Tour of Carbon Capture Technology at The Grand Tier

By Jill Baker

On April 3, GreenHomeNYC toured the Grand Tier, a 30-story residential rental building at 1930 Broadway, near Lincoln Center, built in 2002. The attraction was the building’s point source carbon capture system, designed by CarbonQuest. Brian Asparro, CarbonQuest’s COO, who is also a GreenHomeNYC board member, led the tour.

Built in 2021, the system is estimated to cut 60-70% of the building’s carbon dioxide (CO2) emissions from the combustion of natural gas. It is the first carbon capture system currently installed in a NYC residential building and is CarbonQuest's pilot project to demonstrate its ability to install a carbon capture system in a space-constrained environment. CarbonQuest also uses this facility to test ways to optimize the process and decrease its installation, operation, and maintenance costs.

Packed into an 800-square foot room in the Grand Tier’s garage, adjacent to the boiler room, the carbon capture equipment is remarkably complex.

Point source carbon capture reduces emissions post-combustion by preventing CO₂ in the boiler exhaust from entering the atmosphere. At The Grand Tier, post-combustion CO2 comes from the building’s two 400-horsepower boilers, which are fired by natural gas.

GreenHomeNYC board member and CarbonQuest COO Brian Asparro leads a tour of the carbon capture system at 1930 Broadway.

What Is the Use Case?

Mr. Asparro says that the technology makes sense for large buildings, those of roughly 100,000 square feet or more, that consume a significant amount of natural gas. He said Glenwood Properties, the building’s management company, installed the technology to reduce greenhouse gas (GHG) emissions. They have also implemented lighting retrofits, purchased Renewable Energy Certificates (RECs), and installed a battery storage system.

The Grand Tier’s boilers are relatively young -- only 22 years into their much longer useful lifespans, making replacement with heat pumps uneconomic. Mr. Asparro was not able to share the system’s cost, but indicated its payoff period is 4 -7 years. He also said that CarbonQuest has been involved with studies that indicate that fully electrifying with heat pumps would cost “5x what we’re doing here.”

Carbon capture could help reduce emissions for many large New York City buildings with relatively new boilers, Mr. Asparro suggested. While it admittedly increases direct electricity usage and has only been tested in a handful of residential settings, the technology does reduce CO2 emissions. CarbonQuest says the Grand Tier’s system reduces overall building emissions by about 25%, but did not explain how that figure was determined.

What Drives the Payback?

The payback of 4-7 years is said to be driven by selling the building’s captured CO2 to a concrete block manufacturer called Glenwood Mason, and by 45Q tax credits. The 45Q tax credit is a federal program incentivizing carbon sequestration that pays the participant a dollar amount per metric ton of CO2 permanently sequestered. This amount ranges from $60 to $85 per ton, depending on whether the CO2 is considered “geologically sequestered”, is used for “enhanced oil recovery,” or for an “other qualified use.” The logic of this is that the program intends carbon to be sequestered permanently, rather than put into something that will eventually decay and allow it escape back into the atmosphere. A large portion of 45Q credits have been claimed by companies using captured CO2 for “enhanced oil recovery,” essentially a form of fracking.

Carbon Capture Not Recognized by Local Law 97

Mr. Asparro confirmed that Local Law 97 (LL97), New York City’s emissions reduction law for large buildings, does not currently include carbon capture as a qualifying methodology for emission reduction. This is because LL97’s focus is on reducing the burning of fossil fuels, not capturing combustion emissions. Thus, the claimed 4–7-year payback does not factor in LL97 fines foregone. Nevertheless, Mr. Asparro hopes CarbonQuest’s project at the Grand Tier will help the technology gain consideration for LL97 inclusion.

About 69% of NYC’s greenhouse gas emissions come from buildings, and the largest source of emissions within residential buildings is natural gas. At the Grand Tier, natural gas drives about 60% of building emissions, while electricity accounts for the remaining 40%. Though carbon capture has been tried by other companies at a large scale in power generation, oil and gas, and ethanol facilities, CarbonQuest’s design takes it down to the building level.

Image Source: CarbonQuest

How Does it Work?

The boiler exhaust gases are diverted into the CarbonQuest apparatus. The CO2 is separated from the exhaust gasses and prevented from entering the atmosphere by the company’s Distributed Carbon Capture™ system. After a multi-stage process that includes compression, drying, and cooling to a very low temperature, the end product is liquid CO2 stored securely in a tank.

The process is roughly this: the system takes CO2 from the boilers’ flue gas, where the CO2 is concentrated at about 10%. Mr. Asparro says that about 80% of the flue gas is captured. It then goes through a series of steps, including the separation of CO2 from the nitrogen and water vapor in the flue gas. Mr. Asparro emphasized that CarbonQuest’s process differs from most other CO2 separation processes. Those rely on hazardous chemicals called amines and use steam pressure on very tall adsorbent and desorbent columns that wouldn’t be feasible in the basement of a NY residential building. (Adsorption involves the physical entrapment of CO2 molecules onto the surface of a solid adsorbent material, and desorption is its release.)

Instead, for its “pressure swing adsorption,” CarbonQuest uses a solid biodegradable sorbent which looks like small lentils, packed into beds over which the flue gas passes. This is the part of the process that increases electricity use. The CO2 sticks to the “lentils,” and the nitrogen and oxygen are released up the chimney. Phase change liquifies the CO2, which is then treated, purified, and collected in tanks. Mr. Asparro says the process’s electrical demand is high (a little over 100 kW in the steady state).

Questions Remain

Questions about the efficacy of the process remain. For example, it requires a lot of electric energy that was not previously used by the building. Thus, total building energy use is higher after installing this equipment. There are also questions about just how much of the CO2 is captured and permanently sequestered. For example, in the cement-making process, how much is lost into the atmosphere? Mr. Asparro and CarbonQuest don’t say.

Nonetheless, they hope that by demonstrating their design here in NYC it may someday become another tool in the toolbox to help lower the cost of compliance with Local Law 97. “We think about the time value of carbon,” Mr. Asparro says, “A ton avoided today is more valuable than a ton avoided tomorrow.”