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Leading Geothermal Power Stations by Capacity

Leading Geothermal Power Stations by Capacity

Energy & ResourcesJuly 21, 2026

Electricity generation from geothermal sources is a distinctive process. Unlike wind turbines or solar panels, geothermal energy harnesses the Earth’s deep heat, accumulated over geological timescales, to supply power to urban areas. The warmth near geothermal vents highlights an often-overlooked aspect in energy discussions: geothermal energy serves not only as a power source but also as a tangible link between human society and the planet.

This article is intended for data-oriented readers, including statisticians, energy analysts, and students interested in understanding the existence, significance, and scale of geothermal power stations. It examines the ten largest geothermal power stations by installed capacity, explores the unique characteristics of each, and provides an overview of the eighteen countries leading in geothermal energy development. While the accompanying infographic presents a concise ranking, the article offers additional context and analysis beyond the raw data.

The subsequent sections present the analysis.

What Is Geothermal Power, and Why Does It Matter?

Prior to presenting the rankings, it is important to clarify the subject and its relevance. Geothermal power refers to electricity generated from heat stored beneath the Earth’s surface. This heat originates from the planet’s formation and the decay of minerals deep underground, manifesting as hot water, steam fields, and volcanic activity near tectonic plate boundaries. Engineers extract steam or hot water through drilled wells, which then drives turbines to generate electricity. This process produces a continuous power supply, independent of weather or seasonal variations.

This reliability distinguishes geothermal energy from solar and wind sources. According to the International Energy Agency, global geothermal plants operated at over 75% capacity on average in 2023, compared to less than 30% for wind and under 15% for solar photovoltaic systems. Some modern geothermal facilities achieve capacity factors exceeding 90%. For example, a 300 MW geothermal plant can generate more annual electricity than a 1,000 MW solar farm, underscoring geothermal’s efficiency.

By 2022–2023, global geothermal capacity reached approximately 16,318 MW, distributed across 32 countries, 198 geothermal fields, and 673 power units. Flash-type units constitute about 53% of this capacity, while binary Organic Rankine Cycle (ORC) units represent approximately 25%. Although geothermal power accounts for only 0.34% of global electricity production, it remains a reliable and climate-friendly source. Since 1980, geothermal capacity has increased nearly eightfold, from 2,110 MW to over 16,318 MW in 2023, reflecting consistent growth despite greater attention to solar and wind energy.

The Top 10 Geothermal Power Stations: A Statistical Overview

The accompanying infographic ranks the world’s leading geothermal power stations by installed nameplate capacity. The data are sourced from Wikipedia’s compilation of major geothermal facilities and include the following stations:

1	The Geysers	USA	1,517
2	Cerro Prieto	Mexico	820
3	Larderello	Italy	769
4	Olkaria	Kenya	727
5	Makiling–Banahaw (MakBan)	Philippines	458
6	Sarulla	Indonesia	330
7	Tiwi	Philippines	330
8	Hellisheiði	Iceland	303
9	Coso	USA	270
10	Imperial Valley	USA	403.4

Note: Rankings in this article follow the order presented in the source infographic. Imperial Valley’s 403.4 MW capacity places it ahead of Coso in absolute terms; its position in the list reflects the source ranking sequence.

These ten stations represent some of the largest geothermal power centers globally, spanning four continents, six countries, and more than a century of engineering development. The following sections examine each facility in detail.

1. The Geysers, California, USA — 1,517 MW

The Geysers represents the world’s largest developed geothermal field by a significant margin. Located in the Mayacamas Mountains, approximately 72 miles north of San Francisco, it spans about 30 square miles across Sonoma, Lake, and Mendocino counties. The presence of eighteen power plants emitting white steam from the hillsides creates a visually striking landscape, evoking the impression of the earth itself exhaling.

The numbers here are staggering. The facility draws steam from more than 350 wells, and the nameplate capacity stands at 1,517 MW — meaning, at peak theoretical output, The Geysers could power a significant portion of the San Francisco Bay Area on its own. In practice, operated by Calpine Corporation, the complex produces approximately 725 MW on a sustained basis, which is still enough to power a city the size of San Francisco. It supplies about 50% of California’s in-state geothermal power and provides reliable baseload electricity to the Northern California grid day in, day out.

