Company lists · Data refreshed September 2026

Top 25 Decarbonization consulting firms worldwide

RevenueBase identified 13,624 decarbonization consulting firms worldwide as of September 2026 and tracks 258,427 professional contacts across them, including 80,864 with verified work emails. The United States is the largest market and London the largest hub.

This list covers decarbonization 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 28, 2026. Country and city lists for decarbonization 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 28, 2026 86% judged on-target in blind review
13,624Companies
258,427Contacts tracked
80,864Verified emails
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The 25 largest decarbonization consulting firms worldwide

Ranked by team size
Top 25 of 13,624 decarbonization consulting firms worldwide, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to decarbonization 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceCork, IrelandHQ checked Sep 28, 202610001+52,736 contacts →

Partial evidence

“Johnson Controls is a global leader in thermal management, mission-critical building systems, energy efficiency and decarbonization.”

Source: RevenueBase Database · checked Sep 28, 2026
2Indirect evidenceSydney, AustraliaHQ checked Sep 28, 202610001+34,763 contacts →

Indirect evidence

“Worley is a global professional services company of energy, chemicals and resources experts headquartered in Australia.”

Source: RevenueBase Database · checked Sep 28, 2026
3Indirect evidenceLa Garenne-colombes, FranceHQ checked Sep 28, 202610001+12,011 contacts →

Indirect evidence

“Les activités Infrastructures Energétiques Locales d’ENGIE accompagnent les collectivités, les industries et le secteur du bâtiment sur la voie de la décarbonation.”

Source: RevenueBase Database · checked Sep 28, 2026
4Indirect evidenceLondon, United KingdomHQ checked Sep 28, 20265,001-10,0009,119 contacts →

Indirect evidence

“Sustainability is our business.”

Source: RevenueBase Database · checked Sep 28, 2026
5Indirect evidenceSaint-andré-lez-lille, FranceHQ checked Sep 28, 202610001+8,427 contacts →

Indirect evidence

“Dalkia : ensemble, relevons le défi climatique!”

Source: RevenueBase Database · checked Sep 28, 2026
6Indirect evidenceLondon, ItalyHQ checked Sep 28, 20265,001-10,0008,053 contacts →

Indirect evidence

“Johnson Matthey (JM) is a world leader in platinum group metals (PGMs).”

Source: RevenueBase Database · checked Sep 28, 2026
7Indirect evidenceChicago, WY, United StatesHQ checked Sep 28, 20261,001-5,0004,156 contacts →

Indirect evidence

“Sargent & Lundy is one of the world’s longest-standing full-service architect engineering firms.”

Source: RevenueBase Database · checked Sep 28, 2026
8Indirect evidenceSeattle, WA, United StatesHQ checked Sep 28, 20261,001-5,0002,213 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 28, 2026
9Indirect evidenceAustin, TX, United StatesHQ checked Sep 28, 20261,001-5,0002,121 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 28, 2026
10Indirect evidence港区, JapanHQ checked Sep 28, 20265,001-10,0001,900 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 28, 2026
11Indirect evidenceFramingham, MA, United StatesHQ checked Sep 28, 20261,001-5,0001,383 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 28, 2026
12Partial evidenceAustin, TX, United StatesHQ checked Sep 28, 2026n/a1,145 contacts →

Partial evidence

“OLA Sustainability, LLC OLA Sustainability is a consulting firm that focuses on integrating sustainable practices into commercial and multifamily design projects.”

Source: RevenueBase Database · checked Sep 28, 2026
13Partial evidenceSingaporeHQ checked Sep 28, 202610001+1,105 contacts →

Partial evidence

“Aden Group is a Euro-Asian enterprise delivering comprehensive solutions to boost decarbonization, productivity and energy transition in the built environment.”

Source: RevenueBase Database · checked Sep 28, 2026
14Indirect evidenceLondon, United KingdomHQ checked Sep 28, 20261,001-5,000894 contacts →

Indirect evidence

“Anthesis guides clients to sustainable performance.”

