Select Page

Frequently Asked Questions

[bgsection pex_attr_title=”What can Blue21 do for me?” pex_attr_subtitle=”” pex_attr_undefined=”undefined” pex_attr_style=”section-light2″ pex_attr_bgcolor=”ffffff” pex_attr_image=”” pex_attr_imageopacity=”0.1″ pex_attr_bgimagestyle=”static” pex_attr_titlecolor=”252525″ pex_attr_textcolor=”777777″ pex_attr_height=””]

Blue21's founders have over 14 years of experience in floating development with clients across the world. Our portfolio includes many applications of floating, our most notable being the floating pavilion in Rotterdam and floating homes in Delft, but we have also been involved with other applications such as floating solar, including our project Innozowa. We have  established a broad network of partners and have worked for clients all over the world including Shimizu Corporation (Japan), Seasteading Institute (USA) as well as, world-leading research programs such as the Horizon 2020 project Space@Sea for the development of affordable multi-use floating platforms in maritime conditions.

We are one of the only companies in the world who combines the expertise of the maritime and urban sector. Our company, including our three founders, come from a very multi-disciplinary backgrounds, specialising in many fields including maritime engineering, water quality monitoring, legislation, real estate, architecture, sustainability, civil engineering. We also have several related organizations including, Indymo, a  company which applies underwaterdrone for the ecological monitoring and sustainable impacts of floating buildings, Deltasync a company which is involved more in the urban development of floating constructions and the Blue Revolution Foundations which seeks to bring awareness of floating developments at the legislate and governing perspective and which includes an in-house think tank. Collaboration with a wide variety of partners also plays a strong role in our practice. We have established a global network of expert companies to mobilize the required knowledge and capacities of realizing innovative solutions in practice. Due to our expertise, experience and  specialised network, we are able to take any floating project through the entire value chain from conception all the way through to the final completion and hand-over.

Blue21’s ethos is to promote floating cities (including housing, energy generation, food production, public and commercial functions) as a viable solution to 21st-century challenges such as urbanization ,rising housing demand and climate change. We want to improve people’s living conditions and wellbeing, create spaces which are economically viable and have a positive ecological impact- in balance with nature. Floating can offer many solutions to specific localized issues where building on land is either not economically viable or simply not possible. Cities across the world have the challenge of coping with growing population rise and the majority of our cities are located on the coast. With growing populations comes lack of space, lack of affordable housing, urban sprawl, high CO2 emissions and the heat island effect and when combined with climate change and rising sea levels we are facing a major issue. Our goal is to mitigate these challenges through the innovative and sustainable design approaches that floating cities can offer.

In the early stages, we would recommend a first overall feasibility check, before going into any large investments. This study would similarly consist of analysis of conditions (e.g., environment, wave) and further define the boundary conditions for the site. Information that would influence the costs, the dimension of the development, the use of materials and other topics will be gathered. The results help to decide which locations and types of floating development is interesting for you. We have experience in technical and financial feasibility studies for floating developments and we are able to provide this as part of our portfolio of services.


[bgsection pex_attr_title=”What are the benefits of floating Architecture?” pex_attr_subtitle=”” pex_attr_undefined=”undefined” pex_attr_style=”section-light2″ pex_attr_bgcolor=”ffffff” pex_attr_image=”” pex_attr_imageopacity=”0.1″ pex_attr_bgimagestyle=”static” pex_attr_titlecolor=”252525″ pex_attr_textcolor=”777777″ pex_attr_height=””]

All of Blue21’s projects are aimed to include solutions that ensure efficient and effective resource usage, as well as waste and pollution reduction. For the Floating Island in French Polynesia that Blue21 designed, every resource has been approached according to the following sequence: first reducing the demand; secondly using renewable energy sources and finally increasing efficiency and reducing dependency on external resources. This strategy is based on the goals for the Floating Island to become 100% renewable and 100% self-sufficient. Waste consists of a large number of materials. Most of these materials can be reused. An average of 35% is organic, which will be transformed into gas and fertilizer using a digester. Materials like paper, metals, glass and plastics are highly suitable for recycling (about 45% of total). Wood, leather, rubber and textiles (about 15%) are suitable for upcycling into new products. Clothing and shoes can be sold in second hand stores. Small hazardous waste such as batteries (0.2%) will be disposed of with utmost care. Non-recyclable material can be incinerated or in the long term recycled in a specialist plant. Entrepreneurs can be attracted that want to play a part in the upcycling and recycling business, which will not only reuse materials from the floating project but also from a wider area. More info:

