Experimental City: How Rotterdam Became A World Leader In Sustainable Urban Design

Europe’s largest port–threatened by rising waters and a loss of its major industry–has reinvented itself as a playground for innovative thinkers who are trying to create a resilient city of the future.

Experimental City: How Rotterdam Became A World Leader In Sustainable Urban Design

When Helly Scholten makes dinner, if she needs a tomato or squash or an onion, she heads upstairs–the top floor of her house is a 440-square-foot indoor vegetable garden. She starts cooking before the sun goes down, while warmth is still flooding through the glass walls of the kitchen downstairs. The entire home is wrapped in a greenhouse.


Sitting on the edge of the Port of Rotterdam, Europe’s largest port–with a view of massive cranes out a kitchen window–the house is part of an experiment called Concept House Village, created to push the limits of sustainable design. Down the street, in the middle of a mostly empty field, another house tests features like an energy-producing toilet that harvests phosphate from pee. Another house, built from renewable materials, is designed to be constructed in a day.

Inside each of the three houses built in the “village” so far, volunteer families act as guinea pigs, committing to live there for three years while giving feedback on the designs.

“Of course, it’s a test,” says Scholten. “We knew upfront that everything was not going to be perfect right away.” A rainwater-harvesting system on the roof, which was designed to directly water the vegetables growing in the loft, hasn’t been working correctly, so the family spends at least an hour a day watering the plants by hand. The parts of the house directly under the greenhouse walls can overheat, while the rest of the house can be cold in the winter. The current solar hot waters aren’t enough to keep showers comfortable.


When these new challenges arise, a team of students and professors from the University of Rotterdam–who originally designed and built the home–come over, sit at the kitchen table, and plot solutions, continually tweaking the design.

Sustainable architecture is not unusual in Rotterdam, the second-largest city in the Netherlands. For new buildings, sustainable design is standard. On a plot of land next to the Concept House Village test site, another planned development of 170 homes will be completely energy-neutral–meaning, at the end of each year, the homes will have produced as much power as they used. But the technologies used in the new development (solar panels, LED lights, heat pumps in the ground to heat and cool the houses) are already common on the market. By 2020, all new houses in the Netherlands will have to be carbon-neutral, by law.

Concept House Village is an attempt to take things in different directions, experimenting with more radical features, such as a garden that takes up the entire second floor. It’s an example of something that’s common in Rotterdam: This is a city that loves to play with new ideas.


The city is becoming a sustainable design capital, home to dozens of experimental projects. Next year, the world’s first floating dairy farm will open in a local harbor, followed a few years later by a giant floating high-rise. The city is testing one-of-a-kind recycled bike paths and climate-proof parks; the port will soon start filtering plastic waste from the harbor. Local entrepreneurs are experimenting with mushroom farming, bread recycling, and turning food waste into fake leather.

This is the story of how a gritty port city–once known more for its crime rate than design–became more inventive in sustainability than other cities that are 10 times as large. While other cities are experimenting with some similar projects (Knight Foundation grants, for example, have spurred creative ideas such as turning an old highway into a bike path), the scale and breadth of what is happening in Rotterdam is unique.

Four things were critical: Rotterdam’s roots as a future-obsessed port, the threat of rising seas, an abundance of open space, and a government willing to support original–and sometimes weird–new solutions.

[Photo: Alex MacLean]

A culture open to change

Rotterdam might seem, at first, like an unlikely home for the cutting edge of sustainable design. A fairly small city (with a population around 600,000, about the size Baltimore, its U.S. sister city ), it has working-class roots. For decades, the city’s port was the largest in the world, and the local economy revolved almost entirely around shipping. Now those jobs are declining. Rotterdam is poorer than Amsterdam, has the highest unemployment rate in the country, and the biggest population of unskilled immigrant workers. It also has one of the highest crime rates in Europe.

But if the presence of the port led to some problems, it also helped shape a local openness to change. As long as the city has been a major port, it has embraced ideas from the rest of the world. By the early 1900s, the city was building skyscrapers while nearby towns (and Amsterdam) stayed quaintly old-fashioned.

During World War II, Rotterdam was bombed by the Nazis, flattening entire neighborhoods. The city center was completely destroyed. Instead of rebuilding the past, the city government decided to reinvent itself instead.


