Company lists · Data refreshed September 2026

Top 25 Cleantech startups based in the United States

Name: Cleantech startups based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 19, 2026 2,624 companies tracked

RevenueBase identified 2,624 cleantech startups headquartered in the United States as of September 2026 and tracks 109,488 professional contacts across them, including 42,196 with verified work emails. New York is the largest hub.

This list covers cleantech startups 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 19, 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 19, 2026 86% judged on-target in blind review

2,624Companies

109,488Contacts tracked

42,196Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest cleantech startups based in the United States

Ranked by team size

Top 25 of 2,624 cleantech startups based in the United States, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to cleantech startups: 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	GE Vernova	Indirect evidence	Boston, MA, United StatesHQ checked Sep 19, 2026	10001+	29,528 contacts →
	Indirect evidence “GE Vernova is a purpose-built energy technology company on a mission to electrify to thrive and decarbonize the world.” Source: RevenueBase Database · checked Sep 19, 2026
2	TRANE	Indirect evidence	Davidson, NC, United StatesHQ checked Sep 19, 2026	10001+	10,272 contacts →
	Indirect evidence “Trane is the building technology and energy solutions leader who deploys a depth and breadth of expertise, backgrounds, and perspectives to innovate new technologies and…” Source: RevenueBase Database · checked Sep 19, 2026
3	Carrier	Indirect evidence	Palm Beach Gardens, FL, United StatesHQ checked Sep 19, 2026	10001+	7,665 contacts →
	Indirect evidence “Carrier is a global leader in intelligent climate and energy solutions, pioneering sustainable innovations in climate technologies.” Source: RevenueBase Database · checked Sep 19, 2026
4	The AES Corporation	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 19, 2026	5,001-10,000	5,387 contacts →
	Indirect evidence “The world no longer thinks of energy as a matter of supply and demand.” Source: RevenueBase Database · checked Sep 19, 2026
5	Generac	Indirect evidence	Waukesha, WI, United StatesHQ checked Sep 19, 2026	5,001-10,000	3,797 contacts →
	Indirect evidence “Generac is the total energy solutions company powering a smarter world.” Source: RevenueBase Database · checked Sep 19, 2026
6	Mckinstry	Indirect evidence	Seattle, WA, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,213 contacts →
	Indirect evidence “We're a national construction and energy services company dedicated to innovating the waste and climate harm out of the built environment.” Source: RevenueBase Database · checked Sep 19, 2026
7	Clearesult	Indirect evidence	Austin, TX, United StatesHQ checked Sep 19, 2026	1,001-5,000	2,121 contacts →
	Indirect evidence “CLEAResult is the largest provider of energy efficiency, energy transition and energy sustainability services in North America.” Source: RevenueBase Database · checked Sep 19, 2026
8	Ameresco	Indirect evidence	Framingham, MA, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,383 contacts →
	Indirect evidence “Ameresco, Inc.(NYSE:AMRC) is a leading energy infrastructure solutions provider dedicated to helping customers reduce costs, enhance resilience, and decarbonize to net zero in the…” Source: RevenueBase Database · checked Sep 19, 2026
9	Powur, PBC	Indirect evidence	San Diego, United StatesHQ checked Sep 19, 2026	n/a	1,199 contacts →
	Indirect evidence “The Powur Mission: Accelerate the adoption of clean energy worldwide We're empowering our community of homeowners and advisors to thrive in the global shift to sustainable energy.” Source: RevenueBase Database · checked Sep 19, 2026
10	Community Dreams Foundation	Indirect evidence	Orlando, FL, United StatesHQ checked Sep 19, 2026	1,001-5,000	1,009 contacts →
	Indirect evidence “We are a purpose-driven organization focused on empowering communities through clean energy, technology innovation, and collaborative partnerships.” Source: RevenueBase Database · checked Sep 19, 2026
11	Sunnova Energy	Indirect evidence	Houston, TX, United StatesHQ checked Sep 19, 2026	501-1,000	906 contacts →
	Indirect evidence “Sunnova Energy International Inc.(NYSE: NOVA) is an industry-leading energy services company focused on making clean energy more accessible, reliable, and affordable for…” Source: RevenueBase Database · checked Sep 19, 2026
12	RMI	Indirect evidence	Boulder, CA, United StatesHQ checked Sep 19, 2026	501-1,000	830 contacts →
	Indirect evidence “Rocky Mountain Institute (RMI) is an independent, nonpartisan nonprofit founded in 1982 that transforms global energy systems through market-driven solutions to secure a…” Source: RevenueBase Database · checked Sep 19, 2026
13	Energy Solutions	Indirect evidence	Oakland, CA, United StatesHQ checked Sep 19, 2026	201-500	772 contacts →
	Indirect evidence “Our mission is simple - to combat climate change through market-based, cost-effective energy, carbon, and water management solutions that make big impacts.” Source: RevenueBase Database · checked Sep 19, 2026
14	Resource Innovations	Indirect evidence	Half Moon Bay, CA, United StatesHQ checked Sep 19, 2026	501-1,000	733 contacts →
	Indirect evidence “Resource Innovations (RI) is an energy transformation firm.” Source: RevenueBase Database · checked Sep 19, 2026
15	Grid Alternatives	Indirect evidence	Oakland, CA, United StatesHQ checked Sep 19, 2026	201-500	731 contacts →
