Company lists · Data refreshed September 2026

Top 25 Decarbonization consulting firms based in the United States

Name: Decarbonization consulting firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 28, 2026 1,808 companies tracked

RevenueBase identified 1,808 decarbonization consulting firms headquartered in the United States as of September 2026 and tracks 32,148 professional contacts across them, including 15,442 with verified work emails. Houston is the largest hub.

This list covers decarbonization consulting firms 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 28, 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 28, 2026 86% judged on-target in blind review

1,808Companies

32,148Contacts tracked

15,442Verified emails

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The 25 largest decarbonization consulting firms based in the United States

Ranked by team size

Top 25 of 1,808 decarbonization consulting firms based in the United States, 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Sargent & Lundy	Indirect evidence	Chicago, WY, United StatesHQ checked Sep 28, 2026	1,001-5,000	4,156 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
2	Mckinstry	Indirect evidence	Seattle, WA, United StatesHQ checked Sep 28, 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 28, 2026
3	Clearesult	Indirect evidence	Austin, TX, United StatesHQ checked Sep 28, 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 28, 2026
4	Ameresco	Indirect evidence	Framingham, MA, United StatesHQ checked Sep 28, 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 28, 2026
5	OLA	Partial evidence	Austin, TX, United StatesHQ checked Sep 28, 2026	n/a	1,145 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
6	Energy Solutions	Indirect evidence	Oakland, CA, United StatesHQ checked Sep 28, 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 28, 2026
7	Resource Innovations	Indirect evidence	Half Moon Bay, CA, United StatesHQ checked Sep 28, 2026	501-1,000	733 contacts →
	Indirect evidence “Resource Innovations (RI) is an energy transformation firm.” Source: RevenueBase Database · checked Sep 28, 2026
8	Veregy	Partial evidence	Phoenix, MO, United StatesHQ checked Sep 28, 2026	501-1,000	383 contacts →
	Partial evidence “Veregy is an award-winning NAESCO-Accredited decarbonization company focusing on accelerating and simplifying the Energy Transition.” Source: RevenueBase Database · checked Sep 28, 2026
9	TRIO	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 28, 2026	201-500	383 contacts →
	Indirect evidence “We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.” Source: RevenueBase Database · checked Sep 28, 2026
10	P2s	Indirect evidence	Long Beach, CA, United StatesHQ checked Sep 28, 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 28, 2026
11	NUS Consulting Group	Indirect evidence	Park Ridge, NJ, United StatesHQ checked Sep 28, 2026	201-500	336 contacts →
	Indirect evidence “National Utility Service, Inc.” Source: RevenueBase Database · checked Sep 28, 2026
12	3degrees Group, INC	Indirect evidence	San Francisco, CA, United StatesHQ checked Sep 28, 2026	201-500	324 contacts →
	Indirect evidence “3Degrees is a leading global climate solutions provider, pioneer of environmental markets, and Certified B Corporation.” Source: RevenueBase Database · checked Sep 28, 2026
13	Cascade Energy	Indirect evidence	Portland, OR, United StatesHQ checked Sep 28, 2026	201-500	288 contacts →
	Indirect evidence “At Cascade Energy, we believe in better.” Source: RevenueBase Database · checked Sep 28, 2026
14	Lake Superior Consulting	Indirect evidence	Duluth, MN, United StatesHQ checked Sep 28, 2026	201-500	281 contacts →
	Indirect evidence “We act as an extension of your team, combining deep energy expertise with seamless alignment to your processes to advance projects with confidence.” Source: RevenueBase Database · checked Sep 28, 2026
15	PSC Consulting	Partial evidence	Kirkland, WA, United StatesHQ checked Sep 28, 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 28, 2026
16	Mosaic	Partial evidence	Renton, WA, United StatesHQ checked Sep 28, 2026	201-500	248 contacts →
	Partial evidence “Mosaic is a consulting firm that delivers custom solutions across the energy, utility, grid operations, and grid modernization space.” Source: RevenueBase Database · checked Sep 28, 2026
17	Mantis Innovation	Indirect evidence	Houston, TX, United StatesHQ checked Sep 28, 2026	201-500	233 contacts →
