The energy storage system (ESS) is becoming an important component in power systems to mitigate the adverse impact of intermittent renewable energy resources and improve power grid reliability and efficiency. However, storage devices driven by different technologies can have specific grid impacts. This special section is dedicated to reflecting the latest progress and technologies in ESS, focusing on the key issues in operation, control, reliability impact and market value of multi-type grid-scale energy storage devices. There are 12 papers resented in this special section, 1 of which reviews challenges and progresses of ESS technology, 5 of which discuss the battery energy storage (BES); 2 of which are centered on compressed air energy storage (CAES), 2 of which focus on pumped hydro storage (PHS); 2 of which study the market issue with ESS. In summary, these papers comprehensively review current progresses and clearly reveal technical challenges in ESS research. We hope this section will serve as an introduction for future research aiming at promoting technical development and fostering practical utilization of ESS in power systems.