Top 10 Cleantech Companies | 2023

Sam Peckett, 20 July 2023

Businesses in clean technology, or the cleantech sector, offer products or services that work to improve the long-term health of the environment and our natural ecosystems, and tackle climate change. They do this by mitigating the environmental impacts of traditionally harmful industries by creating innovative products that transform the way these industries work. 

Over the last ten years the cleantech sector in the UK has raised a huge £19.8b in equity fundraising. Cleantech investment grew massively from 2017 to 2021, demonstrating the appetite of investors for cleantech innovation. In 2017, £495m in total was raised, which rose rapidly to £914m in 2018, £1.56b in 2019, £1.79b in 2020 before peaking at £8.75b in 2021. Investment fell in 2021, but remained extremely high at £3.90b, and so far in 2023 £589m has been invested.

We have used the data from our online platform, which tracks 30,000 of the UK’s high-growth companies, to rank the top ten cleantech companies and startups by total funds raised. 

There’s a real mixture of companies on the list, ranging from early stage to established. You’ll find that many are in the energy sector working to mitigate the impact of the climate crisis. Some are using natural resources to create and distribute sustainable clean energy, while others are using new technologies to store energy and use power in an environmentally friendly, cost-efficient manner. There are also innovators and entrepreneurs working on the commercialisation of large scale plastic recycling to reduce waste, and others updating the automobile industry by improving the emissions of traditional fossil-fuelled vehicles, or deploying private and commercial electric vehicles on a large scale. Something they do have in common is innovation. To see the full list, read on! 



Able UK 

Founded: 1966
Location: Stockton-on-Tees
Total funding rounds: 3
Total funds raised: £339m

Able UK develops land and marine sites in the UK. The company operates across a variety of sectors, including land development, demolition, oil and gas rig maintenance, marine decommissions, port building and waste management.

A recent project is Able Energy Park, situated by a port on the Humber Estuary, which has been designed to support the marine renewable energy sector in the UK. The project has received up to £75m of government investment to allow for the energy park to support next-generation offshore wind projects.

The cleantech company has gone through three fundraisings worth £339m. The latest, worth £260m, was in December 2021. Investors include Getting Building Fund, Offshore Wind Manufacturing Investment Scheme and SeAH Wind.


Volta Trucks

Founded: 2019
Location: London
Total funding rounds: 4
Total funds raised: £289m

Volta Trucks create fully electric, zero-emission trucks designed for city driving. The company aims to minimise polluting fumes. Volta Trucks operates a ‘truck as a service’ model, providing trucks, charging infrastructure, maintenance, insurance, training and more under one payment for commercial fleets. Safety is top of mind in the truck designs too, with panoramic windows offering good visibility, cameras for 360 views of other road users and low entry for safe access.

The cleantech company opened its Trucks as a Service hub in London in June 2023. The hub will host admin officers, its training centre, a call centre and was officially opened by the Mayor of London and Tottenham MP David Lammy.

Across four fundraising rounds, Volta Trucks has raised £289m, including £51.9m in its latest round in November 2022. Investors include Agility Logistics, B-FLEXION, Luxor Capital, Proterra and other undisclosed investors.


OVO Group  

Founded: 2009
Location: Bristol
Total funding rounds: 4
Total funds raised: £259m

OVO Group is a cleantech company that aims to create a net-zero carbon world. The company has multiple retail brands focusing on sustainability including OVO Energy, an energy company that’s working to reduce its customers’ carbon footprint, SSE Energy Services, an energy provider and home cover company, Boost, a pay as you go energy company, and Corgi HomePlan, a boiler and home emergency company.

In June 2023, OVO Group launched OVO Solar, a package offering customers solar panels, batteries and a best-in-market energy buying rate. The company claims that over 90% can be saved on energy bills, which it hopes will make solar panels more viable to a new generation.

The cleantech company has been featured on high growth lists such as the Fast Track 100, FT 1000 and 1000 Companies to Inspire Britain. In total, the company has raised £259m from four fundraising rounds. Investors include Mayfair Equity Partners managed by Mayfair Equity Partners, Mitsubishi Corporation, business angels and undisclosed investors.



Founded: 2016
Location: Buckinghamshire
Total funding rounds: 3
Total funds raised: £210m

Working to deliver sustainable energy at scale, GRIDSERVE builds solar farms which then power electric vehicles across the UK through their GRIDSERVE Electric Highway. The Electric Highway aims to offer electric charging connectivity across the whole of the UK’s roads. It places charging points at popular destinations customers already visit, their own forecourts, and also builds fast chargers for quicker charging. The company also offers electric car and van leasing, and plants 100 trees for each new lease.

GRIDSERVE has raised £210m across three fundraising rounds, with the majority of it coming in a £200m investment in August 2022. The company has also received four grants worth £5.52m, and its investors include Hitachi Capital and Infracapital.


