add flexibility into the electrical system by mitigating the availability intermittency, recently made worse by an increased penetration of renewable generation. These systems have different characteristics, costs, and applications. So we have to understand these issues fundamentally for the future design of power systems whether they are for short or long term operations. This paper reviews the current state of storage systems and their characteristics as well as cutting edge technologies. A comprehensive study of their architecture, capacities, and operation characteristics is performed, allowing potential application areas to be identified. In addition, research areas related to energy storage systems are examined to study the impact they will have on the future of power systems.