	Indirect evidence “At Mantis Innovation, our experts provide data-driven, consultative services designed to optimize your facility, sustainability, and energy management strategies, while ultimately…” Source: RevenueBase Database · checked Sep 28, 2026
18	PEG	Indirect evidence	Fairfax, VA, United StatesHQ checked Sep 28, 2026	201-500	214 contacts →
	Indirect evidence “PEG presents a comprehensive capacity for the evaluation and understanding of a broad base of energy and environmental sustainability related programs, policies and initiatives.” Source: RevenueBase Database · checked Sep 28, 2026
19	Dalkia Energy Solutions	Indirect evidence	Beverly, MA, United StatesHQ checked Sep 28, 2026	201-500	210 contacts →
	Indirect evidence “Dalkia Energy Solutions, a subsidiary of the EDF (Électricité de France) Group, is a national leader in energy efficiency and sustainability for commercial, industrial, and…” Source: RevenueBase Database · checked Sep 28, 2026
20	Bright Power	Partial evidence	New York, NY, United StatesHQ checked Sep 28, 2026	51-200	205 contacts →
	Partial evidence “Bright Power is a leading provider of energy efficiency and decarbonization solutions for the real estate industry.” Source: RevenueBase Database · checked Sep 28, 2026
21	Anew Climate	Indirect evidence	Houston, TX, United StatesHQ checked Sep 28, 2026	201-500	200 contacts →
	Indirect evidence “Anew Climate is a global leader of diverse climate solutions, bringing innovative products and services to the public and private sectors to help reduce or offset their carbon…” Source: RevenueBase Database · checked Sep 28, 2026
22	Frontier Energy, INC	Indirect evidence	Pleasanton, CA, United StatesHQ checked Sep 28, 2026	51-200	192 contacts →
	Indirect evidence “Frontier Energy is a professional services firm that excels in market transformation.” Source: RevenueBase Database · checked Sep 28, 2026
23	Cenergistic	Indirect evidence	Dallas, TX, United StatesHQ checked Sep 28, 2026	201-500	190 contacts →
	Indirect evidence “At Cenergistic, energy conservation starts with people.” Source: RevenueBase Database · checked Sep 28, 2026
24	Lindahl Reed INC	Indirect evidence	Bend, OR, United StatesHQ checked Sep 28, 2026	201-500	190 contacts →
	Indirect evidence “Lindahl Reed empowers tomorrow by inspiring change and shaping a better future.” Source: RevenueBase Database · checked Sep 28, 2026
25	Utilicast	Partial evidence	Seattle, WA, United StatesHQ checked Sep 28, 2026	201-500	181 contacts →
	Partial evidence “Utilicast is more than just a consulting company.” Source: RevenueBase Database · checked Sep 28, 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: decarbonization 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 decarbonization consulting firms.
Partial evidence: Its own public description names part of decarbonization consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name decarbonization 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 1,808 decarbonization consulting firms based in the United States

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Decarbonization consulting firms based in the United States at a glance

As of Sep 28, 2026

48.0%Verified-email coverage

17.8Average contacts per company

1-10Median size (employees)

6.0%Largest-city concentration · Houston

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

1,223

11-50

423

51-200

114

201-500

501-1,000

1,001-5,000

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 1,808 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 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.
What qualifies: Companies headquartered in the United States 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. 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, 15,442 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 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 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 based in the United States?

RevenueBase identified 1,808 decarbonization consulting firms 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?

Sargent & Lundy, headquartered in Casper, tops this list with the largest team on record.

Which city has the most decarbonization consulting firms?

Houston leads with 109 headquartered companies, followed by New York (92) and Chicago (52).

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 15,442 verified decision-maker contacts tracked across these 1,808 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.