Mura Technology 

Founded: 2019
Location: London
Total funding rounds: 5
Total funds raised: £164m

Mura Technology is a recycling company, aiming to create hydrocarbons from waste plastics. The company believes this will eliminate pollution from burning plastic, reduce waste and contribute to removing carbon from the petrochemical industry. Over the next decade, Mura Technology helps to create a circular plastics economy.

In September 2022, Mura revealed a partnership with Dow to develop Germany’s largest recycling facility. If the project goes ahead, it should be operational by 2025.

Across five fundraising rounds, Mura Technology has raised £163m. Investors include Dow Venture Capital managed by The Dow Chemical Company, KBR, Six Pines Investments LLC, ingus, and undisclosed investors.


Carbon Clean 

Founded: 2009
Location: London
Total funding rounds: 5
Total funds raised: £151m

Carbon Clean creates a carbon capture technology at a gigatonne scale, offering a world leading decarbonisation solution at an industrial scale. Since being founded in 2009, Carbon Clean has removed 1.82m tonnes of CO2 from the atmosphere.

In May 2023, Carbon Clean was awarded a contract for the design of a carbon capture plant in Sweden. The plant will be designed in a way that makes it easy to build and to be replicated by others in the future. The carbon capture plant will remove carbon from a biomass power plant, which provides eMethanol for the shipping industry, a large carbon emitter.

Carbon Clean has received four grants worth £4.32m, and has gone through five fundraising rounds, totalling £151m. Its latest round raised £123m in May 2023. Investors include AXA Investment Managers, CEMEX Ventures, Chevron Technology Ventures, Icos Capital, Marubeni and TC Energy.


Flexion Energy 

Founded: 2020
Location: London
Total funding rounds: 1
Total funds raised: £150m

An energy storage infrastructure specialist, Flexion Energy builds, owns and runs large-scale energy storage facilities and batteries in the UK. This allows for energy created by solar and wind, which can be volatile due to relying on weather conditions, to be stored for when the demand in the UK requires it. Energy storage is a key need for moving towards the UK’s net zero 2050 commitments. 

Flexion aims to build 1GW of storage over the next five years, with peak demand in the UK at 61.9GW. Its latest grid battery facility will be built in Fraserburgh in Scotland, with a capacity of 50MW of electricity. It will store energy produced at nearby solar and wind farms, ready to release it to the grid as needed.

Flexion Energy has raised £150m from a single funding round from GLIL Infrastructure in July 2022. GLIL Infrastructure is a £2.5b infrastructure fund. 


Estover Energy 

Founded: 2010
Location: London
Total funding rounds: 7
Total funds raised: £143m

Estover Energy supports large energy users to move away from fossil fuels and towards renewable sources. They develop, construct and manage the renewable energy systems that generate both power and steam. The renewable energy systems generate energy from biomass, which includes things like wood, corn, waste from forests and farms, and low-cost energy crops. 

Estover has built plants in Speyside, Cramlington and Kent. Its plants provide power for a variety of uses, including a whisky distillery, two pharmaceutical manufacturers and Discovery Park, a science and technology park in Kent which houses Pfizer along with other manufacturers.

The company has raised £143m across seven fundraisings, the latest for £384k in December 2017. Its investors include Corporate & Acquisition Finance managed by Barclays Corporate Banking, Green Investment Group managed by Green Investment Bank and John Laing Group.



Founded: 2010
Location: London
Total funding rounds: 14
Total funds raised: £140m

Renewable energy company BBOXX aims to use natural resources to ‘solve energy poverty’. BBOXX uses solar power to provide affordable, reliable and clean electricity and other utility services to enable economic development in countries with unreliable electricity supplies. Its energy technology consists of a physical distribution network and digital highways, which allows utility businesses to bring energy generation to more remote and widespread communities. 

So far, the company has provided more than 3.5m people with access to clean energy from solar energy home systems. It operates in ten markets in Africa, including Rwanda, where its solutions provide access to energy for 10% of the households in the country.

Today, BBOXX is a global company of more than 900 people, and was named on the 2020 Fast Track Tech Track 100. Its latest funding round, in May 2023, saw the company raise £499k at a valuation of £159m.


Plastic Energy 

Founded: 2011
Location: London
Total funding rounds: 2
Total funds raised: £124m

Plastic Energy recycles plastics that were previously deemed unrecyclable to new plastics, improving the industry’s commercial competitiveness. It aims to contribute to a low-carbon, circular economy for plastics. This will help to reduce waste and reduce the need for production of new plastics, lowering the CO2 footprint of plastic production. It also keeps plastic out of landfill and our oceans

The company operates two recycling plants in Almeria and Seville in Spain, with aims to expand internationally. In November 2022, it also announced a research and development lab at Loughborough University, where Plastic Energy was previously based in shared lab space. It will use the lab space to test different feedstock and improve the quality of its recycled plastics.

Featured in the Business Growth Programme accelerator in 2018, Plastic Energy has raised £124m in its latest fundraising round in November 2021. The company also raised an undisclosed amount in August 2020.

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