Top 10 Geothermal Companies Driving Global Clean Energy
By : Robert Buluma
Introduction: Geothermal’s Quiet Renaissance
For decades, geothermal energy has played a secondary role in the global renewable energy narrative—overshadowed by the rapid expansion of solar and wind. But that story is changing. Global geothermal power generation capacity stands at approximately 16.5 GW, with the United States leading at 3.9 GW (roughly 24% of global capacity). Yet this represents less than 10% of the estimated global geothermal potential of roughly 162 GW. The gap between current deployment and technical potential underscores the enormous runway ahead.
What is driving this quiet renaissance? Three forces are converging. First, the surging electricity demand from data centers and AI infrastructure has created an urgent need for round-the-clock, carbon-free baseload power—something only geothermal, nuclear, or fossil fuels with carbon capture can provide. Second, technological breakthroughs in Enhanced Geothermal Systems (EGS) , closed-loop architectures, and AI-optimized drilling are dramatically expanding the geographical reach of geothermal beyond traditional hydrothermal hotspots. Third, supportive policy frameworks—including California’s clean-firm procurement mandates and the U.S. Department of Energy’s EGS demonstration program—are accelerating commercial validation and reducing financing risk.
This article profiles the ten companies most actively shaping the global geothermal landscape in 2026—from established utility-scale operators with decades of experience to next-generation innovators redefining what geothermal wells can achieve.
The Established Giants
Ormat stands as one of the most vertically integrated players in the global geothermal industry. With approximately 1,268 MW of combined geothermal and solar capacity, the company has built its reputation on binary-cycle and Organic Rankine Cycle (ORC) technology—systems that efficiently generate power from lower-temperature geothermal resources that would otherwise remain untapped.
In 2025, Ormat took a decisive step into the next generation of geothermal by partnering with SLB (formerly Schlumberger) to accelerate integrated geothermal asset development and EGS deployment. This brings together Ormat’s power plant expertise with SLB’s subsurface engineering capabilities, positioning the company to compete in the rapidly emerging EGS market.
In terms of market positioning, Ormat is among the top five global players, collectively holding 34% of the market share in 2025. The company’s diversified portfolio—spanning power generation, energy storage, and EGS development—makes it a bellwether for the industry’s transition from conventional hydrothermal projects to engineered geothermal systems.
Calpine operates the world’s largest geothermal power complex—The Geysers, located in Northern California’s Mayacamas Mountains. With an installed capacity of approximately 1,520 MW, The Geysers alone represents nearly 40% of U.S. geothermal capacity and is one of the few dry-steam fields in commercial operation globally.
The Geysers is a remarkable piece of energy infrastructure, producing baseload power continuously for over five decades. In recent years, Calpine has invested in reservoir management innovations, including the injection of treated wastewater to sustain steam pressure and extend the field’s productive life. This kind of resource stewardship has made The Geysers a model for long-term geothermal asset management.
Calpine and Ormat together dominate U.S. geothermal capacity, driving commercial activity through new power purchase agreements. The company’s ability to maintain high capacity factors (around 90% for U.S. geothermal plants) exemplifies why geothermal is increasingly valued in grid planning as a firm, dispatchable renewable resource.
Indonesia sits on some of the most abundant geothermal resources in the world, and Pertamina Geothermal Energy (PGE) is the country’s dominant operator. PGE led the global geothermal market in 2025 with over 10% market share, operating within a national installed base of approximately 2.6 GW.
What makes PGE particularly significant is its role within Indonesia’s broader energy transition strategy. The Indonesian government has set ambitious targets to expand geothermal capacity as part of its efforts to reduce reliance on coal—the nation remains one of the world’s largest coal producers and consumers. PGE is central to this push, managing key fields including Kamojang, one of the oldest geothermal plants in Southeast Asia, as well as newer developments like Ulubelu and Lahendong.
The Asia-Pacific region accounts for approximately 36% of global geothermal capacity, with Indonesia and the Philippines leading the charge. PGE’s growth trajectory is closely tied to supportive government policies that streamline permitting and provide exploration risk mitigation. However, challenges remain: high upfront capital costs and subsurface uncertainty continue to constrain the pace of new project development.
Enel Green Power, the renewable energy arm of Italian utility Enel, maintains a global geothermal portfolio of approximately 800 MW, with assets concentrated in Italy’s Larderello region—the birthplace of commercial geothermal power. Larderello has been generating electricity continuously since 1913, making it the oldest geothermal plant in the world.
Beyond Italy, Enel operates geothermal facilities in the United States (primarily through Enel Green Power North America) and Latin America. The company has also been a pioneer in integrating geothermal with other renewables, combining baseload geothermal with intermittent solar and wind to offer hybrid power solutions.
Enel’s broader significance lies in its scale and financial backing. As one of the world’s largest renewable energy developers, the company brings institutional credibility to geothermal investment. Enel’s continued commitment to geothermal—despite lower returns compared to solar and wind—sends an important signal about the value of dispatchable renewables in a decarbonizing grid.
