Company lists · Data refreshed September 2026

Top 25 Energy as a service companies based in the United Kingdom

RevenueBase identified 1,399 energy as a service companies headquartered in the United Kingdom as of September 2026 and tracks 42,585 professional contacts across them, including 14,973 with verified work emails. London is the largest hub.

This list covers energy as a service companies headquartered in the United Kingdom, 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 15, 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 15, 2026 86% judged on-target in blind review
1,399Companies
42,585Contacts tracked
14,973Verified emails
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The 25 largest energy as a service companies based in the United Kingdom

Ranked by team size
Top 25 of 1,399 energy as a service companies based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 15, 2026. RevenueBase Smart Search rates how each company's information relates to energy as a service companies: 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
1Indirect evidenceWindsor, United KingdomHQ checked Sep 15, 202610001+9,238 contacts →

Indirect evidence

“Taking care of things.”

Source: RevenueBase Database · checked Sep 15, 2026
2Partial evidenceWindsor, United KingdomHQ checked Sep 15, 202610001+4,555 contacts →

Partial evidence

“Centrica is an international energy services and solutions company, founded on a 200-year heritage of serving customers in homes and businesses.”

Source: RevenueBase Database · checked Sep 15, 2026
3Partial evidenceLondon, United KingdomHQ checked Sep 15, 20261,001-5,0003,989 contacts →

Partial evidence

“We're on a mission to make a big green dent in the universe by building a truly sustainable energy system globally.”

Source: RevenueBase Database · checked Sep 15, 2026
4Partial evidenceLondon, United KingdomHQ checked Sep 15, 20261,001-5,0002,627 contacts →

Partial evidence

“We help businesses manage energy needs, boost efficiency, control costs and achieve decarbonisation goals for a better energy future.”

Source: RevenueBase Database · checked Sep 15, 2026
5Partial evidenceLondon, United KingdomHQ checked Sep 15, 20265,001-10,0001,064 contacts →

Partial evidence

“Together, we’re delivering technical solutions for a better society and an Electric Britain Dalkia is one of the UK’s leading technical and energy services providers at the…”

Source: RevenueBase Database · checked Sep 15, 2026
6Indirect evidenceManchester, United KingdomHQ checked Sep 15, 20261,001-5,000692 contacts →

Indirect evidence

“We are Calisen.”

Source: RevenueBase Database · checked Sep 15, 2026
7Indirect evidenceWalton-on-thames, United KingdomHQ checked Sep 15, 2026201-500658 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 15, 2026
8Partial evidenceLondon, United KingdomHQ checked Sep 15, 2026501-1,000595 contacts →

Partial evidence

“Kaluza is the Energy Intelligence Platform, turning energy complexity into seamless coordination.”

Source: RevenueBase Database · checked Sep 15, 2026
9Strong evidenceGateshead, United KingdomHQ checked Sep 15, 2026501-1,000509 contacts →

Strong evidence

As leaders in our field, we’re trusted by over businesses to provide a full energy service.”

Source: RevenueBase Database · checked Sep 15, 2026
10Partial evidenceLondon, United KingdomHQ checked Sep 15, 2026201-500402 contacts →

Partial evidence

“Reon Energy is a leading Cleantech company deploying Intelligent Renewable Energy Microgrids across South Asia, GCC & African region.”

Source: RevenueBase Database · checked Sep 15, 2026
11Partial evidenceLondon, United KingdomHQ checked Sep 15, 2026201-500378 contacts →

Partial evidence

“We do energy, you do you.”

Source: RevenueBase Database · checked Sep 15, 2026
12Partial evidenceKirkham, United KingdomHQ checked Sep 15, 2026501-1,000373 contacts →

Partial evidence

“Inspired PLC is a leading technology-enabled provider of energy and sustainability solutions that allow UK and Irish businesses to transition to net-zero carbon and manage their…”

Source: RevenueBase Database · checked Sep 15, 2026
13Partial evidenceRedditch, United KingdomHQ checked Sep 15, 202651-200316 contacts →

Partial evidence

“EIC Partnership: A Legacy of Expertise, A Commitment to Sustainability With origins dating back to 1975, EIC has cultivated nearly 50 years of distinguished service in energy and…”

Source: RevenueBase Database · checked Sep 15, 2026
14Partial evidenceNottingham, United KingdomHQ checked Sep 15, 202651-200273 contacts →

Partial evidence

“Yü Energy was built with a mission to shake up the UK business energy market, offering businesses innovative energy solutions that help save time and money.”

