Earth's heat: Across the Earth
The Ring of Fire, the Rift Valley and Iceland
The Ring of Fire, the Rift Valley and Iceland What this tab covers How the resource varies with latitude, climate, terrain and geology: the richest and poorest regions and the leading countries.High-temperature geothermal resources cluster along plate boundaries and volcanic zones, especially the Pacific Ring of Fire, the East African Rift, Iceland and the Mediterranean. Elsewhere only low-temperature heat is accessible at reasonable depth.
Heat flow is higher under young oceanic crust than under old continents, but what matters for use is where hot fluid comes close to the surface: volcanic arcs, rifts and hotspots. Latitude and climate play no role.
Rich and poor regions
| Region | Resource | Level |
|---|---|---|
| United States (western states, The Geysers) | 3,953 MW installed, end 20259 | high |
| Indonesia and the Philippines (Pacific Ring of Fire) | 2,742 MW and 2,034 MW9 | high |
| East African Rift (Kenya) | 980 MW9 | high |
| Iceland (mid-Atlantic ridge) | 808 MW of power capacity, end 20259 | high |
| Average continental crust | 70.9 mW/m2 heat flow, against 105.4 mW/m2 for oceanic crust3 | low |
Top countries by installed geothermal power capacity 2025 9
| Country | MW |
|---|---|
| United States | 3,953 |
| Indonesia | 2,742 |
| Philippines | 2,034 |
| Turkiye | 1,797 |
| New Zealand | 1,259 |
| Kenya | 980 |
| Mexico | 976 |
| Italy | 916 |
| Iceland | 808 |
| Japan | 607 |
Capacity figures differ by source. ThinkGeoEnergy counts 17,173 MW of installed geothermal power capacity at the end of 2025; REN21 puts end-2024 capacity at about 15.1 GW. A year of growth explains only part of the gap: REN21 warns that capacity values are highly uncertain because reporting is not standardised, and some countries report nameplate rather than achievable capacity. The US, listed at 3,953 MW by ThinkGeoEnergy, had 4.0 GW of nameplate but only 2.7 GW of net operable capacity at end 2024.
Direct heat use has a different geography: China leads by far with an estimated 603 PJ in 2024, followed by Turkiye (about 106 PJ) and Iceland (36.3 PJ in 2023), mostly from moderate-temperature water for heating and bathing.
Sources
- Earth's internal heat budget Wikipedia, 2025
- Global top 10 geothermal power countries at year-end 2025 ThinkGeoEnergy, 2026