Research on the feasibility of compressed carbon dioxide energy storage system with underground sequestration in antiquated mine goaf

Energy storage has recently attracted a great attention as a promising way to utilize the fluctuating renewable energy. This paper proposes a novel carbon dioxide energy storage system, where the energy is stored and released in antiquated mine goaf with a simultaneous benefit of carbon dioxide storage. Different system configurations and their performances are evaluated based on solving steady-state thermodynamic models. Meanwhile, a parametric analysis considering the seepage process is carried out to examine the effect of key factors including heat exchange parameters, device efficiencies, design pressures, reservoir parameters and gas purifies. Besides, a detailed assessment of the system performance in different energy storage cases is conducted to investigate the effects of economic factors. The results show that the system performance can be improved with less compression stage and more expansion stage. The Round Trip Efficiency can be decreased with high Green Energy Index with the increase in reservoir permeability and ambient temperature. The economic analysis suggests that system operates with energy storage can make profit in most step tariff existing cases. The standalone energy storage system shows economic advantage only when the carbon taxes are lower than 47 USD/t and 68 USD/t compared to the integrated system and standalone carbon dioxide storage system, respectively.