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Cleantech Companies in Cardiff: 31 Active Firms (2026)
Cleantech companies in Cardiff develop lower-carbon technologies, energy solutions and environmental services for the city region.
Buying centres tend to sit with estates and facilities teams, infrastructure operators, energy managers, environmental compliance leads and commercial directors trying to cut operating costs or meet contractual climate requirements. Cardiff suppliers are therefore often selling applied engineering, monitoring, advisory or managed-service work rather than pure software licences. Engagements are usually implementation-led: feasibility work, pilot deployments, equipment-backed service contracts, monitoring retainers or project packages for property, public-sector, industrial and energy customers. The buyer profile points more to small and mid-market organisations than to global enterprise procurement, although infrastructure and municipal work can lengthen sales cycles.
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Cardiff has 31 actively trading cleantech companies in this list, making it a small city-region cohort rather than a broad national cluster. Reported headcount totals 303 people, so the employment footprint is modest and likely concentrated in specialist technical, commercial and project-delivery roles. Only 3 companies report turnover above £5M, which fits a market made up largely of lean operators, consultancies and engineering-led suppliers rather than a deep bench of revenue-scale businesses. For researchers, the useful read is less about volume and more about the mix of applied environmental services, low-carbon operations and infrastructure-facing work.
With 8 firms incorporated since 2022, part of the Cardiff cohort is still close to formation and likely to face the usual proof burden around pilots, warranties, insurance cover and procurement eligibility. Cleantech selling into energy, property, infrastructure and public-sector buyers tends to be shaped by compliance evidence as much as by technical claims. Environmental performance has to be auditable, installation work has to fit planning and site constraints, and public buyers usually need enough assurance to defend procurement decisions. That makes reference projects, certification and measurable operating savings more important than general sustainability language.
Future development appears likely to depend on adoption by property owners, local infrastructure managers and industrial operators rather than on a single breakout technology category. The cohort looks practical and service-adjacent, with many suppliers likely to win work through audits, retrofits, monitoring, maintenance and project delivery. Younger firms tend to need demonstrable reference sites before buyers commit, while more mature operators may be pulled into partnerships with engineering, construction or energy-services groups. Consolidation may happen at the margins, but the Cardiff market seems more likely to broaden through steady procurement-led adoption than through speculative company formation.
31
Active firms
2026
3
Above £5M revenue
upper-revenue cohort
8
Recent incorporations
incorporated since 2022
Key facts
About 9% of the trading cohort reports turnover above £5M (3 of 31 firms) — the rest sits below that revenue band.
25% of the cohort was incorporated since 2022 (8 firms), so a sizeable share is in its first few filing cycles.
Cardiff’s cleantech segment spans lower-carbon technologies, energy solutions and environmental services rather than one narrow product category.
The local market acts as a supply base for decarbonisation work across the Cardiff city region.
Business models in this segment appear to mix technology development, service delivery and environmental operations.
Top Cardiff Cleantech companies
SERO LIFE LIMITED
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsProvides retrofit and energy services for social housing, installing technologies such as solar panels and batteries, aggregating homes to purchase electricity and participate in flexibility markets,…
Serves UK social housing landlords and their residents, alongside institutional investors and funders focused on climate and social-impact opportunities in housing retrofit and energy efficiency.
Financial Health
StrongStrong · Hiring · 47% CAGR over 4y
Location
Nu Asset Capital Ltd
Trajectory
2y · 2024–NowFinancial sub-scores
Computed from 2 filingsDesigns, installs and maintains commercial renewable energy systems including solar PV arrays, battery storage and electric vehicle charging infrastructure. Provides consultancy, system integration…
Serves UK businesses and commercial property operators pursuing low-carbon energy projects, plus organisations needing commercial, public or domestic EV charging facilities and EPC contractors in…
Financial Health
StableStable
Location
Trajectory
5y · 2022–NowFinancial sub-scores
Computed from 5 filingsDevelops building management system (BMS) software and controls platform for monitoring and managing building systems. Provides energy metering, live performance monitoring, room and plant control,…
Serves building owners, estate managers and specifiers, including councils, universities, student accommodation providers, construction companies, MEP consultants and off-site building firms across…
Financial Health
WeakWeak · -68% CAGR over 4y
Location
Provides energy infrastructure, smart metering installation and management, and gas and electricity data services. Also delivers energy management, demand flexibility and project delivery services to…
Serves UK energy suppliers, utilities, industrial and commercial organisations, public sector bodies and domestic consumers involved in energy generation, supply and consumption.
