A Huge City Polluter? Buildings. Here’s a Surprising Fix.

By Brad PlumerMarch 10, 2023

A Huge City Polluter? Buildings. Here's a Surprising Fix.

Carbon capture might not work for all buildings. But some are giving it a try.

By Brad Plumer | Photographs by Hiroko Masuike

March 10, 2023

It starts with a building

in Manhattan.

It starts with

a building in

Manhattan.

It starts with

a building in

Manhattan.

It starts with a building

in Manhattan.

It starts with a building

in Manhattan.

On cold mornings in New York City, boilers in the basements of thousands of buildings kick on, burning natural gas or oil to provide heat for the people upstairs. Carbon dioxide from these boilers wafts up chimneys and into the air, one of the city's biggest sources of global warming emissions.

But there is one exception.

At the Grand Tier, a 30-story apartment tower on Manhattan's Upper West Side, the carbon dioxide from its two giant gas boilers is captured, cooled to a liquid and then trucked to a concrete factory in Brooklyn. There, the carbon is mixed with cement and sealed into concrete blocks, where it can't heat the atmosphere.

"This is the first carbon capture system on a building that we’re aware of anywhere in the world," said Brian Asparro, the chief operating officer of CarbonQuest, the company behind the system. "And we expect that it won't be the last."

The boiler releases

carbon dioxide.

The boiler

releases carbon

dioxide.

The boiler

releases carbon

dioxide.

The boiler releases

carbon dioxide.

The boiler releases

carbon dioxide.

The building's owner, Glenwood Management, didn't install the technology purely out of concern for the planet. A sweeping new climate law in New York City aims to cut greenhouse gas emissions from large buildings 40 percent by 2030 and 80 percent by 2050. Starting next year, buildings that exceed emissions limits will face steadily escalating fines.

The law was designed to propel buildings to swap gas and oil for cleaner electric heating. But the costs and logistics of that shift can be extremely challenging. And that has turned New York City into a laboratory of sorts, forcing change and innovation as property owners scramble to avoid huge penalties.

Next is a complicated

process involving

lots of pipes.

Carbon dioxide is captured,

liquified and stored.

Next is a complicated process

involving lots of pipes.

Carbon dioxide is captured,

liquefied, and stored.

Next is a complicated process

involving lots of pipes.

Carbon dioxide is captured,

liquefied, and stored.

Next is a complicated

process involving

lots of pipes.

Carbon dioxide is captured,

liquefied and stored.

Next is a complicated process

involving lots of pipes.

Carbon dioxide is captured,

liquefied and stored.

The novel solution in the basement beneath the Grand Tier's marble lobby is easy to overlook. On a recent morning in a steamy room next to the parking garage, two industrial boilers roared to life as they burned natural gas for heat, just as they’ve done since the building opened in 2004.

But the hot exhaust from those boilers was funneled through a duct to a small, spotless room filled with pipes, rumbling compressors and metal tanks. Inside several of those tanks were dry absorbent materials that look like lentils and bind to carbon dioxide, allowing the machines to filter out other gases like nitrogen and oxygen. The remaining carbon dioxide was then chilled to minus 10 degrees Fahrenheit and turned to liquid.

The equipment is similar to carbon capture machinery used at larger ethanol or natural gas processing plants. CarbonQuest's main innovation was shrinking the system for a residential property and designing it to run automatically, without constant human supervision.

The liquefied CO2 is

pumped outside

the building.

Workers load it into a truck,

ready for a journey.

The liquefied CO2 is pumped

outside the building.

Workers load it into a truck,

ready for a journey.

The liquefied CO2 is pumped

outside the building.

Workers load it into a truck,

ready for a journey.

The liquefied CO2 is

pumped outside

the building.

Workers load it into a truck,

ready for a journey.

The liquefied CO2 is pumped

outside the building.

Workers load it into a truck,

ready for a journey.

