Company lists · Data refreshed September 2026

Top 25 Cleantech consulting firms worldwide

Name: Cleantech consulting firms worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 12,164 companies tracked

RevenueBase identified 12,164 cleantech consulting firms worldwide as of September 2026 and tracks 86,615 professional contacts across them, including 25,667 with verified work emails. The United States is the largest market and London the largest hub.

This list covers cleantech consulting firms worldwide, 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 21, 2026. Country and city lists for cleantech consulting firms follow the table.

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 21, 2026 86% judged on-target in blind review

12,164Companies

86,615Contacts tracked

25,667Verified emails

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The 25 largest cleantech consulting firms worldwide

Ranked by team size

Top 25 of 12,164 cleantech consulting firms worldwide, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to cleantech consulting firms: 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	Montrose Environmental Group	Indirect evidence	Little Rock, AR, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,529 contacts →
	Indirect evidence “Onterris (formerly Montrose Environmental Group) was one of the first to see environmental responsibility as not just an imperative but as a strategic asset.” Source: RevenueBase Database · checked Sep 21, 2026
2	Willdan	Partial evidence	Anaheim, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	851 contacts →
	Partial evidence “Willdan (NASDAQ: WLDN) provides professional consulting and technical services to utilities, public agencies and private industry throughout the United States.” Source: RevenueBase Database · checked Sep 21, 2026
3	Inerco	Indirect evidence	Sevilla, SpainHQ checked Sep 21, 2026	1,001-5,000	688 contacts →
	Indirect evidence “INERCO, with 30 years of experience, offers comprehensive services and develops advanced technologies that contribute to sustainable industrial development, acting as a leader in…” Source: RevenueBase Database · checked Sep 21, 2026
4	Revergy	Indirect evidence	Seville, SpainHQ checked Sep 21, 2026	501-1,000	502 contacts →
	Indirect evidence “REVERGY nace mediante un proyecto de profesionales procedentes de diferentes ámbitos del sector de las energías renovables con el fin de presentar un proyecto marcado por la…” Source: RevenueBase Database · checked Sep 21, 2026
5	Natural Power	Indirect evidence	Castle Douglas, United KingdomHQ checked Sep 21, 2026	501-1,000	500 contacts →
	Indirect evidence “Natural Power is a leading independent consultancy and service provider for the renewable energy sector.” Source: RevenueBase Database · checked Sep 21, 2026
6	Mitcon Consultancy And Engineering Services LTD	Indirect evidence	Pune, IndiaHQ checked Sep 21, 2026	201-500	486 contacts →
	Indirect evidence “MITCON Consultancy & Engineering Services Limited, an ISO 9001:2015 certified company & NSE listed company, was established in 1982.” Source: RevenueBase Database · checked Sep 21, 2026
7	Chakr Innovation	Partial evidence	Gurugram, IndiaHQ checked Sep 21, 2026	501-1,000	476 contacts →
	Partial evidence “Chakr Innovation is a pioneering Indian cleantech startup, founded by IIT Delhi graduates, dedicated to revolutionizing air quality with cutting-edge material science technology.” Source: RevenueBase Database · checked Sep 21, 2026
8	Fichtner Consulting Engineers LTD	Indirect evidence	Stockport, United KingdomHQ checked Sep 21, 2026	51-200	418 contacts →
	Indirect evidence “Fichtner is one of the world's leading independent engineering consultancy firms.” Source: RevenueBase Database · checked Sep 21, 2026
9	Greenflex	Indirect evidence	Paris, FranceHQ checked Sep 21, 2026	501-1,000	390 contacts →
	Indirect evidence “Since 2009, GreenFlex has been a key partner in the energy, environmental and societal transformation of organizations, enabling them to change their trajectory towards an economy…” Source: RevenueBase Database · checked Sep 21, 2026
10	TRIO	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 21, 2026	201-500	383 contacts →
	Indirect evidence “We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.” Source: RevenueBase Database · checked Sep 21, 2026
11	P2s	Indirect evidence	Long Beach, CA, United StatesHQ checked Sep 21, 2026	201-500	375 contacts →
	Indirect evidence “P2S has brought forward-thinking, sustainable engineering solutions to California, the Pacific Northwest, and beyond, for over 30 years.” Source: RevenueBase Database · checked Sep 21, 2026
12	EMM Consulting PTY Limited	Indirect evidence	St Leonards, AustraliaHQ checked Sep 21, 2026	201-500	361 contacts →
	Indirect evidence “At EMM, we believe that a sustainable future is achievable, and we are dedicated to helping our clients and the community make it a reality.” Source: RevenueBase Database · checked Sep 21, 2026
13	Triton Environmental Consultants LTD	Indirect evidence	Vancouver, BC, CanadaHQ checked Sep 21, 2026	201-500	351 contacts →
	Indirect evidence “Triton Environmental Consultants knows western Canada.” Source: RevenueBase Database · checked Sep 21, 2026
14	AESA	Indirect evidence	Barcelona, SpainHQ checked Sep 21, 2026	n/a	351 contacts →
	Indirect evidence “Ingeniería y Consultoría Energética orientada a la búsqueda y el desarrollo de soluciones energéticas de alta eficiencia para sus Clientes.” Source: RevenueBase Database · checked Sep 21, 2026
15	ETP CC	Partial evidence	AustraliaHQ checked Sep 21, 2026	n/a	320 contacts →
	Partial evidence “Management Consulting in the Energy Sector” Source: RevenueBase Database · checked Sep 21, 2026
