For Glenwood Management, one of the many New York City apartment building developers that need to reduce the carbon footprint of its existing properties to keep pace with the city’s stringent environmental regulations, a tech startup called CarbonQuest offers what seems like a potentially game-changing solution.

The four-year-old Spokane, Washington–based company can retrofit an existing building’s heating system with equipment to capture and remove carbon dioxide even before it has a chance to be emitted into the atmosphere. Not only that, but the carbon dioxide is converted to liquified form, enabling it to be repurposed as an ingredient in concrete blocks, making construction of new buildings greener as well.

“We’ve been looking at ourselves, like a lot of our colleagues, and saying, what else can we do to make these huge cuts?” explains Glenwood vice president Josh London, referring to Local Law 97, which takes effect in 2024 and aims to slash large buildings’ greenhouse gas emissions by 40 percent by 2030. Those who do not comply face hefty penalties. “We were willing to be a first mover and a pioneer—not for accolades, but because we were concerned about how to tackle the problem.”

After CarbonQuest outfitted one of Glenwood’s buildings, the Grand Tier, located at 1930 Broadway, with its technology in 2021, the building’s annual carbon dioxide emissions dropped by 25 percent. Glenwood was so thrilled by the results that the two companies recently announced that they are deploying the technology in five additional Glenwood buildings—the Fairmont, located at 300 East 75th Street, the Bristol at 300 East 56th Street, the Paramount Tower at 240 East 39th Street, the Barclay at 1755 York Avenue, and the Somerset at 1365 York Avenue.

The five buildings amount to 2.5 million square feet (232,000 sq m) of residential space, and the installation will prevent up to 5,000 tons (4,536 metric tons) of emissions.

Leveraging Carbon Capture

The concept of carbon capture has been around for years, but until recently, it has been deployed mostly at an industrial scale. Oil producers, for example, capture carbon dioxide and reuse it in the extraction process, and utility plants have been outfitted with carbon-capture technology as well.

However, the idea of capturing carbon from multifamily residential buildings to reduce emissions—and then repurposing it in a way that sequesters the carbon—represents a new evolutionary stage, according to Anna Pavlova, CarbonQuest’s vice president for strategy and market development.

“The technology has improved in carbon capture,” Pavlova says. CarbonQuest’s equipment catches carbon dioxide molecules from the building flue exhaust, using porous materials called solid sorbents to attract the molecules and react chemically with them. “That’s the actual secret sauce in the capture,” she explains. “These solid sorbents are the future of carbon capture technology. The other piece to it is that we’ve figured out to make these systems modular. They come in kits and can be added easily without any disruptions to the building. And the design and engineering of the system can be adapted to almost any environment, whether it’s a school, a hospital, a multifamily building, or a commercial tower. We can do any of those.”

The solid sorbents are shaped into small, solid balls and placed in tanks attached to the building’s heating system. It is possible to add more tanks filled with sorbents to capture more carbon, which makes the technology easily scalable, Pavlova says.An installation by CarbonQuest.

CarbonQuest’s hardware is augmented by an artificial intelligence–powered software platform, which monitors and documents the carbon capture process, enabling the building’s management to track how much is removed, liquefied, and loaded into trucks to be shipped for reuse. “Machine learning is useful in this case, in that it helps us to automate a lot of the carbon accounting process,” Pavlova says.

London says installing the Grand Tier’s carbon capture equipment was “painless” in terms of disruptions for tenants, but that fitting the complicated apparatus into an existing space in a building was the biggest challenge. “I picked that building because it has a huge garage,” he explains. “We were able to give up six parking spaces and create a mechanical room for it.”

Once the pilot system was in place, CarbonQuest brought in an engineer to study the process and figure out how to reduce the footprint by 20 percent, so that installation in additional buildings will be easier, London says.

Bridges to All-Electric



London describes carbon capture in apartment buildings that burn natural gas for heat as a solution that can be implemented quickly and serve as a bridge toward eventual electrification. “We can accomplish something now that’s meaningful, with less pollution, as we wait for that.” In addition, “some buildings are going to be tough to electrify fully,” he says.

Tanks of liquified carbon dioxide captured at the Grand Tier are being trucked over to Glenwood Mason Supply Company, a Brooklyn-based business that coincidentally has a similar name but is not connected to Glenwood Management. Jeff Hansen, Glenwood Mason’s director of architectural sales, says that the carbon is injected into the cement mix, where it becomes a solid by mineralizing with it. “It permanently becomes a part of our block,” Hansen says.

“It’s neat to be able to utilize sustainable carbon dioxide from buildings by taking it here to Brooklyn, putting it into our block, and sending it back to build other buildings,” he explains, describing the process as a “circular economy of the built environment.”

Hansen says that Glenwood Mason, the city’s last remaining block manufacturer, repurposes captured carbon primarily out of environmental stewardship. But the added carbon also slightly improves the performance of the bricks. Glenwood Mason is doing ongoing research to find ways of increasing the amount of carbon that is sequestered in them, possibly through modifications in the curing process.

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