The history of The Geysers is closely linked to the broader development of geothermal energy. Commercial power generation commenced in the early 1960s, reaching a capacity of 82 MW by 1968. During the 1970s, wells were drilled to depths of 7,000 to 8,000 feet. The field reached its peak in the late 1980s at approximately 2,000 MW, but production declined as reservoir pressure decreased. Engineers addressed this by injecting about 20 million gallons of treated municipal wastewater daily into the reservoir, which both recharged the steam field and assisted local communities in managing wastewater. This approach exemplifies circular resource management within the energy sector.

One of the unique features of The Geysers is that it is one of only two places in the world where high-temperature dry steam exists naturally and can be used directly to drive turbines. Most geothermal systems produce hot water that must be converted to steam or used in binary cycle systems. At The Geysers, the dry steam comes up ready to use. This simple setup, thanks to geological luck, is a key reason this site was among the first in the world to be used for commercial electricity generation.

Eight Key Facts: The Geysers, USA

The Geysers is the world’s largest developed geothermal field, spanning approximately 30 square miles in Northern California’s Mayacamas Mountains.
It comprises 18 active geothermal power plants drawing steam from more than 350 wells drilled to depths of up to 8,000 feet.
The facility’s nameplate installed capacity is 1,517 MW, making it larger than the next four ranked stations combined.
Calpine Corporation operates the complex, which provides approximately 50% of California’s entire in-state geothermal electricity generation.
Commercial power production at The Geysers dates to the early 1960s, making it one of the oldest continuous commercial geothermal operations in the world.
Approximately 20 million gallons of treated municipal wastewater are injected daily into the reservoir to sustain steam pressure and recharge the underground resource.
The Geysers is one of only two known sites globally where high-temperature dry steam exists naturally near the surface, enabling direct turbine driving without flash conversion.
Peak capacity at The Geysers reached approximately 2,000 MW in the late 1980s before natural reservoir pressure decline necessitated output reduction.

2. Cerro Prieto, Baja California, Mexico — 820 MW

While The Geysers exemplifies American engineering, Cerro Prieto demonstrates how resource availability and sustained commitment can yield equally significant achievements. Situated in the Mexicali Valley of Baja California, just south of the US-Mexico border, Cerro Prieto is located in one of North America’s most geologically active regions. It is the world’s largest geothermal power station by physical size and the second-largest by energy output, with an installed capacity of 820 MW.

Operated by CFE, the Comisión Federal de Electricidad, which is the largest electricity company in Latin America, Cerro Prieto has been in continuous operation since 1973. That is over five decades of uninterrupted geothermal production. The complex comprises five individual units — known simply as CP1 through CP5 — built progressively between 1973 and 2000. The reservoir beneath Cerro Prieto is a water-dominated system, meaning it produces hot pressurized brine rather than dry steam; this makes it technically different from The Geysers but no less impressive in scale. In fact, with more than 175 wells drilled, Cerro Prieto has historically been described as the largest known water-dominated geothermal reservoir in the world.

What makes Cerro Prieto particularly meaningful from a statistical standpoint is its role in Mexico’s energy mix and its geography. The plant sits in an area where the Pacific and North American tectonic plates interact, creating extraordinarily high geothermal gradients very close to the surface. Engineers have been able to develop this resource with comparatively shallow wells, which reduces drilling costs and project timelines. CFE’s commitment to preserving environmental standards while supplying power has also made Cerro Prieto something of a regional model for responsible geothermal development in Latin America.

Eight Key Facts: Cerro Prieto, Mexico

Cerro Prieto has been in continuous operation since 1973, making it one of the oldest large-scale geothermal complexes in the Western Hemisphere.
The facility comprises five individual generating units (CP1 through CP5), constructed progressively between 1973 and 2000.
With an installed nameplate capacity of 820 MW, Cerro Prieto ranks as the world’s second-largest geothermal energy producing complex by output.
The plant is operated by CFE (Comisión Federal de Electricidad), the largest electricity utility in Latin America.
Cerro Prieto is located in the Mexicali Valley of Baja California, at the boundary of the Pacific and North American tectonic plates, which is one of the most geologically active zones on Earth.
Its reservoir is classified as a water-dominated hydrothermal system, the largest known of its kind in the world, with over 175 wells drilled over its operational history.
The complex’s effective operating capacity is approximately 570 MW due to natural reservoir pressure decline over decades of production.
Cerro Prieto’s location makes it a critical baseload anchor for Baja California’s electricity grid, supplying clean renewable energy to one of Mexico’s fastest-growing border regions.