16	EIC Partnership	Indirect evidence	Redditch, United KingdomHQ checked Sep 21, 2026	51-200	316 contacts →
	Indirect evidence “EIC Partnership: A Legacy of Expertise, A Commitment to Sustainability With origins dating back to 1975, EIC has cultivated nearly 50 years of distinguished service in energy and…” Source: RevenueBase Database · checked Sep 21, 2026
17	Environmental Consulting & Technology, Inc. ECT	Partial evidence	Gainesville, FL, United StatesHQ checked Sep 21, 2026	201-500	305 contacts →
	Partial evidence “Environmental Consulting & Technology, Inc.(ECT) is a multi-disciplinary environmental and sustainability consulting firm delivering strategy, permitting, design, and management…” Source: RevenueBase Database · checked Sep 21, 2026
18	Sólida	Partial evidence	Madrid, SpainHQ checked Sep 21, 2026	201-500	298 contacts →
	Partial evidence “SÓLIDA, a Bureau Veritas Company, is an independent company founded in 2007 that provides high added-value engineering and consulting services within the renewable energy sector.” Source: RevenueBase Database · checked Sep 21, 2026
19	Cascade Energy	Indirect evidence	Portland, OR, United StatesHQ checked Sep 21, 2026	201-500	288 contacts →
	Indirect evidence “At Cascade Energy, we believe in better.” Source: RevenueBase Database · checked Sep 21, 2026
20	Deode Energia	Indirect evidence	Juiz De Fora, BrazilHQ checked Sep 21, 2026	201-500	280 contacts →
	Indirect evidence “A DEODE Energia foi fundada em 2012 proveniente da HF Energy.” Source: RevenueBase Database · checked Sep 21, 2026
21	Eodd Ingénieurs Conseils	Indirect evidence	Villeurbanne, FranceHQ checked Sep 21, 2026	201-500	278 contacts →
	Indirect evidence “Créé en 1991, reconnu comme l’un des meilleurs cabinets français spécialiste de la transformation écologique, EODD ingénieurs conseils apporte sa vision transversale et ses…” Source: RevenueBase Database · checked Sep 21, 2026
22	Infinity	Indirect evidence	Cairo, EgyptHQ checked Sep 21, 2026	201-500	272 contacts →
	Indirect evidence “Established in 2014, Infinity is the only dedicated renewable energy solutions provider in Egypt that develops clean energy solutions across several sectors and scales.” Source: RevenueBase Database · checked Sep 21, 2026
23	Merjent	Partial evidence	Minneapolis, MN, United StatesHQ checked Sep 21, 2026	201-500	264 contacts →
	Partial evidence “Merjent is an environmental, restoration, and engineering consulting firm with a long history serving the energy industry.” Source: RevenueBase Database · checked Sep 21, 2026
24	PSC Consulting	Partial evidence	Kirkland, WA, United StatesHQ checked Sep 21, 2026	201-500	254 contacts →
	Partial evidence “We provide global renewable energy consulting services, focused on empowering clients to navigate the complexities of the energy transition.” Source: RevenueBase Database · checked Sep 21, 2026
25	Valora Consultores	Partial evidence	Madrid, United KingdomHQ checked Sep 21, 2026	51-200	241 contacts →
	Partial evidence “VALORA is a consulting company who focus its activity towards a new professional innovative and thrilling challenge.” Source: RevenueBase Database · checked Sep 21, 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 consulting firms. 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 consulting firms.
Partial evidence: Its own public description names part of cleantech consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name cleantech consulting firms. 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 12,164 cleantech consulting firms worldwide

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Cleantech consulting firms worldwide at a glance

As of Sep 21, 2026

29.6%Verified-email coverage

7.1Average contacts per company

1-10Median size (employees)

1.3%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

8,462

11-50

2,966

51-200

533

201-500

108

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency is reported on each country list linked below.

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 consulting firms, 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.
Coverage: Every country. Country and city lists for cleantech consulting firms are linked below.
What qualifies: Companies worldwide whose own description of what they do matches “cleantech consulting firms”. 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 consulting firms), 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 consulting firms, and records with no verified work email.
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, 25,667 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 21, 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 consulting firms by location

56 lists · largest first

Every Cleantech consulting firms list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

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 consulting firms, 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 consulting firms are there worldwide?

RevenueBase identified 12,164 cleantech consulting firms worldwide 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?

Montrose Environmental Group, headquartered in Little Rock, tops this list with the largest team on record.

Which country has the most cleantech consulting firms?

The United States leads with 1,593 companies, followed by Brazil (947) and France (551). Every cleantech consulting firms list by country and city is linked on this page.

Which city has the most cleantech consulting firms?

London leads with 160 headquartered companies, followed by Sao Paulo (151) and Madrid (120).

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 25,667 verified decision-maker contacts tracked across these 12,164 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 21, 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.