| # | Company | Employees |
|---|---|---|
| 1 | 208,511 | |
| 2 | 85,000 | |
| 3 |
Rolls-Roycerolls-royce.com
Engineering excellence driving critical technologies for air, sea, and land, powering, protecting, and connecting people worldwide. |
31,649 |
| 4 |
National Gridnationalgrid.com
Operate and develop electricity transmission and distribution networks, natural gas systems, and invest in clean energy infrastructure and technology ventures. |
17,432 |
| 5 |
Subsea7subsea7.com
Provides offshore services supporting lower-carbon oil and gas evolution, renewable energy growth, and emerging energy solutions for energy transition. |
13,582 |
| 6 | 12,070 | |
| 7 |
EDF (UK)edfenergy.com
Leading sustainable energy transition, building nuclear power, investing in renewables like wind and solar, and electrifying homes and businesses with low-carbon technology. |
8,774 |
| 8 |
Johnson Mattheymatthey.com
development of sustainable technologies supporting energy, chemicals, and automotive sectors to decarbonise, reduce emissions, and enhance sustainability |
8,592 |
| 9 |
Perencoperenco.com
An independent hydrocarbon producer, involved in the entire lifecycle of projects, from exploration to decommissioning, operating globally with a strong team. |
6,910 |
| 10 |
Octopus Energyoctopus.energy
providing affordable, transparent renewable energy solutions with innovative technology and exceptional customer service across multiple countries and sectors |
5,415 |
| 11 |
Utility Warehouseuw.co.uk
A growing business focusing on simplifying utilities and providing personalized service to help people spend more time on important things |
5,083 |
| 12 |
Vivo Energyvivoenergy.com
A leading energy company in Africa, distributing Shell and Engen branded fuels and lubricants to retail and commercial customers with a focus on safety, innovation, and customer satisfaction |
5,081 |
| 13 |
Shell Energyshell.com
Support businesses with energy management, cost control, efficiency improvement, and achieving decarbonisation goals for sustainable energy futures. |
4,145 |
| 14 |
Ensco plcvalaris.com
A global leader in advanced operations, Valaris prioritizes safety, ethics, and innovation to provide lasting value for employees and partners worldwide |
3,604 |
| 15 |
Invensys - Acquired by Schneider Electricse.com
Designing and supplying advanced technologies that optimize operational performance and profitability for industrial and commercial customers, including software, systems, and controls. |
3,544 |
| 16 |
UK Power Networksukpowernetworks.co.uk
This company is a leading Distribution Network Operator in the UK, serving millions of homes and businesses by maintaining and upgrading power equipment |
3,357 |
| 17 |
Equans UK & Irelandequans.co.uk
Provider of sustainable facilities management, energy, and digital services focused on decarbonisation and supporting low carbon transitions across sectors. |
2,344 |
| 18 |
Krakenkraken.tech
AI-powered operating system enhancing customer satisfaction, product innovation, revenue generation, and operational savings for energy, water, and telco utilities. |
2,125 |
| 19 |
Urenco Globalurenco.com
Supplier of nuclear fuel enrichment services using centrifuge technology, ensuring safe, reliable, and sustainable nuclear fuel supply globally. |
2,027 |
| 20 |
Borr Drillingborrdrilling.com
Offshore drilling contractor providing worldwide services with premium jack-up rigs for safe, efficient, and sustainable operations in water depths up to 400 feet |
1,947 |
| 21 |
E.ON Nexteonnext.com
Helping customers reduce energy bills and environmental impact by facilitating the energy transition and promoting CO2 savings in the UK. |
1,792 |
| 22 |
Huntinghuntingplc.com
Global energy services provider to top oil and gas companies, specializing in manufacturing and distributing products for extraction Headquartered in the UK |
1,713 |
| 23 |
ENGIE UKengie.co.uk
A global energy player with investments in renewable energy and storage, providing energy solutions to organizations, committed to achieving net zero carbon |
1,468 |
| 24 |
Associated British Portsabports.co.uk
Management of 21 UK ports handling significant trade volumes, supporting offshore wind industry, decarbonisation, property development, marine research, and dredging services. |
1,409 |
| 25 |
Octopusoctopusgroup.com
It is an entrepreneurial investment group focused on building businesses that address societal challenges, emphasizing stakeholder interests and sustainability. |
1,234 |
| 26 |
Lightsource bplightsourcebp.com