The Philippines consistently ranks among the top five geothermal producers globally, and Energy Development Corporation (EDC) is the country’s renewable energy powerhouse. EDC is the Philippines’ largest producer of geothermal energy, operating at Leyte, Bacon-Manito, and other major fields.
While precise capacity figures vary, EDC consistently appears among the top five global geothermal companies by market share alongside Pertamina, Ormat, and Calpine. The company has invested heavily in binary-cycle technology to maximize recovery from lower-temperature resources—a strategic move as many of the Philippines’ high-grade hydrothermal fields mature.
What distinguishes EDC is its approach to sustainable operations. The company has pioneered reforestation and watershed management programs around its geothermal fields, recognizing that geothermal reservoirs require careful long-term management of water recharge. This holistic approach to resource stewardship is increasingly being adopted as industry best practice.
6. KenGen (Kenya)
Kenya is the undisputed geothermal leader in Africa, and KenGen (Kenya Electricity Generating Company) is at the heart of that success story. With approximately 1,786 MW of total installed capacity across all technologies and geothermal making up the bulk of that, KenGen generated 8,482 GWh of electricity in 2025, a 1% increase over 2024.
The Olkaria geothermal complex—located within Kenya’s volcanically active Rift Valley—is KenGen’s flagship asset. Current projects include the Olkaria I project (adding 63 MW) with the first turbine expected online by June 2026, and the recently approved Olkaria VII project (80.3 MW) slated for completion by June 2027.
Perhaps most innovative is KenGen’s move beyond electricity generation. In October 2025, KenGen signed a steam supply agreement with Kaishan—a Chinese industrial group—to supply steam for a 165.4 MW geothermal plant that will produce green ammonia and fertilizer. The project, representing approximately $800 million in investment, will produce 100,000 tons of green ammonia annually, expandable to 200,000 tons using purchased grid electricity during off-peak hours. This represents a pioneering model for geothermal-driven green industrial production, turning geothermal heat into not just electricity but low-carbon industrial products.
Kenya is the fastest-growing geothermal market globally, driven by the country’s commitment to expanding baseload renewable capacity and attracting international investment. KenGen’s success demonstrates that geothermal can be a development engine, not just a power source.
The Next-Generation Innovators
7. Fervo Energy (USA)
If any single company embodies geothermal’s technological renaissance, it is Fervo Energy. The Houston-based next-generation geothermal developer has raised over $420 million in non-recourse project financing for its Cape Station project in Utah—one of the largest financing rounds ever for EGS development.
Cape Station is designed to scale to 500 MW, with the first 100 MW expected online by early 2027. The project is fully contracted through power purchase agreements with Southern California Edison, Shell Energy, and community choice aggregators, giving it revenue visibility through the early 2040s. Fervo’s potential IPO, with an estimated price range of $21–$24 per share and a potential contract revenue reserve of approximately $7.2 billion, underscores investor confidence in the EGS business model.
What makes Fervo distinctive is its use of oil-and-gas techniques—horizontal drilling, hydraulic fracturing, and distributed fiber-optic sensing—applied to geothermal reservoir creation. In February 2026, the company announced it had drilled its hottest well yet, confirming reservoir temperatures above 555°F (approximately 290°C) at roughly 11,200 feet depth, achieved in under 11 days using AI-driven subsurface analytics.
Fervo was ranked among the World’s Top GreenTech Companies of 2026, recognized for its breakthrough approach to making EGS commercially viable at scale. Its success is a testament to the power of cross-industry technology transfer—adopting the drilling efficiencies of the oil and gas sector to unlock geothermal’s vast potential.
Mazama Energy is pursuing the industry’s most ambitious technical frontier: superhot rock geothermal. At its pilot site on Newberry Volcano in Oregon, Mazama has already created the world’s hottest EGS reservoir, achieving a bottomhole temperature of 629°F (331°C)—far above the 190–220°C typical of conventional EGS projects.
The technological implications are profound. At superhot temperatures, geothermal power density increases dramatically. Superhot resources allow up to 10 times higher power density, 75% less water usage, and 80% fewer wells compared to conventional approaches. The company expects to reach 750°F (399°C) in 2026, entering the supercritical realm where geothermal fluids behave fundamentally differently and energy extraction becomes even more efficient.
Mazama plans to achieve 15 MW grid-connected generation in 2026, with expansion to 200 MW from the same resource block. The company has already drilled a deviated producer well to approximately 3.2 kilometers, using liquid CO₂ to cool electronic components in the drill string—a novel approach to managing extreme downhole temperatures.
To put Mazama’s achievement in context: the global geothermal industry has no commercially operating wells exceeding 400°C, and previous attempts to drill into superhot formations—in Iceland, Italy, and Japan—were abandoned due to wellbore corrosion, equipment failure, or reservoir instability. If Mazama successfully validates long-term well integrity and heat exchange performance at these temperatures, it could unlock an entirely new class of geothermal resources, potentially making hundreds of gigawatts of power accessible in the United States alone.
Eavor Technologies represents a fundamentally different approach to geothermal—one that eliminates the two biggest risks associated with conventional and EGS projects: induced seismicity and reliance on natural permeability.
