Company lists · Data refreshed September 2026
Top 25 Geothermal power generation companies based in the United States
RevenueBase identified 105 geothermal power generation companies headquartered in the United States as of September 2026 and tracks 4,517 professional contacts across them, including 2,496 with verified work emails. Houston is the largest hub.
This list covers geothermal power generation companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 15, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest geothermal power generation companies based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 2,112 contacts → | ||||
Partial evidence “A business unit of Constellation (NASDAQ: CEG), Calpine Corporation is America’s largest generator of electricity from natural gas and geothermal resources with operations in…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 2 | 1,281 contacts → | ||||
Indirect evidence “With over five decades of experience, Ormat Technologies, Inc.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 3 | 213 contacts → | ||||
Strong evidence “Fervo Energy provides 24/7 carbon-free energy through the development of next-generation geothermal power.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 4 | 69 contacts → | ||||
Strong evidence “With over a decade of experience in the development of clean, efficient renewable energy facilities, Cyrq owns, operates and develops geothermal and solar energy-based power…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 5 | 62 contacts → | ||||
Strong evidence “Quaise develops superhot geothermal power plants for a terawatt-scale world.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 6 | 38 contacts → | ||||
Partial evidence “Darcy Solutions is on a mission to put Geothermal Everywhere.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 7 | 34 contacts → | ||||
Partial evidence “XGS Energy is a geothermal energy company founded and headquartered in Palo Alto, CA.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 8 | 32 contacts → | ||||
Partial evidence “Our vision is to provide clean, reliable power to international markets, to meet rapidly rising demand through efficient, locally appropriate technologies.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 9 | 27 contacts → | ||||
Partial evidence “Project InnerSpace (InnerSpace) is a multi-phase initiative focused on accelerating global geothermal prospecting and development.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 10 | 27 contacts → | ||||
Partial evidence “Our mission is to transform the heating & cooling of buildings, using geothermal energy to radically reduce costs for people and the environment.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 11 | 23 contacts → | ||||
Strong evidence “About GreenFire Energy GreenFire Energy engineers next-generation geothermal systems designed for real-world operating conditions.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 12 | 22 contacts → | ||||
Strong evidence “Open Mountain Energy combines its geothermal and project development expertise with Kaishan Group's power plant technologies and manufacturing to form a cutting-edge industry…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 13 | 22 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 14 | 17 contacts → | ||||
Partial evidence “Geologica excels in Geothermal Resource Consulting by providing high quality global geothermal resource exploration, development and assessment services for private and public…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 15 | 17 contacts → | ||||
Indirect evidence “TEVERRA creates subsurface insight through innovation.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 16 | 16 contacts → | ||||
Strong evidence “Mazama Energy’s mission is to drive human progress by delivering large-scale, clean geothermal power from Superhot Rocks (SHR).” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 17 | 15 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 18 | 15 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 19 | 13 contacts → | ||||
Strong evidence “Sage Geosystems™ is pioneering Pressure Geothermal-a new category of geothermal energy that delivers grid-scale power and long-duration energy storage virtually anywhere.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 20 | 13 contacts → | ||||
Indirect evidence “Dewhurst Group (DG) is an energy exploration and development company.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 21 | 13 contacts → | ||||
Partial evidence “Geothermal Resource Group, Inc.(GRG) provides complete, cost-effective solutions for your resource engineering needs.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 22 | 12 contacts → | ||||
Partial evidence “In the 30 years of operation, Chesapeake Geosystems has earned a reputation as a geothermal contracting firm that delivers projects on time and on budget.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 23 | 10 contacts → | ||||
Partial evidence “Aztech Geothermal, LLC offers a comprehensive solution for renewable geothermal heating and cooling systems in residential and commercial buildings with recognized expertise in…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 24 | 10 contacts → | ||||
Indirect evidence “Veizades and Associates, INC.” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
| 25 | 9 contacts → | ||||
Partial evidence “GTW Designs, Constructs & Operates Econimic NEXT GEOTHERMAL SYSTEMS: •‘Deep Decarbonized’ High Heat for Industry Clients using >220 Deg C • Direct baseload high heat (MMBTU) & MWe…” Source: RevenueBase Database · checked Sep 15, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: geothermal power generation companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names geothermal power generation companies.
- Partial evidence
- Its own public description names part of geothermal power generation companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name geothermal power generation companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 105 geothermal power generation companies based in the United States
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Geothermal power generation companies based in the United States at a glance
As of Sep 15, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 105 companies.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among geothermal power generation companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United States whose own description of what they do matches “geothermal power generation companies”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names geothermal power generation companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among geothermal power generation companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 2,496 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 15, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names geothermal power generation companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many geothermal power generation companies are there based in the United States?
RevenueBase identified 105 geothermal power generation companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
Calpine, headquartered in Houston, tops this list with the largest team on record.
Which city has the most geothermal power generation companies?
Houston leads with 15 headquartered companies, followed by Reno (6) and Austin (5).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 2,496 verified decision-maker contacts tracked across these 105 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 15, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.
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