A global solar leader in partnership with bp, developing, managing, and operating solar projects while prioritizing sustainability and community impact |
1,130 |
| 27 |
Faithful+Gouldatkinsrealis.com
Global engineering services and nuclear organization connecting people, data, and technology to transform infrastructure and energy systems worldwide. |
1,116 |
| 28 |
Trident Energybit.ly
A leading player in oil and gas, specializing in acquiring and revitalizing mid-life assets, focusing on growth, value creation, sustainability, and community engagement |
1,098 |
| 29 |
EDF Tradingedftrading.com
Management of global energy assets including electricity, gas, oil, and environmental products, providing market access and risk management. |
963 |
| 30 |
TNK-BPtnk-bp.com
A company in the oil and gas sector acquired by Rosneft, engaged in the exploration, production, and distribution of oil and natural gas |
888 |
| 31 |
Greenergygreenergy.com
A leading supplier of waste-based renewables and transportation fuels, committed to driving transport decarbonisation through reliable customer service and global supply chain |
879 |
| 32 | 869 | |
| 33 |
Nadaranadara.com
Ownership and operation of around 200 renewable energy sites across Europe and the US producing electricity from wind, solar, waste-to-energy, and biomass. |
836 |
| 34 |
SmartestEnergysmartestenergy.com
An energy company empowering customers, generators, and partners to transition to renewable energy and achieve net zero emissions through innovative solutions |
820 |
| 35 |
Centrica Energycentricaenergy.com
Renewable energy trading company moving energy globally while driving green transition with sustainable costs, fostering a culture of employee engagement and empowerment |
818 |
| 36 |
Assala Energyassalaenergy.com
An energy company in Africa focused on acquiring mature oil and gas assets, increasing production and reserves through field redevelopment |
776 |
| 37 |
Kaluzakaluza.com
Energy software company enabling energy suppliers to streamline operations, enhance customer service, and drive decarbonisation through smart technology solutions |
710 |
| 38 |
Smart DCCsmartdcc.co.uk
Digitising Britain's energy infrastructure through a secure wireless network connecting smart meters to energy suppliers and operators for efficiency. |
684 |
| 39 |
Fieldfield.energy
A company leading the way in renewable energy infrastructure and trading, starting with energy storage to create a reliable national grid |
668 |
| 40 |
SEFE Marketing & Trading Ltdsefe-mt.com
Leading European energy trading company offering physical & financial trading of LNG, gas, power, environmental products, and hydrogen with risk management services |
643 |
| 41 |
Sonnedixsonnedix.com
Delivering clean electricity to customers through solar, wind, and storage assets; acquiring, developing, building, and operating renewable energy projects. |
628 |
| 42 |
Energeanenergean.com
Independent E&P company focused on developing resources in Mediterranean & UK North Sea Committed to sustainable development and being net zero emitter by 2050 |
627 |
| 43 |
EDF power solutions UK and Irelandedf-powersolutions.uk
Renewable energy company in the UK with a portfolio of onshore, offshore, battery, and solar projects, focusing on affordable low carbon electricity and community engagement |
593 |
| 44 |
Atlantica Sustainable Infrastructure Plcatlantica.com
Atlantica is a sustainable infrastructure company investing in renewable energy, storage, natural gas, transmission lines, water assets for stable cash flows and growth |
586 |
| 45 |
Bouygues Energies & Services (UK)equans.co.uk
Facilities management, energy solutions, and connected cities services across the UK and Ireland focused on low carbon and resilience. |
586 |
| 46 |
Octopus Electric Vehiclesoctopusev.com
Specializing in electric car leasing and salary sacrifice packages, providing expert advice, great deals, and charging solutions to empower businesses and employees |
493 |
| 47 |
Podpodenergy.com
Leading provider of electric vehicle charging solutions for homes, public spaces, and workplaces, making clean energy easy, affordable, and accessible. |
453 |
| 48 |
Fuse Energyfuseenergy.com
A global full stack renewable energy company based in London, New York, and Texas Raised $78m from top investors to revolutionize the energy industry |
445 |
| 49 |
Cubico Sustainable Investmentscubicoinvest.com
Develops, constructs, and operates renewable energy projects globally, including wind, solar, and transmission lines, committed to clean energy transition and stable returns. |
435 |
| 50 | 427 | |
| 51 | 416 | |
| 52 |
Navigator Gasnavigatorgas.com