	Indirect evidence “GRID Alternatives is a national leader in bringing affordable solar power, clean mobility, and energy storage to underserved communities while creating pathways to life-changing…” Source: RevenueBase Database · checked Sep 19, 2026
16	Depcom Power, INC	Indirect evidence	Scottsdale, AZ, United StatesHQ checked Sep 19, 2026	1,001-5,000	624 contacts →
	Indirect evidence “DEPCOM Power, a Koch Engineered Solutions Company, is a leading solar energy solutions partner providing Development Support, Engineering, Procurement & Construction (EPC)…” Source: RevenueBase Database · checked Sep 19, 2026
17	Nexamp	Indirect evidence	Boston, MA, United StatesHQ checked Sep 19, 2026	201-500	607 contacts →
	Indirect evidence “Nexamp is leading the transformation to the new energy economy with proven solutions for the deployment and operation of solar energy assets.” Source: RevenueBase Database · checked Sep 19, 2026
18	Apex Clean Energy	Indirect evidence	Charlottesville, VA, United StatesHQ checked Sep 19, 2026	201-500	594 contacts →
	Indirect evidence “Apex Clean Energy was founded with a singular focus: to accelerate the shift to clean energy.” Source: RevenueBase Database · checked Sep 19, 2026
19	Corvias	Indirect evidence	Warwick, RI, United StatesHQ checked Sep 19, 2026	501-1,000	573 contacts →
	Indirect evidence “Our people are the heart and soul of our company.” Source: RevenueBase Database · checked Sep 19, 2026
20	Palmetto	Indirect evidence	Charlotte, NC, United StatesHQ checked Sep 19, 2026	201-500	539 contacts →
	Indirect evidence “Palmetto is a leading clean tech company on a mission to accelerate the transition to a clean energy future.” Source: RevenueBase Database · checked Sep 19, 2026
21	GTI Energy	Indirect evidence	Des Plaines, IL, United StatesHQ checked Sep 19, 2026	201-500	513 contacts →
	Indirect evidence “For more than eight decades, GTI Energy has contributed to the strengthening of energy systems and the communities they serve.” Source: RevenueBase Database · checked Sep 19, 2026
22	Posigen	Indirect evidence	St. Rose, LA, United StatesHQ checked Sep 19, 2026	501-1,000	507 contacts →
	Indirect evidence “PosiGen is the nation's leading residential solar and energy efficiency provider.” Source: RevenueBase Database · checked Sep 19, 2026
23	Atlas Renewable Energy	Indirect evidence	Miami, FL, United StatesHQ checked Sep 19, 2026	201-500	500 contacts →
	Indirect evidence “Atlas Renewable Energy delivers clean energy at scale.” Source: RevenueBase Database · checked Sep 19, 2026
24	Noresco	Indirect evidence	Westborough, MA, United StatesHQ checked Sep 19, 2026	201-500	481 contacts →
	Indirect evidence “NORESCO, a part of Carrier Global Corporation, helps customers modernize aging building systems and upgrade energy and water infrastructure to meet evolving demands.” Source: RevenueBase Database · checked Sep 19, 2026
25	Dupont Water Solutions	Indirect evidence	Wilmington, DE, United StatesHQ checked Sep 19, 2026	10001+	470 contacts →
	Indirect evidence “We’re helping companies in every industry, in every corner of the globe make real progress.” Source: RevenueBase Database · checked Sep 19, 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: cleantech startups. 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 cleantech startups.
Partial evidence: Its own public description names part of cleantech startups, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name cleantech startups. 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 2,624 cleantech startups based in the United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 42,196 reachable decision-makers.

Free signup · no credit card

View the full list →

Cleantech startups based in the United States at a glance

As of Sep 19, 2026

38.5%Verified-email coverage

41.7Average contacts per company

1-10Median size (employees)

3.9%Largest-city concentration · New York

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

1,345

11-50

856

51-200

290

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 2,624 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 cleantech startups, 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 “cleantech startups”. 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 cleantech startups), 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 cleantech startups, 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, 42,196 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 19, 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.

Cleantech startups by metro

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 cleantech startups, 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 cleantech startups are there based in the United States?

RevenueBase identified 2,624 cleantech startups 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?

GE Vernova, headquartered in Boston, tops this list with the largest team on record.

Which city has the most cleantech startups?

New York leads with 102 headquartered companies, followed by Houston (82) and San Francisco (71).

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 42,196 verified decision-maker contacts tracked across these 2,624 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 19, 2026.

Ready to reach these companies? Verified emails and direct dials for all 2,624 cleantech startups based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

Cleantech startups by geography

Browse the directory

Browse: Companies home · All United States lists · All Cleantech startups lists · New lists

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.