Achieving high-efficiency thermoelectric collaborative storage based on a temperature-matching strategy: Combining calcium looping and reversible solid oxide cells

To address the energy storage challenge in large-scale renewable energy integration, the concentrating solar power (CSP) with calcium looping (CaL) system provides a viable solution for long-duration energy storage. However, such a system inherently faces the problem of balancing dynamic response speed and system efficiency when meeting grid peak-shaving requirements. To tackle this issue, this study innovatively proposes a temperature-matching-based thermoelectric integrated storage system. This scheme precisely couples a reversible solid oxide cell (RSOC) with the calcium looping process at the energy grade level, constructing an integrated CSP-CaL-RSOC system. The core concept involves utilizing the RSOC as an electrochemical conversion hub to respond to grid power commands, while a designed thermal flow network synergistically matches the high-temperature reaction heat from the CaL process with the thermal demand of the RSOC. System optimization results demonstrate that the round-trip efficiency (RTE) and exergy efficiency of the integrated system attain 56.91% and 56.57%, respectively. Techno-economic analysis further reveals that its levelized cost of electricity (LCOE) decreases substantially from 153.25 $/MWh to 99.63 $/MWh, a reduction of approximately 34.99%, demonstrating strong cost competitiveness. The global warming potential (GWP) of the RSOC integrated CSP-CaL thermoelectric storage system is reduced to 20.2 kg CO 2 eq./MWh, providing a viable pathway for advancing carbon-neutral energy systems. The proposed system is developed under idealized steady-state assumptions, including constant solar input, prescribed reaction conversion, and the neglect of pressure drops, heat losses, and CaO deactivation. Therefore, the reported results represent theoretical upper-bound performance rather than realistic operating conditions.