Floating architecture can result in a zero carbon emission lifecycle and make efficient use of local materials. Sustainability is the starting point for all Blue21 activities. For the Floating Island we designed for French Polynesia, suing local sources of water and energy as well as minimizing impacts on the environment were key aspects. The main source of energy will be the sun, which will provide electricity for a large variety of purposes: lighting, refrigeration, washing, food preparation, wastewater purification, pumping, etc.  Solar power will be harvested by hybrid solar panels. In these types of panes, PV cells are cooled to increase efficiency and at the same time hot water is produced. To fulfil the needs of the whole floating islands project, about 20% of the development footprint should be covered by solar panels. One of the challenges of electricity is storage. On a short-term, most probably batteries will be used to store the electricity. Other possibilities are being examined, such as storage of energy in biofuels and compressed air.The heat extracted from cooling the solar panels will be used for heating of the tap water, shower and bath and also for the hot-fill washing machine and hot-fill dishwasher (which are a lot more energy efficient than regular ones). In this way, no energy will be lost for heating water. Cooling of rooms will be mainly achieved by natural ventilation, designing spaces in such a way that heat gains are minimized. Rainwater will be collected and stored in the islands and purified to supply clean water (for drinking, showering, dishwashing, cooking, etc.). Wastewater from the shower and tap (grey water) will be collected, filtered and used for flushing the toilet and for irrigation. The water from the toilets will be filtered by a natural filtration system such as helophytes and algae. This prevents excess nutrients in discharge. More info:

Part of our Floating City agenda is a plan we proposed for the Markerwadden area. In the Markermeer we want to connect humans back to nature by letting them reside on water and contribute to the ecological system in a positive way. The floating homes contribute to the water quality and habitat restoration and will offer a new nature experience.


Floating buildings and piers create underwater surfaces that can be colonized by algae and mussels. Algae extract inorganic nutrients, releasing oxygen to the environment, whereas mussels filter the water, feeding with organic nutrients. Floating helophyte filters can be placed next to the platforms, removing dissolved organic matter and diffusing oxygen through their roots. These floating and underwater structures could slow down the current. It will lose the energy to hold particles in suspension so sedimentation can occur again. Under the floating platforms silt could be collected. The dynamics and interactions among platforms, lake water and ecology should be tested and monitored. The knowledge gained will be used to improve productivity and ecological performances within the project. More info:


To evaluate the environmental impact of floating structures, the founders of Blue21 cofounded another company: Indymo. This company uses aquatic drones to collect underwater images, water samples and water quality and ecology data for public and private entities who want to inspect and monitor water systems.  A study was conducted to assess the impacts of floating structures on water quality and ecology. Several locations with floating structures were monitored with underwater drones equipped with cameras and sensors. Within the project, different data collection strategies are being used: benthic scans with underwater drones, transects of water quality parameters, depth profiling and continuous/static measurements. More: information:


In the milestones that were already achieved by the Blue21 team towards realizing the Floating City, participatory approaches played a crucial role. The Harnaschpolder Floating Ecohomes in the city of Delft, the Netherlands was one of these milestones. In this area, six sustainable water homes were developed in the municipality of Delft. A unique characteristic of this project was that the citizens became owner of a water plot and realized their own house with their architect and contractor. As a consequence this was a citizen led initiative.The role of our team was to start up the project in close collaboration with the municipality and the future citizens. In this project we have provided various services including: technical advice, project management, cost estimation, citizen guidance, and architectural sketches and preliminary designs.


