New York City, the Metropolitan Transportation Authority, and New York State have partnered on a feasibility study for the nation’s first Thermal Energy Network inside a transit system, targeting the Brooklyn Bridge-City Hall 4/5/6 and Chambers Street J/Z station complex in Lower Manhattan, where summer platform temperatures averaged 96°F in 2025.
Key Takeaways
- The proposed Thermal Energy Network (TEN) would capture excess heat from subway platforms, store it underground, and redirect it to warm nearby municipal buildings during colder months.
- Brooklyn Bridge-City Hall 4/5/6 recorded average platform temperatures of 96°F during the summer of 2025, with some stations reaching up to 20 degrees hotter than outside air.
- Geothermal boreholes would be drilled beneath an abandoned center platform at Chambers Street J/Z, a 113-year-old station currently undergoing a congestion pricing-funded overhaul.
- The feasibility study contract is expected to be awarded in fall 2026, with design work set to begin in early 2027 if the technology proves viable.
- Radiant cooling technology used in TENs is 25 to 35 percent more energy efficient than conventional air conditioning systems.
Geothermal Boreholes and Radiant Cooling Target One of the System’s Hottest Stations
The proposed system would work by installing radiant cooling panels on the walls, ceilings, or floors of the Brooklyn Bridge-City Hall platforms. These panels circulate chilled water that absorbs heat directly from the surrounding environment. That captured thermal energy would then travel through pipes to geothermal boreholes drilled beneath the abandoned center platform at the adjacent Chambers Street J/Z station. During the winter, the stored heat would be extracted and piped into nearby municipal buildings, including City Hall, Tweed Courthouse, Surrogate’s Court, and the David Dinkins Municipal Building.
The technology is not entirely untested. Thermal energy networks already operate at several hospitals and university campuses, where they move heat between connected buildings and reduce reliance on fossil fuels. What makes this project distinct is the application inside a transit environment, where open entrances, ventilation shafts, and the constant movement of trains introduce variables that controlled campus settings do not present. MTA Chair and CEO Janno Lieber acknowledged that challenge directly, noting that a century-old system with open entry points everywhere makes temperature control a difficult engineering problem.
Brooklyn Bridge-City Hall earned its place as the pilot location for practical reasons beyond its extreme heat readings. The station sits directly below a cluster of city-owned government buildings, which means the infrastructure for heat transfer would not need to span long distances. The 6 train terminal at Brooklyn Bridge-City Hall also generates significant heat from trains idling at the end of the line, compounding the thermal load on the platform.
Chambers Street J/Z Overhaul Opens a Window for Geothermal Testing
The timing of the TEN study is directly linked to a broader revitalization project already underway at Chambers Street J/Z. Governor Kathy Hochul and the MTA announced on August 7 that the 113-year-old station would undergo a comprehensive renewal funded through congestion pricing revenues under the MTA’s 2020-2024 Capital Plan. That project includes structural rebuilds, tile replacement, stairway upgrades, leak mitigation, and ceiling repairs to address decades of water damage.
Because the station’s abandoned center platform is not in active passenger use, the MTA can drill geothermal test boreholes and install monitoring equipment without disrupting daily subway service. That unused platform effectively serves as a built-in laboratory for technology that has never been deployed in a U.S. transit system. The MTA plans to award the construction contract for the broader station renewal by the end of 2026, and the TEN feasibility study will run in parallel with that timeline. If the study confirms that geothermal infrastructure is viable beneath the station, design work on the energy network would begin in early 2027.
City and State Frame the Study as a Climate Resilience Model
Mayor Zohran Mamdani positioned the project as both a quality-of-life improvement and a long-term fiscal play. For the millions of commuters who pass through the subway system daily, the immediate benefit would be measurably cooler platforms during July and August. For the city’s operating budget, the payoff would arrive during the heating season, when stored underground heat supplements or replaces conventional energy sources for government buildings clustered around the Civic Center.
The Governor’s Office framed the initiative as a proof-of-concept for scaling geothermal infrastructure across the wider subway network. Governor Hochul noted that the city-state partnership demonstrates how innovative solutions can emerge when different levels of government coordinate on shared infrastructure challenges.
The study is being managed jointly by the MTA, the New York City Department of Citywide Administrative Services (DCAS), the Mayor’s Office of Climate and Environmental Justice, and the Office of the Deputy Mayor for Operations. Chief Climate Officer Louise Yeung cited the subway TEN alongside other recent city climate projects, including heat-resilient bus shelters and outdoor cooling centers, as evidence of a coordinated strategy to make transit infrastructure more durable against rising temperatures.
Broader Sustainability Push Extends Beyond the Subway
The thermal energy study fits into a wider set of climate-related investments the Mamdani administration has rolled out over the past year. The city released an Urban Forest Plan earlier in 2026 with a target of reaching 30 percent tree canopy coverage citywide. On the energy side, 130 solar installations are under construction on public school rooftops, generating 27.5 megawatts, with an additional 86 projects in the pipeline that would add another 17.2 megawatts.
The city has also crossed the 1,000-vehicle mark for its electric law enforcement fleet and is tracking to fully electrify the Sanitation Department, Parks Department, and DCAS enforcement fleets by 2030, five years ahead of the deadline set by local law.
For subway riders, the near-term reality remains unchanged. Platforms will continue to run hot through the rest of this summer and likely the next. The feasibility study, design phase, and any eventual construction would stretch across several years. But the underlying premise of the project, that the subway’s single most persistent complaint could become a resource rather than a liability, represents a shift in how the city and the MTA are thinking about infrastructure that predates modern climate conditions by more than a century.
FAQs
What Is a Thermal Energy Network and How Would It Work in the Subway?
A Thermal Energy Network captures excess heat from one location and transfers it to another through an underground loop of pipes and geothermal boreholes. In this case, radiant cooling panels on subway platforms would absorb heat and send it to boreholes drilled beneath the Chambers Street J/Z abandoned center platform. During colder months, that stored heat would be extracted and used to warm nearby city government buildings, including City Hall and Tweed Courthouse.
When Would Subway Riders Notice a Difference in Platform Temperatures?
The feasibility study contract is expected to be awarded in fall 2026, with design work beginning in early 2027 if the technology proves viable at the site. Actual construction and installation would follow those phases, meaning noticeable temperature reductions on platforms are still several years away.
Why Was the Brooklyn Bridge-City Hall Station Chosen for This Study?
Brooklyn Bridge-City Hall 4/5/6 recorded average platform temperatures of 96°F during summer 2025, making it one of the hottest stations in the system. The station also sits directly below a cluster of city-owned government buildings, reducing the distance required for heat transfer infrastructure. The adjacent Chambers Street J/Z station has an abandoned center platform that can be used for geothermal testing without disrupting passenger service.