Location
Ecogen Innovations Ltd
Trajectory
1y · 2025–NowDevelops renewable energy systems including waste-to-energy plants that convert municipal waste into electricity, hybrid solar‑wind microgrids with battery storage, modular off‑grid power units, and…
Serves government agencies, municipalities, hospitals, community leaders and businesses needing clean energy infrastructure, including towns, industries, remote or off-grid communities, disaster…
Financial Health
Insufficient historyInsufficient history
Location
TRYDAN GWYRDD CYMRU LTD
Trajectory
2y · 2024–NowFinancial sub-scores
Computed from 2 filingsDevelops and delivers renewable energy generation projects, including onshore wind farms, solar farms and battery energy storage systems. Works with public sector partners and stakeholders to plan,…
Serves Welsh public sector bodies, local communities and stakeholders involved in public-estate renewable energy projects, with benefits intended for people living and working across Wales.
Financial Health
HealthyHealthy · Hiring · 80% CAGR over 1y
Location
Nuvolt Group Ltd
Trajectory
2y · 2024–NowFinancial sub-scores
Computed from 2 filingsDesigns, installs and maintains commercial renewable energy systems including solar PV, battery storage and electric vehicle charging infrastructure. Provides consultancy, system design, installation…
Sells primarily to businesses seeking commercial solar, battery storage and EV charging, including UK commercial clients and EPC contractors. Also serves organisations needing domestic or public EV…
Financial Health
WeakWeak
Location
2 Degrees Kelvin Ltd
Trajectory
4y · 2022–NowFinancial sub-scores
Computed from 4 filingsProvides engineering consultancy and technical services for utility‑scale solar photovoltaic projects, including design and development advisory, construction management, inspection and testing,…
Serves B2B clients involved in utility-scale solar PV assets, including developers, asset owners, investors, EPC/construction partners and operators across design, construction, commissioning,…
Financial Health
StrongStrong · Growing, Hiring · 34% CAGR over 3y
Location
Resolve Bioenergy Ltd
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsProvides consultancy, operational support and maintenance services for biogas and anaerobic digestion plants, including performance optimisation, asset management, monitoring and reporting,…
Serves owners, operators and investors of biogas and anaerobic digestion plants, including privately owned and investor-owned sites.
Financial Health
StrongStrong · Growing, Hiring · 12% CAGR over 4y
Location
CAP SOLAR PARTNERS LIMITED
Trajectory
3y · 2021–NowFinancial sub-scores
Computed from 3 filingsDesigns and manufactures flexible solar panels and onboard solar power systems for vehicles including trucks, vans, boats and recreational vehicles. Provides custom integration, engineering and…
Serves B2B customers in mobility sectors, including transport and logistics fleets, boat builders/operators, recreational vehicle users, and custom van conversion companies needing on-board solar…
Financial Health
StrongStrong · Profitable, Growing, Hiring · 91% CAGR over 3y
Location
REGENCY OILS (WALES) LIMITED
Trajectory
4y · 2022–NowFinancial sub-scores
Computed from 4 filingsProvides waste cooking oil collection and fresh cooking oil delivery for food businesses. Collects used frying oils and fats, supplies containers, handles waste transfer documentation, and sends…
Serves B2B foodservice customers such as restaurants, takeaways, cafés and commercial kitchens in South Wales and surrounding areas that use frying oils and need compliant disposal.