A leading shipping company with the world's largest fleet of liquefied gas carriers, providing international transportation and distribution of LPG, petrochemical gases, and ammonia |
408 |
| 53 |
bp pulsebppulse.com
Delivers reliable and effortless electric vehicle charging solutions for drivers and fleets, changing how the world moves at various locations. |
382 |
| 54 |
Zenob膿zenobe.com
Increases renewable power, accelerates electric fleets, and extends EV battery life by repurposing for various portable power applications, minimizing costs and maximizing sustainability. |
354 |
| 55 |
Luceco Groupluceco.com
Manufacturing and distributing LED lighting products, EV chargers, wiring devices, circuit protection, portable power solutions, and audio-visual accessories for various global industries. |
351 |
| 56 |
Glencore UKglencore.com
Global natural resource company involved in sourcing commodities essential for modern life, including oil trading, production, and strategic investments in handling and storage facilities |
321 |
| 57 |
Mitsui Bussan Commoditiesmitsuibussancommodities.com
Specializes in trading and marketing commodity derivatives for energy, metals, and steel, providing risk management and market expertise. |
311 |
| 58 |
Ohmeohme-ev.com
An end-to-end electric charging solutions provider for homes, businesses, and on-the-go, supporting the global transition to renewables |
310 |
| 59 |
INTEC Energy Solutionsin-tecenergy.com
INTEC Energy Solutions develops and constructs high-quality turnkey solar power plants globally, offering EPC, O&M services, and cutting-edge smart energy solutions for a sustainable future |
304 |
| 60 |
UK Power Networks Servicesukpowernetworksservices.co.uk
The company provides innovative energy solutions for resilience, cost efficiency, and sustainability, enabling clients to navigate the energy transition and decentralization |
293 |
| 61 |
Petroineos Trading Limitedpetroineos.com
Integrated energy trading company supplying crude oil to refineries, trading crude and refined products, operating refineries in Scotland and France. |
290 |
| 62 | 286 | |
| 63 |
Low Carbonlowcarbon.com
Development and operation of renewable energy projects aiming to achieve net-zero emissions and contribute significantly to climate change mitigation. |
231 |
| 64 |
Equitixequitix.com
Responsible investor developing and managing global infrastructure assets, contributing to communities. Employs 200 professionals, manages 360 assets in 20 countries, $12bn AUM. |
223 |
| 65 |
Javelin Global Commoditiesjavelincommodities.com
Global commodities marketing, trading, logistics, financing, and advisory company with expertise in bulk, steel, energy, green carbon, renewable fuels, and soft commodities Operating globally |
214 |
| 66 | 181 | |
| 67 |
ABF Sugarabfsugar.com
Production of sugar and diverse products including ethanol, animal feed, renewable power, and pharmaceutical ingredients from sugar cane and beet. |
180 |
| 68 |
CFP Energycfp.energy
Providing energy and environmental solutions including carbon procurement, risk management, asset optimisation for industrial and commercial clients. |
178 |
| 69 |
Bulbbulb.co.uk
Supplier of 100% renewable electricity and carbon offset gas with transparent pricing and technology to help reduce energy use. |
174 |
| 70 |
Mitie Energymitie.com
Award-winning UK-based energy, utilities, and sustainability solutions provider offering independent end-to-end services to help clients achieve maximum efficiencies and cost-savings |
151 |
| 71 | 148 | |
| 72 | 140 | |
| 73 |
AMP Clean Energyampcleanenergy.com
An energy company providing practical solutions to address climate change and facilitate the transition to sustainable energy practices |
130 |
| 74 |
Hometreehometree.co.uk
providing installation, repair, and financing of low-carbon home energy hardware to help homeowners transition to net zero |
129 |
| 75 |
Genesis Energygenesisenergygroup.net
An Energy Infrastructure Development and Management company operating in Africa, with a focus on providing power solutions to unlock economic growth potentials |
128 |
| 76 |
Pacific Greenpacificgreen.com
Provides sustainable cleantech solutions, addressing climate warming, green energy, and resource scarcity through technological innovation and engineering solutions globally. |
122 |
| 77 |
Connected Kerbconnectedkerb.com
An electric vehicle charging company dedicated to making charging inclusive, convenient, and reliable, while supporting sustainable mobility and future technologies #ConnectedForGood |
120 |
| 78 | 112 | |
| 79 |
Believbeliev.com
