Sustain 100: the European sustainability startups to watch in 2021

Europe now boasts 800 climate techs and huge successes like Arrival, Northvolt and Oatly. But which other sustainability startups do you need to know about?

Sustainability is only getting hotter and hotter. Europe now boasts six unicorns, from Tesla-rival Arrival to oat milk brand Oatly — both set to IPO in the coming months.

But who could be next?

We’ve cherrypicked the 100 most innovative startups across climate tech, cleantech, greentech and beyond — they’ve got sustainability at the heart of their mission and messaging and are providing very necessary tech solutions to the climate crisis.

12 of the companies launched in the last year, including smart construction company 011h and Sylvera, the platform investigating carbon offsetting initiatives.

We’ve by no means forgotten big players with big raises to match — like refurbished product marketplace Back Market, which raised €110m; or vertical farming startup Infarm, which raised $170m in 2020.

You can view the full list below.

(P.S The data (including valuation estimates) is from Dealroom. If anything is wrong, please let us know by email at [email protected]).


Year founded

Amount raised

Last funding round



011h's logo


New generation building construction company

construction / manufacturing

Barcelona, Spain






Sifted Take

011h is out to to clean up the construction industry, which is responsible for a whopping 39% of global carbon emissions. Through digitisation and constructing high-tech, wooden ‘smart’ buildings, it’s hit a critical niche in the global industry worth 13% of global GDP.

In December 2020, it raised €8m in its first funding round, which included Fundamental, A/O Proptech, Cultivate Capital and angel investor Giuseppe Zocco.

It begins its first building project in March 2021 on a housing development just outside Barcelona.

3fbio's logo


Biotech making protein sustainable

biotech / food

Glasgow, UK






Agricool's logo


Growing fruits and vegetables in recycled shipping containers

food / agritech

La Courneuve, France






Sifted Take

Is the urban farmers' market our only sustainable option for urban fruit and veg? Perhaps not for long. Two farmers' sons cofounded French startup Agricool, which grows fruits and vegetables in recycled shipping and storage containers in cities.

It hopes to bring locally-produced, GMO- and pesticide-free food to cities across Europe. Its containers are also designed to be built within cities as opposed to on a rural farm, and are therefore designed to reduce the distance that food has to travel to get to city dwellers.

The startup’s last funding round was its $28m Series A in December 2018 from investors including Kima Ventures and Bpifrance.

Back then, it said it would launch a hundred containers in Paris and Dubai by 2021 and hire around 200 people. It currently has 76 employees.

Airinum's logo


An urban breathing mask for the 21st century

marketplace & ecommerce / healthtech

Sweden, Stockholm






Airly's logo


Our goal is to make distributed network of air quality sensors and provide reliable air quality data

SaaS / energy

Kraków, Poland






Sifted Take

Airly is one of the key players in personal air quality sensors — an area that’s been recognised by academics for improving how we understand and improve the invisible but urgent problem of air pollution. More than 10m people die each year from air pollution, which disproportionately affects people of colour and people with lower incomes.

Airly recently raised $3.3m to scale its platform and sensors to a global level. Its algorithms can predict air pollution 24 hours into the future with a verifiability of 95% thanks to its platform and network of sensors.

The issue goes way beyond carbon dioxide emissions, so its sensors are primed to detect particulate matter and gases like nitrous oxide and ozone.

In 2020, Airly’s revenue passed 200%, with its network now deployed in a whopping 600 cities and its sensors used by 2m people. The next step is to open offices in the UK and US as well as doubling its staff count — which currently stands at 35.

Alpha 311's logo

Alpha 311

Local renewable energy for the world

energy / manufacturing

Kent, UK





Sifted Take

Sure, Alpha 311 is all about local energy production, but it's also changing the face of wind energy.

Instead of those majestic wind turbines atop hillsides and alongside motorways, its vertical axis turbines are blending into lampposts, railway and road signs. Extraordinarily, it produces power even with a slight breeze, but motorways are an ideal spot due to the airstreams created by traffic.

According to the company, one turbine can generate as much power as 24 solar panels.

Notably, AEG is a client — London's O2 Arena (the Millennium Dome) is now the first venue in the world to trial their turbines. 10 will be installed at present, which is enough to power one of the arena's restaurants — but AEG is planning to install the turbines at its arenas worldwide.

Back Market's logo

Back Market

Online marketplace for refurbished products

marketplace & ecommerce / SaaS

Paris, France






Sifted Take

Back Market has become a staple of the circular economy. The Parisian startup, launched in 2014, is fast approaching a $1bn valuation and sells refurbished products otherwise sent to landfill.

In 2018, it was working with over 270 factories. At present it has partnerships with Dyson, Bosch and Siemens — though it sells products from all the big brands including Apple and Microsoft.

So far it’s raised €158m — most recently a huge €110m raise in May 2020 led by Eurazeo, Aglaé Ventures and Goldman Sachs Asset Management.

beworm's logo


Worms that eat plastic

biotech / waste solution

Munich, Germany





Sifted Take

Launched in 2020, beworm is brand new but it’s got big ambitions — and they involve plastic-eating worms.

The worms (as well as fungi and bacteria) are capable of degrading polyethylene — a polymer found in many plastics — which can then be reused for new petrochemical products or plastics.

