Company lists · Data refreshed September 2026

Top 20 Geothermal energy developers based in the United Kingdom

RevenueBase identified 43 geothermal energy developers headquartered in the United Kingdom as of September 2026 and tracks 366 professional contacts across them, including 171 with verified work emails. London is the largest hub.

This list covers geothermal energy developers 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 16, 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 16, 2026 86% judged on-target in blind review
43Companies
366Contacts tracked
171Verified emails
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The 20 largest geothermal energy developers based in the United Kingdom

Ranked by team size
Top 20 of 43 geothermal energy developers based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to geothermal energy developers: 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
1Partial evidenceSudbrooke, United KingdomHQ checked Sep 16, 202651-20083 contacts →

Partial evidence

“Star Energy Group plc is a British energy business.”

Source: RevenueBase Database · checked Sep 16, 2026
2Strong evidenceLondon, United KingdomHQ checked Sep 16, 202651-20060 contacts →

Strong evidence

“Rendesco is the UK’s leading clean energy tech developer and operator, focusing on the electrification of heat using heat pumps and heat networks to decarbonise Britain’s…”

Source: RevenueBase Database · checked Sep 16, 2026
3Strong evidenceGreat Yarmouth, United KingdomHQ checked Sep 16, 202611-5028 contacts →

Strong evidence

“CeraPhi Energy is a leading project development company delivering global geothermal energy solutions at scale.”

Source: RevenueBase Database · checked Sep 16, 2026
4Partial evidenceStokesley, United KingdomHQ checked Sep 16, 202611-5021 contacts →

Partial evidence

“Carlton Power Group is an independent, UK energy development company formed in 1995, with offices in Stokesley, North Yorkshire and Edinburgh.”

Source: RevenueBase Database · checked Sep 16, 2026
5Strong evidenceRedruth, United KingdomHQ checked Sep 16, 20261-1014 contacts →

Strong evidence

“GEL has brought the most experienced geothermal engineers together with leading industry partners to develop the UK's first large-scale geothermal energy plant in Cornwall.”

Source: RevenueBase Database · checked Sep 16, 2026
6Partial evidenceEdinburgh City, United KingdomHQ checked Sep 16, 202611-5014 contacts →

Partial evidence

“We are an award-winning geothermal company based in Edinburgh, Scotland and a leading specialist in all aspects of the UK’s geothermal resources.”

Source: RevenueBase Database · checked Sep 16, 2026
7Partial evidenceAylesbury, United KingdomHQ checked Sep 16, 202611-5014 contacts →

Partial evidence

“We specialise in Geothermal Ground Source Boreholes and Water Boreholes up to 300m.”

Source: RevenueBase Database · checked Sep 16, 2026
8Partial evidenceEdinburgh, United KingdomHQ checked Sep 16, 202611-5013 contacts →

Partial evidence

“Gravitricity develops long-life underground technologies that help solve the problem of intermittent renewable energy by storing excess energy during periods of low demand and…”

Source: RevenueBase Database · checked Sep 16, 2026
9Indirect evidenceLondon, United KingdomHQ checked Sep 16, 20261-109 contacts →

Indirect evidence

“Smart, sustainable heating and cooling, powered by the earth.”

Source: RevenueBase Database · checked Sep 16, 2026
10Strong evidenceLondon, United KingdomHQ checked Sep 16, 202611-508 contacts →

Strong evidence

“The Geothermal Energy Forum a new, dedicated platform within the REA, to help drive growth in this high potential sector was created following the acquisition of GEAA by the REA…”

Source: RevenueBase Database · checked Sep 16, 2026
11Strong evidenceCornwall, United KingdomHQ checked Sep 16, 202611-507 contacts →

Strong evidence

“Eden Geothermal Ltd is a partnership between Eden Project, EGS Energy Ltd, and Bestec (UK) Ltd, set up to unlock the geothermal energy deep in the granite beneath Cornwall.”

Source: RevenueBase Database · checked Sep 16, 2026
12Partial evidenceLondon, United KingdomHQ checked Sep 16, 20261-105 contacts →

Partial evidence

“dCarbonX is a pioneering asset-focused GeoEnergy company established to develop subsurface assets for energy storage and for the sequestration of CO2.”

Source: RevenueBase Database · checked Sep 16, 2026
13Strong evidenceBordon, United KingdomHQ checked Sep 16, 202611-504 contacts →

Strong evidence

“At Onsen Energy, we provide homeowners, developers, sports clubs, schools and the wider energy market with ground source heating systems and drilling services.”

Source: RevenueBase Database · checked Sep 16, 2026
14Strong evidenceCambridge, United KingdomHQ checked Sep 16, 20261-104 contacts →

Strong evidence

“Primeval Energy is a geothermal solutions company, newly established by seasoned oil and gas, geothermal, finance and commercial professionals.”

Source: RevenueBase Database · checked Sep 16, 2026
15Indirect evidenceLondon, United KingdomHQ checked Sep 16, 20261-103 contacts →

Indirect evidence

“Clean.”

Source: RevenueBase Database · checked Sep 16, 2026
16Strong evidenceAberdeen, United KingdomHQ checked Sep 16, 20261-103 contacts →

Strong evidence

“In a world that is looking for clean, reliable, and renewable energy solutions, ZeGen Energy has developed a model to effectively identify potential heat and power production by…”

Source: RevenueBase Database · checked Sep 16, 2026
17Strong evidenceCheshire, United KingdomHQ checked Sep 16, 202611-502 contacts →

Strong evidence

“Geo Energy Holding is a UK based global renewable energy holding with the vision of utilizing each droplet of geothermal brine and steam, maximizing power generation efficiencies…”

Source: RevenueBase Database · checked Sep 16, 2026
18Partial evidencePortadown, United KingdomHQ checked Sep 16, 20261-102 contacts →

Partial evidence

“Gravity Fellow is a deep-tech clean energy company pioneering the next generation of renewable energy production and storage.”

Source: RevenueBase Database · checked Sep 16, 2026
19Strong evidenceLondon, United KingdomHQ checked Sep 16, 202611-501 contacts →

Strong evidence

“EEW Eco Energy World (‘EEW’), founded by entrepreneur Svante Kumlin is an independent global pure-play renewable energy projects developer,focusing on utility-scale solar…”

Source: RevenueBase Database · checked Sep 16, 2026
20Partial evidenceBournemouth, United KingdomHQ checked Sep 16, 20261-101 contacts →

Partial evidence

“Welcome to OGPEG, where we uncover the truth behind our energy choices and their profound impact on our planet.”

Source: RevenueBase Database · checked Sep 16, 2026

Showing 20 of 43 geothermal energy developers based in the United Kingdom

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Geothermal energy developers based in the United Kingdom at a glance

As of Sep 16, 2026
46.7%Verified-email coverage
8.5Average contacts per company
1-10Median size (employees)
30.2%Largest-city concentration · London
Sep 16, 2026Page data refreshed

Companies by employee count

1-10
24
11-50
17
51-200
2

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 43 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 geothermal energy developers, 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 “geothermal energy developers”. 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 geothermal energy developers), 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 geothermal energy developers, 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, 171 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 16, 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 geothermal energy developers, 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 geothermal energy developers are there based in the United Kingdom?

RevenueBase identified 43 geothermal energy developers 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?

Star Energy Group PLC, headquartered in Lincoln, tops this list with the largest team on record.

Which city has the most geothermal energy developers?

London leads with 13 headquartered companies, followed by Edinburgh (3) and Great Yarmouth (2).

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 171 verified decision-maker contacts tracked across these 43 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 16, 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.