Analysis of Influence Factors on Air Tightness of Underground Cavern for Compressed Air Energy Storage

Abstract:

Renewable energy resources are usually intermittent and instable. Compressed air energy storage (CAES) provides a good solution to this problem. Underground air storage cavern is an important part of CAES. Artificiallyexcavated hard rock cavern attracts wide attention for its little restriction to geology and wide adaptability. The influence of concrete lining permeability on air tightness of underground cavern was investigated. Based on the Darcy’s law, analytical formulas for calculating the amount of air leakage within underground cavern were derived. Using the derived formulas, air leakage condition under a typical CAES operation pressure was analyzed. Furthermore, some influence factors, including lining permeability, lining thickness and cavern shape, were also analyzed. The results show that, when the inner pressure is 8 MPa and impervious concrete of P8 level is used as lining, air leakage rate will be less than 1%, meeting the operational requirements of compressed air energy storage power station. Air leakage will increase linearly with the increase of lining permeability. Compared with spherical cavern, cylindrical cavern has a better leakageproof effect.