Company lists · Data refreshed September 2026

Top 25 Geothermal project developers based in the United States

Name: Geothermal project developers based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 20, 2026 188 companies tracked

RevenueBase identified 188 geothermal project developers headquartered in the United States as of September 2026 and tracks 5,655 professional contacts across them, including 2,945 with verified work emails. Houston is the largest hub.

This list covers geothermal project developers 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 20, 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 20, 2026 86% judged on-target in blind review

188Companies

5,655Contacts tracked

2,945Verified emails

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The 25 largest geothermal project developers based in the United States

Ranked by team size

Top 25 of 188 geothermal project developers based in the United States, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to geothermal project developers: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Calpine	Partial evidence	Houston, TX, United StatesHQ checked Sep 20, 2026	1,001-5,000	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 20, 2026
2	Ormat Technologies, INC	Indirect evidence	Reno, NV, United StatesHQ checked Sep 20, 2026	1,001-5,000	1,281 contacts →
	Indirect evidence “With over five decades of experience, Ormat Technologies, Inc.” Source: RevenueBase Database · checked Sep 20, 2026
3	Fervo Energy	Partial evidence	Houston, CA, United StatesHQ checked Sep 20, 2026	51-200	213 contacts →
	Partial evidence “Fervo Energy provides 24/7 carbon-free energy through the development of next-generation geothermal power.” Source: RevenueBase Database · checked Sep 20, 2026
4	Competitive Power Ventures	Indirect evidence	Silver Spring, MD, United StatesHQ checked Sep 20, 2026	51-200	167 contacts →
	Indirect evidence “Competitive Power Ventures (CPV) has 25 years of unprecedented success in the development and operation of highly efficient and low emitting electric generation and renewable…” Source: RevenueBase Database · checked Sep 20, 2026
5	Dandelion Energy	Partial evidence	Mount Kisco, NY, United StatesHQ checked Sep 20, 2026	51-200	118 contacts →
	Partial evidence “Dandelion Energy is the nation’s leading residential geothermal provider, on a mission to make the world’s most efficient heating and cooling technology accessible to everyone.” Source: RevenueBase Database · checked Sep 20, 2026
6	Brightcore Energy	Indirect evidence	Armonk, NY, United StatesHQ checked Sep 20, 2026	51-200	108 contacts →
	Indirect evidence “Brightcore Energy is a leading renewable energy solutions provider serving commercial, institutional, and government clients.” Source: RevenueBase Database · checked Sep 20, 2026
7	Cyrq Energy	Partial evidence	Salt Lake City, UT, United StatesHQ checked Sep 20, 2026	51-200	69 contacts →
	Partial 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 20, 2026
8	Quaise Energy	Partial evidence	Houston, MA, United StatesHQ checked Sep 20, 2026	51-200	62 contacts →
	Partial evidence “Quaise develops superhot geothermal power plants for a terawatt-scale world.” Source: RevenueBase Database · checked Sep 20, 2026
9	Heelstone Renewable Energy, LLC	Partial evidence	Durham, NC, United StatesHQ checked Sep 20, 2026	51-200	57 contacts →
	Partial evidence “Heelstone Energy is a leading independent power producer developer with expertise in developing, financing, constructing, operating, and maintaining solar photovoltaic, wind, and…” Source: RevenueBase Database · checked Sep 20, 2026
10	Allied Well Drilling	Indirect evidence	Laurel, MD, United StatesHQ checked Sep 20, 2026	51-200	52 contacts →
	Indirect evidence “We at Allied Well Drilling are a full service commercial and residential gethermal heating/cooling system installer, specializing in vertically drilled closed loop systems.” Source: RevenueBase Database · checked Sep 20, 2026
11	Agilitas Energy	Indirect evidence	Wakefield, MA, United StatesHQ checked Sep 20, 2026	11-50	48 contacts →
	Indirect evidence “Agilitas Energy is the largest fully integrated independent power producer (IPP) in the Distributed Generation (DG) sector with a full range of asset classes, including solar…” Source: RevenueBase Database · checked Sep 20, 2026
12	Darcy Solutions	Partial evidence	New Brighton, MN, United StatesHQ checked Sep 20, 2026	11-50	38 contacts →
	Partial evidence “Darcy Solutions is on a mission to put Geothermal Everywhere.” Source: RevenueBase Database · checked Sep 20, 2026
13	XGS Energy	Partial evidence	Palo Alto, CA, United StatesHQ checked Sep 20, 2026	11-50	34 contacts →
	Partial evidence “XGS Energy is a geothermal energy company founded and headquartered in Palo Alto, CA.” Source: RevenueBase Database · checked Sep 20, 2026
