Reusing abandoned natural gas storage sites for compressed air energy storage

This study aims to investigate the feasibility of reusing uneconomical or abandoned natural gas storage (NGS) sites for compressed air energy storage (CAES) purposes. CAES is recognised as a viable means of high-capacity short- to mid-term energy storage. However, the widespread implementation of CAES is limited to geological and geographical settings and requires substantial infrastructure and capital investment. Utility-scale CAES requires a suitable trap that can contain compressed air without significant loss or leakage. Reusing of existing NGS systems and converting them into CAES can reduce the costs of exploration, geomechanical risk assessment and drilling into the trap, as well as the infrastructure cost, compressors and inter/after coolers. The cost, therefore, would be limited to acquirement of the site and installation of turbines, recuperators and transmission lines. The present study compares the net stacked benefit of converting NGS sites into CAES against that of conventional energy storage and development of CAES from the ground up. While site-specific economic analyses and technological viability are needed prior to large-scale implementation, results of this feasibility study suggest that reusing NGS sites for CAES has the potential to offer a cost-effective alternative for utility-scale energy storage.