3. Larderello, Tuscany, Italy — 769 MW

Larderello is not merely a geothermal power station; it is the birthplace of geothermal electricity. On May 8, 1818, Francesco Larderel initiated the first industrial use of geothermal energy in Tuscany. In 1904, Prince Ginori Conti conducted the first experiment to generate electricity from natural steam, successfully lighting five bulbs and marking a pivotal moment in energy history. Commercial power generation commenced in 1913, and the site has provided electricity for over a century.

Today, Larderello remains one of the most productive geothermal complexes on the planet, with an installed capacity of 769 MW. Italy operates 33 to 34 active geothermal plants concentrated entirely in Tuscany — in the provinces of Grosseto, Pisa, and Siena — and Larderello is the heart of that system. The province of Pisa alone contributes more than half of Italy’s national geothermal production. Geothermal power accounts for approximately 1.6% to 1.8% of Italy’s total electricity production and about 7% of all renewable energy the country generates. Geothermal technology was essentially born here, and Italy’s continuous refinement of that technology over 120 years has produced lessons that the entire world continues to learn from.

When you look into Larderello, you get a strong sense of continuity, as if a civilization has worked with its own geology for generations. New closed-loop systems being developed could lower the cost of geothermal electricity to $30–50 per MWh by 2050, making it competitive with other renewables. Italy’s PNIEC (National Integrated Energy and Climate Plan) aims for an extra 1 GW of geothermal capacity by 2030. The story at Larderello is far from over.

Eight Key Facts: Larderello, Italy

Larderello is the world’s oldest continuously operated geothermal power site, with industrial use of geothermal energy dating back to 1818.
The first-ever electricity generated from natural geothermal steam was produced here by Prince Ginori Conti in 1904, initially lighting just five light bulbs.
Commercial geothermal power generation began at Larderello in 1913, more than 45 years before The Geysers began commercial operations in California.
Italy’s geothermal capacity is concentrated entirely in Tuscany, with Larderello at its center; 33 to 34 active plants operate in the Grosseto, Pisa, and Siena provinces.
The complex has an installed capacity of 769 MW, making it the third-largest geothermal power facility in the world by nameplate capacity.
Geothermal energy accounts for approximately 1.6%–1.8% of Italy’s total electricity production and roughly 7% of its total renewable energy output.
The total geothermal energy produced in Italy reached 5,660 GWh in 2015, all from dry steam fields that allow direct turbine driving — the same fundamental technology pioneered here more than 100 years ago.
Italy’s national energy plan targets an additional 1 GW of geothermal capacity by 2030, with emerging closed-loop systems projected to bring costs to $30–50/MWh by 2050.

4. Olkaria, Kenya — 727 MW

Olkaria represents a significant chapter in Africa’s energy history. Located in Hell’s Gate National Park in Kenya’s Rift Valley, near prominent wildlife reserves, the Olkaria geothermal complex has evolved from a small experimental station into a 727 MW facility that has transformed Kenya’s electricity sector. The Olkaria geothermal fields are the second most productive globally, following The Geysers in California.

Kenya’s investment in Olkaria has been systematic and bold. Olkaria I was the first geothermal plant in Africa. Olkaria II was commissioned in 2003. Olkaria IV (150 MW) came online in October 2014 and Olkaria IAU (150 MW) followed, dramatically expanding capacity. The addition of Olkaria V in November 2019 — representing 154 MW (172 MW was the figure cited when it pushed Kenya’s total capacity to approximately 860 MW) — enabled Kenya to overtake Iceland and rank eighth in the world for geothermal power at that time. Today, more than 35% of Kenyan households rely on geothermal power for electricity. The government’s ambition is to achieve 3,000 MW of geothermal capacity by 2030.

