| 1 | Olkaria Geothermal Area | Kenya East African Rift | High-temperature volcanic system suitable for electricity generation and direct heat applications. | Approximately 250–340°C in productive zones. | Common production-drilling range: approximately 1,500–3,000 m. | Large-scale commercial development with additional expansion and drilling potential. | Confirm geothermal resource rights, land access, water permits, drilling approvals, power-sale arrangements, and foreign-investment requirements. | Water use, brine management, induced seismicity, protected habitats, land access, and community benefit obligations. | High potential Strong resource quality and grid relevance, subject to permit and infrastructure risk. | Independent review of pressure decline, non-condensable gases, reinjection performance, and remaining well inventory. | Kenya energy authority |
| 2 | Kızılcahamam–Kızıldere High-Temperature Belt | Türkiye Western Anatolia | High-enthalpy fault-controlled resource; electricity and district-heating uses are established in the region. | Approximately 200–300°C, varying by reservoir and depth. | Often approximately 1,500–4,000 m for commercial targets. | Developed geothermal market with continuing exploration and field-redevelopment opportunities. | Verify operating license, exploration or exploitation rights, drilling permits, electricity-market eligibility, surface rights, and royalty obligations. | Mineral scaling, boron and other dissolved constituents, reinjection integrity, groundwater protection, and local air-quality controls. | High potential Strong regional supply chain and established geothermal expertise. | Validate sustainable capacity rather than relying only on initial well output; review reinjection and reservoir compartmentalization. | Turkish Ministry of Energy |
| 3 | Reykjanes Peninsula | Iceland Southwest volcanic zone | Very high-temperature volcanic resource with potential for electricity, heat, and industrial applications. | Commonly above 250°C; temperatures can be substantially higher in deep zones. | Approximately 2,000–5,000 m for deep high-temperature wells. | Highly developed geothermal region with active volcanic and subsurface conditions. | Assess exploration and utilization licenses, land-use planning, drilling consents, grid access, water rights, and restrictions related to volcanic hazards. | Volcanic activity, hydrogen sulfide, brine disposal, groundwater interaction, visual effects, and seismic risk. | High potential Excellent resource quality but elevated geological and permitting complexity. | Require current volcanic-hazard modeling, well-integrity reports, corrosion data, and contingency plans for interruptions. | Icelandic energy authority |
| 4 | The Geysers Geothermal Region | United States California | Vapor-dominated geothermal system with long operating history and extensive production data. | Approximately 230–260°C in productive steam zones. | Commonly approximately 1,500–3,500 m. | Established commercial field with mature wells, redevelopment needs, and declining-field management considerations. | Review federal, state, county, air-quality, water-discharge, land-use, and well-abandonment requirements. | Induced seismicity, steam emissions, water supply, noise, habitat impacts, and long-term well plugging liabilities. | Moderate–high Excellent operating history, but mature-field decline can reduce upside. | Analyze steam decline curves, make-up water availability, remaining useful life, and abandonment security obligations. | California energy authority |
| 5 | Salton Sea Geothermal Region | United States California | High-temperature, high-salinity brine resource with electricity and mineral-recovery potential. | Approximately 280–350°C in deep productive formations. | Approximately 2,000–3,500 m is common for deep targets. | Commercially developed area with brownfield and expansion opportunities. | Confirm mineral and geothermal rights, water and injection permits, hazardous-material rules, air permits, land access, and power interconnection. | Very high salinity, silica scaling, corrosion, subsidence, induced seismicity, air emissions, and brine-handling risk. | Moderate–high Strong heat resource but technically demanding fluids and infrastructure. | Obtain independent tests for scaling, corrosion, injectivity, brine chemistry, and net power after parasitic loads. | U.S. land and geothermal regulator |
| 6 | Larderello–Travale Geothermal District | Italy Tuscany | Historic high-temperature system with steam-dominated and mixed-fluid characteristics. | Approximately 200–350°C depending on depth and sector. | Approximately 1,500–4,000 m for commercial wells. | Very mature geothermal district with brownfield optimization and life-extension potential. | Check concession duration, production limits, grid rules, environmental authorization, cultural-landscape constraints, and closure obligations. | Hydrogen sulfide, subsidence, emissions, landscape protection, seismic monitoring, and reinjection or condensate management. | Moderate–high Reliable infrastructure but limited greenfield upside and mature-asset risk. | Review remaining concession life, historical output, maintenance backlog, and decommissioning liabilities. | Italian environmental and energy authority |
| 7 | Tiwi Geothermal Area | Philippines Bicol Region | High-temperature volcanic resource with established electricity-generation history. | Approximately 250–330°C in productive zones. | Approximately 1,500–3,000 m. | Mature field with potential for rehabilitation, additional drilling, and equipment modernization. | Confirm geothermal service-contract rights, environmental compliance certificates, ancestral-domain or community issues, grid arrangements, and water permits. | Watershed protection, acid fluids, hydrogen sulfide, typhoon exposure, reinjection, and community consultation. | Moderate–high Good resource base, balanced by brownfield and regulatory execution risk. | Verify well integrity, production decline, steam-field bottlenecks, and the legal transferability of operating rights. | Philippine energy department |
| 8 | Wayang Windu Geothermal Area | Indonesia West Java | High-temperature volcanic resource in a densely developed geothermal province. | Approximately 230–300°C. | Approximately 1,500–3,500 m. | Commercially developed field with potential for infill drilling and asset optimization. | Review geothermal working-area rights, forestry or protected-area approvals, land acquisition, power-purchase arrangements, and local-content requirements. | Forest and watershed impacts, slope stability, biodiversity, resettlement, brine handling, and induced seismicity. | Moderate–high Large national market and resource depth, with complex land and licensing matters. | Confirm forest-use permissions, social-license status, transmission capacity, and sustainable reservoir drawdown. | Indonesian energy and mineral authority |
| 9 | Los Humeros Geothermal Area | Mexico Puebla–Veracruz volcanic belt | High-temperature volcanic system with electricity-generation potential and extensive exploration history. | Approximately 250–350°C in deep reservoirs. | Approximately 1,500–3,500 m. | Developed field with redevelopment, make-up drilling, and reservoir-management opportunities. | Check federal geothermal permits, water rights, land tenure, indigenous consultation, environmental impact authorization, and grid access. | Acid gas and brine chemistry, seismicity, water competition, land disturbance, and community engagement. | Moderate Strong temperatures but requires careful technical and social due diligence. | Request recent pressure-temperature surveys, well tests, production history, and independent estimates of remaining reserves. | Mexican energy authority |
| 10 | Hatchobaru–Kuju Geothermal District | Japan Kyushu | High-temperature volcanic resource suitable for base-load electricity and direct-use heat. | Approximately 200–300°C. | Approximately 1,000–3,000 m. | Established geothermal district with further development constrained in some areas by land-use and stakeholder considerations. | Review hot-spring rights, national-park restrictions, drilling permissions, land access, local consultation, and electricity-market rules. | Hot-spring interference, volcanic hazards, landscape protection, seismicity, water use, and tourism-related impacts. | Moderate Reliable resource and strong technical standards, but stakeholder risk can be significant. | Conduct a hot-spring interference study, confirm community agreements, and examine restrictions on well locations and production rates. | Japanese economy and energy authority |