A typical skyscraper has a massive carbon footprint, both embedded in the production of materials such as concrete and steel and from the energy used to keep it running. But if this new, conceptual 105-story skyscraper is built, it could operate with essentially no carbon footprint at all.

“The prototype is a way of saying to the world, look, we can actually make buildings zero carbon,” says Craig Applegath, founding principal of Dialog, the Toronto-based architecture firm that worked on the design along with engineering and construction partners. “And not just saying it’s zero carbon by buying offsets from a forestry company or buying electricity from a wind farm 20 miles away, but actually on-site, in situ, zero carbon.”

Solar panels integrated into the building’s walls (along with batteries) are designed to cover around a quarter of the electricity used. A combined heat and power plant in the building provides the rest of the power, using waste heat from the system for both heating and cooling. The plant runs on natural gas, but the emissions are fed into a bioreactor that feeds the pollution to algae, so they don’t escape to the atmosphere.

It’s not a permanent solution, because although it eliminates emissions at the building, it doesn’t get rid of emissions that happen during natural gas production, such as leaks of methane, a potent greenhouse gas. Still, the same design could potentially be used with renewable natural gas made from methane captured at landfills or on farms. And it’s one way to significantly cut total lifecycle emissions. (Moving to fully electrified buildings, running on renewable energy, is another.)

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