In Philadelphia, a Former Navy Yard Wins on Sustainability

New York Times

22-04-2025

From an elevated section of Interstate 95 in South Philadelphia, drivers can look down on several mothballed war ships moored at the edge of the Delaware River. They recall a time when Philadelphia's Navy Yard hummed with naval shipbuilding and repair, but for the last quarter-century the area has been a growing campus for businesses ranging from cake making and clothing manufacture to molecular diagnostics and gene therapy.
Now, it's evolving further to become a pioneer for sustainable development with energy-efficient buildings, innovative storm-water management, construction that's designed to withstand future sea-level rise and green spaces that provide an inviting environment for the campus's approximately 15,000 employees.
The Navy Yard's sustainability transformation began with its previous developer, Liberty Property Trust, and is being continued by Liberty's successors, Ensemble Investments, LLC and Mosaic Development Partners JV. They have been jointly developing the site in partnership with Philadelphia Industrial Development Corp., a public-private economic development agency, since winning the development rights in 2020.
Those efforts have just been recognized by the U.S. Green Building Council which gave a portion of the Navy Yard a gold certification in its Leadership in Energy and Environmental Design program for Neighborhood Development, known as LEED-ND. The certification, which covers 39 existing and 38 planned buildings over 295 of the site's 1,200 acres, makes the project the biggest of its kind in the United States and the first in Philadelphia. The new certification also follows earlier LEED awards to individual buildings at the site, according to Peter Templeton, chief executive at the council.
To qualify for LEED-ND, properties must meet Green Building Council standards for building construction and operation and provide evidence that energy, water and materials are being used more efficiently than in conventional building. The council also credits projects that use previously developed sites and avoid urban sprawl by being located near existing town centers. In addition, the awards are given to compact, walkable, mixed-use communities that have good access to public transit.
The Navy Yard developers have created energy-efficient buildings in a village-like setting that's designed to help tenants attract and retain workers. The approach has been a success: There are no vacancies across the campus, which has 150 companies occupying 7.5 million square feet of office, manufacturing and laboratory space.
Since 2000, when the City of Philadelphia purchased the land and began transitioning the Navy Yard from its use as a military base, its tenants have only been commercial. But starting this fall, the development will have its first residential component. A complex of 614 rental apartments is under construction and will include two- and three-bedroom units starting at about $2,000 a month, as well as affordable units starting at about $1,100 a month for a studio. Eventually, Ensemble and Mosaic intend to build 4,000 residential units at the site.
The developers expect the new apartments will draw people who work at the Navy Yard but also those who work elsewhere and are attracted to a community that combines the density and amenities of city living with the space and cleanliness of a suburban environment. To support the new residents, they plan to dedicate 40,000 square feet to ground-floor retail space, and 75,000 square feet of space to amenities such as a gym, a pet spa and a golf simulator.
Scott Kelly, founder of Re:Vision, a sustainability consulting practice that helped the project earn its LEED-ND designation, predicts the site will become a template for other projects around the United States. 'What's happening here in the Philadelphia Navy Yard really is a game changer, showing others what good development should look like,' he said.
These interviews have been edited for clarity.
How did the developers use LEED principles?
Liberty wanted to incorporate LEED into what we were doing from a development standpoint. We realized we could use it as a framework to create better buildings that were more energy efficient and that were focused on the occupant experience, including air quality in the building, access to natural light and thermal comfort.
How do office workers respond to a sustainable office environment?
In today's world, to get people to leave their homes and come to work, you need to create an environment that people react really well to. People take less vacation, they work in the buildings longer, they enjoy being in the office.
What will attract the first residents to the Navy Yard?
I think we are going to draw people from every neighborhood in the city because of the uniqueness of the urban-suburban feel. The city struggles a lot with cleanliness, but we don't deal with that here because this is an offshoot of the city.
Do the sustainable building practices at the Navy Yard meet environmental goals?
Having uplifting and positive examples like this shows people what's possible. If you care about the environment, and you look at what's happening in Washington D.C., you probably think, 'I'm watching the unraveling of 50 years of the modern environment movement right before my eyes.' Projects like this give a sense of hope and optimism that we can still as a society roll up our sleeves and accomplish good things.