Introduction  The selection of types and sites of underground repository for compressed air storage is one of the most important issues of large scale compressed air energy storage (CAES) plant planning.

  Method  The advantages and disadvantages of 4 types of underground repository for compressed air storage were concluded based on comparison of analyzing literatures published domestic and oversea. The geology characteristics and distribution region of the suitable hard stratum for construction of underground rock cavern were also analyzed. The technology feasibility of rock cavern for compressed air storage was validated by the in-situ experiment results obtained from the first pilot repository for CAES in China. Sites planning method of underground repository for large scale CAES plant was studied taking Guangdong province for example.

  Result  Rock caverns built in salt and hard rock stratum are the most feasible types of the underground cavern for CAES plant and hard rock stratum widely exists in most windy and solar energy abundant aera in China.

  Conclusion  Wide distribution of the suitiable stratum for underground cavern construction in intermittent energy generation area solves the difficult problem of site selection for large scale CAES plant. Experiment data indicates that good quality of the rock mass is helpful for the solution of key problems such stability and sealing of underground cavern. All in all, it is feasiblity in technology at the present stage in China.