Stanford Geothermal WorkshopFebruary 9-11, 2026

Why should we be concerned about geothermal reserves standards? Unlike the petroleum industry, the geothermal industry has no universally recognized set of guidelines, standards, or protocols to guide what are called ‘reserves’ or ‘resources’ in technical evaluations, financial statements and company annual reports. Consistency in reserves and resources classifications (wherein reserves are the commercially viable subset of resources), estimation methodologies, and the related disclosures is needed by geothermal asset teams, investors, regulators, and corporate management teams to geothermal opportunities and clearly communicate the differences using terms that are well defined and understood. In our previous work (Gardner and Faulder 2024), we explored the applicability to the formulation of a classification framework for geothermal resources based on the SPE Petroleum Resources Management System (SPE-PRMS) and proposed an initial geothermal resources management system (GRMS). In this study, we will provide practical examples from certain geothermal projects and interpretations for applying the GRMS based on SPE-PRMS concepts. This work aims to provide case studies to assist geothermal professionals in: 1) determining a geothermal project, 2) classifying resources based on commercial maturity, 3) quantifying and categorizing resources based on technical uncertainty, 4) and designating the development status of resources, all using the same framework. While we recognize that certain situations may arise requiring a departure from the PRMS as a guideline, the PRMS for hydrocarbons provides a good analogy and framework for the establishment of a GRMS and has an important advantage by being familiar and accepted by many energy stakeholders, including many new entrants into the geothermal market space. The adoption and use of the GRMS are strategic to aid in the development and growth of clean and sustainable geothermal energy by promoting consistency, reliability, and transparency in estimates and reporting, which in turn help open the gates for greater geothermal investment.

Topic: General