New Denny Substation To Be Built

s048676Seattle's next major infrastructure project is about to get underway in SLU's Cascade neighborhood. Here Seattle City Light (SCL) plans to build its largest substation, the first in 30 years, at John Street and Pontius Avenue North, designed by NBBJ. Necessitated by recent and anticipated growth primarily in South Lake Union, the Denny Triangle and downtown, the Denny substation will connect to a new network of distribution and transmission lines, spreading north, south and west from the substation. SCL's preferred equipment configuration will require expanding the site to Minor Avenue North by vacating Pontius between Denny and John streets, an action that requires approval by SDOT and the Seattle City Council in exchange for a package of public benefits. For this purpose, SCL has proposed on-site amenities consisting of open space featuring a pocket park and an off-leash area for dogs, street level and elevated walkways across the site, and two interior shell spaces to house an energy education center on Denny and provide community meeting space on the west facade. Off-site, two new pedestrian crossings and a bus shelter on Denny Way have been proposed plus right-of-way enhancements on Denny, John and Pontius.

The Final EIS will be issued in January. If SCL receives approval from the Seattle Design Commission and City Council by March, construction of Phase 1 of the distribution lines will begin in the third quarter of 2015, the substation itself in the first quarter of 2016 and the transmission lines in 2019 at the earliest. The substation is expected to be energized by the third quarter of 2017.

A task force comprised of SLUCC board members and other neighborhood stakeholders has been working with SCL over the past year to provide recommendations about the substation's area of greatest impact, the Cascade neighborhood. Our input to SCL include ways to communicate and mitigate construction impacts, ways to activate the shell community space, and feedback on the package of public benefits. This is Seattle's first substation to be built in such a dense residential neighborhood, with 36 multi-family apartment buildings, including over 80% of South Lake Union's low income and social service housing in the vicinity. SCL also meets periodically with a larger Community Forum it assembled to keep stakeholders in affected areas informed of the project’s progress. For details about the Denny Substation, go to