Review on assessment methodology for hydrothermal resources based on renewable energy attributes

Accurate and effective assessment of hydrothermal resources is crucial in the geothermal industry, given that the global installed capacity for direct use (173 303 MW) significantly exceeds that for geothermal power(16 260 MW). Despite the widespread application of various geothermal resource assessment methods, including the volumetric method, Monte Carlo method, analogy, statistical analysis, and numerical methods, there are still limitations faced in terms of data precision and model uncertainty assessment, fracture heterogeneity, boundary conditions, renewable energy attributes, integration of geothermal compensation mechanisms under the "extraction-injection" balance, diversification of economic evaluation metrics, and the establishment of standardized assessment criteria. This review outlines the various methods suitable for different stages of the hydrothermal resource assessment process, and proposes future technical approaches for sustainable development, including improving the accuracy of assessments and establishing standards for geothermal resource evaluation methods, in order to enhance the efficiency of geothermal resource utilization. • A comprehensive overview of assessment methodologies for hydrothermal geothermal resources • Identification of key challenges and uncertainties in utilization of hydrothermal geothermal energy • Future future research directions aimed at enhancing the rationality and sustainability of geothermal resource utilization