Advances and emerging directions in thermal energy storage for concentrated solar power systems

Abstract The accelerating global shift toward renewable energy has intensified the demand for reliable solar power generation. Concentrated solar power (CSP) plants offer a promising utility-scale solution due to their inherent dispatchability, yet their performance is constrained by the intermittency of solar irradiation. Thermal energy storage (TES) mitigates this limitation by storing excess heat during peak insolation and delivering it during low-solar periods, enabling stable and flexible power output. This review examines key TES pathways – sensible heat storage (e.g., molten salts), latent heat storage using phase-change materials (PCMs), and thermochemical energy storage (TCES) – and their roles in improving CSP system performance. TES integration can increase CSP capacity factors from 25–30 % to 40–50 % while reducing the levelized cost of electricity. Current molten-salt systems provide 6–15 h of storage, whereas PCMs and TCES offer up to two- to three-fold higher energy densities compared with conventional sensible-heat media. This review critically compares these technologies in terms of performance, scalability, and integration challenges, identifies key research gaps in high-temperature materials and system design, and outlines future strategies to advance CSP–TES deployment in sustainable energy systems.