Great news for the future development of international, sustainable climate resilience:Read More›
We’re pleased to share the Seasteading Institute(TSI)’s Guest Blog article written by Rutger De Graaf-van Dinther. Rutger is the co-founder of DeltaSync and Blue21, which are determined to realize the first sustainable floating islands in French Polynesia. His scientific vision is also featured in the Seasteading book published by Joe Quirk.
How cities will save the rainforests with floating production
Cities use vast areas of agricultural land all over the planet for their energy and food supply. To achieve the Paris climate agreement, even more space is needed to capture all the CO2 that cities produce. By implementing floating algae production systems, cities can find this 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 who 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.
Cities: from parasites to solution space
Cities are still 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. The water offers a new perspective here because it can provide the required space for floating algae systems, in particular in coastal cities where a large part of the urban population is located.
How floating algae systems can make a difference
The study of Dal Bo Zanon et al (2017) published in the Journal of Cleaner Production shows how floating algae systems can change the urban parasitic metabolism. Two very different coastal cities were used as case study: the city of Rotterdam, the Netherlands, as developed coastal city and the city of Manila, the Philippines as rapidly developing coastal city. Figure 1 demonstrates the system. Nutrients from domestic wastewater and CO2 emissions from industries are used in open algae ponds with selective environments to encourage the most productive algae (Mooij et al., 2013). The fats that algae produce are used for biofuel production. The proteins are used to feed fish in so-called aquaponics systems. In these systems, the waste excrements of the fish are used for cultivation of fruits and vegetables. Because food and energy production on the water is much more efficient than on land, space on land is saved and CO2 emissions of the cities are reduced.
Towards circular coastal cities
How much food can floating algae systems produce? The calculation model of Dal Bo Zanon shows that cities can produce a large part of their own food. This is contrary to current practice in which cities import almost everything. By using all waste nutrients, floating algae systems can supply 29% of the total vegetal consumption and 20% of the total protein consumption of the city of Rotterdam. For Manila, floating algae systems can provide 22% of the city’s vegetal consumption and 37% of the total protein consumption. Moreover, the model shows that floating production in Rotterdam can be at least 130 times as efficient as land based agriculture. For Manila, the efficiency is even better: to achieve the same food production on land, 189 times as much space would be needed.
Figure 1. How CO2 and wastewater can be productively used by cities (Source: Blue21/ Dal Bo Zanon et al., 2017)
Now we have proven the benefits of floating production systems on paper, we want to demonstrate it in practice. The next step is the design and realization of a real-time monitored floating production pilot project to recycle wastewater and CO2 and produce energy and food. For this purpose we are looking for coastal cities all over the world to build the pilot and help them to become more resilient for climate change.
The full study can be downloaded at: https://www.blue21.nl/wp-content/uploads/2017/03/Journal-of-Cleaner-Production.pdf
Funding for this study or preliminary studies was provided by Centre of Expertise Deltatechnology, Topsector Water, Municipality of Rotterdam and Blue21.
Dal Bo Zanon, B, Roeffen, B, Czapiewska, De Graaf-Van Dinther, R.E.; and Mooij, P.R. (2017) Potential of floating production for delta and coastal cities. Journal of Cleaner Production 151, 10-20
Mooij, P.R., Stouten, G.R., Tamis, J., van Loosdrecht, M.C.M., Kleerebezem, R. (2013) Survival of the fattest. Energy Environ. Sci. 6, 3404–3406. doi:10.1039/c3ee42912a
Image source: MARIN
In co-operation with Blue21, MARIN has carried out some impressive tests last week!
Please read MARIN’s press release herebelow:
MARIN tests first floating mega island
Floating ports and cities possible solutions to sea level rise and overcrowded cities.
Last week MARIN (Maritime Research Institute) tested an innovative concept for a floating
mega island. The island comprises 87 large floating triangles that are flexibility connected to
one another. Together they form a flexible floating island that can be as large as 1 to 5 km in
Olaf Waals, project manager and the concept developer: “As sea level rises, cities become
overcrowded and more activities are carried out at sea, raising the dikes and reclaiming land
from the seas are perhaps no longer an effective solution. An innovative alternative that fits
with the Dutch maritime tradition is floating ports and cities.”
Floating mega islands offer future-proof living and working space at sea for:
• Developing, generating, storing, and maintaining sustainable energy (offshore wind,
tidal energy, wave energy and floating solar panels);
• Loading and transhipping cargo in coastal areas where there is little infrastructure;
• Cultivating food, such as seaweed and fish;
• Building houses and recreation close to the water.
These types of solutions are part of the Blue Future in which the seas and oceans (70% of
the earth’s surface area) are used sustainably.
The technological challenges are enormous. How do we develop floating mega structures
that are strong and safe enough to withstand winds and currents? How can these systems
be connected together and to the seabed? What is the extent of an island’s motion, and
what effect does this have on the people who live and work on the island? How can we
organise traffic and transport?
But there are also ecological issues. What is the effect of a large floating community on the
water under and around it? How can we make the system cyclic in terms of water, energy,
raw materials and waste?
MARIN is carrying out this research using computer simulations and model tests in its
Offshore Basin (40 x 40 m) in which wind, waves and currents can be simulated at scale.
On June 20th, BNR Nieuwsradio Eyeopeners broadcast an interview with Bas Buchner, Director of MARIN (Maritime Research Institute Netherlands), and our Karina Czapiewska, explaining the need and extensive possibilities for floating developments, such as floating energy, aquaculture and cities.
Blue21 has recently collaborated with MARIN, Maritime Research Institute Netherlands, to bring the concept of floating cities to the next level. MARIN has developed a numerical model that can predict the response of different floating design configurations in waves. Meanwhile, Blue21 has investigated into different possibilities of floating city design configuration and connections. This model turns out to suit the interests of both parties very well as Blue21 could learn more about hydrodynamic interactions between connections at sea in several model tests and MARIN could use the results from model tests to validate the response of the floating island.
Want to know more? Read MARIN’s full article here.