From a statistical perspective, Olkaria’s development trajectory is one of the fastest in global geothermal history. What makes it even more extraordinary is the environmental context: these plants operate within a national park, next to grazing wildlife, under the terms of agreements that have tried to balance energy development with ecological preservation. The Ormat Olkaria III plant, the first privately funded geothermal project in Africa, cost USD 445 million across its first three phases — an investment whose returns have been felt far beyond the energy sector, in job creation, rural electrification, and national energy independence.

Eight Key Facts: Olkaria, Kenya

The Olkaria geothermal fields are the second most productive in the world after The Geysers, representing Africa’s most significant geothermal development.
Kenya’s Olkaria complex includes multiple plants (Olkaria I through V) built over several decades, with total installed capacity reaching 727 MW by the period covered in this article.
The addition of Olkaria V in November 2019 pushed Kenya’s total geothermal capacity to approximately 860 MW, enabling the country to overtake Iceland as the world’s eighth-largest geothermal producer.
The Ormat Olkaria III plant was the first privately funded geothermal project in all of Africa, with an initial investment of approximately USD 445 million across its first three development phases.
All of Kenya’s Olkaria geothermal plants are located within or next to Hell’s Gate National Park in the Great Rift Valley, creating a unique mix of heavy industry and wildlife conservation.
More than 35% of Kenyan households now rely on Olkaria-sourced geothermal power for their electricity, a direct result of sustained government and private investment over multiple decades.
Kenya’s national energy plan targets a geothermal production capacity of at least 3,000 MW by 2030, which would represent more than a fourfold increase from current installed figures.
The Olkaria fields sit atop the East African Rift System, one of the planet’s most geologically active continental rifts, giving Kenya access to surface geothermal gradients that are among the highest anywhere in Africa.

5. Makiling–Banahaw (MakBan), Philippines – 458 MW

The Philippines has effectively utilized its geothermal resources, exemplified by the Makiling–Banahaw Geothermal Power Plant (MakBan), a 458 MW complex spanning Laguna and Batangas provinces in Luzon. Operational since 1979, MakBan is among Asia’s earliest large-scale commercial geothermal projects. Currently operated by AP Renewables, it ranks as the fourth-largest geothermal facility globally.

The MakBan complex sits in the shadow of Mount Banahaw, a dormant stratovolcano, and draws from a hydrothermal system that has proven remarkably productive over four-plus decades. What is particularly striking about MakBan from a data standpoint is what it represents alongside its sister plant, Tiwi (330 MW): together, these two Philippine facilities account for approximately 15% of the power supply to Luzon’s electricity grid — the grid that serves the Philippines’ most populous and economically vital island. In a country of 7,000-plus islands with a rapidly growing economy and population, that kind of baseload contribution from a carbon-free source is genuinely remarkable.

The Philippines as a nation has consistently ranked in the top three global geothermal producers by installed capacity, and MakBan is a cornerstone of that achievement. The Asian Development Bank recognized the significance of these facilities by supporting the Philippines’ first-ever green bond issuance — a $225 million-equivalent bond by AboitizPower’s AP Renewables — to finance operations, maintenance, and expansion at both Tiwi and MakBan. The Philippines government aimed to boost geothermal capacity by 70% by 2030.

Eight Key Facts: MakBan, Philippines

The Makiling–Banahaw (MakBan) complex is the world’s fourth-largest geothermal facility, with a nameplate capacity of 458 MW located across Laguna and Batangas provinces on Luzon.
Commercial operations at MakBan began in 1979, making it one of the oldest continuously operating major geothermal power stations in Asia.
The plant is operated by AP Renewables (a subsidiary of AboitizPower) and draws thermal energy from the geothermal system beneath Mount Banahaw, a dormant stratovolcano.
MakBan and Tiwi together supply approximately 15% of the electricity to the Luzon grid, making them collectively critical to the Philippines’ most populous island’s power security.
A landmark green bond transaction — the first green bond in Philippine financial history — raised $225 million to finance operations and expansion of MakBan and Tiwi, supported by an ADB guarantee.
MakBan is located in one of the most geologically rich geothermal corridors in Southeast Asia, benefiting from the Philippines’ position on the Pacific Ring of Fire.
The Philippines consistently ranks among the world’s top three nations by geothermal installed capacity, and MakBan has been a central driver of that standing since the late 1970s.
The Philippine government set a target to boost geothermal capacity by 70% by 2030, reflecting the strategic importance of facilities like MakBan to the country’s long-term energy security and decarbonization goals.

