UNDERGROUND HYDROGEN STORAGE SITES SELECTION IN CENTRAL ASIA USING FUZZY LOGIC

Abstract

Global economic transition towards low-carbon economies and rising demands for clean energy identify the immediate need for efficient high-capacity energy storage facilities. Hydrogen as a highly prospective energy source faces the hurdle of cost-efficient and safe storage, particularly in large volumes. The study attempts to identify optimum underground hydrogen storage (UHS) sites in Central Asia utilizing the Fuzzy TOPSIS (The Technique for Order of Preference by Similarity to Ideal Solution) multi-criteria decision-making strategy with due regard for the innate uncertainty and subjectivity in the evaluations by the experts. An initial list of nineteen technical, geological, and socio-economic criteria was generated through a comprehensive literature review. These were later condensed to six most significant factors - sealing efficiency, storage capacity, caprock permeability, cavern stability, storage cost, and hydrogen injection/withdrawal rate - based on expert questionnaires and fuzzy logic. Storage alternatives like salt caverns, aquifers, and depleted gas fields were considered, with depleted gas fields being most suitable due to their good geological conditions and infrastructure availability. Subsequently, four gas-depleted fields in Kazakhstan and Uzbekistan were selected for detailed study. Sensitivity analysis using Computer Modelling Group (CMG) software was conducted where reservoir data were unavailable in an attempt to estimate missing parameters. An expert evaluation of two stages using Fuzzy TOPSIS identified the Kashagan field as the best place for UHS. Preliminary economic appraisal also established it as cost-effective. This research provides a data-driven, systematic approach to UHS site selection in Central Asia and contributes valuable insights to the regional hydrogen economy development, supporting broader global energy transition objectives.