Ninety-six degrees. That’s what the Brooklyn Bridge-City Hall platform averaged through the summer months of 2025, and the heat has nowhere to go. On August 10, Gov. Kathy Hochul, Mayor Zohran Mamdani and the MTA announced they’ll study whether that heat can become an asset instead of a complaint.
The proposal is a Thermal Energy Network at the Brooklyn Bridge-City Hall 4/5/6 and Chambers Street J/Z complex. It would be the first TEN installed in a U.S. transit system.
How it would work
Radiant cooling panels absorb heat off the platform. That heat is piped into geothermal boreholes drilled beneath the abandoned center platform at Chambers Street, where it’s stored until winter and then drawn back out to heat nearby municipal buildings. Radiant cooling is roughly 25% to 35% more energy efficient than conventional air conditioning, which matters in a system where every added mechanical load also adds waste heat.
The abandoned center platform is what makes the whole thing buildable. Drilling boreholes under a live station without one would be a very different conversation.
“Bringing down the temperature is a real challenge in a century-old system with open entrances and vents everywhere,” said MTA Chair and CEO Janno Lieber. “Together with Governor Hochul and Mayor Mamdani, we’re exploring solutions, previously untested in transit, to make stations more comfortable while helping to reduce energy costs. Everybody wins.”
Jamie Torres-Springer, president of MTA Construction & Development, framed the constraint: “Many subway stations are more than a century old and weren’t designed to handle today’s extreme heat, making creative solutions essential.”
It’s riding an existing capital project
This is the detail contractors should note. The study attaches to the comprehensive revitalization of the 113-year-old Chambers Street J/Z station, already funded through congestion pricing revenue in the MTA’s 2020-2024 Capital Plan. The MTA will award that construction contract by the end of 2026, the feasibility study contract this fall, and start design in early 2027 if geothermal proves feasible.
So the sustainability scope arrives as a change to an in-flight capital project, not as a greenfield demonstration. Geothermal drilling under an operating station, radiant panel installation in a 113-year-old structure, and coordination across MTA Construction & Development, DCAS and the Mayor’s climate office, all bolted onto a station rehab that’s about to bid.
Thermal energy networks have been a campus-and-hospital technology to date. If this one works, “waste heat is inventory” stops being a slide and starts being a line item in transit and large-facility retrofit scopes.
Compare the district-scale approach with a single-building energy strategy at Clinch River Unit 1, where TVA is betting on passive systems instead.