Financial Health
HealthyHealthy · Hiring · 26% CAGR over 3y
Location
Develops and promotes onshore wind energy parks. Plans and manages renewable energy projects, including site development, consultation and planning applications, to generate electricity from wind and…
Serves energy-sector and public stakeholders in Wales, including local communities, groups and services involved in renewable energy parks, community benefit funding and decarbonisation projects.
Location
RESOURCES MANAGEMENT U.K. LIMITED
Trajectory
3y · 2019–NowFinancial sub-scores
Computed from 3 filingsProvides waste management and recycling services including skip hire, trade refuse collection and operation of waste transfer stations and recycling centres. Processes commercial and household waste,…
Serves households, trades and commercial organisations across Wales, the Welsh borders and parts of the West Midlands, plus equestrian customers using recycled carpet surfaces.
Financial Health
StableStable · -27% CAGR over 2y
Location
ECO2 MANAGEMENT SERVICES LIMITED
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsProvides asset management and development services for renewable energy projects, including biomass, wind, solar and anaerobic digestion plants. Services include operational and financial management,…
Serves renewable energy asset owners and investors, including UK investment funds, large portfolio holders and small operators of biomass, wind, solar and anaerobic digestion assets.
Financial Health
StableStable · -63% CAGR over 4y
Location
Sustainable Energy
Provides engineering and consultancy services for renewable and low‑carbon energy systems, including district heating and decentralised energy networks. Services cover energy masterplanning,…
Serves public sector bodies, large utility companies and organisations developing renewable, low-carbon and district heating projects across the UK, including decentralised energy and…
Location
Trajectory
2y · 2021–NowFinancial sub-scores
Computed from 2 filingsDevelops renewable energy projects, focusing on onshore wind farms and solar generation. Plans and promotes proposed wind farm sites, secures investment, and manages project development through…
Financial Health
StrongStrong
Location
HYDROLOGISTICS AFRICA LIMITED
Trajectory
5y · 2020–NowFinancial sub-scores
Computed from 5 filingsProvides software and data platforms for water utilities and distributors, integrating IoT sensors and smart meters to monitor water networks, analyse consumption, detect leaks, and manage metering,…
Serves water utilities, businesses, industrial water users and households across Africa, including organisations managing water distribution networks and consumers paying utility bills.
Financial Health
StrongStrong · Hiring · 11% CAGR over 5y
Location
BIOMAN SERVICES LIMITED
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsProvides servicing, maintenance and repair for biomass boiler systems. Offers commissioning, remediation, spare parts supply and remote monitoring, along with plant room service contracts and…
Serves UK organisations and property owners operating biomass boiler systems, from small kW installations to MW-scale plant, including customers with ongoing failures, maintenance contracts or RHI…
Financial Health
HealthyHealthy · Hiring · 7% CAGR over 4y
Location
FLEETEV LIMITED
Trajectory
4y · 2022–NowFinancial sub-scores
Computed from 4 filingsProvides electric vehicle leasing and salary sacrifice schemes for businesses, public sector organisations and employees. Also offers fleet electrification consultancy, vehicle procurement and…
Serves UK businesses, public sector organisations and large fleet operators, plus employees accessing salary sacrifice schemes and individuals seeking electric vehicle leasing.
Financial Health
HealthyHealthy · -55% CAGR over 3y
Location
WP GRID STORAGE 5 LIMITED
Trajectory
3y · 2023–NowFinancial sub-scores
Computed from 3 filingsDevelops, constructs and manages distributed energy assets including gas‑fired peaking plants, grid stability infrastructure and battery storage projects, providing flexible power generation and…
Serves B2B energy asset owners, developers and infrastructure investors with flexible generation, grid stability and battery projects for electricity networks across the UK.
