Company lists · Data refreshed September 2026

Top 25 Renewable energy consulting firms based in the United States

Name: Renewable energy 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 5, 2026 3,803 companies tracked

RevenueBase identified 3,803 renewable energy consulting firms headquartered in the United States as of September 2026 and tracks 72,141 professional contacts across them, including 31,856 with verified work emails and 29,829 with mobile numbers. Houston is the largest hub.

This list covers renewable 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 5, 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.

How to read this list HQ checked on every row Match evidence on every row Refreshed Sep 5, 2026 86% judged on-target in blind review

3,803Companies

72,141Contacts tracked

31,856Verified emails

29,829Mobile numbers

Explore all 3,803 companies → Free signup · no credit card · 500 free credits

The 25 largest renewable energy consulting firms based in the United States

Ranked by team size

Top 25 of 3,803 renewable energy consulting firms based in the United States, ranked by team size, largest first. Data refreshed Sep 5, 2026. Evidence rates how directly each company's own description names renewable energy consulting firms: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#	Company	Headquarters	Employees	Contacts
1	Sargent & LundyIndirect evidence	Chicago, WY, United StatesHQ checked Sep 5, 2026	1,001-5,000	4,156
	“Sargent & Lundy is one of the world’s longest-standing full-service architect engineering firms.” Source: company website · checked Sep 5, 2026
2	FTIStrong evidence	Menasha, WI, United StatesHQ checked Sep 5, 2026	1,001-5,000	2,741
	“Faith Technologies Incorporated (FTI) is a dynamic organization comprised of construction, engineering, manufacturing and renewable energy experts.” Source: company website · checked Sep 5, 2026
3	Langan Engineering & Environmental ServicesIndirect evidence	Parsippany, NJ, United StatesHQ checked Sep 5, 2026	1,001-5,000	2,177
	“Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.” Source: company website · checked Sep 5, 2026
4	Westwood Professional ServicesIndirect evidence	Plano, TX, United StatesHQ checked Sep 5, 2026	1,001-5,000	1,661
	“At Westwood, our purpose is to create a better world for people through our work.” Source: company website · checked Sep 5, 2026
5	AmerescoPartial evidence	Framingham, MA, United StatesHQ checked Sep 5, 2026	1,001-5,000	1,383
	“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 5, 2026
6	Partner Engineering & Science, INCIndirect evidence	Torrance, CA, United StatesHQ checked Sep 5, 2026	1,001-5,000	1,358
	“Partner Assessment Corp.” Source: company website · checked Sep 5, 2026
7	Solv EnergyStrong evidence	San Diego, CA, United StatesHQ checked Sep 5, 2026	1,001-5,000	1,286
	“SOLV Energy is a renewable energy solutions provider for utility solar, energy storage, and high voltage projects in North America.” Source: company website · checked Sep 5, 2026
8	OLAPartial evidence	Austin, TX, United StatesHQ checked Sep 5, 2026	n/a	1,145
	“OLA Sustainability, LLC OLA Sustainability is a consulting firm that focuses on integrating sustainable practices into commercial and multifamily design projects.” Source: company website · checked Sep 5, 2026
9	Barr Engineering COPartial evidence	Minneapolis, MN, United StatesHQ checked Sep 5, 2026	1,001-5,000	1,088
	“Barr provides engineering and environmental consulting services to clients across the Midwest, throughout the Americas, and around the world.” Source: company website · checked Sep 5, 2026
10	Wanzek Construction, Inc., A Mastec CompanyStrong evidence	Fargo, ND, United StatesHQ checked Sep 5, 2026	1,001-5,000	933
	“Wanzek Construction, Inc, a MasTec Renewables company, is a leading general construction contractor and clean energy services company headquartered in Fargo, North Dakota.” Source: company website · checked Sep 5, 2026
11	WilldanPartial evidence	Anaheim, CA, United StatesHQ checked Sep 5, 2026	1,001-5,000	851
	“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 5, 2026
12	Resource InnovationsPartial evidence	Half Moon Bay, CA, United StatesHQ checked Sep 5, 2026	501-1,000	733
	“Resource Innovations (RI) is an energy transformation firm.” Source: company website · checked Sep 5, 2026
13	SEL Construction CorporationStrong evidence	Loomis, CA, United StatesHQ checked Sep 5, 2026	n/a	722
	“Experienced commercial contractor specializing in renewable energy, electrical, and roofing projects for privately-owned buildings as well as state/local government buildings in…” Source: company website · checked Sep 5, 2026
14	Electric Power EngineersIndirect evidence	Austin, TX, United StatesHQ checked Sep 5, 2026	501-1,000	630
