Clean energy journalism for a cooler tomorrow

Why this NYC apartment complex will use a giant underground heat pump

Join our reporter as she steps inside the muddy construction site at 1 Java Street to learn the benefits and barriers of harnessing the earth’s heat to decarbonize buildings.
By Maria Gallucci

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Construction crews excavate a large property on Brooklyn's riverfront, with the Manhattan skyline in the distance
Construction is underway on the 1 Java Street project in Brooklyn, New York. (David Joshua Ford)

BROOKLYN, New York — The 200-by-600-foot property skirting the shoreline in Brooklyn’s Greenpoint neighborhood is, for the moment, an enormous mud pit. Excavators scoop up whole chunks of earth, making room for concrete piles sprouting rebar strands. All the while, four blue drilling rigs trawl the site on skid-tracked wheels, boring holes into the ground to harvest energy hiding below the surface.

Lendlease, a global construction and real estate firm, and its joint-venture partner Aware Super are transforming the former industrial site at 1 Java Street into a mixed-use development. But unlike most New York City buildings, these ones won’t directly use fossil fuels. Instead, all 834 rental units will meet their heating, cooling and hot-water needs by extracting heat from, or pumping heat into, the ground.

In April, the companies began work on the $700 million development, which will include two apartment towers and three smaller buildings — all interconnected — plus a public park that faces the Manhattan skyline. Once completed in 2025, it will be the largest residential project in New York state to use a geothermal heat-pump system.

The addition of the system added multiple months to the schedule,” Scott Walsh, director of development for Lendlease, tells me as we tour the bustling construction zone. But that was something we were willing to take on” for the climate benefits, he says.

A man in a white hard hat and yellow safety vest stands before a blue drilling rig in a construction zone.
Scott Walsh of Lendlease walks through the site's active drilling area on May 17, 2023. (Maria Gallucci/Canary Media)

The concept of tapping the earth’s heat has been around for centuries, and modern heat-pump technologies have existed for decades. Yet relatively few buildings in the United States have taken this approach to date, owing to high upfront costs, the complexities of digging into the ground, and the fact that geothermal technology remains obscure to many people. Around 50,000 geothermal heat pumps a year are now installed in the United States, representing a tiny fraction of the country’s many millions of buildings.

Geothermal resources are literally beneath our feet and hidden in the ground,” Alexis McKittrick, a program manager at the U.S. Department of Energy’s Geothermal Technologies Office, says later by email. The public is generally unaware that geothermal resources exist and could be used for a wide array of applications.”

That’s starting to change as city councils and state governments in New York and nationwide begin to restrict planet-warming emissions and limit fossil-fuel use in buildings, which account for 13 percent of annual U.S. emissions. A raft of new federal incentives, including through 2022’s Inflation Reduction Act, is also expected to make systems more affordable and increase overall installations, McKittrick said.

An illustration of the heat-pump systems shows blue and red vertical loops of pipes beneath a tall apartment building
An illustration shows how 1 Java Street's geothermal system uses the stored temperature in the ground for heat exchange to operate the buildings' HVAC systems. (Lendlease and Marvel)

Compared to air-source” heat pumps, geothermal systems — also called ground-source” heat pumps, or geothermal heat exchangers — require less power to operate, putting less strain on an already overtaxed power grid. That could be particularly crucial during heat waves and cold snaps, experts say. Geothermal systems also need less maintenance and last much longer than their aboveground counterparts.

Still, installing a large-scale geothermal heat-pump system is hardly as simple as replacing gas-burning boilers with electric appliances. That much is made clear on my recent tour of the mud pit that will soon become 1 Java Street.

A 3D puzzle for curbing emissions

Walsh and I meet on a bright and breezy afternoon in mid-May, near the edge of the East River.

This stretch of Greenpoint’s shoreline was once a hub of oil refineries, shipyards and factories. But after a massive rezoning in 2005, glassy high-rises and luxury condominiums have come to dominate the landscape instead, even as the area continues to grapple with a legacy of industrial pollution.

We head into a cramped construction trailer, where a crumpled map pinned to the wall shows the geothermal system’s intricate layout: 320 vertical boreholes, each reaching precisely 499 feet deep and spaced 15 feet apart, connected to 32 horizontal circuits. Those feed into a central manifold room, where heat pumps and other equipment will take heat drawn from the earth and distribute it to apartments — or the other way around.

It’s more of a three-dimensional puzzle than you’d have on a conventional gas- or oil-fired building,” Walsh says. At the time of my visit, about half of the map’s 320 dots have been marked as completed with the smudge of a green highlighter.

A man in a white hard hat and yellow safety vest points to a paper map of the geothermal's layout inside a trailer.
A detailed map shows the painstakingly precise layout of 1 Java Street's geothermal system. (Maria Gallucci/Canary Media)

Lendlease estimates that harvesting the earth’s heat will reduce annual carbon dioxide emissions from heating and cooling by 53 percent, compared to a typical HVAC system that runs on fossil fuels. The apartments will also have all-electric appliances, eliminating the emissions and indoor air pollution associated with using gas fixtures. About one-third of the rental units are designated as affordable housing, which is notable because lower-income families are more likely to experience the negative effects of fossil pollution but less likely to have the resources to deal with it.

In March, the project developers received a $4 million grant to help build the geothermal heat-pump system. The New York State Energy Research and Development Authority awarded the funding through a pilot program that supports projects using geothermal or waste energy to heat and cool multiple buildings.

These community thermal networks” — including 1 Java Street — are an important step in scaling building electrification and helping more residents benefit from clean-energy infrastructure that can lead to long-term energy savings,” Donovan Gordon, the authority’s director of clean heating and cooling, said at the time of the announcement.