Source: RevenueBase Database · checked Sep 28, 2026
15Indirect evidenceZurich, SwitzerlandHQ checked Sep 28, 2026501-1,000811 contacts →

Indirect evidence

“South Pole is the world's leading carbon asset developer and climate consultancy.”

Source: RevenueBase Database · checked Sep 28, 2026
16Indirect evidenceOakland, CA, United StatesHQ checked Sep 28, 2026201-500772 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 28, 2026
17Partial evidenceGuelph, ON, CanadaHQ checked Sep 28, 2026501-1,000737 contacts →

Partial evidence

“We are a leading global climate and performance engineering consulting firm dedicated to creating harmony between the built and natural world.”

Source: RevenueBase Database · checked Sep 28, 2026
18Indirect evidenceMumbai, IndiaHQ checked Sep 28, 2026201-500735 contacts →

Indirect evidence

“CleanMax is India’s largest commercial and industrial (“C&I”) renewable energy provider with 3 GW of operational, owned and managed capacity.”

Source: RevenueBase Database · checked Sep 28, 2026
19Indirect evidenceHalf Moon Bay, CA, United StatesHQ checked Sep 28, 2026501-1,000733 contacts →

Indirect evidence

“Resource Innovations (RI) is an energy transformation firm.”

Source: RevenueBase Database · checked Sep 28, 2026
20Indirect evidenceSevilla, SpainHQ checked Sep 28, 20261,001-5,000688 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 28, 2026
21Indirect evidenceWalton-on-thames, United KingdomHQ checked Sep 28, 2026201-500658 contacts →

Indirect evidence

“We are passionate about driving sustainable change for our planet.”

Source: RevenueBase Database · checked Sep 28, 2026
22Indirect evidenceThe Hague, NetherlandsHQ checked Sep 28, 20261,001-5,000651 contacts →

Indirect evidence

“The Energy Transition brings new challenges and opportunities to all of us.”

Source: RevenueBase Database · checked Sep 28, 2026
23Indirect evidenceAmsterdam, NetherlandsHQ checked Sep 28, 2026501-1,000556 contacts →

Indirect evidence

“As the leading environmental solutions partner for organizations globally, ACT helps its partners meet increasing environmental action and disclosure expectations from regulators…”

Source: RevenueBase Database · checked Sep 28, 2026
24Indirect evidenceAmsterdam, NetherlandsHQ checked Sep 28, 2026501-1,000502 contacts →

Indirect evidence

“STX Group is a leading global firm in environmental commodities trading and climate finance.”

Source: RevenueBase Database · checked Sep 28, 2026
25Indirect evidenceSalvador, BrazilHQ checked Sep 28, 2026501-1,000493 contacts →

Indirect evidence

“Somos uma empresa com uma grande experiência integral em energia sustentável fortemente comprometida com a Transição Energética.”

Source: RevenueBase Database · checked Sep 28, 2026

Showing 25 of 13,624 decarbonization consulting firms worldwide

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Decarbonization consulting firms worldwide at a glance

As of Sep 28, 2026
31.3%Verified-email coverage
19.0Average contacts per company
1-10Median size (employees)
2.6%Largest-city concentration · London
Sep 28, 2026Page data refreshed

Companies by employee count

1-10
9,644
11-50
3,103
51-200
615
201-500
120
501-1,000
37
1,001-5,000
35
5,001-10,000
8
10001+
15

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 decarbonization 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 decarbonization consulting firms are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “decarbonization 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 decarbonization 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 decarbonization 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, 80,864 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 28, 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.

Decarbonization consulting firms by location

81 lists · largest first

Every Decarbonization 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 decarbonization 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 decarbonization consulting firms are there worldwide?

RevenueBase identified 13,624 decarbonization 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?

Johnson Controls, headquartered in Milwaukee, tops this list with the largest team on record.

Which country has the most decarbonization consulting firms?

The United States leads with 1,808 companies, followed by the United Kingdom (1,123) and France (1,048). Every decarbonization consulting firms list by country and city is linked on this page.

Which city has the most decarbonization consulting firms?

London leads with 355 headquartered companies, followed by Paris (218) and Madrid (143).

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 80,864 verified decision-maker contacts tracked across these 13,624 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 28, 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.