ESSs are essential for the large-scale deployment of RESs and for achieving sustainable energy systems. Consequently, it is now a strategic goal to incorporate advanced storage technologies into RESs [1–8]. This chapter presents various storage technologies and presents the criteria used to evaluate and select them [3–7] (Fig. 2.1). It highlights the essential performance indicators along with some applications. Through clear definitions, technical parameters, comparative tables, and relevant examples [9–11], this chapter gives readers a systematic understanding of how to combine storage solutions to renewable energy challenges.