Carbon and energy storage in salt caverns under the background of carbon neutralization in China

China plans to reach the peak of its CO2 emissions in 2030 and achieve carbon neutrality in 2060. Salt caverns are excellent facilities for underground energy storage, and they can store CO2. Combined with the CO2 emission data of China in recent years, the volume of underground salt caverns in 2030 and the CO2 emission of China are predicted. A correlation model between salt cavern energy storage and CO2 emission is developed. An evaluation model of carbon capture capacity is developed. A method of comprehensive utilization of salt cavern energy storage is proposed. A flow chart of salt cavern energy storage and salt cavern carbon storage is summarized. The research shows that underground salt caverns with a volume of 300 million m3 will be formed in China by 2020–2030, and China's CO2 emissions will reach 14.4 billion tonnes by 2030. There is a negative correlation between salt cavern development and CO2 emissions. The CO2 reduction percentages of salt cavern comprehensive utilization are: 28.3% for compressed air energy storage; 13.3% for natural gas storage; 10.3% for oil storage; 6.6% for liquid flow battery; 24.8% for hydrogen storage; 16.8% for carbon dioxide storage. The research results have certain reference values for the large-scale development of salt caverns and carbon neutralization. •A relationship between CO2 neutralization and salt cavern energy storage is analyzed.•A model of comprehensive utilization of salt cavern energy storage is adopted.•An evaluation model of carbon capture capacity of salt cavern is established.•The volume of underground salt caverns in China and the CO2 emission of China are predicted.•The problems of salt cavern energy storage and salt cavern carbon storage are analyzed.