One developer wants to build ‘the most sustainable block in Downtown Brooklyn’

In a few short years, the triangular lot where Flatbush Avenue and State Street meet in Downtown Brooklyn is going to look very different.

The low-rise buildings that once stood there will be replaced with two huge skyscrapers, all part of the massive mixed-use development known as 80 Flatbush. The project’s developers, Brooklyn-based firm Alloy Development, have big goals: In addition to building hundreds of apartments (a chunk of which will be permanently affordable), 80 Flatbush will come with a new elementary school, a new facility for the Khalil Gibran International Academy, office space, and the restoration of several 19th-century buildings that abut the site.

But Alloy’s ambitions are even bigger than bringing new housing units and amenities to the neighborhood. “This is a full block development, and we want to make this the most sustainable block in Downtown Brooklyn,” says Jared Della Valle, Alloy’s co-founder and CEO.

To that end, the firm has set a particularly aggressive goal for the first phase of the development, which will include the new schools and the smaller of the two skyscrapers (which has an address of 100 Flatbush Avenue). The schools, which will be designed by Architecture Research Office and built in partnership with the NYC’s School Construction Authority, will be built to passive house standards, a first for the city. The 38-story tower, meanwhile, will be entirely electric, with all of the functions that would typically use natural gas—stovetops, for example, or boilers for heating—replaced with electric energy. It will also have a number of other measures (including cooling towers, triple-pane windows, and energy recovery units) that will help lower its carbon output.

Alloy’s projects typically include some sort of sustainability measures; One John Street, located on the Dumbo waterfront, is LEED Gold certified, and its Dumbo Townhouses have passive house features, such as thermal and air barriers that reduce heating and cooling costs. The fact that 80 Flatbush will be its biggest project to date gave the firm’s principals more incentive to take bigger steps toward energy efficiency.

“We’re working in this part of Brooklyn, where we’ve worked for 10-plus years,” says AJ Pires, the president of Alloy. “We know the place very well, and there’s an extent to which we feel increasingly responsible and accountable for the impact of our work. That touches a lot of things, and one of them is obviously buildings’ impact on our environment.”

In New York City, buildings of more than 25,000 square feet account for 30 percent of the city’s overall carbon emissions. In April, the City Council took a major step toward reducing that output by passing the landmark Climate Mobilization Act, a package of bills geared toward reducing New York’s greenhouse gas emissions by 40 percent by 2030. The most ambitious piece of legislation, Local Law 97, requires retrofits for existing large buildings to make them more energy-efficient—things like replacing old HVAC systems with wind power or geothermal wells, or upgrading window insulation

Though the Climate Mobilization Act has only been law for a few months, it’s already impacting how architects and developers approach not just their existing buildings, but projects on the horizon. Della Valle and Pires were already thinking about how to incorporate eco-friendly measures into the larger 80 Flatbush project, but the passage of the climate act—along the the monthslong National Grid moratorium that affected residents of New York City and Long Island—led them to pursue an all-electric skyscraper.

“The architecture community spends a lot of time trying to convince clients to think about the environment and compel clients to be progressive as it pertains to sustainability,” says Della Valle. “Insofar as we get to make the decision and we’re also the developer, we have nobody to point at, so we need to be responsible and make those choices that are more progressive and difficult, but also to lead the industry.”

All-electric systems in multifamily housing is a “forward-thinking” approach, according to Colin Schless, a vice president at Thornton Tomasetti who leads its sustainability group; the firm is working with Alloy on implementing these sustainability measures at 80 Flatbush. “What is unique is seeing a lot of these high-performance buildings going all-electric,” he says. “New York has always had cheap natural glass, so high performance projects have always used it. Alloy is one step ahead here.”

In the skyscraper, for instance, apartments will have induction cooktops rather than gas ones, which Schless says will require less ventilation in the individual units (and pose less of a risk for gas leaks). Energy recovery units in both the residential and commercial part of the skyscraper will ensure that approximately 75 percent of the exhaust air leaving the building will be repurposed. Heating and cooling systems will also be electric, with a water loop system instead of the gas boilers typically found in apartment buildings. “All of these things ultimately are about the quality of the experience inside the units,” says Della Valle.

Similarly, the school buildings will have many features that Della Valle and Pires hope will improve the experience of learning for the students who will enroll there. The design incorporates a green roof and plenty of windows, so there will be exposure to natural light in all of the classrooms. In keeping with passive house standards, the building envelope will have triple-pane windows and other energy recovery efforts that will ensure it’s airtight and a healthy environment for kids.

“Maybe it’s idiosyncratic and not the way it’s traditionally done, but we should not be in a moment of looking historically at how to build a building,” says Della Valle. “We should be looking into the future.”