The neon billboards that line Hong Kong streets may eventually do more than just sell products. In a new project, a group of designers hopes to use the signs—along with a fleet of drones—to suck CO2 out of city air.
During the day, the drones (or, as the designers call them, "parasitic robots") would perch on billboards. Coated in a polymer known for its carbon-sucking powers, the robots spread their wings and collect pollution as long as the sun is up.
At night, when the billboards light up, the robots would attach to them, using the heat from the neon in the next step of the process. Heating up the polymer to a certain temperature releases the CO2, which can be collected and used in energy production.
The CO2 also helps boost the growth of plants on the robots' wings, so the robots can double as miniature farms. "The plants and robot work as a hybrid, because the main goal is to reduce CO2," says Michal Jurgielewicz, a Beijing-based architect who is part of the design collective NAS-DRA.
"The plants are planted and harvested by humans using hydroponic farming," he explains. "We're aware that urban conditions can be harsh and growing the plants for food can be difficult. It should be adjusted to the place and conditions, so using sensors, one can modify how plants should be grown."
The system would collect organic waste from the plants to create biogas, while the extra CO2 would be used to create methane. Some of the power from these fuels can run the robots themselves, making the system self-sufficient.
For the designers, the project is a way to reclaim city streets. "This movement of creating the robots is a DIY bottom-up approach, and it's in the direct opposition to dynamic and exploding urban conditions driven mostly by the market itself," Jurgielewicz says. "It's purely fighting for a green on the street, for less air pollution, light pollution, noise pollution and information pollution."
They also see the mix of biology, technology, and common urban infrastructure as a next step in the evolution of urban farming. The design isn't quite ready for the street, however. The CO2-collecting polymer is still in lab tests at UCLA. The designers plan to make more models and prototypes until it can be tested at a larger scale.