6. Sarulla, North Sumatra, Indonesia — 330 MW

Sarulla exemplifies the new generation of geothermal projects. Unlike The Geysers and Larderello, which have extensive operational histories, Sarulla is a 21st-century development. It was designed, financed, and constructed using modern integrated geothermal combined-cycle technology to maximize resource utilization. Located in North Tapanuli, North Sumatra, the 330 MW Sarulla Geothermal Power Plant commenced full commercial operation in May 2018, following construction that began in 2014. It is among the largest geothermal plants constructed under a single contract worldwide.

The numbers behind Sarulla’s development are worth examining closely. The project cost approximately $1.7 billion and is owned by a consortium of five companies: Kyushu Electric Power (25%), Itochu (25%), PT Medco Power Indonesia (18.99%), INPEX (18.25%), and Ormat International (12.75%). That mix of Japanese, Indonesian, and American companies reflects the genuinely international character of modern large-scale geothermal development. The plant comprises three 110 MW generating units — one at the Silangkitang (SIL) reservoir in Pahae Jae and two at the Namora-I-Langit (NIL) reservoir in Pahae Julu — connected into a single operational system. It can generate enough electricity to power approximately 2.1 million Indonesian households and offsets approximately 1.3 million tonnes of CO₂ emissions annually.

What makes Sarulla especially important in the global context is what it represents for Indonesia’s extraordinary untapped potential. Indonesia has the world’s largest identified geothermal resource — potential capacity of approximately 29 GW. Yet less than 5% of that potential has been utilized. Sarulla, massive as it is, barely scratches the surface. The electricity generated at Sarulla is sold to PLN (Perusahaan Listrik Negara), the Indonesian state electricity company, under a 30-year power purchase agreement — a commercial structure that can serve as a template for hundreds more projects like this across the Indonesian archipelago.

Eight Key Facts: Sarulla, Indonesia

The 330 MW Sarulla Geothermal Power Plant in North Tapanuli, North Sumatra, is one of the largest geothermal developments completed under a single commercial contract in global energy history.
Construction began in May 2014 and full commercial operation was achieved in May 2018, with three 110 MW units commissioned sequentially over that four-year period.
The project cost approximately $1.7 billion and is owned by a five-company international consortium including Kyushu Electric Power, Itochu, Medco Power, INPEX, and Ormat International.
Sarulla generates sufficient electricity to power approximately 2.1 million Indonesian households and offsets an estimated 1.3 million tonnes of CO₂ emissions per year.
The plant uses an integrated geothermal combined-cycle (IGCC) concept developed by Ormat, drawing from two separate geothermal reservoirs: Silangkitang (SIL) and Namora-I-Langit (NIL).
Indonesia has the world’s largest geothermal resource potential at about 29 GW, but less than 5% of this has been developed. This makes Sarulla a milestone in a much longer national development story.
Electricity generated at Sarulla is sold to PLN, the Indonesian state electricity company, under a 30-year power purchase agreement — a commercial structure designed to provide investor certainty and long-term grid stability.
By the end of 2025, Indonesia’s total installed geothermal capacity reached 2,742 MW, making it the world’s second-largest geothermal power producer and the fastest-growing major geothermal market globally.

7. Tiwi, Albay, Philippines — 330 MW

Tiwi is recognized as Asia’s oldest continuously operating commercial geothermal field. Located at Mount Malinao in Albay Province, approximately 350 km southeast of Manila, Tiwi has generated electricity since May 1979, coinciding with the commissioning of MakBan. In 1982, Tiwi became the world’s first water-dominated geothermal system to surpass 160 MW of electricity production, demonstrating the industrial-scale potential of hot-water-dominated reservoirs.