The Munich-based startup is in its early days — bootstrapped and with a four-person team made up of its four ‘bioneer’ cofounders. Its goal is to show the world how biotic recycling systems can save us from plastic pollution.

While this year it will be scaling up its experiments to achieve a demonstrable process, watch out for 2022 — when it will be looking for its first raise. Currently it's partnered with the Greentech Alliance.

Bulb Energy's logo

Bulb Energy

Provides 100% renewable electricity and gas to homes across the UK

energy / marketplace & ecommerce

London, UK






Sifted Take

London-based Bulb provides 100% renewable energy and gas to homes across the UK, Spain and Texas.

In March 2021, the Financial Times crowned the startup Europe’s fastest growing in its FT 1000 list, for achieving compound annual revenue growth of 1,159%.

A month prior, cofounder Amit Gudka stepped down from his role at Bulb to start a new energy storage company called Virmati Energy.

Bulb's working on other innovations aside from its energy supply services — such as home battery tech for solar power owners and an app-powered charger product for electric vehicles.

What’s next for Bulb, Europe’s fastest growing startup?

Carbon Clean Solutions's logo

Carbon Clean Solutions

Carbon capture company providing lowest cost cutting-edge technology for energy industry

energy / waste solutions

London, UK






Sifted Take

Carbon Clean Solutions has two main missions, to help businesses capture carbon and to make it affordable.

It seems well on its way — as chief executive Aniruddha Sharma tells Sifted that it’s capturing carbon in some cases at less than $40 per metric tonne.

For context, the EU Emissions Trading System has seen a spike in the ‘carbon market price’ to €42 per metric tonne at the time of writing, a sign that appetite for carbon capture technology may soon boom.

The startup has some big clients like e.on and Imperial College London. In February 2021, Carbon Clean Solutions publicly announced its partnership with resource management giant Veolia to capture carbon from Energy from Waste plants.

Read more: How are Europe's startups capturing carbon?

Cervest's logo


Cervest is pioneering Earth Science AI to help businesses, governments and growers adapt to climate volatility

AI / enterprise software

London, UK






Circular IQ's logo

Circular IQ

Improving accessibility to sustainability data throughout supply chains, so performance can be compared objectively across companies, products and suppliers

energy / enterprise software

Amsterdam, Netherlands





Circulor's logo


Providing traceability-as-a-service, to verify responsible sourcing, to underpin effective recycling and to improve efficiency

SaaS / logistics and delivery

London, UK





Clim8's logo


Sustainable investing app

fintech / investing

London, UK






Sifted Take

Launched in 2019, Clim8’s investment app is on a roll. In 2020, it raised €5m on Crowdcube — and its waitlist has 15k people signed up.

Though the app hasn’t quite launched yet, it’s developed a lot of hype — so we’re watching to see whether it lives up to it.

Clim8 is set to allow its users to invest up to £20k in a curated, sustainable portfolio that avoids big tech. Instead, it focuses on six themes: clean energy, cleantech, clean water, the circular economy, sustainable food and clean mobility. That’s because it “struggles to see how Big Tech companies offer solutions to the demands of the circular economy; or how they participate in the development of clean energy.”

Climeon AB's logo

Climeon AB

Climeon's vision is to become the #1 climate solver. We turn heat into clean electricity 24/7, unaffected by weather conditions

energy / energy efficiency;cleantech;waste solution

Stockholm, Sweden






Climeworks's logo


Commercialises a highly energy efficient technology for CO2 capture from air

energy / manufacturing

Zurich, Switzerland






Sifted Take

Climeworks is a carbon capture startup in Europe to watch. It’s the most funded carbon capture startup in the continent, receiving €114m in funds so far.

The startup has developed high tech fans that suck carbon dioxide out of the air. Its tech has caught the eyes of some big names, like Microsoft (who will help fund the startup with its Climate Innovation Fund) and the Norwegian government.

Cloud and Heat's logo

Cloud and Heat

Cloud-based computing, the waste heat of which is used to heat buildings and to heat water

energy / hosting

Dresden, Germany






Sifted Take

If climate change is the key theme of the 21st century, data is in second place — Cloud and Heat is occupying the intersection between the two.

The cloud hosting company cools down its data centres using water, which once heated is redirected for reuse in domestic and commercial buildings.

In its last funding round — a Series B in September 2018 — it won backing from the science-focused environmental VC firm ETF Partners, raising €10m alongside Inven Capital.

Deep Branch's logo

Deep Branch

A carbon recycling company converting CO2 into high-value products

energy / agritech

Nottingham, UK






DeepSea's logo


Specialises in bringing innovative and user-friendly deep learning powered solutions to the shipping sector

transporttaion / AI

Athens, Greece






Sifted Take

Maritime shipping can generate billions of tonnes of carbon dioxide emissions in one year. After all, it is one of the largest industries in the world (80% of goods are carried by ships).

This is where Athens-based startup DeepSea comes in. It’s built an AI-based software platform to optimise the routing and maintenance of ships. This allows shipowners and charterers to track their emissions and shift their operations and routing to reduce them.

The startup last received funding in April 2020 — €3m from ETF Partners. It’s grown its team by 75% in the past 12 months.

Donkey Republic's logo

Donkey Republic

A global bike-sharing platform

marketplace & ecommerce / mobility

Copenhagen, Denmark






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