“I think that decision is a very good characterization of how the culture in Rotterdam is,” says Paula Verhoeven, director of the city’s department of development. “It’s very much entrepreneurial, very much looking toward what is good for the city in the future.”

The early changes weren’t always successful: As the downtown filled with office towers and streets widened, some of the social life in the center disappeared, and planners are now working to make the city denser (their attitude toward design is one of continual iteration: If something doesn’t work, you just try again). But other midcentury changes seem innovative even now.

In the 1940s, when Rotterdam built a traffic tunnel through a major river, it also installed a massive bike tunnel and separate pedestrian tunnel; every day, thousands of cyclists take an escalator down to the tunnel to make their commute. In 1953, the city built the world’s first car-free shopping district.


Now, much of the innovation is focused on trying to help the city lower its carbon footprint and prepare for climate change. A district heating system uses waste heat from the port to keep local houses warm in the winter, and will soon expand. The city is in the process of adding a huge wind farm at the port to power 200,000 houses, and will help cover other homes with solar panels. The public transit system is spotless. Like other parts of the Netherlands, the city has an extensive network of separated bike lanes; about a quarter of all journeys are made by bike.

Because the quality of infrastructure is already so high, it leaves room for designers to experiment with more radical ideas.

“For all intents and purposes, their city, as a machine for living in, is more or less finished,” says Nels Nelson, an urban planner and designer who used to work in Rotterdam, and now works in Boston. “It works so well. There’s not this issue with people getting killed on their bicycles every day like we have in Boston. Things just work. When you’re operating on that level–and you have thousands of architects living in your city– you’re going to start to do really interesting and creative things.”


Some of that creativity is focused on one of the city’s major challenges in the near future: 90% of Rotterdam is below sea level, and as the climate changes, the city faces more risk from flooding.

Watersquare [Photo: Pallesh and Azarfane]

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Sponge city

“I think we’re about four meters under sea level right now,” says urban designer Dirk van Peijpe. We’re sitting on concrete steps in Rotterdam’s center. The country’s extensive water protection systems–including 787-foot-long floodgates that can swing open in a storm surge to hold back the North Sea–mean that we’re not underwater.

But as sea levels rise, the city is facing different problems. When it rains, (something that had happened three or four times so far that day) high groundwater means there’s nowhere for the rain to go.

[Image: De Urbanisten]

“It’s basically a bathtub we’re living in,” says van Peijpe. The city could have built bigger pipes to try to deal with the heavy, frequent storms that are coming because of climate change. Instead, they worked with van Peijpe and fellow designers from his architecture firm, De Urbanisten, to build something that had never existed before: a concrete park that doubles as water storage when it rains.

When it’s dry, the concrete basin can be used as a basketball court or a soccer field. The stadium-like stairs act as seating for plays by theater students in the school next to the park, or for churchgoers from the church on the other side. If it suddenly rains, the basin fills up with water, and then slowly releases it into the ground, giving the city’s overloaded sewers a break.

The park is part of a larger district that the city is making climate-proof, tearing up asphalt and concrete and replacing it with new paving that can hold water. A nearby building, surrounded by skyscrapers, is topped with Europe’s largest rooftop farm–part of the city’s push to cover roofs in greenery that can absorb water in storms. Already, more than 200,000 square meters of roofs have been greened. The city’s network of trams winds through tracks surrounded by grass and flowers, not pavement. An underground parking garage, like the concrete park, doubles as water storage when it’s needed. Ultimately, infrastructure may be redesigned so stormwater is all stored and no longer flows into the sewer system at all.


All of these changes are the result of a sweeping resilience plan. The city, which is part of the Rockefeller Foundation’s 100 Resilient Cities initiative plans to be fully climate-proof by 2025, so every neighborhood will be protected from problems like heavier rainfall, overflowing waterways, and heat waves. “Doing nothing is not an option,” Ahmed Aboutaleb, Rotterdam’s mayor, wrote in the original adaptation plan in 2012. “The proper functioning of the city is much too important to be left to chance.” With a full commitment to change, the government had the motivation–and the funding–to take on original projects like the water-storing park, projects that have started to inspire other cities like Copenhagen.

