Effects of multiple insufficient charging and discharging on compressed carbon dioxide energy storage

Compressed carbon dioxide is a promising energy storage technology. However, renewable energy variability can lead to insufficiency during charging and discharging. The present work systematically investigates the effect of charging/discharging insufficiency on compressed carbon dioxide energy storage systems from the viewpoint of transient thermodynamic cycles. The insufficiency extent is defined based on the pressure at the high-pressure tank when disturbances occur. Then the effects of insufficiency extent are investigated in three typical scenarios. In the results, the effects of charging/discharging insufficiency on the efficiency, storage density and power output of the energy storage system during long-term operation are demonstrated. The efficiency of the system during the whole working period is 57.78%, lower than the design efficiency of 59.66%. In particular, the energy storage density is reduced dramatically to 197.60 kJ center dot m(-3), which is 78.2% of the storage density of 252.68 kJ center dot m(-3) at design conditions. Besides, the average output power of the turbine is reduced to 95.70% of the design value. The present work provides an improved understanding of the charging and discharging for compressed carbon dioxide energy storage, especially when renewables are integrated.

Automated summary

This study investigates the effects of charging/discharging insufficiency on compressed carbon dioxide energy storage systems from the viewpoint of transient thermodynamic cycles. The results demonstrate that insufficiency significantly reduces the energy storage density, efficiency, and power output of the system, highlighting the importance of understanding charging and discharging in integrated renewable energy systems.