Techno-economic assessment and sustainable pathways of medium-to-low temperature geothermal resources: A comprehensive framework for carbon neutrality

Medium-to-low temperature geothermal resources (25–150 °C) represent strategically significant renewable energy sources for regional decarbonization and carbon neutrality objectives. This study employs systematic review methodologies to examine sustainable development models and techno-economic evaluation systems, constructing a comprehensive analytical framework spanning development model evolution, techno-economic evaluation, environmental and social benefits, and implementation challenges. Development models have evolved through four progressive stages: single extraction, closed-loop circulation, cascaded integrated utilization, and intelligent "source-grid-load-storage" integration, enhancing utilization efficiency from 15–25 % to 75–85 % through resource optimization, technological innovation, supportive policy frameworks, and climate imperatives. The techno-economic evaluation system has expanded from conventional economic analysis to encompass life cycle assessment (LCA) and advanced intelligent evaluation methodologies, progressing toward integrated assessment paradigms featuring uncertainty quantification and multi-objective optimization. Environmental and social benefit research has advanced significantly in carbon reduction accounting, ecological impact identification, and social value quantification, establishing a comprehensive four-dimensional "carbon-ecological-social-economic" evaluation framework, though challenges persist including fragmented standards and incomplete cross-dimensional coupling mechanisms. Five key constraints are identified: insufficient deep resource identification precision, elevated drilling costs, extended payback periods, inadequate risk-sharing mechanisms, and fragmented evaluation systems. The study proposes a transformative pathway centered on deep detection, cost-reduction drilling, intelligent reinjection, multi-energy complementarity, and multi-value enhancement, constructing a four-tier support system encompassing standardized data foundations, intelligent evaluation engines, scenario-based policies, and replicable financing models. This research provides essential methodological support for multi-scale, high-quality geothermal development within carbon neutrality processes.