Natural is Better
The building sector has been estimated responsible for 35% of global energy usage and 40% of energy related CO2 emissions. However, bio-integrated and bio-climatic building design is becoming an increasingly attractive opportunity for climate change adaptation and mitigation and meeting net zero targets, particularly the use of bioactive elements on buildings’ façades. These have included, but are by no means limited to; cork, coffee husk, newspaper wood, mycelium, recycled diapers, plastic bricks and seaweed. Due to their environmentally friendly nature, bioactive façades positively affect CO2 capture and the management of some important factors such as thermal comfort, energy efficiency, wastewater treatment. These factors contribute additional cumulative benefits for global warming, pollution control, social wealth, and sustainable development on a larger scale.
Seaweed has become a forerunner to create benefits at every stage of its use. The extant macroalgal biome has a similar in extent to the amazon rainforest, can absorb CO2 up to 30 times faster than trees on land and provide a critical habitat for marine life, many of which are commercially valuable species.
Seaweed Structures Save Lives
Even where seaweed is considered a problem it can become a solution, as was found the Mexican start up SargaBlock. Sargassum seaweed washing up on the shores of Cancun would lie on the beaches and rot, putting off tourists, leading to governments being required to clear as much as 40,000 tonnes. However, SargaBlock’s founder Omar saw more potential in this vast resource, diverting almost almost 6,000 tons from landfill and firing them into usable bricks that can last up to 120 years. His resourcefulness has further created jobs for 300 local families and Omar has even donated 14 houses to those in need.
The buoyant properties of seaweed bricks have also been prospected by companies such as SeaBrick for developing floating platforms to support ambitious floating cities, as have been suggested for the Maldives, essential as sea levels rise with climate change.
Seeing Through Seaweed
Another novel take is being introduced in a new student residence in Paris, due to open its doors in September 2024, however this time capitalising on microalgae. The windows will feature standard double glazing, however an extra layer filled with warm water and connected to a pump system will provide optimum conditions for microalgae to be grown. This addition promises to deliver benefits for both the building and the algae. The insulation properties of the windows could cut the building’s energy consumption by 50%, while the algae will require 80% less energy to grow. Algae-integrated buildings can sequester CO2 with an average sequestration rate of 5 g/ft2/day when optimum growing environments and operation modes are implemented.
Furthermore, microalgae offers a growing number of commercial uses, including; health foods, biofuel, pharmaceuticals and cosmetics. Microalgae from the Paris student residence has been projected to be initially commercialised as a fresh product utilised for its health benefits. Long term similar projects could be exploited by the pharmaceutical and cosmetic industries, with the strictly controlled conditions of the algae windows providing pure products.
In summary, while the building sector has historically represented a disproportionately large contribution to energy consumption and CO2 emissions, the future of this industry could in fact be a global asset to carbon sequestration, reduced emissions and even food security.