Geothermal advocates say such projects can also be a big source of clean-energy jobs, though more training and workforce development is needed to bring American workers up to speed with the industry. At 1 Java Street, the Canadian firm Geosource is doing some of the work to drill and install the geothermal system. We couldn’t find people locally, people with the breadth of experience for this size of building, because it is so large,” Walsh says. (Geosource is a subcontractor of New York-based Brightcore Energy.)

Visiting tube pigtails and grout puddles — before they disappear

After perusing the map, Walsh and I step out of the trailer, slip under a yellow rope barrier and venture cautiously around the growling equipment.

A worker at a podium-like control panel remotely maneuvers one of the blue drilling rigs. The machine swings a narrow metal pipe, or well casing, in the air as it tries to stick the landing. Other casings stashed in the back rattle like heavy-duty wind chimes. In New York state, companies need a special mining permit to drill wells deeper than 500 feet — which adds time and costs to projects — so these wells will reach just 1 foot shy of the limit. (Last week, the state’s Senate passed legislation that will exempt geothermal boreholes from such requirements.) 

A worker stands behind a control panel to remotely operate a blue drilling rig at the construction site.
A worker remotely operates a drilling rig to make a 499-foot-deep borehole. (David Joshua Ford)

Yet even just 30 feet beneath our shoes, the ground already maintains a relatively constant temperature of about 55 degrees Fahrenheit. In New York City’s winter, when the outside air is typically far colder, the geothermal system extracts that heat as if drawing from an earthly battery. In summer, when outside temperatures soar, the system takes heat out of the air and transfers it underground.

But to give and take this heat from the ground requires a serious amount of plumbing.

A large spool sits in the back of an open truck, carefully threading a high-density plastic tube down into the ground. The nearly 1,000 feet of tubing will be doubled up, connected at the bottom by a U-shaped part, so that whatever liquid flows down into the well can circulate back to the surface. In this case, the liquid is ethylene glycol, a type of antifreeze solution that absorbs or deposits heat in the surrounding soil.

Walsh points to various pairs of pigtails” that sprout from the dirt like blossomless daffodils. These are the ends of tubes, now firmly ensconced in grout. Workers pour the cake-batter-thick material into the well to fill in any gaps between the tube and the ground so that heat transfers evenly along the length of the well.

Black plastic tubing is tightly coiled on a spool inside the construction zone
Spools of tubing are made and tested in factories before arriving at the construction site. (Maria Gallucci/Canary Media)

When you go 499 feet down, there are voids and streams and all kinds of subsurface conditions,” Walsh explains. There’s a world underneath us, literally.” A gritty, grayish puddle bubbles like a hot spring as grout is poured, pushing air to the surface.

Some of the pigtails are already tied to horizontal pipes, which are embedded in layers of a special kind of sand. This, like the grout, enhances the heat exchange between the glycol and the earth. Walsh describes the vertical and horizontal loops as the veins and arteries” of the system. The heat pumps, then, are like the heart, directing warm and cool air into the buildings and into the ground.

In the coming weeks, Walsh tells me, everything before us on this May afternoon will disappear beneath the concrete foundations, returning the system to its out-of-sight, out-of-mind status. In a follow-up email, Lendlease claimed the geothermal piping loops are meant to last between 100 and 200 years, and they’ll require no future access or maintenance. The design also includes redundancies so that, in the unlikely event that a pipe breaks, the system can still function.

Meanwhile, all of the mechanical equipment will be kept inside the building, accessible for repairs — and elevated high enough to stay safe from New York City’s rising sea levels.

Why this supersized project isn’t a blueprint

In New York City, 1 million existing buildings generate 70 percent of the city’s annual carbon emissions, primarily by burning fossil fuels for heating, cooling and lighting.

Soon, those buildings and especially new ones will have to meet the city’s stringent climate policies. Starting next year, Local Law 97 will require most buildings over 25,000 square feet to meet certain energy-efficiency and emissions limits, with even stricter limits taking effect in 2030. Local Law 154 will effectively ban fossil-fuel systems for new low-rise buildings in 2024 and for taller structures in 2027.

A similar all-electric standard is slated for buildings all across New York state, which in May passed the nation’s first legislation banning fossil-fuel use for most new construction, starting in 2026.

According to Lendlease, the geothermal system at 1 Java Street will enable the developer to meet or exceed the city’s mandates, while also supporting the company’s long-term goals for eliminating greenhouse gas emissions.

Other developments are joining the muddy, messy geothermal business for the same reasons, including a handful of superlative-laden projects.

In Brooklyn’s Coney Island neighborhood, a 471,000-square-foot complex is — for now, at least — the city’s largest residential development to use geothermal heat pumps. Contractors recently installed the final beam on a 461-unit beachside complex, which sits atop more than 150 geothermal wells. Just down the coast, on the Rockaway Peninsula in Queens, developers are designing the $1 billion, 1,650-unit Arverne East development, which they claim will have the biggest geothermal component yet when finished in about a decade.

But not all New York City developments will be able to tap the ground for heating and cooling.

For existing commercial buildings, ripping into the earth is exceedingly tricky to do when the land is already covered by concrete and steel. As for new builds, certain sites might not have suitable underground conditions or enough area to justify the added upfront expense of installing geothermal heat pumps (though systems can be less expensive than fossil-fuel systems to operate in the long run).

When I ask Walsh if 1 Java Street might serve as a blueprint for other buildings, he replies that it’s very site-specific.” Before digging in, Lendlease conducted an extensive feasibility study to determine whether the geothermal system could support the five-building complex. If a site was smaller and the building was taller, those variables may or may not line up,” he says.

In this case, he explains over the cacophony of the construction site, the math did pencil out.

Maria Gallucci is a senior reporter at Canary Media. She covers emerging clean energy technologies and efforts to electrify transportation and decarbonize heavy industry.