Today, after decades of production, Tiwi’s installed capacity stands at approximately 234 MW across four generating units (Wikipedia’s figure from December 2021), though its listing in the top-10 infographic at 330 MW reflects the broader Tiwi geothermal field’s historical nameplate and contractual capacity figures. Operated by AP Renewables, Tiwi sits atop one of the Philippines’ richest hydrothermal systems, and its longevity speaks to the remarkable sustainability of well-managed geothermal resources. More than 40 years of continuous commercial production. That is not just impressive — it is proof of concept for the long-term viability of geothermal as a permanent element of a clean energy system.

The Tiwi field’s exploration agreement dates to 1971. The first exploratory well, Naglagbong-1, was completed in June 1972. Pilot operations transitioned into full commercial activity just seven years later — a relatively short development timeline for a project of this scale in that era. Tiwi and MakBan, though separated by hundreds of kilometers, form a complementary pair in the Philippines’ energy portfolio, and their combined contribution to Luzon’s grid has provided a baseload foundation that has enabled the archipelago’s economic growth for generations.

Eight Key Facts: Tiwi, Philippines

Tiwi is Asia’s oldest continuously operating commercial geothermal field, with pilot operations beginning in 1970 and full commercial power generation commencing in May 1979.
In 1982, Tiwi became the world’s first water-dominated geothermal system to exceed 160 MW of electricity production, a groundbreaking milestone in geothermal engineering.
The plant is located at Mount Malinao in Albay Province, Philippines, approximately 350 km southeast of Manila, and sits on one of the most productive hydrothermal systems in Southeast Asia.
Tiwi’s exploration contract dates to 1971, with the first exploratory well completed in 1972 — a development timeline that moved from discovery to commercial production in less than a decade.
Operated by AP Renewables, Tiwi has now delivered more than four decades of continuous commercial geothermal power generation, making it one of the longest-running geothermal operations in Asia.
Together with MakBan, Tiwi supplies approximately 15% of the electricity to the Luzon grid, collectively representing the Philippines’ most important geothermal baseload contribution.
The Tiwi plant currently operates four generating units, and the site has been sustained through decades of reservoir management, steam field maintenance, and progressive upgrades to turbine and control systems.
The Philippines’ geothermal sector — including Tiwi — directly benefits from the country’s location on the Pacific Ring of Fire, which provides extraordinarily high subsurface heat gradients within reachable drilling depths.

8. Hellisheiði, Iceland — 303 MW

Iceland exemplifies a society deeply integrated with geothermal energy. Nearly every building in Reykjavík is heated by geothermal sources, and the nation generates the majority of its electricity from renewables. Energy innovation is central to Iceland’s national identity. Within this context, the Hellisheiði Power Station, the largest geothermal plant in Iceland, serves as a testament to the potential of comprehensive resource utilization.

Located at Hengill in southwest Iceland, approximately 20 km from central Reykjavík, Hellisheiði is a combined heat and power (CHP) facility that generates 303 MW of electrical power along with approximately 200 MWth to 400 MWth of thermal energy for district heating. The plant was commissioned in five phases between 2006 and 2011, operated by ON Power (formerly known as Orkuveita Reykjavíkur). The electricity primarily serves aluminum refineries and industrial customers in the capital region. The thermal energy — hot water piped directly to buildings — is what heats one of the most comfortable cold-weather cities on Earth.

Hellisheiði is also the site of one of the world’s most ambitious carbon capture projects. The Orca project, which started at Hellisheiði in September 2021, was the world’s largest direct air carbon capture and storage plant at the time, using geothermal energy to pull CO₂ from the air. It’s impressive—a power plant that not only emits very little carbon (about 5% of what a coal plant would) but also helps remove carbon dioxide from the atmosphere.

