NYC skyscrapers turning to carbon capture to lessen climate change

In a vertical city like New York, any serious effort to address climate change has to focus on the greenhouse gas emissions caused by buildings

From the outside, the residential high-rise on Manhattan's Upper West Side looks pretty much like any other luxury building: A doorman greets visitors in a spacious lobby adorned with tapestry and marble.

Yet just below in the basement is an unusual set of equipment that no other building in New York City — indeed few in the world — can claim. In an effort to drastically reduce the 30-story building's emissions, the owners have installed a maze of twisting pipes and tanks that collect carbon dioxide from the massive, gas-fired boilers in the basement before it goes to the chimney and is released into the air.

The goal is to stop that climate-warming gas from entering the atmosphere. And there's a dire need for reducing emissions from skyscrapers like these in such a vertical city. Buildings are by far the largest source of greenhouse gas emissions here, roughly two-thirds, according to the city buildings department.

New York state’s buildings also emit more air pollution than any other state's.

So building owners must make dramatic cuts starting next year or face escalating fines under a new city law. About 50,000 structures — more than half the buildings in the city, are subject to Local Law 97. Other cities such as Boston and Denver followed suit with similar rules.

As a result, property managers are scrambling to change how their buildings operate. Some are installing carbon capture systems, which strip out carbon dioxide, direct it into tanks and prepare it for sale to other companies to make carbonated beverages, soap or concrete.

They see it as a way to meet emissions goals without having to relocate residents for extensive renovations. In this case, the carbon dioxide is sold to a concrete manufacturer in Brooklyn, where it's turned into a mineral and permanently embedded in concrete.

“We think the problem is reducing emissions as quickly as possible," said Brian Asparro, chief operating officer of CarbonQuest, which built the system. “Time is not on our side, and this type of solution can be installed quickly, cost-effectively and without a major disruption.”

Yet critics, many of them representing environmental groups, say building managers should be going much further: They argue that to achieve meaningful reductions in emissions, buildings should be significantly upgraded and switched to renewable-powered electricity instead of continuing to burn fossil fuels. They also express concerns about the safety of storing large amounts of carbon dioxide, an asphyxiant, in a densely populated community.

“Carbon capture doesn’t actually reduce emissions; it seeks to put them somewhere else,” said Anthony Rogers-Wright, director of environmental justice at New York Lawyers for the Public Interest. “The emissions still exist. And we should be clear that the only way to reduce emissions ... is to stop emitting.”

It’s still unclear whether carbon capture technology will even be recognized by New York City as a qualifying emissions reduction; the city has yet to decide. Asparro and others are trying to persuade city officials to accept it.

CAPTURING THE CULPRIT

In the basement of the Upper West Side apartment building, two hulking 500-horsepower boilers rumble, burning natural gas and releasing carbon dioxide. The boilers, which are expected to last another 10 or 20 years, produce roughly half the building's emissions, Asparro said.

The other half of the emissions that, in the city's view, the building is responsible for, are those generated at the power plants where the building gets its electricity. The carbon capture system, Asparro said, is trapping about 60% of the boilers' emissions. All told then, including the electricity to power the system, it's reducing the building's emissions by roughly 23%.

“Boilers like this are installed everywhere, in schools and hospitals around the world,” Asparro said. “It's a really big challenge that buildings are facing in order to reduce emissions.”

The carbon dioxide and other gases are diverted from the chimney and piped into a room where a few parking spaces have been repurposed to house the carbon capture system. The gases flow over a special material that separates out the carbon dioxide. Then it’s compressed and cooled to minus-10 degrees Fahrenheit (minus-23 Celsius), turning it into liquid that's then stored in tanks. That process takes energy, and capturing carbon dioxide does increase the building's electricity use, but overall the system is still reducing the building's emissions.

More pipes lead to spigots outside the building, where a truck pulls up once or twice a week to load up with liquefied CO2. The truck carries it through city streets and across a bridge to Brooklyn, where it's sold to a concrete manufacturer.

Carbon capture technology has existed on an industrial scale for decades, used by oil and gas companies and some manufacturing plants to capture climate-warming carbon dioxide and either sell it, or use it to wrestle more oil from underground.

But now a handful of green tech companies and building owners are trying for the first time to deploy this technology on a much smaller scale on residential buildings. New York City's law requires buildings exceeding 25,000 square feet to reduce emissions. In Minnesota, Radisson Blu Mall of America, a hotel, has installed a system that captures carbon dioxide that's eventually used to make soap.

Building owners that can afford to pay for carbon capture equipment do receive some federal tax breaks for installing the systems. There are other incentives available to help update buildings, according to NYC Accelerator, a program that helps homeowners and property managers find ways to reduce emissions.

To reduce energy use, the apartment building also has computerized motors, fans and pumps, LED lighting and battery storage, said Josh London, senior vice president at Glenwood Management Corp., which manages the building. The company plans to install carbon capture systems in five other buildings this year.

Without action, similar high-rise buildings could face fines of nearly $1 million annually starting in 2030, Asparro estimated.

Nearly 70% of New York City’s large buildings have steam boilers that run on natural gas or oil, according to NYC Accelerator. Many have heating systems more than a half-century old, and often they’re under-maintained, said Luke Surowiec, director of building decarbonization at ICF, a consulting firm which manages NYC Accelerator.

“Our buildings are very old and inefficient, and that’s the reality,” Surowiec said. “There are a ton of opportunities that haven’t been realized.”

MINERALIZING INTO CONCRETE

Over in Brooklyn, the floor rattles and shakes as yellow machines churn at Glenwood Mason Supply Company Inc., a concrete maker unrelated to Glenwood Management Corp. Grey blocks rattle down a conveyor line under a din of metal gears and motors. Somehow, birds have moved in and fly between towering piles of blocks.

It’s into this clamor that a truck delivers the liquefied carbon dioxide collected at the Manhattan apartment building. Then, using equipment provided by a company called CarbonCure, the liquid carbon dioxide is compressed and turned into a solid.

As concrete ingredients churn in a structure resembling a pizza oven, the carbon dioxide, now essentially dry ice, flows in like a mist. The carbon dioxide reacts with calcium ions in cement, one of the ingredients of concrete. This forms calcium carbonate, which becomes embedded in the concrete.

Once carbon dioxide is in that mineral state, it's secure and it won't be released unless it's heated to about 900 degrees Celsius (1652 degrees Fahrenheit), said Claire Nelson, a geochemist who specializes in carbon capture at Columbia Climate School.

“So unless a volcano erupts on top of your concrete building, that carbon is going to be there forever,” Nelson said.

One main ingredient of concrete is cement, which contributes about 7% of all greenhouse gas emissions worldwide, according to a study by PBL Netherlands Environmental Assessment Agency.

Adding mineralized carbon dioxide to concrete can reduce its carbon footprint, though not by much. On average, concrete producers using CarbonCure technology reduce their carbon footprint by just 5% to 6%, said Robert Niven, CEO of CarbonCure, which works with 700 concrete producers in 30 countries.

Connie Cincotta, owner of Glenwood Mason, said her company takes other measures as well, for example to reduce the amount of cement in its concrete mix, by adding post-industrial glass that would have gone to landfills.

“If there's any way we can get cement out of the mix, that’s helpful,” she said.

The company's concrete blocks with mineralized CO2 have been used in buildings owned by Amazon and a Manhattan charter school, among others.

QUESTIONS REMAIN

Many environmental groups remain skeptical of carbon capture and instead favor investing in a transition to renewable energy. They also fear that it could be unsafe to store carbon dioxide, which in extreme concentrations can lead to suffocation, in a residential dwelling.

After a carbon dioxide pipeline ruptured in Satartia, Mississippi, in 2020, 45 people sought medical attention at local hospitals, including people who had been caught in a vapor cloud while driving, according to a report from the Pipeline and Hazardous Materials Safety Administration. People exposed to high concentrations of carbon dioxide, the report said, may experience rapid breathing, confusion, elevated blood pressure and increased arrhythmias. Extreme concentrations of carbon dioxide can lead to death by asphyxiation.

Storing concentrated carbon dioxide under a residential building is worrisome, because “in the case of Mississippi, people weren’t actually living right on top of it,” Rogers-Wright said. “We’re talking about big buildings here in New York City. So the risks are unknown, but they certainly are apparent.”

There's also a risk of leaks, he said, if a truck transporting carbon dioxide were to get into an accident.

Proponents of carbon capture technology respond that there are safeguards to prevent such scenarios. The carbon capture technology installed in the Manhattan apartment, Asparro said, was permitted by multiple city agencies.

“We have carbon dioxide everywhere in cities," he added. "Hospitals, restaurants, breweries — all utilizing carbon dioxide. And it’s being done in a fairly safe and manageable way.”

Nelson, the Columbia geochemist, who also started a carbon capture company, contends that having natural gas stored in basements is more dangerous than storing carbon dioxide, and many people accept those risks posed by natural gas.

The biggest challenge, proponents say, is scaling this and other solutions fast enough to make a difference in climate change.

That's why proponents say many solutions should be deployed at once.

Back in Manhattan, powering the apartment building entirely with renewable electricity isn’t possible yet because the local utility doesn’t have enough renewable energy to sell to all New York customers, London said.

And “with solar, you need a bigger footprint than what we have in a building like this,” he added.

London said he wants to buy power from wind farms once it becomes more widely available.

But “that’s going to take a long while, so I don’t think we have the luxury of sitting,” he said. “We can reduce our emissions while we wait for that.”

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