Cultivating moss, Green City Solutions and success

A horticulturalist and computer scientist may seem like an unlikely duo, but Green City Solutions’ cofounders, Peter Sänger and Liang Wu, have been driven by a shared goal to create a biotech air filter that reduces air pollution. We learned about their growth together from studying at university to successfully marketing their CityTree and CityBreeze products, which combine dust and carbon dioxide-absorbing moss with internet of things (IoT) technology, creating fresh air zones in many European cities.

The school of moss and internet of things (IoT)

“It was pretty clear to us that we had to do something.” – Wu

Green City Solutions’ story began in the summer of 2011 when co-founder Liang Wu was an intern in Shanghai and first noticed the impact of the city’s air pollution on his health in stark comparison with the cleaner air he was used to in Dresden as a student. On returning to Germany to continue his media informatics course, he was determined to do what he could to improve air quality for friends and family still living in Shanghai. 

Enlisting the help of two university friends, he began working on an idea that would marry technology with biology. Undaunted by the size of the task, they knew they wanted to create something organic and biological to combat air pollution: the biggest outstanding economic and health threat caused by human activities.

The missing link? Horticulture student, Peter Sänger, whose background with his family’s horticulture business (spanning four generations, since 1898) gave the group intelligence about moss superpowers and the expertise to establish a company of their own. 

Sänger recounts the moment he first met Wu: “I stepped into the office and Liang was sitting there coding and texting.” Wu explains, “We don’t have that founders’ garage story, but we have something that comes close to that. There was a rundown building we could use free of charge from the university.” 

Time passed between this first meeting and when Sänger concretely joined the team. In that period, the students had decided on a concept of merging moss with performance enhancing IoT technology. 

“That was a very interesting time: coming from studying – something very theoretical and out of books – to people who were very open-minded, very consequent, testing things and doing things.” – Sänger 

First steps to the world’s first biotech air filter

“Between these two worlds – Liang as the IT guy and me as the green – we tried to figure out something that interacts and works together” – Sänger

Sänger and Wu describe how their office space soon became a makeshift mossy workshop with building materials purchased from the local hardware store, and in 2014, they managed to develop a rudimentary proof of concept of their CityTree: the world’s only sustainable biotech air filter. Although reluctant to even call their first attempt a prototype (because of how different it was from the current model), the vision of what the CityTree could become motivated the team onwards.

And so, Green City Solutions was founded. 

“Of course, it was a risk that we took, but looking back, I don’t think there was a real alternative there. I feel that we grasped the zeitgeist – the things people were starting to see.” – Wu 

Like many startups, the founders sought public funding, and attribute much of the early robustness and independence of Green City Solutions to this; Sänger and Wu reinvested everything they received into the company. Even the application process disciplined them to create a financially sound business and budgeting plan.

Since, Green City Solutions have acquired regional, national and Horizon 2020 public funding, which has been integral to their development and the strength of their products.

Green City Solutions’ founders knew they had a superhero in moss and a biotech air filter design that could make a huge positive change for our climate and people’s health. Now, they are a successful SME, marketing their CityTree and CityBreeze products, which can filter 82% of dust particles, absorb the equivalent of over 44 kilograms of carbon dioxide per integrated moss module per year (with both direct absorption and by filtering particles that have global warming potential, like black carbon) and reduce the surrounding air temperature by up to 4 degrees Celsius. 

Refreshing primeval moss

Green City Solutions’ original design has evolved. Their current CityTree and CityBreeze products include IoT technology that measures and controls many parameters, like irrigation, ventilation and footfall, optimising the moss’s performance. 

“The idea is the same – combining biology and technology to provide the most sustainable filter and cooling solution. The product concept is still focused on that puzzle piece, but how we make, test and validate it changed tremendously.” – Sänger

The company launched a second generation of their CityTree in 2020, improving energy efficiency, refining the technology and changing the previous aluminium structure into a stylish wooden slatted design. Having both been very involved in the operational side of Green City Solutions’ work too (helping to install many of the 30 projects running in Europe), Sänger and Wu understood the way their products could be adapted for easier transportation, installation and maintenance.

Sänger reminisces about travelling between the first projects they set up in front of the Frauenkirche in Dresden and at the Place de la Nation in Paris: “We were in the car moving between these two projects and trying to ensure everything was being realised and fine. Those were crazy times – when we sat together in the nights preparing for the installations.”

Setting up a business? Just do it

Passion for their company shines through, and Sänger and Wu emphatically encourage young innovators to set up a business of their own if they have a novel idea.

“Of course, it’s a risky thing to start your own business. Of course, you’re working more than maybe in a common job, but from our experiences, impressions and rises and falls, we learned so many things in this short period of time – about ourselves, people, our business and the climate.” - Sänger

They advise not having a fixed plan (to avoid disappointment if goals are not achieved), talking to people from different academic, professional and cultural backgrounds to unlock new solutions and taking advantage of complementary funding programmes.

Green City Solutions founders have also developed a powerful personal and professional relationship that feeds into the company’s success and positivity. Wu explains, “We still stick together, no matter how big the difficulties or problems are. We’re still very close on a personal level. That’s astonishing to me and something I will always cherish.”

Gathering moss around the world

When asked whether Green City Solutions will come full circle and bring their CityTree and CityBreeze products to Shanghai to reduce the air pollution that Wu noticed there, he said, “Not immediately, but I think eventually, yes”.

Wu expects that even if their own biotech products do not reach the metropolis, copycat moss-based technologies could follow in Green City Solutions’ footsteps and improve air quality. He says, “I still hope we will do it by ourselves, but it is also really motivating to know that just by creating this idea, there’s already a high possibility that it will be present in China at some point.”

Although not yet influencing the lives of family and friends in one of the world’s most polluted cities, Green City Solutions’ products have already reduced air pollution and improved the health of thousands in Europe. 

Green City Solutions have participated in a project funded by our Eurostars programme: an international funding programme for innovative SMEs.

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Posted 22 November 21