Financial Health
StableStable
Location
Trajectory
2y · 2024–NowFinancial sub-scores
Computed from 2 filingsDevelops and operates AI-based ESG and sustainability intelligence platforms that collect, verify and analyse environmental, social and compliance data. Provides tools for carbon emissions tracking,…
Serves governments, sovereign funds and large enterprises, including sustainability, risk, supply-chain and reporting teams subject to ESG disclosure, audit, compliance and carbon-market requirements.
Financial Health
StableStable
Location
Vision Clean Limited
Trajectory
5y · 2022–NowFinancial sub-scores
Computed from 5 filingsInvests in and develops clean energy and waste conversion technologies through subsidiary companies, including facilities that convert waste plastic into fuels and hydrogen and development of…
Serves investors and partners interested in clean-economy technologies, and B2B markets in waste management, recycling, energy and industrial power seeking plastic conversion and hydrogen fuel cell…
Financial Health
DistressedDistressed · -18% CAGR over 4y
Location
Trajectory
3y · 2023–NowFinancial sub-scores
Computed from 3 filingsProvides ESG and energy transition consulting to oil, gas and mining companies. Develops standards for reporting environmental, social and governance performance, and offers research funding…
Serves oil, gas, mining and energy resources organisations, including large and small private or public companies, plus related stakeholders such as investors, policymakers and capital markets…
Financial Health
StableStable
Location
GB-SOL LIMITED
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsManufactures solar photovoltaic panels and roof‑integrated solar systems including solar slates and full‑roof PV coverings. Provides mounting systems, battery storage integration, and installation…
Serves homeowners, architects, developers, commercial building owners, industrial operators, social housing providers and marine customers across Great Britain.
Financial Health
HealthyHealthy · -1% CAGR over 4y
Location
TEWDRIC ENERGY CYMRU LTD
Trajectory
1y · 2025–NowDesigns and installs solar photovoltaic (PV) systems, battery energy storage, and electric vehicle charging points for homes, businesses, and community projects, providing on‑site renewable…
Serves homeowners, businesses, councils, housing associations and local community groups across South Wales seeking solar, battery storage and EV charging solutions.
Financial Health
Insufficient historyInsufficient history
Location
BIPV LIMITED
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsManufactures building‑integrated photovoltaic systems, including flexible thin‑film and semi‑flexible solar modules and solar roof tiles designed for integration with roofing systems. Supplies solar…
Serves architects, developers, roofing contractors and building owners in commercial, industrial and residential projects, plus modular builders and operators of fleets, leisure vehicles, carports…
Financial Health
WeakWeak · -63% CAGR over 4y
Location
Bryn Power Limited
Trajectory
3y · 2023–NowFinancial sub-scores
Computed from 3 filingsOperates anaerobic digestion facilities that process food waste and cattle slurry to produce biogas, generating renewable electricity and heat. Produces digestate biofertiliser and uses biomass…
Serves commercial and organisational food-waste producers across South Wales needing disposal routes, with renewable power supplied to the national grid.
Financial Health
StrongStrong · Growing · 0% CAGR over 2y
Location
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsDevelops integrated renewable energy systems including wind, solar and anaerobic digestion projects. Manufactures and supplies low‑carbon cementitious materials, including supplementary cementitious…
Serves concrete product manufacturers and construction projects across the UK, plus stakeholders, schools and local communities connected to renewable energy developments in Wales.
Financial Health
StableStable · -66% CAGR over 4y
Location
Trajectory
4y · 2022–NowFinancial sub-scores
Computed from 4 filingsDevelops, delivers and operates grid-scale battery energy storage systems (BESS). Procures and manages fast-response storage projects that store electricity and provide grid-balancing services,…
Serves UK power-sector stakeholders, infrastructure investors and mixed-use development partners involved in grid-scale battery storage, private-wire, micro-grid and EV charging projects.