"We want to make this as innocuous and as boring as we can," Mr. Asparro said.

The system currently captures about 60 percent of the carbon dioxide emitted by the Grand Tier's boilers, Mr. Asparro said. That reduces the building's overall emissions by about one-quarter, enough to meet the limits set by the new climate law. (The rest of the Grand Tier's emissions come from electricity consumption, which actually increased moderately to power CarbonQuest's compressors and cooling systems.)

But that still leaves the matter of what to do with the liquefied carbon dioxide. For the Grand Tier, the answer is concrete.

Every week or so, a small tanker truck pulls up to the Grand Tier and workers connect a hose to the side of the building that sucks out the liquid carbon with a loud hiss.

They truck it to Glenwood Mason Supply, a concrete manufacturer tucked beside a residential neighborhood in East Flatbush, Brooklyn. (No relation to Glenwood Management, which owns the Grand Tier.)

Next stop: a concrete

plant in Brooklyn.

Next stop: a concrete plant in Brooklyn.

Next stop: a concrete

plant in Brooklyn.

Next stop: a concrete

plant in Brooklyn.

In a cavernous, clanking warehouse that used to be a brewery, Glenwood Mason makes thousands of concrete blocks per day used in construction all over the city. One tall stack of blocks outside was marked for an Amazon warehouse in Queens.

On this day, workers at the plant took the liquid carbon from the Grand Tier, used a new technique to convert the liquid into a powder resembling dry ice and dumped it into giant mixers, along with cement, sand and aggregate. The cement reacted with the carbon dioxide to turn it into a mineral, calcium carbonate, which was then sealed into concrete that was formed into blocks. Even if the blocks are later smashed up, the carbon dioxide can't escape.

CO2 is transferred from

the truck to this tank.

Yep, more pipes.

CO2 is transferred

from the truck to

this tank. Yep,

more pipes.

CO2 is transferred

from the truck to

this tank. Yep,

more pipes.

CO2 is transferred from

the truck to this tank.

Yep, more pipes.

CO2 is transferred from the truck

to this tank. Yep, more pipes.

"It creates this circular economy," said Jeff Hansen, vice president of architectural sales and marketing at Glenwood Mason. "We’re taking carbon dioxide from a building in Manhattan, turning it into a block in Brooklyn and then sending that block out to build more structures in the city."

Some proponents of injecting carbon dioxide into concrete will claim that it can make the blocks stronger or reduce the amount of cement needed, but company officials say they haven't noticed a big difference so far. While they’re paying for the carbon dioxide, they are not charging a premium for their blocks.

But there is a potential business case: Around the city, a younger generation of architects are interested in using "greener" materials for their buildings. New Jersey recently passed a law providing incentives for lower-carbon concrete. Glenwood Mason, which has been experimenting with a range of techniques to reduce the climate impact of its blocks, is trying to position itself as a pioneer in more sustainable concrete.

CO2 is converted to a solid

that looks like dry ice. And

then added to a cement mix.

CO2 is converted to a solid that looks like dry ice.

And then added to a cement mix

CO2 is converted to a solid that looks like dry ice.

And then added to a cement mix

CO2 is converted to a solid

that looks like dry ice. And

then added to a cement mix.

CO2 is converted to a solid

that looks like dry ice. And

then added to a cement mix.

"We’ve never approached this as a big moneymaker, it's always been about sustainability for us," said Connie Cincotta, the owner of Glenwood Mason Supply. "But we do want to make this sustainable approach attractive for as many people as possible."

Questions remain about whether this elaborate carbon capture process makes sense as a strategy to fight climate change.

For Glenwood Management, which owns nearly 30 large buildings around the city, the technology has been a boon. Ahead of the new climate law, the company had made all the easy changes to save energy and reduce emissions: it replaced incandescent light bulbs with LEDs, upgraded old fan motors and improved insulation.

