The world largest geothermal facilities generate hundreds of megawatts each from wells drilled into hot underground reservoirs. This guide ranks the 15 largest operational fields and plants, covering The Geysers, Cerro Prieto, Larderello, and the Southeast Asian giants.
Ranking notes
Geothermal facilities are counted differently across sources. Some rankings use single plants; some use whole fields. Here we combine both approaches with a preference for field level totals where multiple plants share one reservoir.
The list
| Rank | Field or plant | Country | Capacity (MW) |
|---|---|---|---|
| 1 | The Geysers (field) | US (California) | ~700 to 900 |
| 2 | Larderello (field) | Italy | ~800 |
| 3 | Cerro Prieto (field) | Mexico | ~720 |
| 4 | Olkaria (field) | Kenya | ~800 |
| 5 | Sarulla | Indonesia | 330 |
| 6 | Wayang Windu | Indonesia | 227 |
| 7 | Malitbog | Philippines | 230 |
| 8 | Tiwi (complex) | Philippines | ~300 |
| 9 | Hellisheidi | Iceland | 303 |
| 10 | Palinpinon | Philippines | 192 |
| 11 | Kizildere | Turkey | 260 |
| 12 | Coso | US (California) | ~270 |
| 13 | Salton Sea | US (California) | ~325 combined |
| 14 | Kamojang | Indonesia | ~200 |
| 15 | Kawerau | New Zealand | ~150 |
The Geysers
The Geysers in Northern California is the largest single geothermal field globally. Historically over 2 GW of capacity was installed; some units have retired but around 700 to 900 MW currently operates. Operated by Calpine and other developers. The field has been generating continuously since 1960.
Larderello
Larderello in Tuscany is the historical birthplace of geothermal power generation, in continuous operation since 1904. The field spans multiple plants totalling around 800 MW. Operated by Enel Green Power.
Cerro Prieto
Cerro Prieto in Baja California, Mexico produces around 720 MW from multiple flash steam units. Operated by state owned CFE. The field has been producing since 1973 and remains one of the largest single reservoir developments.
Olkaria
Olkaria in Kenya has grown steadily to around 800 MW across multiple plants. It supplies a substantial share of Kenya national grid. Operated by KenGen. Represents the East African Rift geothermal potential.
Southeast Asian giants
Sarulla, Wayang Windu, Malitbog, Palinpinon, and Kamojang together represent the concentration of geothermal generation in Indonesia and the Philippines. Both countries sit on the Pacific Ring of Fire.
High capacity factor
All top 15 fields operate at 75 to 90 percent capacity factor. This means 700 MW of geothermal generates the same annual electricity as roughly 2 GW of solar. Base load characteristic makes each MW extraordinarily productive.
Typology by technology
| Technology | Where in top 15 |
|---|---|
| Dry steam | The Geysers, Larderello |
| Flash steam | Cerro Prieto, Olkaria, Wayang Windu, Sarulla |
| Binary and combined cycle | Some Turkish, some newer additions |
Ongoing expansion
Several of the top 15 have expansion plans: Olkaria continuing growth, Larderello continued renewal, Cerro Prieto and Malitbog considering additions. New commercial EGS pilots may enter the top ranks by 2030.
Global context
Future rankings
Expect Olkaria and Indonesian fields to grow. EGS pilots may enter the ranks in the late 2020s or early 2030s. New Ethiopian projects could add hundreds of MW. Iceland Krafla continues incremental growth. See the International Geothermal Association for pipeline tracking.
Frequently asked questions
What is the largest geothermal facility?
The Geysers field in California at roughly 700 to 900 MW currently operational.
How is size measured?
Installed MW capacity. Some rankings use annual generation instead.
Are these all base load?
Yes, geothermal is dispatchable base load.
Do fields lose capacity over time?
Some do if extraction exceeds reservoir recharge. Managed sustainably they can produce for decades.
Are these the same as EGS?
No. Top 15 use natural reservoirs. EGS uses enhanced systems in hot dry rock; still in pilot scale.
Where can I see facility data?
The UtilityRadar directory lists geothermal plants globally.
How long has The Geysers operated?
Since 1960 continuously.
Which country has most of top 15?
US, Indonesia, and Philippines share several entries each.
Are there any European entries?
Larderello in Italy and Hellisheidi in Iceland.
What is the next likely addition?
Watch Olkaria expansion, Sarulla expansion, and Ethiopian pipeline projects.
Summary
The world 15 largest geothermal facilities combine roughly 6 GW of capacity across the US, Italy, Mexico, Kenya, Indonesia, Philippines, and Iceland. The Geysers field leads at around 700 to 900 MW. Southeast Asia is the largest regional concentration. All operate as base load, generating disproportionate electricity per MW. Growth focus is on Indonesian, Kenyan, and future EGS additions to the ranking.
Next reading
- How many geothermal plants in the world
- Geothermal energy explained
- Geothermal countries lead
- Browse the UtilityRadar directory
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