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Company lists · Data verified August 2026

Top 25 Clean energy consultancy companies based in the United States

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 4,153 companies tracked

There are 4,153 clean energy consultancy companies headquartered in the United States (RevenueBase, August 2026). RevenueBase tracks 68,689 professional contacts across them, including 30,790 with verified work emails and 29,271 with mobile numbers. Houston is the largest hub.

This list covers clean energy consultancy companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Data current as of August 28, 2026.

4,153Companies
68,689Contacts tracked
30,790Verified emails
29,271Mobile numbers
Unlock all 4,153 companies Free account · no credit card · 2 minutes

The 25 largest clean energy consultancy companies based in the United States

Ranked by team size
Top 25 of 4,153 clean energy consultancy companies based in the United States, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#CompanyHQEmployeesContactsVerified emails
1Sargent & LundyMidland, TX1,001-5,0004,1451,118
2FTIMenasha, WI1,001-5,0002,7121,126
3Langan Engineering & Environmental ServicesEl Segundo, CA1,001-5,0002,1361,662
4Westwood Professional ServicesLake Charles, LA1,001-5,0001,6311,058
5Swca Environmental ConsultantsPhoenix, AZ1,001-5,0001,6181,159
6AmerescoFramingham, MA1,001-5,0001,4751,125
7Davey Resource Group, INCKent, OH1,001-5,0001,407681
8Barr Engineering COWashington1,001-5,0001,098828
9WilldanAnaheim, CA1,001-5,000838636
10Energy SolutionsOrange, CA201-500768419
11Resource InnovationsChandler, AZ501-1,000724558
12InercoDelaware1,001-5,00068290
13Tighe & BondPortland, ME501-1,000638394
14Depcom Power, INCBedminster, NJ1,001-5,000623273
15XODUSBoston, MA201-500527302
16Natural PowerSeattle, WA501-1,000505349
17Hunt Guillot & Associates HGARuston, LA501-1,000499369
18TRIOMclean, VA201-500382245
19VeregyPhoenix, AZ501-1,000376284
20Manhard ConsultingFort Worth, TX201-500373215
21P2sIrvine, CA201-500370208
22TakkionEvansville, WY1,001-5,000360128
23Wendel CompaniesMiddletown, CT201-500354238
24U.S. EnergyHouston, TX1,001-5,000327130
253degrees Group, INCSan Francisco, CA201-500325216

Showing 25 of 4,153 clean energy consultancy companies based in the United States

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Clean energy consultancy companies based in the United States at a glance

As of Aug 28, 2026
1-10Median size (employees)
HoustonLargest hub · 178 HQs
29,271Contacts with mobile numbers
195Emails re-verified in last 30 days

Companies by employee count

1-10
2,563
11-50
1,119
51-200
330
201-500
69
501-1,000
19
1,001-5,000
34
5,001-10,000
2

Clean energy consultancy companies by metro

MetroCompanies
Clean energy consultancy companies in Houston178
Clean energy consultancy companies in New York168
Clean energy consultancy companies in Washington97
Clean energy consultancy companies in Chicago81
Clean energy consultancy companies in Denver76
Clean energy consultancy companies in Los Angeles63
Clean energy consultancy companies in Austin63

How this list was built

Source
The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion
Companies whose own business descriptions match “clean energy consultancy companies”, with match quality audited by blind human judging, and headquartered in the United States.
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
Contact records re-verify on a rolling cadence; 195 contacts on this list were re-verified in the last 30 days.
Refresh
Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

How many clean energy consultancy companies are there based in the United States?

There are 4,153 clean energy consultancy companies headquartered in the United States as of August 2026 (RevenueBase).

What is the largest company on this list?

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

Which city has the most clean energy consultancy companies?

Houston leads with 178 headquartered companies, followed by New York (168) and Washington (97).

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 30,790 verified decision-maker contacts tracked across these 4,153 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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Related lists

Browse: Companies home · All United States lists · All Clean energy consultancy companies lists · New lists

About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.

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