Eight Key Facts: Hellisheiði, Iceland

Hellisheiði is the largest geothermal power station in Iceland, generating 303 MW of electrical capacity and between 200–400 MWth of thermal energy for district heating in the Reykjavík metropolitan area.
The plant is a combined heat and power (CHP) facility built in five commissioning phases between 2006 and 2011, operated by ON Power (a subsidiary of Reykjavík Energy).
Hellisheiði is located at the Hengill geothermal system in southwest Iceland, one of the country’s most extensive and active high-temperature geothermal fields.
The facility ranks as the eighth-largest geothermal power station in the world by installed electrical capacity, according to global rankings consistent with the Wikipedia source used in this article.
Hellisheiði produces approximately 5% of the CO₂ emissions that an equivalent coal-fired power plant would generate, making it one of the lowest-carbon baseload generation sources in operation anywhere.
The Orca direct air carbon capture and storage (CCS) project, described as the world’s largest direct air CCS plant when it launched in 2021, began operations at the Hellisheiði site using geothermal energy to power CO₂ extraction from the atmosphere.
The electricity generated at Hellisheiði is primarily supplied to aluminum refineries and heavy industry in the capital region, reflecting Iceland’s strategy of using abundant clean baseload power to support energy-intensive manufacturing.
Iceland added 22 MW of new geothermal capacity nationally in 2025 through an expansion at the Svartsengi plant, bringing the country’s total geothermal capacity to 808 MW by year-end 2025.

9. Coso, California, USA — 270 MW

Inyo County in the eastern Sierra Nevada features a landscape characterized by volcanic hills, dry alkali flats, and the distant Sierra Nevada mountains to the west. Beneath this terrain lies the Coso geothermal resource, one of the most productive in the United States. The Coso geothermal project is operated by Coso Operating Company on land leased from the U.S. Navy at the China Lake Naval Weapons Center, representing a distinctive partnership in American energy development.

The Coso facility consists of four separate but interconnected geothermal power plants comprising nine generating units. Its nameplate capacity reaches 270 MW, as reflected in the infographic, though current net output is approximately 135 MW — the difference reflecting decades of natural reservoir decline that is characteristic of all mature geothermal fields. At its peak, Coso was delivering around 270 MW. Even at current production levels, it is the third-largest geothermal plant in the United States after The Geysers and the Salton Sea-area facilities. The plants were constructed between 1987 and 1989 using approximately 105 production wells that tap into a geothermal reservoir maintained at temperatures reaching 600°F — nearly three times the boiling point of water. That is the kind of thermal intensity that engineers dream about.

Coso supplies power to Southern California Edison and contributes approximately 8% of the entire geothermal power generated in the United States. Given what geothermal provides to California’s decarbonization goals — reliable, carbon-free baseload — that contribution has significant value well beyond its raw megawatt count. SCPPA (Southern California Public Power Authority) entered into a 20-year Power Purchase Agreement with Coso Geothermal Power Holdings in 2022, achieving a 99% capacity factor in its first partial year of deliveries. The resource beneath Coso continues to be studied and carefully managed, with injection programs designed to sustain long-term productivity.

Eight Key Facts: Coso, USA

The Coso geothermal project in Inyo County, California, consists of four interconnected power plants with nine generating units on land leased from the U.S. Navy at China Lake.
At peak production, Coso has generated as much as 270 MW of electricity — sufficient to supply approximately 250,000 homes — though current net output is approximately 135 MW.
The Coso plants were constructed between 1987 and 1989, with the first unit going online in May 1987, and operate on a geothermal reservoir maintained at temperatures reaching 600°F.
Coso is the third-largest geothermal plant in the United States by capacity, after The Geysers in Northern California and the Imperial Valley complex in the southern part of the state.
Approximately 105 production wells tap the underground reservoir, which has been in continuous operation for nearly four decades through careful reservoir management and injection programs.
Coso supplies electricity to Southern California Edison and contributes approximately 8% of the total geothermal power generated across the entire United States.
A 20-year Power Purchase Agreement between the Southern California Public Power Authority (SCPPA) and Coso Geothermal Power Holdings, beginning in January 2022, delivered a 99% capacity factor in its first partial year of operation.
Coso is located within the Long Valley Caldera system, one of the largest volcanic systems in North America. This gives it access to geothermal gradients that are exceptional, even by California standards.

10. Imperial Valley, California, USA — 403.4 MW

The final entry in the top ten returns to California, specifically the Imperial Valley in the southeastern part of the state, adjacent to the Salton Sea—a terminal lake recognized for its unique characteristics. Beneath the silty, mineral-rich sediments of this lake lies one of the most significant geothermal resources globally. The Imperial Valley Geothermal Project is a complex of eleven geothermal power stations located in the Salton Sea Geothermal Field, collectively generating approximately 403.4 MW of installed capacity. Ten of these plants are owned by BHE Renewables and one by EnergySource. The field’s total estimated geothermal potential is a staggering 2,950 MW, of which approximately 2,250 MW is currently developable. That means the existing 403.4 MW of installed capacity represents only about 14% of what this single resource could theoretically produce. The annual net output of this field is approximately 1,741 GWh.

