Carbon dioxide energy storage systems: Current researches and perspectives

To increase the share of electricity generation from renewable energies for both grid-connected and off -grid communities, storage systems are needed to compensate for their intermittent nature. Compressed air energy storage (CAES) processes are of increasing interest. They are now characterized as large-scale, long-lifetime and cost-effective energy storage systems. Compressed Carbon Dioxide Energy Storage (CCES) systems are based on the same technology but operate with CO2 as working fluid. They allow liquid storage under non-extreme temperature conditions. A literature review of this new technology was conducted. The difference between the systems lies in the presence or absence of an external heat source, the thermodynamic state of the stored CO2, and the means of heat recovery and utilization. To better understand the wide variety of configurations, they have been classified according to the external heat use and the storage location (underground or aboveground). As there is no dynamic model for liquid storages, one is presented in this paper and bring new challenges that have to be considered in future researches. Also, experimental studies are lacking to validate the CCES behaviour and some components like turbomachines and thermal storages.