Eavor’s patented Eavor-Loop™ system is a closed-loop geothermal architecture. Instead of fracturing rock to create permeability (as in EGS), Eavor drills a network of multilateral wellbores that form a sealed circuit. A proprietary working fluid circulates through this closed loop, extracting heat from surrounding rock via conduction alone. No fluid is injected into the formation, no fractures are created, and the process is entirely independent of geological hotspots—it works virtually anywhere.
Eavor was named “Overall CleanTech Innovation of the Year” in the 2026 CleanTech Breakthrough Awards. The company was also ranked No. 2 among 250 companies on TIME’s World’s Top GreenTech Companies 2026 list. While Eavor’s Geretsried project in Germany faced execution challenges that prevented it from meeting original targets, the company maintains that the project successfully demonstrated that large-scale closed-loop geothermal can generate both heat and electricity—validating core physics even under suboptimal conditions.
Eavor’s technology is particularly well-suited for district heating applications and data center power, where consistent, dispatchable heat and electricity are paramount. By eliminating geological risk entirely, closed-loop systems could dramatically expand geothermal’s addressable market beyond the traditional Ring of Fire to virtually any location with sufficient subsurface temperature at drillable depths.
The tenth spot recognizes a company that is rarely featured in “geothermal developer” lists but is indispensable to industry growth: Toshiba Energy Systems & Solutions. As one of the world’s leading manufacturers of geothermal turbines, Toshiba enables the power plants that other companies operate. The company’s steam turbines are found in geothermal fields across Japan, the United States, Indonesia, and elsewhere.
Alternatively, Cyrq Energy, a private U.S.-based geothermal developer operating primarily in Utah, Nevada, and California, has built a diversified portfolio of conventional and low-temperature geothermal assets. Cyrq has focused on binary-cycle plants and strategic acquisitions—including assets previously owned by U.S. Geothermal and Enel Green Power North America—to scale its operating footprint. The company represents a model of disciplined growth through asset aggregation, demonstrating that geothermal does not always require greenfield exploration to be economically viable.
The Integration of AI and Advanced Drilling
Beyond the individual companies, two underlying trends are reshaping the geothermal landscape.
Artificial intelligence and machine learning are being deployed across the geothermal value chain, from exploration to operations. A portfolio of projects harnesses supervised and unsupervised machine learning to improve exploration, reduce drilling costs, and optimize production. Fervo’s success in using AI-driven subsurface analytics to identify novel geothermal plays and optimize drilling trajectories—achieving a well in under 11 days—illustrates the potential for AI to compress development timelines and reduce subsurface uncertainty.
Meanwhile, advancements in Enhanced Geothermal Systems (EGS) are redefining where geothermal can be developed. Traditional hydrothermal geothermal requires three conditions: heat, permeability, and fluid—typically found only in volcanic regions. EGS, by contrast, creates its own permeability through engineered fracturing, dramatically expanding the geographical reach of geothermal. Five core technical domains define next-generation geothermal well technology: EGS and hydraulic fracturing of hot dry rock; novel closed-loop architectures; supercritical and ultra-deep drilling; repurposing of legacy oil and gas wells; and downhole pump innovations.
Economics and Market Outlook
The economic case for geothermal is strengthening. The global weighted-average levelized cost of electricity (LCOE) for geothermal fell 16% in 2024, from $0.072/kWh to $0.060/kWh. For next-generation EGS, costs are projected to decline further: EGS LCOE could reach $50/MWh within 10–15 years.
The broader geothermal energy market—including power generation, heat pumps, and direct-use applications—was valued at approximately $67–69 billion in 2025 and is projected to reach $110 billion by 2035, representing a CAGR of 5.5%. The geothermal electricity market alone is expected to grow from approximately $8.6 billion in 2025 to over $15 billion by 2032.
Challenges and the Path Forward
Despite the momentum, significant challenges remain. High upfront capital costs (typically $2,500–$5,000 per installed kW for conventional geothermal, and higher for EGS) and subsurface exploration risk continue to constrain investment. Drilling dry wells remains a real possibility, and the capital intensity of geothermal means that financing remains more difficult than for solar or wind.
Policy support is critical. The U.S. Inflation Reduction Act’s investment tax credit and production tax credit provisions have improved the economics of geothermal projects. California’s clean-firm procurement mandate—requiring at least 1,000 MW of capacity from resources like geothermal—provides long-term revenue visibility for developers. The DOE’s EGS demonstration program is underwriting the field validation needed to reduce perceived subsurface risk.
Conclusion
The ten companies profiled here represent a spectrum of approaches to geothermal development—from Calpine’s century-old dry-steam operations to Mazama’s superhot rock frontier. What unites them is a shared recognition that geothermal offers something other renewables cannot: 24/7, weather-independent, baseload clean power.
As data centers multiply and decarbonization deadlines approach, the value of firm, dispatchable renewable energy will only increase. The companies that succeed in reducing costs, mitigating exploration risk, and scaling deployment will not only capture market share—they will help define the future of the global electricity system.
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