A pair of Chicago-based architects have designed what may be the ultimate green skyscraper.

The site straddles the terminus of the Eisenhower Expressway, which adjoins Congress Parkway, an east-west artery extending the entire length of Chicago's South Loop. Recognizing that some 77,000 vehicles cross the interchange every day, architects Danny Mui and Benjamin Sahagun have designed a pair of towers that would capture resulting carbon dioxide with filters – or carbon scrubbers – that feed it to algae gardens atop the two structures. The algae subsequently would be converted to biofuel intended for eco-friendly cars.

“The scrubbers are the first step in a process that generates fuel for a fleet of eco-friendly cars for building residents,” the two designers elaborate on the Council on Tall Buildings and Urban Habitat (CTBUH) website. “The system raises public awareness of air pollution and its impact on the health of Chicagoans.”

The two towers – dubbed CO2gress Gateway Towers – also would feature a naturally vented atrium, courtesy of an operable facade, and what the two designers refer to as a “double skin” – or two layers of windows – to contend with traffic-generated noise. The double skin also would create enclosed balconies.

Mui and Sahagan designed the towers while studying architecture at Chicago's Illinois Institute of Technology, with CTBUH awarding the scheme an honorable mention in a 2012 student competition.

There are no immediate plans to build CO2gress Gateway Towers, or any such structure. Still, it's something to ponder.