What makes Imperial Valley increasingly important is not just its electricity production but also its brine chemistry. The geothermal brines beneath the Salton Sea are extremely rich in dissolved lithium, the metal used in electric vehicle batteries, grid storage systems, and the global shift to clean energy. The U.S. government estimates that this single geothermal field could yield 600,000 metric tons of lithium. Companies like Controlled Thermal Resources are planning new geothermal plants in northern Imperial County that would produce 600 MW of electricity and extract lithium for large-scale battery manufacturing and data center power. The future of this resource may be as much about minerals as electricity, making Imperial Valley one of the most strategically important energy sites in the world.

Eight Key Facts: Imperial Valley, USA

The Imperial Valley Geothermal Project is a complex of eleven power stations located in the Salton Sea Geothermal Field, with a combined installed capacity of approximately 403.4 MW.
It is the second-largest geothermal field in the United States by capacity, after The Geysers in Northern California, and generates approximately 1,741 GWh of electricity annually.
Ten of the eleven plants are owned by BHE Renewables (a Berkshire Hathaway subsidiary) and one by EnergySource, reflecting significant private-sector investment in California’s renewable energy base.
The Salton Sea Geothermal Field has an estimated total geothermal potential of 2,950 MW, of which approximately 2,250 MW is currently developable — meaning only about 14% of the field’s potential has been tapped so far.
The geothermal brines beneath the Salton Sea are estimated to contain approximately 600,000 metric tons of lithium — enough to make this single site potentially one of the most important lithium sources in the United States.
Companies including Controlled Thermal Resources are planning up to 600 MW of new geothermal capacity in northern Imperial County, partly aimed at powering large-scale data centers and supporting AI computing infrastructure.
The earliest plants in the Imperial Valley complex began operation in 1982, with the A.W. Hoch plant (45.5 MW) commissioned in 1989 — making this one of California’s longest-running commercial geothermal developments.
Imperial Valley’s potential combination of clean electricity generation and domestic lithium extraction positions it as one of the most strategically valuable energy resource sites in the United States, sitting at the intersection of geothermal power and the electric vehicle supply chain revolution.

Why This All Matters: The Statistical Case for Geothermal’s Future

This review has encompassed a broad range of geographic regions and technical information, from Northern California to Kenya’s Rift Valley, and from Tuscany’s historic steam fields to Sumatra’s geothermal developments. The question remains: what do these data indicate about the future of geothermal energy? Several key statistics illustrate geothermal energy’s potential. Since 1980, global geothermal capacity has increased nearly eightfold. According to the International Energy Agency (IEA), geothermal plants operated at over 75% capacity on average in 2023, compared to less than 30% for wind and under 15% for solar photovoltaic systems. Despite this, geothermal energy accounts for only about 0.34% of global electricity production—a relatively small share given its potential. The IEA reports that “the full technical potential of next-generation geothermal systems to generate electricity is second only to solar PV among renewable technologies and sufficient to meet global electricity demand 140 times over.”

While achieving 140 times the world’s electricity demand is a technical limit rather than a practical objective, this figure underscores geothermal energy’s vast potential. Geothermal is not merely a niche or local resource; it is a global asset that remains largely underutilized. Currently, ten countries account for 93% of global capacity, primarily due to financial and institutional barriers rather than resource scarcity. Should next-generation geothermal costs decrease by 80% by 2035, enabling new plants to compete at approximately $50 per MWh, a broader range of countries could emerge as leaders in geothermal development.

The energy sector is at a pivotal moment: geothermal technology, long recognized for its practicality, is now becoming economically viable on a large scale. The top ten power stations highlighted in the infographic represent more than a century of engineering progress. These facilities demonstrate the substantial potential of geothermal resources. The development of geothermal energy is ongoing, with significant advancements anticipated in the future.

Data sourced from Wikipedia’s compilation of Leading Geothermal Power Stations by Capacity, supplemented by IEA, ThinkGeoEnergy, Global Energy Monitor and more.