Five years ago, it was apparent that Seattle’s urban redevelopment was expanding at a pace that would require more electrical output. Adding urgency to the city’s growth plans was the fact that its aging Broad Street substation was reaching its load limits, and part of that substation’s feeder system would be de-energized over time to accommodate the construction of the Alaskan Way Viaduct replacement tunnel.
Seattle City Light, the city-owned electrical utility, finally got design approval in 2012 for the Denny Substation, which had been in the works for nearly a decade. Soon after, Amazon announced that it would build its massive new headquarters complex along the Denny Way thoroughfare. “That made all of us look smart,” says Michael Clark, PMP, Seattle City Light's Program Manager on the Denny Substation project.
Seattle City Council gave this $209 million substation—the first to be built in Seattle in 30 years—the final go-ahead in August 2015. Construction of the 110,000-sf substation began nine months later on a 120,000-sf lot where a decommissioned Greyhound bus maintenance terminal once stood. Seattle City Light expects Denny Substation to be operating by late 2018.
What makes the Denny Substation different from similar facilities is that it is designed to invite people to the site and offer them recreational activities. The project has 44,000 sf of open space and an off-leash dog park, plus an ADA-accessible quarter-mile walking loop that rises 16 feet above street level to provide pedestrians views of a public park, a landscaped terrace, and the cityscape.
One side of the building will include an area that can accommodate food trucks and other open-space activities. The design incorporates a learning center that provides information about Seattle City Light and how it promotes renewable energy. The substation will be powered by 89.9% hydroelectric energy and 3.9% wind energy, with exhibition and meeting spaces producing more power than they expend.
Metal-clad walls, 35 feet high, slope inward toward the substation, reducing its mass at the pedestrian level. Translucent glass panels will emit a soft glow at night.
An off-leash dog park at Denny Substation. Project team: NBBJ (architect), Power Engineers (electrical design), KPFF Consulting (SE, CE), Shimmick Construction (underground network distribution system), and The Walsh Group (GC). Image Courtesy NBBJ.
The city mandated that 1% of this project’s budget be spent on public art. Built into the corners of the substation are two commissioned pieces. "Switchwall," by artist Ned Kahn, consists of a series of “switches” that move when the wind blows and turn on different-colored LED lights, creating a moving pattern. "Transforest," by Lead Pencil Studio’s Annie Han and Daniel Mihalyo, is a 120-foot-high tower installed in the open space, which combines the beauty of the Pacific Northwest with the history of local power generation and transmission.
Community input and debate are integral to the city’s design-review process, known as The Seattle Way. “A utility must serve other than just its mission,” explains Clark. The dog park and walkway came out of this process, to provide public offsets for vacating a nearby street.
The site also needed extensive environmental cleanup, which required digging 40 feet below grade to remove soil contaminated by diesel fuel from the bus terminal.
Seattle City Light commissioned NBBJ to design the substation partly because of the firm’s reputation for developing concepts that all stakeholders could embrace. “There was substantial outreach, and we took the opportunity to invite the community into the process,” says Carl Tully, AIA, LEED AP, Principal and NBBJ’s project manager for the substation.
Tully credits Clark, who has been on the city’s redevelopment committee since 2002, with keeping the substation project in play. As for NBBJ’s contribution, he says, “We opened the city’s eyes to what’s possible, not just to cloak or cover up the building, but to make it a point of civic engagement.”
Tully says the design needed to account for “fixed parameters” that include a high-pressure fluid-filled 115-kV transmission cable that runs through the property. Some of the facility’s electrical equipment is quite tall, so NBBJ relocated them to the interior and placed lower equipment to the periphery. This helped reduce the scale of the substation and created opportunities for elevated walkways and occupiable space, says Tully.
He believes the concept for the Denny Substation—taking public infrastructure and creating public space—could be duplicated in other cities. But Clark doesn’t think Seattle will need another substation of this magnitude for some time. “The buildings going up are exercising much better power management, so our load has remained relatively flat,” which also means future revenues could be lower.
Clark suggests that with more cities moving toward microgrids for growing neighborhoods, there could be a need for smaller substations to support them.
Related Stories
Resiliency | Aug 19, 2021
White paper outlines cost-effective flood protection approaches for building owners
A new white paper from Walter P Moore offers an in-depth review of the flood protection process and proven approaches.
Industrial Facilities | Jul 2, 2021
A new approach to cold storage buildings
Cameron Trefry and Kate Lyle of Ware Malcomb talk about their firm's cold storage building prototype that is serving a market that is rapidly expanding across the supply chain.
Resiliency | Jun 24, 2021
Oceanographer John Englander talks resiliency and buildings [new on HorizonTV]
New on HorizonTV, oceanographer John Englander discusses his latest book, which warns that, regardless of resilience efforts, sea levels will rise by meters in the coming decades. Adaptation, he says, is the key to future building design and construction.
Sustainability | Jun 23, 2021
The world’s first Passive House Certified cidery completes
River Architects designed the project.
Digital Twin | May 24, 2021
Digital twin’s value propositions for the built environment, explained
Ernst & Young’s white paper makes its cases for the technology’s myriad benefits.
Industrial Facilities | Apr 22, 2021
The country’s largest supplier of brewer’s yeast moves to new production facilities
Valerio Dewalt Train designed the project.
Market Data | Feb 24, 2021
2021 won’t be a growth year for construction spending, says latest JLL forecast
Predicts second-half improvement toward normalization next year.
Reconstruction Awards | Jan 30, 2021
Repositioning of historic Sears Roebuck warehouse enlivens Boston’s Fenway neighborhood
Developer Samuels & Associates asked Elkus Manfredi Architects to reimagine the former Sears Roebuck & Co. warehouse in Boston’s Fenway neighborhood as a dynamic mixed-use destination that complements the high-energy Fenway neighborhood while honoring the building’s historical significance.
Architects | Jan 5, 2021
Ware Malcomb finds itself in the mix for multiple diverse projects
Its latest completion is an office/factory/warehouse combo for one of Marvin Window’s brands.
Giants 400 | Dec 16, 2020
Download a PDF of all 2020 Giants 400 Rankings
This 70-page PDF features AEC firm rankings across 51 building sectors, disciplines, and specialty services.