To develop a geology-driven screening and ranking methodology for prioritizing global prospect areas suitable for combined co₂ sequestration and geothermal energy production
This study develops a geology-driven screening and ranking methodology for prioritizing global prospect areas suitable for combined carbon dioxide (CO₂) sequestration and geothermal energy production. Geological CO₂ storage is widely recognized as an essential climate mitigation technology, while geothermal energy represents a reliable, low-carbon, and dispatchable energy source. Increasing interest in integrated subsurface utilization has highlighted the potential to use injected CO₂ not only as a stored greenhouse gas but also as a working fluid for geothermal heat extraction. However, geological conditions that ensure long-term CO₂ containment and those that enable viable geothermal energy production do not always coincide, creating a critical need for systematic, integrated site-selection methodologies.
To address this challenge, a tiered, geology-first screening framework is developed that treats storage security as a non-negotiable constraint and geothermal potential as a graded attribute. The methodology integrates geological containment and trapping theory, geothermal reservoir and sustainability theory, coupled subsurface utilization concepts, and multi-criteria decision analysis (MCDA). Prospect areas are evaluated using four interacting domains: CO₂ storage suitability, geothermal energy potential, risk and monitoring feasibility, and enabling factors. Fatal-flaw screening is applied to eliminate geologically unsuitable settings, followed by basin-scale and prospect-scale evaluation using standardized scoring and normalization procedures. Weighted aggregation within an MCDA framework produces composite suitability indices and ranked prospect lists. Uncertainty and sensitivity analyses are incorporated to test ranking robustness and identify data gaps.
The methodology generates basin-scale suitability classifications, prospect-level rankings, domain-specific score profiles, and shortlists of robust candidates for detailed appraisal. The framework is transferable across geological settings and supports transparent, reproducible, and defensible decision-making. By providing a unified geological basis for identifying prospects capable of delivering both long-term CO₂ storage and geothermal energy production, this study contributes a practical tool for advancing integrated subsurface energy and storage systems in support of global decarbonization.
Keywords: CO₂ sequestration; geothermal energy; integrated subsurface systems; screening and ranking methodology; geology-driven framework; MCDA; site prioritization.
