Performance benchmark of thermal energy storage concepts in concentrating solar power

Thermal energy storage (TES) plays a critical role in enhancing the efficiency and dispatchability of concentrating solar power (CSP) plants by mitigating solar energy intermittency. Although molten salts remain the dominant TES solution, alternative systems such as solid-state and latent heat storage offer promising advantages. This study analyses the performance impact of different TES technologies—two-tank molten salt, concrete-based storage, and phase change materials (PCMs)—when integrated into CSP systems. By comparing key performance indicators under identical operating conditions, this study provides insights into the suitability of each TES technology for CSP plant operations. The results highlight the trade-offs between energy yield, efficiency, and footprint. All three concepts demonstrated comparable performance at both the system and TES levels, with disparities of less than 3 %. The advantage of PCM lies in its substantial volume reduction of approximately 27 % compared to molten salt, whereas concrete TES achieves similar outcomes with a slight increase in volume relative to molten salt TES volume. • Energy dispatch of CSP plant remains consistent across TES systems. • TES concept employed has a negligible impact on the round-trip efficiency. • Concrete TES performs similarly to molten salts but requires more space. • PCM TES is suitable for space-constrained applications (∼27 % reduction).