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Seattle City Light takes a 'not your grandfather's substation' approach

Seattle City Light is about to build a substation with a glowing facade, an elevated walkway and an off-leash dog park that the public power utility expects will be a destination landmark for the neighborhood and city.

"It's not your grandfather's substation," said Michael Clark, Seattle City Light project manager for the Denny substation.

When the public hears "substation," they think: industrial, functional and chain link fence, according to Clark. "Out of the gate, we knew that wouldn't be a successful approach," he said.

Typically, utilities try to hide their urban substations, sometimes underground or behind faux facades, according to Clark. Seattle City Light took the opposite approach for the first substation it has built in 30 years.

The public power utility decided it wanted the substation's owners — the citizens of Seattle — to be drawn to the project so they could see it in action, according to Clark. "This substation facility needs to be an asset to the community," he said. "We want it to blend in, but celebrate that there's a substation there."


Seattle's new substation will have a glowing facade. Image courtesy of NBBJ

Carl Tully, a principal at NBBJ, the architecture firm that designed the project, said that the project was driven by the need for the substation, which includes heavy infrastructure such as gas insulated switchgear and transformers that have specific demands, but that the project was crafted to create a place in Seattle that people will want to gather at and feel a part of.

On the practical front, the roughly $210 million substation will take power from an existing 115-kV transmission line that runs under the site and prepare it for delivery onto the city's 13-kV distribution network. Depending on growth in the area, another 115-kV line might feed the substation around 2020, according to Clark.

Most of the substation equipment will be in enclosed structures that only utility employees can enter. Safety and security elements were part of the project design, according to Clark.

Designing the electric side of the substation was perhaps the project's easiest part, Clark said.

Because the substation's site required taking part of a street, Seattle City Light was required by city rules to show that the substation would provide benefits, which are estimated to total about $10.6 million, Clark said.

The project includes two major pieces of art, viewing portals so residents can see the substation's workings and community event spaces. It includes a quarter mile of wheelchair accessible walkways and will be more pedestrian friendly than what is there now, according to Clark. Also, the substation's sloping walls include translucent glass panels that will glow at night.

Reflecting Seattle City Light's "green" emphasis, the substation will include solar panels and a heat recovery system to provide all the heating needed by the facility.

The substation, plus an underground distribution network, has been in the works since about 2003, when Seattle's City Council approved a policy of trying to attract biotechnology and high-tech industry to the South Lake Union area, which at the time was home to warehouses and light manufacturing, according to Clark.

The hoped-for development would need improved power supply and in 2006 Seattle City Light selected a substation site that included an old Greyhound maintenance facility. In 2012, after gaining control of the site and cleaning up the bus facility, Seattle City Light started a parallel track process of designing the substation and going through an environmental impact statement process.

At the same time, while holding public meetings on the project, the neighborhood was starting to see significant development, with the Bill & Melinda Gates Foundation headquarters, a University of Washington medical facility and biotech and high-tech facilities moving into the area, according to Clark.

Seattle City Light expects construction on the substation to begin by May, according to Clark. The project's schedule calls for energizing the substation in early 2018 and finishing the community spaces around the facility a few months later, he said.

The project can't come soon enough, with Amazon, the online retailer, recently deciding to build its main campus in the area. Amazon's move wasn't expected and has sped up the need for increased power supply from the substation, Clark said.