A new underground substation: 9 things you need to know
April 22, 2025
As we turn to more electrification in our cities, we will also need novel design solutions to help deliver that power. Here’s an example.
A version of this blog first appeared as “Nine things you need to know about America’s new underground substation” in Design Quarterly, Issue 23.
As cities across the country are looking to move towards electrification and away from fossil fuels, they will be met with a new set of questions. The biggest ones are likely these: Where is all this power coming from? And is the grid going to be ready to support it?
For an answer, let’s look at the BXP Life Sciences Center development in Cambridge, Massachusetts. Our team is the architect of record for two new life sciences buildings (250–290 Binney Street—Kendall Square MXD Commercial Towers) and the design architect and architect of record for a new residential building (121 Broadway) there.
We are also the architect of the new electric substation, which will be located underground. We are collaborating with the local utility, Eversource Energy, and its designers to increase power capacity in the area. On the surface, above the substation, we are coordinating the design of the plaza, working with architects and landscape architects. It will be the second underground power station in North America and the first fully underground substation in the US.
250-290 Binney Street in Cambridge, Massachusetts. It is part of a development that is using an underground electric substation. (Stantec/Pickard Chilton)
It’s clear, a lot is going on.
Why are we designing this underground substation? And what does this first-of-its-kind project tell us about how decarbonization will require new types of buildings?
1. It helps towns and cities like Cambridge go all electric
New developments in many urban cores are going 100 percent electric. They will need new forms of infrastructure and buildings to deliver more electricity to our communities. The 121 Broadway building will be the tallest building in Cambridge—and it will be fully electric.
A global life science hub, Kendall Square has its own growing power needs. The City of Cambridge is promoting electrification with programs like Electrify Cambridge. The new underground substation—built on a former garage site—will support the large mixed-use development.
How did we land on an underground substation? The project site is close to schools and parks. And the community was skeptical about locating a typical substation in the neighborhood. This led to a partnership between City of Cambridge, Cambridge Redevelopment Authority, Eversource Energy (the energy provider), and BXP (the developer). Their goal? To look at inventive solutions that could provide the area’s demand for electricity. And they landed on the idea of an underground substation.
The planned underground substation is part of the Greater Cambridge Energy Program. The program’s goals are to back increased electric demand in the region, enhance resiliency, and support decarbonization.
Center Plaza at BXP Life Sciences Center in Kendall Square in Cambridge, Massachusetts. (Renderings courtesy of Sasaki and NBBJ)
2. It’s an engine for development
Underground substations can drive development and generate income. How? Often, above-ground sites that utilities use for power stations sit on valuable real estate.
With this new model, however, cities can put some of their electrical infrastructure underground. This opens up space and allows for development—either above or next to the power infrastructure. It allows for a wider variety of development in the vicinity of the infrastructure. Seen this way, an underground substation can be an income generator and engine for development.
In the case of Kendall Square, putting the 35,000-square-foot substation underground allows for an ambitious development on the adjacent site. Combined, the buildings have more than 1.2 million square feet. Two of them are life sciences space, and the other is a residential building, with more than 430 units.
3. It sounds like a simple box, but it isn’t
The building that houses an underground substation is basically a large concrete box, which sounds simple. But this 100-foot-deep concrete box is not simple. It has six levels, three sets of stairs, and an elevator.
Most of its complexity comes from its unique role as a new model for more resilient and accessible power infrastructure that connects to the electrical grid in the urban condition. It has lots of connections, and all of them must go underground. And it must be safe and resilient. However, it has a secondary role above ground, which benefits the public but adds further complexity to its design.
Underground substations can drive development and generate income. How? Often, above-ground sites that utilities use for power stations sit on valuable real estate.
4. It’s a new public plaza
With the substation moving underground, we can use the space on the surface for something else—as long as we can maintain utility access and safety. At Kendall Square, the Cambridge community benefits because the project has a public plaza on top of the substation. Instead of a substation (or the previous parking garage) taking up space, the community will have a new, accessible outdoor space.
The plaza project comes with its own design complexities. Our goal was to give residents a park-like experience while still accommodating the large exterior structures that the substation needs. The public space is intended to be multifunctional, serving residents and commercial tenants. We worked closely with our landscape team to create inviting seating areas and nooks that lend themselves to activity.
Our team envisioned a plaza with a mix of hardscape and outdoor green space. It can host a food truck festival, yoga classes, or outdoor movies in the park. The design also has a children’s play space that will serve residents of the residential building and the community at large.
5. It has surface structures for a reason
A substation generates heat year-round. If we can avoid refrigerant-based cooling, we will have a more efficient facility. If we design an air-cooled substation, it needs to take that air in and exhaust it. An underground substation needs to reach above the surface to get fresh air and let out heat exhaust.
The structures serving air intake and exhaust for the underground substation at Kendall Square will be 60 feet tall. We’ve designed them as integrated features in the plaza design for the public park. Acoustic dampers and designed air flow will mitigate their environmental sound impact. They should enhance the plaza experience by serving as a backdrop for activity.
The new underground substation in Cambridge, Massachusetts, will be located between Broadway and Binney Street in Kendall Square. It will be integrated into a large mixed-use development project at the former Kendall Center Blue Garage site.
6. It had to be waterproof
We know that water and electricity don’t mix. So, an underground substation built deep into the underground water table must be designed to mitigate leaking and handle stormwater runoff safely.
Cambridge recently revised its flood projections for resiliency. Often, new buildings in Boston and Cambridge require a podium to raise the building above grade, which helps protect critical infrastructure in the event of a flood. But our underground substation couldn’t be raised that way. Instead, we had to make it impervious to flooding. Every vertical penetration had to be raised above the level of the 100-year sea level rise and storm surge projections, including additional height defined by the utility. To put it simply, there are no holes in the roof where projected flooding could rise above and flood the underground substation.
This underground substation must be safe. So, the design was completed with extensive coordination with our partners to help it withstand a variety of worst-case scenarios. The process involved third-party testing and modeling of fire and smoke propagation, as well as structural analysis for potential events within the substation.
7. It’s a node
The primary role of any substation is to bring power to the community. This underground substation is a node for a network of distribution lines that will serve the grid in greater Cambridge. It will take high voltage coming in from a remote power-generating station and transmit it locally.
The new Kendall Square power station will feature five duct banks housing eight new high-voltage transmission lines. It will be a hub for transmission routes interconnecting to existing substations in Allston/Brighton areas of Boston, as well as Cambridge and Somerville.
Putting the electric substation underground allows for the creation of Center Plaza at BXP Life Sciences Center. Valuable real estate is not taken up by a traditional above-ground substation. (Renderings courtesy of Sasaki and NBBJ)
8. It needs a hatch and a deck
Technicians from the utility company need access to the substation for maintenance and monitoring. In the event they need to replace something, technicians may need to remove and install large pieces of equipment.
To do so, the substation features a large hatch, inspired by hatches from cargo ships, that allows technicians access from grade down to every level of the substation. The design of the plaza has incorporated a “deck” above this feature. However, the entire deck can be lifted off when the technicians need to use a crane to move massive pieces of equipment in and out of the substation.
9. It’s a sign of the times
Generally speaking, we are in the early days of the electrification era in North America. Many cities, towns, and campuses will be looking for solutions to provide more electricity to their residential and commercial districts while maximizing the use of available land.
This project at Kendall Square likely won’t be the last underground substation we design. The electrified future will need many more.