Dutch Windwheel [Image: DoepelStrijkers]

There’s something in the water

Some of Rotterdam’s most experimental projects are directly on the water itself. In 2017, a huge floating dairy farm–home to 60 cows, and greenhouses growing grains to feed them–will open in a harbor in the western part of the city, producing hyperlocal yogurt and milk. If buildings float, they can’t flood.

In another harbor, a team of engineers and researchers are planning a ring-shaped skyscraper that will generate three times more energy than it needs, a world-first for a high-rise. “In small buildings, with solar photovoltaics on the roof, it’s quite easy to make an energy-neutral building,” says Duzan Doepel, partner and founder at DoepelStrijkers, the firm creating the building, called the Dutch Windwheel. “But when you’re talking about a building with more than 60,000 square meters, it becomes a completely different story.”

Dutch Windwheel [Image: DoepelStrijkers]

The inner circle of the building will use a new form of wind technology that generates power silently, without moving parts. Organic waste from the apartments inside will generate biogas, sending power back to the apartments. Solar panels will add more energy. All together, the hybrid system will produce energy on a scale that usually happens on wind or solar farms outside cities. The building will be self-sufficient.

Floating in yet another harbor, dome-shaped pavilions host events. Near the port, architects are planning a floating hotel, and a dock built for entrepreneurs will soon test new floating technology. An artist built a “forest” of floating trees. A new neighborhood of floating apartments will open in 2017 in another harbor.

The projects are partly a way to make use of available space; harbor areas that were once used for shipping are now empty. In the 1970s, when the oil crisis shut down parts of the port, many workers were laid off and left the city. By the early 2000s, ports in Hong Kong, Shanghai, Singapore, and other Asian cities had overtaken Rotterdam in size. The port, while still huge, became a smaller part of the local economy. Because newer, massive container ships also couldn’t fit in the old harbor areas, commercial shipping started to consolidate on new areas of reclaimed land next to the sea. That left empty spaces that the city wanted to fill, and room for the inventive plans that are happening now.


“When the port activities moved, they left a very large inner city area which offers huge chances for redevelopment,” says Verhoeven. “Those areas are right in the city center–very strategic locations.”

The city ports, called Stadhavens Rotterdam, left 1,600 hectares of abandoned space available for use. As the city invested in redevelopment, one of its strategies is to focus on experimentation in new designs for climate change and sustainability–including the new floating infrastructure. On brownfields next to the water, the city has also started turning old industrial buildings into cleantech hubs. Former harbors are now city-driven innovation districts.

Rotterzwam Mushrooms

In abandoned warehouses, there’s room to play

Throughout the city, the abundance of open space has also helped drive experimentation by giving creative people a cheap place to work. As the shipping industry moved, it left huge empty warehouses next to harbors throughout the city–places where entrepreneurs or designers could easily find affordable space to rent. After the last financial crisis, even more vacant space opened up.


At the Tropicana, a former glass-domed public swimming pool next to the Maas River, a group of entrepreneurs are turning the space into a hub for sustainable business. “I was just driving by this building, and I thought, Hey, this is a big, empty greenhouse that we have in the middle of the city,” says entrepreneur Siemen Cox. “Let’s do something there.”

Originally, Cox considered using the massive space for aquaculture and vertical farming, but the owner wanted to use the former swimming pool area for something else. So Cox moved into the basement–a damp, humid area perfect for growing mushrooms. His startup, Rotterzwam, collects coffee grounds from coffee shops around the city, making collections on cargo bikes and in electric vehicles. Then it cultivates mushrooms in the coffee.

Rotterzwam Mushrooms

Inside former dressing rooms for swimmers, racks of plastic bags–filled with a mix of coffee and mushroom spores–hang from the ceiling for several weeks at a time in the dark, before moving to “fruiting” rooms. Everything smells like coffee. When the mushrooms are ready for harvest, the company sells them to local restaurants. (It also makes mushroom-growing kits for consumers–who kept asking the startup how they could donate their own coffee grounds–to use at home.)

The business likely would not have been possible without Rotterdam’s cheap rents. “The first three to four months we were in here for free,” says Cox. “There was nothing here–there was one place with running water in the entire building. Then for one year we had a sort of anti-squatting fee of 250 euros per month. We had the time to develop our business model, our business case, and expand the investments in the facility. If we would have had to pay top rent from the beginning, we would have never been able to develop.”