Another milestone project our team worked on was the Floating Pavilion in Rotterdam. The Floating Pavilion already has become a prominent landmark and an international icon of climate adaptation. The building plays a key role in strengthening stakeholder awareness for flood resilient urban development.  Multiple research and education institutions collaborated in the project, such as Delft University of Technology, Rotterdam University of Applied Sciences, Albeda College, Erasmus University Rotterdam - Dutch Research Institute for Transitions(Drift) and Urgenda. Students from many different fields were given the opportunity to do research on structural and architectural design aspects, sustainable building development, and to serve as interns during the construction process. Several information meetings for stakeholders, citizens and companies were organized.  Stakeholder and community participation feedback was carefully incorporated in the design process.

The Blue21 Floating City Unit can be mass-produced to drive down costs and provide an affordable flexible solution. Specifically for the Philippines we have looked into the possibility of providing affordable floating housing for the urban poor. To develop a solution for this urgent demand for affordable accommodation, a pre-fabricated pilot house was designed with a target retail value of approximately €9,000. The aim of this initiative was to reduce the vulnerability of urban poor communities that live in flood prone areas by introducing low-cost floating housing schemes. Much like The Netherlands, the Philippines is a low lying country and is highly susceptible to flooding, In Metro Manila alone, the damage brought by flooding is approximately €146 million every year with at least 71,000 houses damaged annually. Floating communities may be the answer to the frequent flooding in the Philippines, particularly in Metro Manila. The low-cost floating housing project was proposed to the community in Muntinlupa.  More info:

Blue21 applies state-of-the art lightweight floating technology to enable floating urban development. In the realized projects our team was involved in, different materials were applied such as concrete, polystyrene, steel and lightweight composites. Blue21 is workpackage leader in the European Commission Horizon 2020 project Space@Sea. In this project, sustainable and affordable workspace at sea is developed with 17 European partners by developing a standardized and cost-efficient modular island with low ecological impact. R&D is at the core of our company. Two of our team members have completed a PhD at the Delft University of Technology. We work with world renowned research institutes such as Deltares and Marin to be at the forefront of technical innovation. We developed an innovative bi-facial floating solar system which is rotating with the sun to optimize energy yields in the Innozowa project for which a patent is pending. The Floating City Unit (FCU) is our Flagship Product. This is a modular and expandable system consisting of a floating structure that is easily adaptable to many coastal locations in the world. It is customizable according to project needs with regard to size and materials and  has integrated wastewater treatment, rainwater management and local energy solutions. By connecting FCU's with each other floating projects can modularly expand into a floating urban development project. This technology was tested in the wave basis of Marin for hydrodynamic behaviour.  To get a more detailed idea of our R&D, please look at our knowledge base:

Real estate development on land is mostly characterized by a rather conventional process of selling public land to private developers who subsequently develop the buildings and sell and rent it to their customers. This process has many disadvantages. It is susceptible to corruption, it may lead to land speculation driving up costs and excluding vulnerable social groups, and it provides an incentive for governments to develop nature into urban areas. On the water all of this can be entirely different. Floating city developers are not interested in ownership of the land or sea. Neither do they like to spend their money on land or water property because they might want to leave in the future. They just want to have the permit to be able to anchor their floating property at a certain place. This opens more opportunities for vulnerable social groups to live in a resilient way.  We have been working on designs for floating housing targeted at the urban poor.


[bgsection pex_attr_title=”Why not reclaim land instead?” pex_attr_subtitle=”” pex_attr_undefined=”undefined” pex_attr_style=”section-light2″ pex_attr_bgcolor=”ffffff” pex_attr_image=”” pex_attr_imageopacity=”0.1″ pex_attr_bgimagestyle=”static” pex_attr_titlecolor=”252525″ pex_attr_textcolor=”777777″ pex_attr_height=””]

Cities around the world are looking more actively than ever into ways to stimulate digital growth, adopt new technologies, modernize and expand urban areas without creating a negative impact on the environment. Floating development can be an alternative to land reclamation and has  many advantages, for instance, they:

  • could save costs (less materials and time)
  • are more innovative and attractive, good marketing imagine for a visionary port seeking for sustainable innovation
  • are more eco-sensitive
  • do not disrupt the ocean
  • are adaptable and modular, very suitable to fit scaling facilities and growing market over time
  • are future-proof and could cope with expected and unexpected sea level rise
  • do not rely on sand imports (requiring 100 times less sand)
  • could be constructed elsewhere, towed and installed at site fast, preventing causing noise or air pollution to the local environment.