	“Electric Power Engineers (EPE) is a global advisory and engineering firm advancing grid reliability, resilience, flexibility, and affordability.” Source: company website · checked Sep 5, 2026
15	Depcom Power, INCPartial evidence	Scottsdale, AZ, United StatesHQ checked Sep 5, 2026	1,001-5,000	624
	“DEPCOM Power, a Koch Engineered Solutions Company, is a leading solar energy solutions partner providing Development Support, Engineering, Procurement & Construction (EPC)…” Source: company website · checked Sep 5, 2026
16	Hunt Guillot & Associates HGAPartial evidence	Ruston, LA, United StatesHQ checked Sep 5, 2026	501-1,000	505
	“HGA is a leading engineering, consulting, and program management company that has been delivering innovative and sustainable solutions to our clients for over 29 years.” Source: company website · checked Sep 5, 2026
17	RRC CompaniesPartial evidence	Round Rock, TX, United StatesHQ checked Sep 5, 2026	201-500	494
	“RRC is a top-tier designer of utility-scale wind, solar, energy storage, data center, and oil & gas projects in the US and select international markets.” Source: company website · checked Sep 5, 2026
18	Babcock PowerIndirect evidence	Danvers, MA, United StatesHQ checked Sep 5, 2026	501-1,000	476
	“Finding a single capable partner to support both large- and small-scale power generation needs can be challenging.” Source: company website · checked Sep 5, 2026
19	Synergy Consulting, INCPartial evidence	Washington, DC, United StatesHQ checked Sep 5, 2026	51-200	434
	“Synergy Consulting is Global Leader in Financial and Corporate Advisory.” Source: company website · checked Sep 5, 2026
20	Signal EnergyStrong evidence	Houston, TX, United StatesHQ checked Sep 5, 2026	1,001-5,000	409
	“Signal Energy is a leading full service design/build contractor providing Engineering, Procurement, and Construction (EPC) services for renewable energy & infrastructure projects.” Source: company website · checked Sep 5, 2026
21	TRIOPartial evidence	Irvine, CA, United StatesHQ checked Sep 5, 2026	201-500	383
	“We are Trio – built from Edison Energy, Alfa Energy, and Altenex Energy.” Source: company website · checked Sep 5, 2026
22	Energyscape RenewablesIndirect evidence	Denver, United StatesHQ checked Sep 5, 2026	501-1,000	379
	“Established in 2019.” Source: company website · checked Sep 5, 2026
23	P2sIndirect evidence	Long Beach, CA, United StatesHQ checked Sep 5, 2026	201-500	375
	“P2S has brought forward-thinking, sustainable engineering solutions to California, the Pacific Northwest, and beyond, for over 30 years.” Source: company website · checked Sep 5, 2026
24	Manhard ConsultingPartial evidence	Lincolnshire, IL, United StatesHQ checked Sep 5, 2026	201-500	365
	“Manhard Consulting has joined Atwell, a national consulting, engineering, and construction services firm with 2,100 technical professionals across the country.” Source: company website · checked Sep 5, 2026
25	TakkionPartial evidence	Evansville, WY, United StatesHQ checked Sep 5, 2026	1,001-5,000	358
	“TAKKION is Moving Energy Forward.” Source: company website · checked Sep 5, 2026

Showing 25 of 3,803 renewable energy consulting firms based in the United States

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Renewable energy consulting firms based in the United States at a glance

As of Sep 5, 2026

1-10Median size (employees)

HoustonLargest hub · 152 HQs

29,829Contacts with mobile numbers

Sep 5, 2026Data refreshed

Companies by employee count

1-10

2,111

11-50

1,170

51-200

367

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Verified emails by last verification

0–30

29,726

31–60

1,972

61–90

90–180

180+

140

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 renewable 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 “renewable 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 renewable 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, 31,856 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 5, 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.

Renewable energy consulting firms by metro

Frequently asked

How many renewable energy consulting firms are there based in the United States?

RevenueBase identified 3,803 renewable 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?

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

Which city has the most renewable energy consulting firms?

Houston leads with 152 headquartered companies, followed by New York (120) and Denver (71).

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 31,856 verified decision-maker contacts tracked across these 3,803 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 5, 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.