Philly Navy Yard wins ‘gold’ ribbon for sustainable development on site at risk of climate-driven flooding

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A redevelopment of Philadelphia’s Navy Yard has earned a gold star for compact, sustainable development.

Roughly a quarter of the 1,200-acre former naval shipyard has been certified “LEED Gold” for Neighborhood Development. It’s the largest project to receive the designation in the country, developers say.

“Philadelphia deserves to be first,” Mayor Cherelle Parker said at an Earth Day press event at the Navy Yard announcing the certification Tuesday. She said the development advances her goals to make Philly the “safest, cleanest, greenest big city in the nation with access to economic opportunity for all.”

The LEED, or Leadership in Energy and Environmental Design, certification is a marker of green design within the building industry.

The Navy Yard, which is undergoing a multi-billion dollar redevelopment and plans to welcome its first residents later this year, is already home to several LEED-certified buildings. But the certification announced Tuesday, covering 39 existing buildings and 38 buildings that are planned, is Philly’s first on a neighborhood scale.

What LEED Gold certification for neighborhood development means

The U.S. Green Building Council describes its LEED neighborhood development certification as an “antidote” to sprawl.

To achieve certification, a development plan can earn points from a menu of attributes that reflect environmental sustainability and quality of life — for example, affordable housing, mixed-use neighborhoods and access to quality transit. Renewable energy production, district heating and cooling, rainwater management and tree-lined streets also earn projects credit, but are worth fewer points. Certified green buildings that achieve certain energy efficiency standards, walkable streets, compact development and wetland conservation are required.

The Navy Yard’s “Gold” certification is the second best out of four certification levels, following “Platinum.”

The Navy Yard earned points for restoring old buildings, landscaping with native plants, managing stormwater, mitigating the heat island effect and installing renewable energy, said Monique Owens, regional director for market transformation and development activities at the U.S. Green Building Council.

“These strategies increase the efficiency, resilience and livability of the entire community,” she said in a written statement.

Green space and all-electric apartments

Members of the development team say the Navy Yard’s five publicly accessible parks, riverfront trail and shuttle that connects parts of the site to SEPTA service helped earn the certification.

“It’s why when you enter the Navy Yard, it just feels good,” said Brian Cohen, managing director of Ensemble, one of the companies developing the site alongside the Philadelphia Industrial Development Corporation, Mosaic Development Partners and Korman Communities. “When you walk the streets, it’s a pleasant experience.”

New buildings at the Navy Yard are constructed to be energy efficient, Cohen said. This means installing efficient appliances and building systems, as well as using window shades and orienting buildings to minimize solar heat gain in the summer.

Solar panels on the roofs of buildings currently supply on average around 10% of the complex’s energy use, Cohen said. Developers hope to install more, so that when the project is finished, on-site solar supplies 15% to 20% of the site’s total energy needs.

The residential buildings under construction will not contain any fossil fuel-burning appliances, such as heaters or stoves, Cohen said.

“It’s all electric,” he said.

But Philadelphia Gas Works supplies other parts of the LEED certified site with natural gas. Both electricity supplied by the regional grid and natural gas burned on site contribute to climate change, but the carbon footprint of electrified buildings can shrink as the grid shifts toward more renewable energy.

Challenges of building at the Navy Yard include climate-driven sea level rise

The Navy Yard is vulnerable to flooding. Most of the complex sits within the Federal Emergency Management Agency’s high-risk flood zone, although Philadelphia Industrial Development Corporation officials previously told WHYY News this does not reflect redeveloped parcels that have already been raised up.

The Navy Yard is located along the tidal Delaware River, meaning it’s exposed to sea level rise driven by climate change. An analysis by the Delaware Valley Regional Planning Commission shows that under a high climate pollution scenario, sea level rise combined with tidal flooding events such as spring tides or storm surges could inundate parts of the site, including roads, several times a year by 2100.

The Navy Yard’s developers say they’re preparing for higher seas. A 2022 plan for the site, developed by the Philadelphia Industrial Development Corporation, recommends raising new buildings and roads, installing swales and other green stormwater management elements and constructing new mixed-use buildings over a floor of parking. It also recommends a notification system to alert residents ahead of flood events to move their cars and evacuate.

The new residential buildings and roads being built at the Navy Yard will be raised an extra 2.5 feet above the city’s floodplain standards, to reflect 75 years of sea level rise, Cohen said. The city already requires buildings within the Federal Emergency Management Agency’s high-risk zone to be built above the 100-year flood level, plus 1.5 feet of buffer space.

In the event of a flood, residents who move into the Navy Yard later this year would need to evacuate by roads that are not raised to this higher level, Cohen said. But developers plan to elevate certain roads so that when the development is completed in 15 to 20 years, the evacuation route will be raised above the floodplain for decades to come.

“We have a lot of critical facilities — life science facilities, advanced manufacturing facilities, data centers — so both the buildings themselves [and] the access to and from those buildings becomes really important in any sort of major storm or flood event,” he said. “Also for residents and visitors that are down here, making sure that critical infrastructure is above the floodplain based on anticipated sea level rise is something that we felt is responsible and important as assets that will last for hopefully hundreds of years going forward.”