A Review of the Mechanics of Lined Engineered Cavities and their Implications on Hydrogen Storage
Abstract
Large-scale hydrogen storage at scales ranging from gigawatt-hours (GWh) to terawatt-hours (TWh) is currently projected to be an important component of the lowest cost options for a 100% variable renewable energy system, driven partly by benefits to the grid from converting variable renewable electricity into hydrogen and partly by the anticipated growing role of hydrogen in a future net-zero energy system. Lined engineered cavities (LEC)s are among the prospective types of underground storage technology because they enable hydrogen storage at highpressure in the gaseous form and are expected to not rely on specific types of rock mass. They fill a niche in moderate storage capacity and cost because of their complementary advantages. An overview of various possible configurations and materials suitable for LECs for storing hydrogen is first reviewed to identify potential cost savings and performance improvements. Amongst the various LEC configurations, lined engineered shafts (LES) are identified as having the greatest potential for cost reduction in softer rock masses, such as sedimentary formations, due to reduced excavation and construction complexity. Despite these advantages, significant gaps remain in understanding the long-term behaviour of LES under cyclical loading, as revealed through a review of the theoretical and experimental techniques used to study similar LEC configurations. This review paper con cludes with several recommendations for future research in numerical model formulation and material advancement, with strong potential to increase the feasibility of LESs for hydrogen storage.