Adsorption-based compressed CO2 energy storage system using commercial adsorbent pellets: Experimental screening and thermodynamic-economic assessment

Adsorption-based compressed CO 2 energy storage (AB-CCES) offers a promising route for compact low-pressure CO 2 storage, however, the selection of optimal adsorbents for practical applications remains uncertain and requires further investigation. This study systematically screened five commercial adsorbent pellets and evaluated the performance of the corresponding AB-CCES system by integrating material characterization, CO 2 adsorption-desorption experiments, ad-desorption kinetics, thermodynamic simulation, and techno-economic analysis. Zeolite 4A emerged as the most promising candidate because it combined high CO 2 uptake with favorable kinetics, regenerability, and cyclic stability under the special conditions of AB-CCES. The experimentally derived adsorption model was incorporated into the system simulation, demonstrating a substantial reduction in low-pressure tank volume and an approximately 36 times increase in volumetric energy density over conventional CCES while maintaining competitive energy and exergy efficiencies. Lower adsorption temperatures could reduce the storage-tank volume and increased energy density, whereas higher desorption temperatures enhance power output but reduce exergy efficiency. Further techno-economic analysis indicates that AB-CCES achieves lower equipment-related and land-related costs, resulting in a lower LCOE value of 0.1237 $/kWh and a dynamic payback period of approximately 11.2 years. Economic sensitivity analysis further suggests that the desorption temperature should be maintained at 200-250 °C to balance thermodynamic performance and cost-effectiveness.