Building and operating reliable, accessible, and sustainable EV charging networks in the UK for communities, local authorities, landowners, and businesses, powered by 100% renewable energy. |
110 |
| 80 |
eEnergyeenergy.com
Funding and delivering energy-saving and energy-generating solutions across multi-site public sector and commercial portfolios, cutting energy waste, reducing operating costs, and improving building resilience. |
105 |
| 81 |
Highviewhighviewpower.com
Leading energy infrastructure business, uniting proprietary power systems analytics, world-class technologies, and strategic finance to build and operate grid-scale assets for clean energy goals. |
104 |
| 82 |
Cory Environmentalcoryenvironmental.co.uk
A leading UK recycling, waste management, and energy recovery company with over 100 years of experience managing 35 million tonnes annually Employing over 1,000 people nationwide |
101 |
| 83 | 93 | |
| 84 |
Cummins Europecummins.com
Design, manufacture, and service advanced powertrain technologies including diesel, electric, hydrogen, and components for diverse industries across Europe. |
90 |
| 85 |
NextEnergy Capitalnextenergycapital.com
Specialist investment and asset manager in the solar sector, leading transition to clean energy through private and public investment platforms globally. |
86 |
| 86 |
CARNOTcarnotengines.com
We develop highly efficient, zero emission powertrains for long-haul transport and off-grid power, aiming to reduce global CO2 emissions and accelerate the transition to net zero |
84 |
| 87 |
Quinbrookquinbrook.com
Specialist investment manager, focusing on infrastructure for energy transition. Conceives, develops, constructs, operates diverse innovative infrastructure projects and growth platforms. |
84 |
| 88 |
Energy Driveenergydrivesystems.com
Energy Drive specializes in providing sustainable energy solutions for energy-intensive industries globally, reducing energy consumption through innovative technology and long-term partnerships |
76 |
| 89 |
Source - EVsource-ev.com
Builds safest, most reliable, accessible electric vehicle charging network across UK and Ireland, ensuring stress-free dependable charging experience for all drivers. |
69 |
| 90 |
Osprey Charging Networkospreycharging.co.uk
Funds, installs, and manages a UK-wide rapid electric vehicle charging network, powered by 100% renewable electricity, accepting various payment methods. |
68 |
| 91 |
Octopus Electroverseelectroverse.com
Octopus Electroverse provides a seamless charging experience with one card and app for electric vehicles, offering access to a vast network of global public chargers |
67 |
| 92 |
Innovainnova.co.uk
Developing, building, and operating utility-scale renewable energy projects with multi-technologies to take large energy users off-grid, benefiting communities. |
64 |
| 93 |
Nexta Capital Partnersnexta-capital.com
Originates, develops, finances, builds, and operates renewable infrastructure assets, combining technological and financial expertise for carbon neutrality. |
60 |
| 94 |
Transmission Investmenttinv.com
Investment, development, and management of electricity infrastructure assets, including offshore wind transmission and interconnectors, along with providing technical and commercial assurance for investors. |
58 |
| 95 |
Hypervolthypervolt.com
Leading provider of residential EV charging solutions, focusing on powerful software, design, and user experience to accelerate clean energy with smart tech. |
57 |
| 96 |
Supercriticalsupercritical.solutions
Innovative company producing high pressure, ultra-efficient electrolyzers to generate pressurized green hydrogen at a low cost |
50 |
| 97 |
Bluefield Partners LLPthebluefieldgroup.com
Investing in European renewable energy assets, including solar, wind, and battery storage, across various stages, managing significant assets under management. |
49 |
| 98 |
South East London Community Energy (Selce)selce.org.uk
A not-for-profit co-operative specializing in renewable energy projects, energy efficiency, and community initiatives in South East London |
34 |
| 99 |
Zapgozapgo.co.uk
A UK-based electric vehicle charge point operator creating a Rapid and High Power Charger network in high traffic areas |
31 |
| 100 |
The EV Networktheevnetwork.com
Develops, funds, builds, and owns ultrafast EV charging hubs across the UK, Europe, and USA, providing infrastructure as a service for landlords, operators, and fleets. |
31 |
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Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Oct 24, 2026.
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