Empowering modern power systems with thermal energy storage in China: A comprehensive review

Energy storage empowers power systems by enhancing flexibility, stability, and renewable integration, playing a critical role in maintaining the dynamic balance between generation and load. In China, pumped hydro storage (PHS) and lithium-ion batteries (LIBs) represent the dominant forms of energy storage participating in grid dispatch, accounting for 42.4% and 55.2% of the total installed storage capacity, respectively. However, the deployment of PHS is often constrained by geographical requirements, while LIBs are primarily limited to short-duration storage due to cost considerations. In contrast, thermal energy storage (TES) imposes no specific geographical constraints and offers distinct advantages in cost-effectiveness, long-duration capability, and high energy density, positioning it as a crucial enabler for synergistic energy management and regulation within integrated electric–thermal systems. Despite this potential, the development of integrated source–grid–load–storage regulation technologies centered on TES has yet to achieve an effective closed-loop system, resulting in TES currently accounting for only 0.8% of total capacity. Aiming to empower the modern power system through TES, this study identifies three critical gaps: (1) the absence of mature TES materials and advanced devices; (2) the lack of reliable pathways for high-efficiency thermal energy utilization; and (3) limited insight into the role of TES in grid dispatch. Through in-depth discussion spanning materials, devices, systems, and mechanisms, this work aims to provide actionable insights and a foundational reference for realizing a next-generation power system underpinned by advanced TES technology.