Company lists · Data refreshed September 2026
Top 25 Green energy consulting firms based in the United States
RevenueBase identified 4,315 green energy consulting firms headquartered in the United States as of September 2026 and tracks 52,375 professional contacts across them, including 22,256 with verified work emails and 21,356 with mobile numbers. Houston is the largest hub.
This list covers green energy 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, how directly it supports the match, and when it was last checked. Data refreshed September 3, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, 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.
The 25 largest green energy consulting firms based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | Westwood Professional ServicesIndirect evidence | 1,631 | |||
“At Westwood, our purpose is to create a better world for people through our work.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 2 | 1,618 | ||||
“Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 3 | 1,475 | ||||
“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: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 4 | WilldanPartial evidence | 838 | |||
“Willdan (NASDAQ: WLDN) provides professional consulting and technical services to utilities, public agencies and private industry throughout the United States.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 5 | 768 | ||||
“Our mission is simple - to combat climate change through market-based, cost-effective energy, carbon, and water management solutions that make big impacts.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 6 | 727 | ||||
“We’re on a mission to make power personal.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 7 | 724 | ||||
“Resource Innovations (RI) is an energy transformation firm.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 8 | 452 | ||||
“We are Groundwater & Environmental Services, Inc, better known as GES.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 9 | 382 | ||||
“We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 10 | 376 | ||||
“Established in 2019.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 11 | 370 | ||||
“P2S has brought forward-thinking, sustainable engineering solutions to California, the Pacific Northwest, and beyond, for over 30 years.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 12 | 360 | ||||
“TAKKION is Moving Energy Forward.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 13 | Wendel CompaniesPartial evidence | 354 | |||
“Wendel is an Architecture, Engineering, Energy Efficiency, and Construction Management Firm that delivers customized solutions and turnkey projects in innovative ways.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 14 | 335 | ||||
“Customized Energy Solutions is at the forefront of competitive energy markets.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 15 | 325 | ||||
“3Degrees is a leading global climate solutions provider, pioneer of environmental markets, and Certified B Corporation.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 16 | 303 | ||||
“Environmental Consulting & Technology, Inc.(ECT) is a multi-disciplinary environmental and sustainability consulting firm delivering strategy, permitting, design, and management…” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 17 | 290 | ||||
“At Cascade Energy, we believe in better.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 18 | Ecology And Environment, INCIndirect evidence | 277 | |||
“E&E is now WSP USA.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 19 | 274 | ||||
“People.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 20 | 264 | ||||
“We provide global renewable energy consulting services, focused on empowering clients to navigate the complexities of the energy transition.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 21 | 263 | ||||
“Merjent is an environmental, restoration, and engineering consulting firm with a long history serving the energy industry.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 22 | 250 | ||||
“Mosaic is a consulting firm that delivers custom solutions across the energy, utility, grid operations, and grid modernization space.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 23 | 221 | ||||
“At Kleinschmidt, we work primarily with energy companies and government agencies in North America to protect and enhance the environment without compromising performance.” Source: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 24 | 212 | ||||
“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: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 25 | 211 | ||||
“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: company website · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
Showing 25 of 4,315 green energy consulting firms based in the United States
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Green energy consulting firms based in the United States at a glance
As of Sep 3, 2026Companies by employee count
Verified emails by last verification
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 green energy consulting firms, so some rows will be adjacent to the category rather than pure plays. The description and evidence 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 SmartSearch, 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 “green energy consulting firms”. Matching reads each company's description, not its industry code or its name.
- What we exclude
- Companies whose own description does not clearly place them among green energy 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 an evidence 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, 22,256 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 3, 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.
Green energy consulting firms by metro
- Green energy consulting firms in Houston184
- Green energy consulting firms in New York162
- Green energy consulting firms in Denver90
- Green energy consulting firms in Chicago86
- Green energy consulting firms in Washington84
- Green energy consulting firms in San Francisco64
- Green energy consulting firms in Austin63
Frequently asked
How many green energy consulting firms are there based in the United States?
RevenueBase identified 4,315 green energy 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?
Westwood Professional Services, headquartered in Lake Charles, tops this list with the largest team on record.
Which city has the most green energy consulting firms?
Houston leads with 184 headquartered companies, followed by New York (162) and Denver (90).
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 22,256 verified decision-maker contacts tracked across these 4,315 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 3, 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 SmartSearch, 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.
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