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Energy Geo-Storage: A Large- to Medium- and Small-Scale Compressed Air Energy Storage and Geomechanical Analysis

Jingtao Zhang, University of Nebraska - Lincoln


Compressed air energy storage (CAES) has been re-emerging as a viable energy storage option in the last decades. Large-scale porous media-CAES (PM-CAES) denotes the storage and withdrawal of compressed air energy using a porous aquifer. In this study, various 2-Dimensional pore-network micromodels are fabricated to examine repetitive drainage-imbibition processes at the fundamental pore-scale. It is observed that different fluid flow mechanisms may prevail during the drainage and imbibition steps depending on the pore geometry. Sweep efficiency, residual saturation, flow morphology, and pressure gradient are quantitatively examined during the repetitive fluid flows. The flow rate, pore-space heterogeneity, and pore geometry are observed to exert a major influence on the efficiency of injection and withdrawal of nonwetting fluid. Those thorough understandings of repetitive two-phase fluid flow using the pore-network micromodels can be used for an upscaled analysis of PM-CAES. A geomechanical study using analytical and numerical methods is conducted to assess the feasibility of the medium- or small-scale CAES using a shallow salt dome formation. The stress state at the crown of the storage cavity is observed to be a decisive factor for determining the allowable ranges of air storage pressure. The energy storage capacity of this concept is expected to be between 1 and 10 MJ/m3 based on the analysis results. A model test pile is prepared to study the concept of the pipe-pile-based small-scale CAES (PPMS-CAES) in-depth in the laboratory setting. The mechanical and thermodynamics response of the model pile, soil, and the air is examined in-depth using this test setup. In parallel, numerical simulations based on the nonlinear elastoplastic t-z model and the 1-D load transfer method are conducted to examine the long-term mechanical response of the CAES pile. Both experimental and numerical study results suggest that the PPMS-CAES concept will not compromise the mechanical integrity and serviceability of the pile foundation. Lastly, case studies on the various types of buildings are conducted for two strategies, building-to-solar energy (B2SE) and building-to-grid (B2G) integration.

Subject Area

Civil engineering|Energy

Recommended Citation

Zhang, Jingtao, "Energy Geo-Storage: A Large- to Medium- and Small-Scale Compressed Air Energy Storage and Geomechanical Analysis" (2021). ETD collection for University of Nebraska - Lincoln. AAI28490435.