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Broad Street Substation


City of Seattle, City Light


Seattle, WA


Public, Infrastructure

MidMountain workers on site

The Broad Street Substation is located near Seattle Center on the block between 6th Avenue North, Harrison, Thomas and Broad streets. Distributing electricity to local neighborhoods, the Broad Street Substation plays a vital role in the transmission of high voltage electricity to the Puget Sound region. The Broad Street Substation project aims to reduce congestion and upgrade the reliability of the transmission system, lessening the risk of region-wide customer power outages in the future.


MidMountain is overseeing the demolition of existing surface utilities; construction of below grade improvements; shoring and excavation, including the removal of contaminated soil; installation of substation screen wall, equipment vaults, and foundations; grounding system; construction of an oil containment system, firewall system, and water deluge system; and interface with other contractors hired by Seattle City Light (major equipment supplier).


Project Stats:

  • Project size: 4,000 SF of new equipment

  • Existing substation: ~78,000 SF

Services Provided:

  • Underground utilities

  • Structural concrete

  • Earthwork & grading

  • Rigid-shoring systems

Project Gallery

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