Like other entrepreneurs in the Netherlands, Cox also could have used the country’s social safety net if the startup hadn’t gone as planned. “The socialist democracy here really helps spur innovation,” says Steve Kennedy, a British professor who heads a program in sustainable innovation at Rotterdam’s Erasmus University.

“Entrepreneurs know they can set up a business and they can fail and there’s a good safety net,” he says. “Innovations can be more radical because you have this kind of socialist model behind it.”

Cox, who had worked in financial services for 15 years, felt comfortable taking a leap into an unproven business. “When I was working in financial services I was making a lot of money, but I wasn’t happy or content anymore,” he says. “Now I’m hardly making money or just very little money. But if I become a millionaire tomorrow, this is what I will stay doing. It’s really a sort of calling. It feels very good to do this.”

Spurred on by the success of Rotterzwam, the building has become the center of a bigger initiative called Blue City, meant for entrepreneurs working in the “blue economy”–a name for the next step in the circular economy, where businesses don’t just reuse their own products, but turn waste from other industries into new products. Besides mushrooms growing in coffee waste, there’s also “stone paper,” made from ground-up building waste. One successful startup that was in the building (until recently expanding) turns wasted food into soups and juices.

Inside the former swimming pool, the first businesses are already working together. A woodworker uses beeswax from a beekeeper to finish his furniture; carbon dioxide from the mushrooms helps feed algae for a company growing algae. A restaurant upstairs sends its organic waste to the mushroom company.

It’s the kind of entrepreneurial experimentation that has happened, to some extent, in other postindustrial cities that have a lot of cheap warehouse space. In Rotterdam, though, it has unusually strong support from the city.

Rooftop Farm [Photo: DakAkker]

How the city helps drive innovation

It’s part of Rotterdam culture to come up with solutions (“The Dutch love a good problem to solve,” says Kennedy). But the city also helps push to make those solutions happen. A competition called CityLab010, for example, will give out more than 3 million euros in 2016 to the best new ideas–in categories like sustainability and education–to improve the city.

Previous winners span a large range of ideas. One project, recently funded with 200,000 euros, will turn old bread, a large source of litter on city streets, into energy. “It started with a wild, idealistic idea, and from then on, it starts to grow and become real,” says Angelique Vandevenne, founder of the project, called Broodnodig (a play on brood, the word for bread, and broodnodig, which means “highly necessary”).

Working with engineers from a firm called Better Future Factory, the team is building mini-digesters that can be used at bakeries, schools, and other locations to turn bread waste into biogas for on-site energy use. They’re also working to help prevent people from throwing bread away in the first place. In typical Rotterdam style, they’re continuing to revise their ideas–and considering redesigning bread itself.

“Maybe bread could have a sensor in it,” says Vandevenne. “And it could say, put me in the freezer. Or when it gets dry, it could say, ‘Help, make me into a grilled cheese sandwich.'”

The city government also sets up programs that encourage unique development. On an abandoned hockey field in the eastern part of the city, the government offered lots for people to build homes however they want–as long as they meet certain sustainability criteria and some other constraints. The new neighborhood is designed for low car use; it’s a 10-minute bike ride to the city center, and near tram stops.

“When you’re thinking about designing a house for yourself, at a certain point it becomes like a game,” says Stefan Prins, an architect who designed a house for himself and his girlfriend. “We’re thinking of adding a stainless-steel slide from the balcony. In a way, the house is like a playground for us–just like Rotterdam can use the city as a playground and experiment in different ways of living.”

The city also helps connect people with ideas with other sources of funding. Landscape architect Tieme Haddeman was looking out his apartment window when he started thinking about the lack of green space. “When I look outside, I see about 400 apartments,” he says. “Altogether, we see three trees. In my opinion, that’s not the right balance.”

Haddeman lives next to one of the city’s unused harbors, and realized that even though there wasn’t room on land for new parks, there might be in the water. He came up with a design for a floating park, filled with plants that could help clean the murky water and attract fish (the harbors are mostly empty of life now). The city liked the idea, and though they didn’t have the money to fully fund the project, they helped connect him with another government agency that could.

Floating Island [Photo: Tieme Haddeman]

The Water Board, which wanted to find new ways to improve water quality, funded the first version, a 300-square-foot artificial island, complete with trees, that floats near the apartment complexes. Haddeman is now developing a larger version that people will be able to walk on.

