Geological and Geomechanical Analyses for Hydrogen Storage in Salt Caverns, Central Kansas

ABSTRACT: The H-2-SALT study aimed to assess the feasibility of a power-to-hydrogen system utilizing salt cavern storage of hydrogen in Kansas. Two specific sites were evaluated in this study, including Gordon Evans Energy Center (GEEC), located near Colwich, KS; and the Hutchinson Energy Center NG-EGU (HEC), located northeast of Hutchinson, Kansas. The existing well and Kansas Department of Health and Environment (KDHE) salt cavern data were collected at the two sites and adjacent area to develop a hydrogen storage potential database for site characterization efforts. The Hutchinson Salt Member, a bedded salt formation, exists in central to western Kansas, dipping towards the west and providing prospective potential for hydrogen storage in designed salt caverns. GEEC and HEC contain 200-300 ft (61-91 m) Hutchinson salt under the 300-450 ft (91-137 m) overburden formation. Little or no major stability issue is existed at the study area. Potential stability issue such as cavern closure, roof collapse, interbed slip, and tensile fracturing can be avoided by limiting the cavern parameters during the hydrogen storage operation. Pressure, size limitation, and distribution of potential salt caverns for each site were determined to meet the criteria of cavern stability. Future research should focus on obtaining core and log data, and 2D or 3D seismic surveying to characterize the salt formation and mechanical behavior for pre-FEED (front end engineering and design) studies. 1. INTRODUCTION Natural, bedded salt formations can be considered as host rocks for cavern storage of hydrogen produced by the conversion of excess energy to hydrogen via electrolysis. There are three active facilities in the US and one facility in the UK stores hydrogen in salt caverns (Zivar et al., 2021). Thick salt deposits underlie south-central Kansas (Sawin and Buchanan, 2002; Walters, 1978). Kansas has a mature salt industry, including traditional mining, solution mining, and underground liquid hydrocarbon storage in salt caverns. A comprehensive understanding of the geology and geomechanics principles is vital to understanding site selection, sizing, and designing a hydrogen storage facility. The H-2-SALT study aimed to assess the feasibility of a power-to-hydrogen system utilizing salt cavern storage of hydrogen in Kansas. Sponsorship of this study was provided by the National Energy Technology Laboratory, US Department of Energy.