Due to the inefficiency and increasing reduction of fossil fuel resources and the advancement of technology and smart grid design, in order to produce optimal power for power shocks, special threats are needed. In the meantime, the optimal use of production capacity and storage of excess power can improve the performance of power networks and reduce the amount of production capacity. For this purpose, energy storage systems (ESS) are considered as one of the important elements in power network design. In this chapter, the updated equipment of several energy storage technologies is reviewed and their various features are analyzed. These studies include their use, classification, storage capacity, the current state of the industry, and future installation. This chapter also examines the main features of energy-saving technologies suitable for renewable energy systems.