CO2 Storage Site Selection: A Comprehensive Review of Current Approaches

Global warming, driven by increasing anthropogenic greenhouse gas emissions, has emerged as a critical environmental concern. Carbon capture and storage (CCS) technology offers a promising solution for reducing CO ₂ emissions, but its effectiveness depends on identifying suitable candidates that can ensure safe, long-term storage of CO ₂. This study proposes a systematic four-stage workflow for selecting optimal CO ₂ storage sites, developed through a comprehensive review of existing approaches. The workflow begins with preliminary, large-scale assessments of broad geographic areas, such as sedimentary basins, using geological, technical, environmental, and economic criteria. Although these assessments provide valuable regional insights, they often lack the resolution required for precise evaluations. Site-specific frameworks bridge this gap by examining individual candidates, such as saline aquifers and depleted reservoirs. However, basic frameworks frequently oversimplify suitability evaluation by neglecting the interdependencies and uncertainties inherent in real-world conditions. To address these challenges, advanced frameworks are incorporated to apply multi-criteria decision-making (MCDM) methods and optimization techniques, such as pinch analysis and process graphs. MCDM-based frameworks weigh conflicting criteria, whereas optimization-based frameworks ensure the technical and economic feasibility of CO ₂ allocation in the source-to-sink matching problem. Applying this workflow to the UK context reveals the need for advanced assessments of storage candidates such as the Bunter Sandstone Formation, demonstrating that relying solely on basic frameworks is insufficient. The findings underscore the importance of integrated approaches that combine both basic and advanced suitability evaluations to enhance the robustness of site-selection practices.