Future Eco Towers Scrub Smog from Paris Air

An urban plan for Paris could reduce the city's greenhouse gas emissions by up to 75 percent in 2050.

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All big cities have a problem with trapped heat and air quality; it's not just those in China. And as populations increase, so too will pollution. To that end, Paris City Hall commissioned

Vincent Callebaut Architectures

to come up with a plan for Paris in the year 2050 that would reduce the city's greenhouse gas emissions by up to 75 percent. Callebaut's proposal, called 2050 Paris Smart City, is a remarkable collection of eight high-tech towers that emphasize nature, greenery, and sustainable design. We devote this weekend's Tasty Tech Eye Candy to this project, which will have you rethinking what cities may look like in the future.

What do you get when cross a farm with a skyscraper? A farmscraper. These towers are vertical farms that, as Callebaut puts it, "repatriate the countryside in the heart of the city." Three vegetable towers would not only filter the air but allow food production to happen locally. Organic waste would be composted with methane captured and reused to produce electricity. Rain water could be collected and recycled to water the plants.

Callebaut proposes that two "Bridge Towers” be constructed over the Seine to serve as the river gates of Paris. These two bridges with "jellyfish silhouettes" emerge from the water in an organic shape. Multi-blade wind turbines as well as hydroelectrical turbines produce electricity, while a heat pump would heat and cool residential apartments that overlook the water.

In the US, we call it low-income housing, but in Paris, it's called "housing at a moderate rent." These apartments are generally built with cheap materials and little attention to aesthetics. But Callebaut's Honeycomb Towers aim to change that. Here, individual mini-houses are interlocked and interspersed with vegetable gardens as well as suspended orchards to provide fresh food for the inhabitants. Prefabricated, double-walled units will improve insulation and reduce noise. On the roof, thermal and photovoltaic solar panels produce electricity.

Callebaut wants to transform an abandoned railway hub, the

Petite Ceinture

, into a triple-use ecological corridor. Here, railways, cycle paths and walkways would accommodate commuters as well as meadows, woods and gardens. Overlooking the area are cyclone-shaped towers that remove smog thanks to the abundant plants as well as a coating of titanium dioxide. The coating reacts with sunlight to neutralize airborne pollutants. Axial wind turbines located on residential balconies will generate electricity and on the roof, a photovoltaic flexible textile will harvest not only sunlight for electricity but also rain and dew for water. Tunnels along the path will be lit by electricity created from piezoelectrical circuits embedded in the pathway. Each step will generate energy along the promenade.

Paris's rue de Rivoli, which runs east to west for almost a mile along the bank of the Seine river, is one of the most famous streets in the city. It was created in the 18th century to resolve traffic jams and the hygiene problems of an increasingly overcrowded district. Callebaut wants to cap the iconic buildings on this street with peaks of greenery and renewable energy. During the day, solar-powered shields (one photovoltaic, the other solar-thermal) will produce electricity and hot water. Any excess electricity will be stored in the form of water in a pump station at the top of the buildings. At night, the water will be allowed to cascade down into basins, turning turbines along the way to generate electricity. Lastly, garden balconies surrounding the residential apartments will filter air and water.

Four structures make up the Bambo Nest Towers. Named the Puccini, Palerme, Rimini and Verdi -- as an homage to Le Corbusier’s Athens Charter, Italy 13 development which was carried out in Paris in the 1960s -- the buildings will house the highest concentration of people in the city. A plaited bamboo exoskeleton will support individual vegetable garden balconies and community orchards that will increase the coolness of the air, naturally. Funnels in the braided exterior would accelerate wind speeds and increase the output of the embedded wind turbines. Additional electricity would be supplied by a concentrating solar-thermal collector on the roof that would produce steam to turn a turbine.

Callebaut wants to make the 689-foot glass and steel skyscraper, known as

Tour Montparnasse

, unrecognizable in 2050. Public promenades with embedded piezoelectric materials will generate electricity with every footstep that falls onto this carbon-neutral vertical park. A phyto-purification lagoon will purify and recycle gray water to nourish the hanging gardens. In the glass exterior, photobioreactors will cultivate green micro algae, which will capture heat from the sun, keeping the interior cool. Callebaut estimates that such bioreactors could improve the efficiency of the building's heating and cooling system by 50 percent. Methane produced by the algae will be processed in a biofuel refinery housed in the basement and used to generate electricity.

Inspired by mangrove trees, these towers will be rooted to the Gare du Nord, one of six large railways stations in Paris. The towers will accommodate offices, hotels and housing dedicated to travelers. State of the art renewable energy technology will work together to produce more energy than the station uses. Here, piezoelectrical capacitors will harvest kinetic energy from footsteps to train motion and convert it into electricity. Thin-film solar panels, shown here in green, will run throughout the towers, converting sunlight into energy. A coating of white titanium dioxide on the exterior will react with sunlight to breakdown pollutants, while myriad plants -- a staple in Callebaut's designs -- will absorb CO2 and freshen the air.