January 15, 2016

Walsh Group will start substation next month

Image courtesy of NBBJ [enlarge]

The $209.5 million Denny Substation will distribute power to north downtown.

The Walsh Group has been selected as general contractor for the $209.5 million Denny Substation in South Lake Union.

Seattle City Light plans to start work next month on the substation at Denny Way and Pontius Avenue North. It will be complete in December 2018, but transmission line and electrical components will be added later.

The substation will distribute electrical power to north downtown, provide back-up power to other substations and support the regional transmission grid.

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

The design shows a structure with sloped walls, metal cladding and glass panels that will glow at night. City Light said sloping the walls will reduce the size of the building at street level, and make more room for pedestrians.

An interpretative pedestrian walkway and double-cantilever screen wall will wrap the exterior.

The footprint is 120,000 square feet.

There will be an off-leash area along Minor Avenue North and a 3,800-square-foot community space programmed by Seattle Office of Arts & Culture. A 2,900-square-foot learning center will be along Denny Way.

City Light said the equipment will be mostly hidden from public view, and no overhead wires will come in or out of the substation.

Eventually, the substation could have nine transformers up to 22 feet tall in the interior yard, but City Light said they would not be visible from the street.