Improved substations mean greater reliability


The secret is out and Oregon’s population is growing. Official estimates predict 1,000 new Portland residents are arriving each month and that by 2035, we’ll have 1 million new residents. This growth—affects the layout of our communities and overall demand on residential areas and businesses. To meet this growing need, we are making upgrades to many substations in the area—and building new ones—to improve your reliability.

Marquam Substation

The new Marquam substation is being built under the I-405/I-5 interchange in Southwest Portland. The station will serve Portland's downtown and South Waterfront—replacing 60-year-old substation equipment on the east side of the Willamette River.

Although the existing equipment and river-crossing cables have performed admirably, the downtown core area continues to grow and is the nerve center of the region’s business and government. Investing in a new substation here helps the hub of our city operate and thrive.

In addition, Marquam will eventually be connected with other PGE substations serving the west side. This “radial” capability will further increase reliability by allowing the substation to serve as a backup power source for nearby parts of the PGE energy grid.

  • We’re boring four tunnels under I-405 to accommodate underground transmission lines that will supply the Marquam substation – each over 200 feet long. Two of the four tunnel casings have been completed successfully, and work on the third is underway.
  • Each of the tunnels has a diameter of 48 inches and measures approximately 235 feet long. The work of boring the tunnel casings began with the digging of a 25-foot deep pit, designed so that the tunnels would be at an appropriate depth beneath the freeway and to allow for future construction of equipment above them.
    Marquam Substation
  • In addition to the tunnel casings, work is also well underway on building a new retaining wall on the southern part of the property. An existing wall will remain in place, and the space between the new and existing wall will be backfilled. The Marquam substation improvement project is scheduled for completion in 2018.

West Union Substation

We’re rebuilding the existing West Union substation in Northwest Portland to support continued industrial development in the Hillsboro area, especially north of Highway 26. For example, we’re placing the substation’s new feeders underground to reduce exposure to weather. West Union takes some of the load off the Sunset substation while also providing redundant power to back up the nearby Shute substation.

Bell Substation

The Bell substation on Johnson Creek Blvd. in Milwaukie is now using modern GIS high-voltage equipment and an additional transformer to increase reliability and expand capacity. It also features several upgraded distribution lines that use larger conductors to increase capacity and provide stronger connections to adjacent substations.

Stay tuned to Power Report for more updates on improvements in your area.