Source: RevenueBase Database · checked Sep 15, 2026
15Partial evidenceBury, United KingdomHQ checked Sep 15, 2026201-500206 contacts →

Partial evidence

“Who we are » The UK’s leading Energy Management company » Our aim is to increase energy performance within buildings » Deliver energy projects to maximise customer return on…”

Source: RevenueBase Database · checked Sep 15, 2026
16Partial evidenceLytham, United KingdomHQ checked Sep 15, 2026501-1,000190 contacts →

Partial evidence

“Inenco Group has been acquired by Sustainable Energy First.”

Source: RevenueBase Database · checked Sep 15, 2026
17Strong evidenceLondon, United KingdomHQ checked Sep 15, 2026201-500183 contacts →

Strong evidence

As a trusted end-to-end partner in the energy space, Brook Green Supply delivers the insight and expertise our customers need to make informed decisions, transact energy with…”

Source: RevenueBase Database · checked Sep 15, 2026
18Partial evidenceLondon, United KingdomHQ checked Sep 15, 2026201-500171 contacts →

Partial evidence

“CFP Energy is a leading provider of energy and environmental solutions for industrial and commercial clients.”

Source: RevenueBase Database · checked Sep 15, 2026
19Partial evidenceHebburn, United KingdomHQ checked Sep 15, 2026201-500159 contacts →

Partial evidence

“At Consultiv Utilities, we help organisations to take control of their energy strategy and support them in navigating the complexities of energy, with confidence.”

Source: RevenueBase Database · checked Sep 15, 2026
20Indirect evidenceChilworth, United KingdomHQ checked Sep 15, 202651-200157 contacts →

Indirect evidence

“Zenergi supports and empowers your journey to net zero.”

Source: RevenueBase Database · checked Sep 15, 2026
21Partial evidenceBristol, United KingdomHQ checked Sep 15, 202651-200142 contacts →

Partial evidence

“Optimised exists to accelerate the shift to a low-carbon future by making energy management work; commercially, operationally and sustainably.”

Source: RevenueBase Database · checked Sep 15, 2026
22Strong evidenceLeicester, United KingdomHQ checked Sep 15, 202651-200129 contacts →

Strong evidence

“Recognised as the Consultancy of the Year in 2021 by Energy Live News, Consultus delivers world-class consulting, buying and management services for Business Energy and Business…”

Source: RevenueBase Database · checked Sep 15, 2026
23Partial evidenceCorby, United KingdomHQ checked Sep 15, 202651-200128 contacts →

Partial evidence

“Utility Bidder is a revolutionary service, set up to ensure customers get the best gas and electricity tariffs on their business energy.”

Source: RevenueBase Database · checked Sep 15, 2026
24Partial evidenceLondon, United KingdomHQ checked Sep 15, 202651-200125 contacts →

Partial evidence

“Mitie Energy are an award-winning, UK-based energy, utilities and sustainability solutions business.”

Source: RevenueBase Database · checked Sep 15, 2026
25Partial evidenceCardiff, United KingdomHQ checked Sep 15, 202651-200124 contacts →

Partial evidence

“We are an award-winning energy consultancy and certified B Corp™.”

Source: RevenueBase Database · checked Sep 15, 2026

Showing 25 of 1,399 energy as a service companies based in the United Kingdom

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Energy as a service companies based in the United Kingdom at a glance

As of Sep 15, 2026
35.2%Verified-email coverage
30.4Average contacts per company
1-10Median size (employees)
15.5%Largest-city concentration · London
Sep 15, 2026Page data refreshed

Companies by employee count

1-10
744
11-50
486
51-200
111
201-500
27
501-1,000
8
1,001-5,000
7
5,001-10,000
2
10001+
5

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 1,399 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 energy as a service companies, 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 Kingdom whose own description of what they do matches “energy as a service companies”. 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 energy as a service companies), 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 energy as a service companies, and records with no verified work email. Companies headquartered outside United Kingdom 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, 14,973 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 15, 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.

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 energy as a service companies, 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 energy as a service companies are there based in the United Kingdom?

RevenueBase identified 1,399 energy as a service companies headquartered in the United Kingdom 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?

British GAS, headquartered in Windsor, tops this list with the largest team on record.

Which city has the most energy as a service companies?

London leads with 217 headquartered companies, followed by Manchester (44) and Leicester (25).

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 14,973 verified decision-maker contacts tracked across these 1,399 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 15, 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.