Design, off-design and operation study of concentrating solar power system with calcium-looping thermochemical energy storage and photovoltaic-driven compressed CO₂ energy storage

The combination of thermochemical energy storage (TCES) based on calcium-looping (CaL) and concentrating solar power (CSP) is favorable as the potential choice for large-scale, low-cost green power production in the future. However, the self-consumption power of TCES based on CaL accounts for a relatively large proportion compared to the existing molten salt energy storage. To this end, this paper innovatively proposes a 50 MW CSP system integrated with CaL-TCES and photovoltaic (PV)-driven compressed CO₂ energy storage (CCES). The percentage of system self-consumption has been significantly reduced after system being optimized based on the results of energy and energy analysis. Consequently, the overall system performance is significantly improved with the energy and exergy efficiencies increased from 14.6 % to 15.7 %–29.4 % and 31.6 %, respectively, at design-point. Furthermore, a parametric study of the optimized system is investigated. Moreover, the annual operational performance of the optimized CSP-CaL system located in Delingha, China is predicted on an hourly basis. Finally, from a techno-economic perspective, the solar multiple (SM) and TCES capacity are optimized aiming the minimal levelized cost of electricity (LCOE). The results indicate that LCOE ranges from 0.010 to 0.159 $∙kWh⁻¹ for different plant sizes and TCES capacities.