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Puget Sound Energy transmission line and substation project

Spurgeon Creek substation, switching station and transmission line projects


Spring 2015 project updates

  • Construction of the substation and switching station is expected to take place as early as 2016.
  • 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

PSE is planning to upgrade the electric system in southeast Olympia and southwest Lacey to increase the system’s capacity and improve reliability for our customers. This upgrade will include building a new distribution substation, a new transmission switching station, and connecting transmission and distribution lines.

Roughly 25,000 customers in Thurston County are currently served by a single 13-mile 115 kilovolt (kV) transmission line between Lacey and Tumwater. This line provides power to four neighborhood distribution substations. These substations are approaching capacity limits and need to be upgraded to continue meeting our customers’ electricity need. Additionally, because this area is served by only one transmission line, there is not enough redundancy in the system to provide power if this line experiences an outage.

The multi-year construction effort includes the following projects and anticipated timelines. Please note that project timelines may be subject to change.


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Project map


  • Upgrade the existing distribution lines along Diagonal, Rich and Rainier roads - completed in 2013
  • Construct a new distribution substation and a new transmission switching station in Olympia - anticipated as early as 2016
  • Construct three new 115 kV transmission lines - anticipated as early as 2016-2018
    • Two lines will run from the new switching station to two points on our existing 115 kV transmission line along Yelm Highway SE.
    • One line will run from the new switching station to the Airport substation in Tumwater.
  • Construct associated 12.5 kV distribution lines - anticipated as early as 2016-2018


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. These 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.