Financial Health
WeakWeak
Location
Gensol Engineering Services Ltd
Trajectory
5y · 2021–NowFinancial sub-scores
Computed from 5 filingsProvides engineering, procurement and construction services for solar power projects, including design, installation and operations. Develops solar tracking systems and offers electric vehicle…
Serves businesses, utilities and public-sector buyers developing clean energy infrastructure, including solar project owners, commercial and industrial energy users, EV fleet operators, and…
Financial Health
WeakWeak · -11% CAGR over 4y
Location
Trajectory
3y · 2023–NowFinancial sub-scores
Computed from 3 filingsDevelops EV charge point management software and mobile apps that connect and control charging infrastructure. Platform supports workplace, fleet, public and residential charging, enabling tariff…
Serves businesses, public-sector organisations and charge point operators managing EV charging for workplaces, fleets, public sites and residential users, plus installers, car dealerships, energy…
Financial Health
WeakWeak · Hiring · 33% CAGR over 2y
Location
Infinite Renewables Wales Ltd
Trajectory
2y · 2024–NowFinancial sub-scores
Computed from 2 filingsDesigns, develops and manages renewable energy projects including wind, solar and battery storage systems. Supplies wind turbines and microgrid solutions, and provides consultancy, asset management,…
Serves businesses and organisations seeking renewable energy infrastructure, including industrial sites, sustainability teams, remote or off-grid operators, and international project partners.
Financial Health
WeakWeak · 0% CAGR over 1y
Location
Green Earth Supplies Ltd
Trajectory
5y · 2020–NowFinancial sub-scores
Computed from 5 filingsSupplies EndoTherm, a chemical additive for wet heating systems used in commercial and domestic buildings to improve heat transfer efficiency, reduce energy consumption and fuel use, and lower carbon…
Serves B2B customers operating commercial buildings and sites with wet heating systems, particularly organisations seeking to reduce energy costs and carbon emissions; also addresses domestic heating…
Financial Health
WeakWeak · Hiring · 28% CAGR over 5y
Location
G24 POWER LIMITED
Trajectory
5y · 2020–NowFinancial sub-scores
Computed from 5 filingsDesigns and manufactures dye‑sensitised solar cells (DSSC) that convert ambient light into electrical energy. Produces thin, flexible photovoltaic modules using roll‑to‑roll manufacturing for…
Sells to global OEMs and product manufacturers, particularly in portable consumer electronics, wireless sensors and actuators, retail display systems, and other indoor electronic or battery-powered…
Financial Health
WeakWeak · -62% CAGR over 5y
Location
CLAYTON POWER SYSTEMS UK LTD
Trajectory
3y · 2023–NowFinancial sub-scores
Computed from 3 filingsDesigns and supplies lithium battery‑based mobile power systems for off‑grid and vehicle applications, including inverter/chargers, battery packs, solar panels and DC‑DC converters used in commercial…
Serves commercial vehicle specialists, fleet operators and converters in automotive sectors such as refrigerated and service vehicles, as well as leisure customers with campervans, cottages, yachts…
Financial Health
StableStable · -23% CAGR over 2y
Location
LIGHTHOUSE DEVELOPMENT CONSULTING LIMITED
Trajectory
4y · 2023–NowFinancial sub-scores
Computed from 4 filingsProvides planning and development consultancy for clean‑technology and renewable energy projects. Advises developers on planning strategy, prepares planning applications and supporting documentation,…
Serves B2B clean-tech and renewable energy developers, innovators, and project sponsors seeking planning consent for UK sustainable infrastructure projects, including solar farms and battery energy…
Financial Health
StrongStrong · Hiring · 59% CAGR over 3y
Location
NEMEIN LTD
Trajectory
5y · 2022–NowFinancial sub-scores
Computed from 5 filingsDesigns and manufactures thermal management and sensing technologies for drilling operations, including downhole power, imaging and telemetry systems, thermal shields and centralisers. Provides data…
Serves B2B energy and drilling organisations working in harsh downhole environments, including geothermal borehole operators and drilling teams involved in deep, hot wells.
