Altaf Usmani

Energy storage technologies are evolving rapidly, driven by the need for efficient and sustainable solutions. Large-scale underground energy storage solutions are pivotal for managing energy resources efficiently, especially as we transit towards renewable resources and low carbon emitting solutions. With increase in global concerns towards changes in patterns of energy usage; from hydrocarbons to green energy, mass scale storage requirements are also adding up challenges to create safe and secured repositories. Underground storage solutions for various type of liquids and gases, varies as per their storage states under ambient temperature conditions. Underground storage solutions are tailored for hydrocarbons and other gaseous products as per their behaviour under storage temperature conditions as it influences the design and engineering aspects of storage systems. Thus, selection of a mass scale storage solution and its functionality beneath the surface depends on many factors such as temperature, pressure, volume, and the chemical properties of the substance. 

Underground mass storage solutions can be achieved in form of unlined rock caverns and lined rock cavern systems. Unlined rock caverns are sealed within the rock cavity under the umbrella of outside static water pressure head, for liquids and gases that can be stored in liquid state under ambient temperature conditions. However, technical requirements; depth, overburden and storage chamber design can vary depending upon whether the stored product is crude oil or LPG.  High pressurised compressed  gases; Natural Gas, Hydrogen and other similar products can also be stored in underground rock caverns; however, the system requirement changes to a more innovative emerging technique of lined rock caverns. This storage system ensures storability of compressed gases at shallower depths, providing high deliverability and turnover rates, underscoring its adaptability to diverse geological conditions along with offering flexibility for future expansion.

This paper presents a case study focused on Lined Rock Cavern (LRC) technology to assess structural performance and stability of underground storage system for varying pressure requirements of up to 200 bars. The findings from the study highlights vital requirements to be considered for carrying out design and engineering of lined rock caverns structures along with associated risk and challenges. Numerical analysis studies demonstrate that internal pressure significantly influences deformation and stress distributions of rock mass and associated concrete lining structure .Technical findings summarised as part of this study critically analyses feasibility of these storage systems for storing compressed gases for pressures varying from 50 to 200 bars.