Like many projects in Rotterdam, the island came to life just because someone wanted to do something, and then started to do it. The city is proudly working class, and likes to compare itself with more intellectual Amsterdam by saying that “we don’t talk, we just do.”

“It’s nice to speak about innovation and think about innovation, but innovation only shows you things when you do. You have to build, you have to create, you have to make things,” says Haddeman. “And as soon as you’re making things and you’re building things, the innovation shows if it’s innovation or bullshit. You will find it out after you build it or make it.”

As in other cities, the process isn’t always easy; the experimental village is struggling to get the needed contracts to build more houses. Watersquare took years to plan because of red tape. But the city does what it can to make the process easier. “What we try to do is to enable innovative entrepreneurs or businesses or startups to offer them room for experiments and pilots,” says Verhoeven. “We offer them literal room for experiments–we have an area in our city where innovative business is very welcome to settle–but we also offer room to experiment in a more figurative way, by bending the rules a little or offering a regulatory framework that enables innovation more.”

The government is also experimental in its own work as it tries to solve the many challenges it faces, from high unemployment rates to dirty streets. At the port, which aims to be the most sustainable in the world, a new terminal is fully electric (including equipment) and powered by wind energy. This fall, the port launched a pilot project to use ocean-going drones to filter plastic waste from the port area before it drifts out to sea.

In a former port area that once imported most of the fruit in Europe, a stretch of road has been converted into a laboratory. The engineering department is testing new kinds of pavement that can store water or capture CO2. A bike path is the first to be made from recycled pavement, while a previous test looked at making roads from recycled plastic bottles. In other parts of the city, they’re testing roads that can generate electricity to power streetlights when people drive over, or glow-in-the-dark lane markings so streetlights aren’t needed. Another road is testing ways to wirelessly charge electric cars.

“That might not be for the future,” says Jaap Peters, an engineer for the public works department. “But if you invest small, maybe it’s going to be something for the city. It’s learning money, not only for your city, but also for other cities.”

A constant flow of visitors from around the world comes to look at projects like the Watersquare; Rotterzwam has taught entrepreneurs from a couple dozen countries about how to start an urban mushroom farm. Cambridge Innovation Center, a startup incubator originally from the Boston area, opened its first international location in Rotterdam in 2015.

“There’s this willingness to try new things that’s really unique to this city,” says Melissa Ablett, general manager of the center’s Rotterdam location. Compared to Boston, she says, Rotterdam is far more willing to experiment.

Day to day, that experimentation means people live differently. “After a year, it still feels like we’re on a holiday,” says Scholten of her light-filled, plant-filled greenhouse home. “A house like this, it gets something going in your head about how do we live, why do we live that way. Then we change it. It’s nice to say we did it. It’s not all convenient, but it’s fantastic.”

“Real innovation will happen not in an app, but in the physical world, on a city scale,” says Rotterdam-based designer Daan Roosegaarde, known for building projects such as a smog-eating tower, solar-powered roads, and a bicycle path that glows in the dark. “How can you make places which are smarter, more sustainable, more energy friendly, more social, more inclusive?”

While Roosegaarde says he could have set up an office anywhere, he wanted to work in Rotterdam. “Why not be in a city where you can test it, make a mistake, learn something?” he says. “It’s a playground where you experiment, you show what works. Then you scale and go onwards.”

Can other cities follow this example and essentially “Rotterdam-ize” themselves? Nelson, the architect who has worked in both Rotterdam and the U.S., says that it would require a massive shift in culture and support. “A lot of it comes down to what the people value and what the government values,” he says.

First, he says, most cities need to start by looking at the more basic issues Rotterdam has already addressed–separated bike lanes, for example. “Having spent some time there and working on really conceptual, avant-garde stuff like they’re doing, and then coming back to the States, what I found was that the type of work that we need done here was like child’s play to them,” he says. “All of my projects here are focused on building walkable urbanism. Which is great, but that’s the kind of thing that we need first before we start being like a Rotterdam.”

“We need to build an urban fabric that can then support the really great stuff that they have,” he adds. “Doing that in the cities across the United States is going to take at least a generation. We’re lagging behind, but I think there’s hope.”


About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley