In New York City, more and more high-rise buildings need to be renovated to become more climate-friendly. Some skyscrapers are experimenting with capturing the emitted carbon dioxide, cooling it into a liquid and mixing it into concrete, where it turns into a mineral. This requires installations of coiled pipes and tanks to capture the CO2 from the buildings’ huge gas-fired boilers. One provider of such a solution is the US company CarbonQuest.
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US skyscrapers must become more sustainable
According to The Associated Press, building owners in New York will have to make drastic carbon savings or face increasing fines starting next year. This is a new law that will affect around 50,000 buildings – more than half of the buildings in the city. Other US cities such as Boston and Denver have enacted similar laws. To accommodate this, some property management companies are installing carbon capture systems.
“Time is not on our side and this type of solution can be installed quickly, inexpensively and without major disruption,” said Brian Asparro, CarbonQuest’s chief operating officer. According to him, the CO2 capture system captures about 60 percent of the emissions from the boilers. However, it is unclear whether the City of New York will recognize carbon capture as a qualifying emissions reduction.
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CarbonQuest mixes CO2 with concrete
Carbon dioxide and other gases flow out of the boilers over a special material that captures the CO2 in a system. Then it is compressed and cooled to a temperature of minus 23 degrees Celsius, turning it into a liquid. The pipes lead to tapping points outside the building, where a truck loads the liquefied CO2 and takes it to a concrete manufacturer in Brooklyn, for example. Mixed into the concrete, the liquid CO2 eventually turns into a mineral.
According to CarbonQuest, once the carbon dioxide is in this mineral state, it is safe and cannot be released again unless heated to around 900 degrees Celsius. Adding mineralized carbon dioxide to concrete can reduce its carbon footprint, although not significantly. On average, concrete manufacturers using CarbonCure technology reduce their carbon footprint by five to six percent.
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Criticism of the safety of CO2 capture
Many environmental groups are skeptical about carbon capture and prefer investing in renewable energy. They also worry that storing carbon dioxide in homes could be unsafe. After a CO2 pipeline rupture in Mississippi in 2020, 45 people sought medical attention at local hospitals. People exposed to high levels of CO2 can experience rapid breathing, increased blood pressure and abnormal heart rhythms. Extreme concentrations can even lead to asphyxiation.
However, carbon capture advocates point out that safety precautions are in place and the technology installed in Manhattan has received permits from several city agencies. The biggest challenge is scaling these and other solutions fast enough to stop climate change.