14	EDEN	Indirect evidence	Somerville, MA, United StatesHQ checked Sep 20, 2026	11-50	31 contacts →
	Indirect evidence “Eden is a leader in sustainable natural resource recovery.” Source: RevenueBase Database · checked Sep 20, 2026
15	Midwest Geothermal	Partial evidence	Grand Rapids, MI, United StatesHQ checked Sep 20, 2026	11-50	28 contacts →
	Partial evidence “Geothermal Systems are becoming a critical component in the effort to make buildings more environmentally friendly.” Source: RevenueBase Database · checked Sep 20, 2026
16	Project Innerspace	Strong evidence	Houston, United StatesHQ checked Sep 20, 2026	11-50	27 contacts →
	Strong evidence “Project InnerSpace (InnerSpace) is a multi-phase initiative focused on accelerating global geothermal prospecting and development.” Source: RevenueBase Database · checked Sep 20, 2026
17	Bedrock Energy	Partial evidence	Austin, TX, United StatesHQ checked Sep 20, 2026	11-50	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 20, 2026
18	Greenfire Energy INC	Partial evidence	Oklahoma City, OK, United StatesHQ checked Sep 20, 2026	11-50	23 contacts →
	Partial evidence “About GreenFire Energy GreenFire Energy engineers next-generation geothermal systems designed for real-world operating conditions.” Source: RevenueBase Database · checked Sep 20, 2026
19	The SUN Company	Partial evidence	Tucson, AZ, United StatesHQ checked Sep 20, 2026	11-50	23 contacts →
	Partial evidence “Founded by Joley Michaelson in 2018, The Sun Company Americas Inc.(TSC) is a Master Developer and Integrator of renewable energy solutions, transforming how clean energy is…” Source: RevenueBase Database · checked Sep 20, 2026
20	Open Mountain Energy	Strong evidence	Reno, NV, United StatesHQ checked Sep 20, 2026	11-50	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 20, 2026
21	Geologica Geothermal Group, INC	Partial evidence	Reno, NV, United StatesHQ checked Sep 20, 2026	11-50	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 20, 2026
22	Teverra	Indirect evidence	Atlanta, United StatesHQ checked Sep 20, 2026	11-50	17 contacts →
	Indirect evidence “TEVERRA creates subsurface insight through innovation.” Source: RevenueBase Database · checked Sep 20, 2026
23	247solar, INC	Indirect evidence	Great Falls, VA, United StatesHQ checked Sep 20, 2026	11-50	17 contacts →
	Indirect evidence “247Solar, an MIT spin-out, is commercializing an innovative solution for clean, industrial process heat and baseload renewable energy.” Source: RevenueBase Database · checked Sep 20, 2026
24	First Mile Development	Partial evidence	Richfield, MN, United StatesHQ checked Sep 20, 2026	11-50	16 contacts →
	Partial evidence “First Mile Development is a renewable energy developer focused on the early development stage – greenfield to interconnection.” Source: RevenueBase Database · checked Sep 20, 2026
25	Mazama Energy	Partial evidence	Frisco, TX, United StatesHQ checked Sep 20, 2026	11-50	16 contacts →
	Partial 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 20, 2026

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 project developers. 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 project developers.
Partial evidence: Its own public description names part of geothermal project developers, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name geothermal project developers. 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 188 geothermal project developers based in the United States

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Geothermal project developers based in the United States at a glance

As of Sep 20, 2026

52.1%Verified-email coverage

30.1Average contacts per company

1-10Median size (employees)

8.5%Largest-city concentration · Houston

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

1,001-5,000

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 188 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 project developers, 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 project developers”. 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 project developers), 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 project developers, 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, 2,945 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 20, 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 project developers, 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 project developers are there based in the United States?

RevenueBase identified 188 geothermal project developers 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 project developers?

Houston leads with 16 headquartered companies, followed by Austin (8) and Reno (6).

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 2,945 verified decision-maker contacts tracked across these 188 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 20, 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.