Feasibility analysis of using salt caverns for storage of redox flow batteries

Abstract

Renewable energy holds significant promise of replacing the conventional energy sources. However, the wind and solar energy exhibit the obvious discontinuity, instability, and uncontrollability problems. Redox flow batteries are a novel energy technology, whose most appealing features are high efficiency, long life, and reduced environmental impact. Salt rock has low porosity and permeability, and can self-heal from damage. A salt chamber after water-dissolution is considered as an excellent geological body for energy storage. This study reviews in detail the current worldwide status of salt cavern utilization. Drawing on the salt-carven oil and gas storage technology, the feasibility of storing electrolytes in salt caverns is analyzed considering the physical characteristics of salt rock deposits, and economic and environmental factors. Two medium salt caverns in Jiangsu Province were selected and used as a case study for storage for the all-vanadium flow batteries. The working principle of salt cavern is introduced, and the efficiency of energy storage of the entire system is approximately calculated. Based on the assessment of the existing salt caverns in China, it has been found that using salt caves for electrolyte storage can solve the current problems of disposing old battery electrolyte.