The benefits of floating design is that it can be both modular and constructed in a closed environment, so you can essentially manufacture entire buildings or infrastructures off-site, in for example a dry dock, where there are no influences such as weather which can cause delays, there’s also no excavation required. Floating construction is a lot faster than regular construction, especially in terms of larger-scale infrastructural projects where additional land is required. Land reclamation is a common method but this is can be time intensive where large projects can take upwards of a decade to complete due to the extraction, transport and settling period of soil.

In future land reclamation is proving to no longer be a viable solution. The result of large-scale reclamation projects around the world is that the availability of sand is reducing and therefore the prices are expected to rise significantly in the coming decade, rendering it simple uneconomically viable in future.

At present, in terms of large-scale infrastructural projects where additional land is required, floating can potentially be a far more economically viable solution due to the short length of construction time and potential of prefabrication. From our studies, we have determined that for depths >15m floating becomes significantly more financially attractive than land reclamation. As land reclamation is extremely costly and time-consuming due to the extraction and settling process. Additionally, there are many adverse effects in an ecological sense due to the disruption to surrounding marine life.  Floating, on the other hand, can be constructed a lot faster, it can be more cost-effective and it is far greater in an ecological sense.


[bgsection pex_attr_title=”What are the benefits of floating cities?” pex_attr_subtitle=”” pex_attr_undefined=”undefined” pex_attr_style=”section-light2″ pex_attr_bgcolor=”ffffff” pex_attr_image=”” pex_attr_imageopacity=”0.1″ pex_attr_bgimagestyle=”static” pex_attr_titlecolor=”252525″ pex_attr_textcolor=”777777″ pex_attr_height=””]

Floating cities will not be connected to mainland electricity and water networks. Mainly decentralized technologies for water and energy production will be used. Floating cities are a great testing and developing ground for these technologies but at the same time, they would also be a growing market for them. This will increase the attractiveness for companies to invest in research and development of these technologies. Lower costs and a higher quality will be the result. Also jobs will be created. Ultimately, decentralized sustainable technologies will be better able to compete with the land based outdated infrastructures that are dependent on fossil fuel input and were invented during the industrial revolution. Floating cities therefore also provide the means for land based cities to become more sustainable by developing a new model of city and generating more efficient and competitive clean technologies.

Blue21 architect and researcher Barbara Dal Bo Zanon participated in a study which was presented at the Amsterdam International Water Week 2015. In this research it was found that growing food on water as part of a Floating City is up to 200 times more efficient compared to average agriculture on land. The research was about the potential of floating productive developments for urban areas. We estimated the amount of nutrients and carbon dioxide produced by cities and used these data as input for calculating microalgae yields. Basing on biofuel and food yields from microalgae, we estimated the water surface required for floating productive developments. There is strong indication that food production on water needs 130 to 150 times less area compared to global agriculture on land. Considering the sequestration area (forest carbon storage) which is necessary for compensating the emissions of land agriculture and it would be saved by growing food on water, this efficiency can be over 200 times. More info:

Floating cities adapt to high water level that occur during storm surges. Whilst coastal cities can be flooded in such event, the floating city will adapt to the water level. Naturally waves will have an impact on floating cities as well. For this purpose we have evaluated the hydrodynamic effects of waves on floating platform in the European Commission Horizon 2020 Research Program Space@Sea. These important topics were investigated by numerical simulations and physical tests in the wave basin. For more information see:

In addition Blue21 founder ir. Karina Czapiewska participated in a research study by Delft University of Technology to develop safe high rise platforms in maritime conditions that are subject to heavy storms. This research shows that it is technically feasible to create floating high-rise buildings of 15 floors at sea, even under hurricane conditions. It was found that the way to do this is to build the city with several modular floating platforms rigidly connected to each other. This way, the total length and width of the floating city will become larger than the wavelength. This causes the waves to have less effect on the floating city, which will only experience very small displacements, so small that inhabitants won’t feel them. This study also showed that the larger the water depth gets, the less expensive a floating city becomes compared to land reclamation, simply because for the latter you need more sand for larger water depths. More info:

Floating cities require new infrastructure and transportation systems for their inhabitants. To study this important topic. A research on a transportation systems for passenger transportation in floating cities was executed in collaboration with Delft University of Technology.  Three possible systems were developed: a personal system, a public system and a water based system. These systems were scientifically evaluated using criteria such as costs, comfort, travel time, safety, walkability and emissions. The results show that a collective transportation system was the preferable option. More information:

Cities use vast areas of agricultural land all over the planet for their energy and food supply. They are huge importers of resources such as food, while they mainly produce waste. Citizens in urban areas also account for the majority of global greenhouse gas emissions. This so-called parasitic metabolism causes various environmental problems such as air and water pollution, CO2 emissions and a high dependency on global networks for critical resources. However, the concentration of people and industries in large cities also make cities a unique solution space for technological innovations. A promising solution for cities to use waste as a resource is using wastewater and CO2 in algae systems to produce biofuel.  Algae can fix carbon up to 50 times as fast as land based vegetation. However, in dense urban environments, the space for these systems is often scarce and expensive.  A key characteristic of the Blue21 Floating City is floating algae production systems. These systems enable cities to find the required production space and even save huge areas of agricultural land. This is shown by a recent study of Blue21, Rotterdam University of Applied Sciences and TU Delft in the Journal of Cleaner Production. In this Floating City research we evaluated the potential of these systems in two very different coastal cities: Rotterdam and Manila. Rotterdam can save 12 times its own area. For Manila, 74 times the city area in agricultural land can be saved. These particular saved areas do not have to be created by cutting rainforest or cultivating other nature areas. Therefore, if coastal cities all over the world would start using floating production, the world’s rainforest can be saved.

The main role we fulfill as citizens in Western civilization is the role of a passive consumer. Every day we are called to this role continuously by commercials, advertising and social media. On the long term however, being a consumer only, is disappointing. People are capable of much more. In a floating city, decentralized concepts for water supply, energy production and other utilities can be tested and applied. Citizens and groups of citizens have the opportunity to manage their own utilities and produce electricity and water instead of only being a passive consumer of large utility companies that are still dependent on fossil fuels. This will increase the influence of citizens in society and strengthen their independence compared to their fellow citizens in land-based cities. Citizens are better capable than ever before to take up such a role, since the level of education and access to technical information has never been as high as it is today.


Floating Cities can treat wastewater, absorb CO2, provide ecological habitat, reduce wave height and create jobs for the coastal cities where they are anchored. This is the symbiosis between the cities on land and water on which our philosophy of the Blue Revolution is based. Floating developments should be based on costs/benefits, quality and total system impacts rather than costs/benefits only. For this purpose, it is key to start with having to build something with a positive ecological impact. We need buildings and infrastructure that 1) absorb CO2 and pollutants, 2) will create ecological habitat and 3) economic livelihood for local citizens at the same time. Then the next step is we need to use and develop technical innovations to make that affordable.

Concerning urban planning policy it is a great advantage that floating development is not an irreversible intervention. Urban planners have the opportunity to remain actively involved in the shaping of floating developments even after implementation. In this sense the concept of floating urbanization introduces a new adaptable approach to urban planning and development. The mobility of floating buildings enables a dynamic and flexible urban fabric. As a consequence, floating urban planning can focus more on organic growth strategies than traditional blueprint spatial planning. The floating district can be easily adapted to the ongoing changing requirements of the community and changing circumstances, such as the rise in sea level but also changes in economical and spatial requirements.  The Rotterdam Floating Pavilion example demonstrates that such a project can function as catalyst for further urban development on the water.

Population growth is particularly strong in urban coastal areas and around rivers, in deltas that are vulnerable to sea level rise, floods, and other climate change impacts. It is estimated that the average global flood losses in coastal cities will multiply from US$6 billion per year in 2005 to US$52 billion per year by 2050, taking into account just the socio-economic costs of floods, such as the impact on populations and property values. The total size of global urban areas exposed to both floods and droughts is expected to increase by more than 250% in 2030 compared to 2000. In 2060, the global population in low elevation coastal zones could more than double compared to the year 2000. Floating city can improve quality of life in particular in developing countries who are most vulnerable to impacts of climate change and who are most rapidly growing.