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Puget Sound Energy electric transmission line and substation projects

Spurgeon Creek substation, switching station and transmission line projects

Fall 2014 project updates​
  • Construction of the substation and switching station is expected to take place as early as 2015.
  • Construction of the transmission and new distribution lines is expected to begin as early as 2016 and would be completed as soon as 2018.
Project overview

Roughly 25,000 customers in Thurston County are currently served by one 13-mile 115 kilovolt transmission line between Lacey and Tumwater (see map). This line provides power to four neighborhood distribution substations in the Olympia and Lacey areas, which are approaching electric capacity limits in meeting customer demand. In addition, if the line serving these substations experiences an outage, a significant number of customers lose power, because there is not enough redundancy in the electric system to serve them on another line. To solve these problems and ensure customers’ electric needs are met now and in the future, Puget Sound Energy plans to upgrade the electric system in southeast Olympia and southwest Lacey, increasing capacity and improving reliability for customers in the area. We plan to build a new electric distribution substation, a new transmission switching station, and associated transmission and distribution lines.

The multi-year construction effort includes the following projects and anticipated timelines (note: project timeline may be subject to change):

Download full-sized map
Project map
(190 KB PDF)
2013 projects
  • Upgrade existing distribution lines along Diagonal, Rich and Rainier roads
2015-16 projects
  • Construct a new distribution substation at 7802 Diagonal Road SE in Olympia
  • Construct a new transmission switching station at 7802 Diagonal Road SE in Olympia
2016-2018 projects
  • Construct three new 115 kV transmission lines (see map)
    • Two lines will run from the new switching station to two points on our existing 115 kV transmission line along Yelm Highway Southeast
    • One line will run from the new switching station to the Airport substation, located at 910 93rd Ave. SW in Tumwater
  • Construct associated 12.5 kV distribution lines


    What is a substation?

    Substations are critical links in the electricity distribution system, containing utility circuit protection, voltage regulation, and wiring that steps down higher voltage to lower voltage. Before reaching homes and businesses, power is routed through the transmission system to a substation where it is changed to a lower voltage that can be utilized by customers.

    What is a switching station?

    A switching station is a transmission substation where the utility can switch or reroute power flow from one line or path to another to allow the power to be isolated to clear a fault (e.g., a fallen tree in the wires) or to take the power line out of service for maintenance. It also may act as a point of interconnection between two different transmission operators (e.g., Bonneville Power Administration and PSE). Unlike a substation with a transformer serving neighborhood circuitry, switching stations do not step power up or down; they integrate power from one or more transmission sources on the regional and local grid to serve neighborhood substations.

    What is a transmission line?

    Transmission lines are key elements in the electrical distribution system. The lines safely transport high voltage electricity from power generation sources like dams and wind generating facilities to substations in local communities. Transmission normally takes place at voltages of 55 kV and higher.

    Committed to keeping you informed

    PSE will continue to provide updates to the community. We will notify residents and businesses near the project area when construction will occur. We aim to complete the work with as little disruption as possible.

    Download the information

    March 22, 2011 public meeting

    Public meeting invite, March 2011
    Community ad, March 2011
    Why outages differ
    Existing conditions aerial map
    What is happening to your local electric system?
    Reliability: Before and after
    Project benefit area
    Thurston County area projects
    Spurgeon Creek site plan
    Spurgeon Creek landscape plan
    Route selection criteria
    Examples of typical transmission lines
    Undergrounding transmission lines (Revised August 2012)
    Utility landscaping zone
    Project map
    Project aerial map
    Project fact sheet, March 2011