Financial Health
StrongStrong · Growing · 0% CAGR over 4y
Location
QUANTUM ES LIMITED
Trajectory
3y · 2023–NowFinancial sub-scores
Computed from 3 filingsDesigns and supplies gas‑fuelled engines and generator sets for power generation. Builds systems using industrial engine cores to run on natural gas, LPG, biogas and syngas, including bespoke units…
Serves commercial and industrial organisations, power generation projects and biogas operators worldwide needing site-specific gas engine or generator sets for continuous power, CHP or off-grid…
Financial Health
DistressedDistressed · -12% CAGR over 2y
Location
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How Cardiff Cleantech companies work and how to sell to them
What they do
Cardiff cleantech firms usually earn revenue from projects, retained services and equipment-backed delivery rather than from licence-only software. A typical sale starts with an audit, feasibility study or site assessment, then moves into installation, monitoring, maintenance or advisory work if the buyer can see an operating saving or compliance benefit. Pricing therefore tends to mix fixed project fees, day-rate consultancy, hardware margin, service retainers and outcome-linked renewals. Gross margins can vary by job because subcontracted engineering, site access, warranties and ongoing support sit inside the commercial model. For sellers, that means budget ownership often follows the asset or site, not just the sustainability team.
Who they sell to
Most buyers are property owners and occupiers, facilities managers, infrastructure operators, public-sector teams and industrial firms with energy, waste or environmental obligations. The named decision-maker is often a Head of Estates, energy manager, operations director, environmental compliance lead or commercial director; finance teams tend to enter once payback, contract length and installation risk are clear. Sales motions are consultative and evidence-led. Smaller audits and monitoring retainers can move through direct sales, while retrofit, infrastructure and municipal work may involve frameworks, partner channels or formal tenders with slower procurement. Typical suppliers need case material, method statements and quantified savings rather than a purely climate-led pitch.
What they buy
Most cleantech firms tend to spend on tools and services that help them quote, deliver and prove projects. Useful categories include CRM, bid management, project costing, field-service scheduling, asset monitoring, customer reporting, billing, document control and carbon or energy analytics. Engineering-led suppliers may also need cloud hosting for sensor feeds, device management, cyber security, testing facilities, insurance, health and safety support and specialist recruitment. Professional-services spend often sits around planning, contracts, procurement compliance, tax, accounting and funding administration. The common thread is traceability: buyers downstream ask for evidence of performance, so internal systems that turn site work into auditable reports can be easier to justify.
Why and how to sell to them
Cleantech buyers tend to evaluate vendors when delivery pressure rises: a pilot becomes a multi-site rollout, a public-sector tender lands, a new commercial lead wants a cleaner pipeline, or a customer asks for better measurement of carbon, energy or waste outcomes. Common frictions are long proof cycles, hardware cashflow, site disruption, warranty exposure and the need to translate technical work into procurement-ready evidence. Outbound works best when it is tied to these moments rather than to generic sustainability claims. A credible angle is usually reduced admin, faster project delivery, clearer payback evidence, lower compliance risk or support winning and servicing larger contracts.
How this list is built
Data sources
This list is built from UK Companies House filings, XBRL accounts data, and semantic analysis of each company's public website. Revenue and headcount figures come from the most recent filed accounts; where the company has not filed, values are estimated using a model trained on filed history and peer benchmarks and are labelled as estimates.
Classification
Rather than relying solely on SIC codes, Firmbase classifies each company semantically: the company's website is crawled, an AI model reads what the company actually sells, and the company is placed into the relevant industry and subsectors. SIC codes are used as one signal but not the only one. This means a company that registered under a generic SIC code but pivoted into (for example) fintech is correctly identified as fintech, not as its original SIC category.
Freshness
The underlying company data is refreshed from Companies House continuously; filings appear in the list within days of submission. The curated list ordering is regenerated when the underlying data moves meaningfully (company count changes by more than 5%, a new company enters the top-ranked segment, or the filed-revenue numbers for the top firms change). You can see the last-updated timestamp near the top of the page.
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Frequently asked questions
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