But it wasn't enough: The Grand Tier was set to face roughly $100,000 per year in fines starting in 2024, rising to $400,000 per year in 2030, because of those two giant carbon-spewing boilers in the basement.

When the CO2 reacts with

cement, it turns into a

mineral, no longer able to

heat the planet.

When the CO2 reacts with cement, it turns into a

mineral, no longer able to heat the planet.

When the CO2 reacts with cement, it turns into a

mineral, no longer able to heat the planet.

When the CO2 reacts

with cement, it turns into

a mineral, no longer able

to heat the planet.

When the CO2 reacts with cement, it

turns into a mineral, no longer able

to heat the planet.

The company explored replacing the boilers with electric heat pumps, a solution favored by environmentalists, but that posed serious challenges, said Josh London, a senior vice president at Glenwood Management. He was nervous about the building-wide renovations and rewiring that would be required and had questions about how well New York City's already-strained electric grid would hold up during the coldest days of winter, when heating demand spiked.

Capturing the carbon looked far simpler, he said. The company just had to clear six spots in the underground parking garage for CarbonQuest to install its equipment. And the boilers could keep burning gas.

"I’m not sure any of our tenants even noticed when we put the carbon capture system in," Mr. London said. "Whereas if we had to rewire the building, well, we do a lot of disruptive stuff but that would take the cake."

The resulting mixture is

poured and shaped.

The resulting

mixture is poured

and shaped.

The resulting

mixture is poured

and shaped.

The resulting mixture is

poured and shaped.

The resulting mixture is

poured and shaped.

He sees electrified buildings powered by clean energy as the ultimate goal, but carbon capture can offer a "bridge" for now, he said. Glenwood Management is working to install carbon capture in at least five more of its buildings.

Mr. London wouldn't disclose what the company paid for the Grand Tier system but said it was cheaper than electrification and will pay for itself within six years through avoided penalties as well as the sale of hundreds of tons of carbon dioxide to Glenwood Mason. (Carbon dioxide can sell for more than $300 per ton.)

CarbonQuest officials are hoping to capitalize on the discomfort with electrification as the new climate law bites down. "We’ve been inundated by phone calls by people who have done electrification studies and said, this is too expensive, this is too difficult," said Anna Pavlova, vice president for strategy and market development at CarbonQuest.

10.

And there you have it.

A carbon-sequestering

concrete block is born.

10.

And there you have it. A carbon-

sequestering concrete block is born.

10.

And there you have it. A carbon-

sequestering concrete block is born.

10.

And there you have it.

A carbon-sequestering

concrete block is born.

10.

And there you have it. A carbon-

sequestering concrete block is born.

For now, however, carbon capture faces an enormous hurdle: It has not been approved by the city as a solution that complies with Local Law 97, since the technology didn't exist when the law was drafted. The Department of Buildings, which enforces the law, said it is reviewing CarbonQuest's system but has a number of questions, such as how to verify the emission reductions claimed by the Grand Tier.

"Until we know more about how this innovative technology is actually performing, and specifically, how and if the carbon is, in fact, being permanently sequestered, we cannot determine whether it is consistent with the intent of the law," said Andrew Rudansky, a spokesman for the Department of Buildings.

If CarbonQuest expands its business, it will have to persuade more concrete companies to stash all that carbon dioxide. Glenwood Mason has all it needs at the moment.

Experts and environmentalists point out electrification still has considerable advantages, like curbing indoor air pollution and being insulated from swings in gas prices. The technology is also improving quickly: New York State is currently funding a round of novel electric heat pump and efficiency projects that could serve as models for other buildings.

"The main way we decarbonize is still likely to be doing everything we can on energy efficiency, electrifying most buildings, and greening the grid," said John Mandyck, chief executive of the Urban Green Council, an umbrella group that includes real estate developers and environmentalists. "But we’re still in the early stages of what's going to be a massive market transformation," he added. "The changes required are so big that I don't think we can rule out any approach just yet."