Construction of Denny Substation to Start in March

An artist’s rendering of the future Denny Substation.

Construction on Seattle City Light’s Denny Substation is scheduled to begin in March, led by The Walsh Group, which has been hired as the general contractor.

“The Denny Substation is a critical project for providing reliable service to our growing community now and for many years to come,” Interim Customer Service and Energy Delivery Officer Mike Haynes said. “We’re pleased to have The Walsh Group as our general contractor. Walsh has a clear focus on safety and brings experience from a wide variety of large construction projects across the country and the local connection of a regional office in Tukwila.”

When finished, the Denny Substation at Denny Way and Stewart Street will be the utility’s largest. This is the first substation City Light has built in 30 years.

Power Engineers will serve as the project manager and is overseeing electrical design. The team also includes NBBJ, architect; and KPFF Consulting Engineers, structural and civil engineer. Valley Electric, W.A. Chester and Transcon are key subcontractors.

Substation work will coincide with the underground distribution network being built to ensure more reliable power delivery to customers and a transmission line that will carry power to the substation.

The Denny Substation will distribute electrical power to north downtown, provide back-up power to other substations and support the regional transmission grid. The project will be complete in Q1/Q2 2018 with transmission line and electrical components added later.

The Denny Substation is one of the major initiatives in Seattle City Light’s Strategic Plan. The project includes: a major new electrical substation near Denny Way and Stewart Street, a transmission line from the new station south to an existing substation in the SODO neighborhood, and a network distribution system extending north of Denny Way.

The Denny Substation will ensure high reliability and sufficient electrical infrastructure to meet customer needs as growth continues throughout the South Lake Union, Cascade, Denny Triangle, Uptown, and Belltown and First Hill areas. More information on the project can be found at:

Seattle City Light is the 10th largest public electric utility in the United States. It has some of the lowest cost customer rates of any urban utility, providing reliable, renewable and environmentally responsible power to about 750,000 Seattle area residents. City Light has been greenhouse gas neutral since 2005, the first electric utility in the nation to achieve that distinction.