Annual performance of a calcium looping thermochemical energy storage with sCO2 Brayton cycle in a solar power tower

This study presents a techno-economic assessment of a novel concentrated solar power plant configuration integrating a calcium-looping thermochemical energy storage system with a supercritical CO2 Brayton cycle. The system enhances dispatchability and efficiency in solar power tower plants through high-temperature thermal storage and flexible operation. The proposed configuration features a polar heliostat field, a central receiver acting as a calciner, and separate storage for CaO and CO2. Dynamic simulations developed in OpenModelica, with Python-based control, evaluate the system under realistic and time-dependent solar profiles. Results demonstrate that replacing molten salt with TCES-CaL enables a more compact solar field, reduces parasitic losses, and improves thermal integration. The optimal configuration, with a solar multiple of 2.6 and 24 hours of storage capacity, achieves a plant efficiency of 39.0% and reduces the levelized cost of energy by 8.5% compared to a molten salt-based reference system. This work highlights the role of storage capacity and concentration factor in maximizing energy yield and economic performance. The integration of TCES-CaL with a sCO2 power cycle shows strong potential for large-scale CSP deployment, providing high efficiency, improved dispatchability, and cost competitiveness. These results contribute to advancing CSP technologies aligned with decarbonization targets and support the integration of thermal energy storage systems at the grid level for future sustainable energy systems.