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Puget Sound Energy substation and transmission project

Yelm area reliability projects

Overview of PSE Yelm Area Projects

Puget Sound Energy is working to upgrade the electric system in Yelm and Thurston County in order to increase our customers' electric reliability and meet growing demand for power in the area. Currently, the region is only served by two north-south transmission lines, which are prone to tree-related outages and limit the power flow in Thurston County. From 2010 through 2018, we will be completing four projects, collectively called the Yelm area reliability projects. These projects entail adding three new transmission lines, rebuilding an existing transmission line, and upgrading two substations, allowing us to move power throughout the county more efficiently and provide additional sources of power in the event of scheduled or unscheduled outages.

Winter 2014 project updates
  • We are currently in the route analysis stage for our new St. Clair-Yelm transmission line
  • We are currently in the preliminary design stage for our Longmire and Blumaer-Yelm transmission lines
  • Construction of the Blumaer-Yelm transmission line rebuild project is expected to begin in 2015 and be completed by 2017
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Project map

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Project map


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Project map

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Project map


Yelm transmission line and substation - COMPLETE

The Yelm transmission line and substation project entailed constructing four miles of new 115 kilovolt transmission line from the Yelm substation (at the intersection of Railway Road Southeast and Middle Road Southeast) to a point along the Blumaer-Yelm 115 kV transmission line at the intersection of Koeppen Road Southeast and 123rd Avenue Southeast. The new transmission line is located primarily in and along public road rights of way. In addition to the new transmission line, we upgraded the Yelm substation and provided space to add a second electric transformer, which will allow PSE to double the capacity in the future without changing the substation footprint.


Blumaer-Yelm transmission line rebuild

The existing 17-mile transmission line between Blumaer substation (122 Garfield Ave. E in Tenino) and Yelm substation (at the intersection of Railway Road Southeast and Middle Road Southeast in Yelm) is approaching electric capacity, which strains the local electric system and makes it difficult to reliably meet the energy needs of our customers in Yelm, Rainier, and Tenino areas. Additionally, the line was originally installed in the 1960s and the poles and wire are aging and in need of replacement. We plan to rebuild the existing line with new wood poles and higher-capacity wire, which will alleviate the strain on the system and improve electric reliability for our customers. Construction is expected to take place in two phases. Phase one, which is expected to take place in 2015 and 2016, entails rebuilding the line between Tenino and Rainier. Construction for phase two, which entails rebuilding the line between Rainier and Yelm, is expected to occur in 2016. All work should be completed by 2017.


Longmire transmission line

The Longmire transmission line project entails constructing three to four miles of 115 kV transmission line from the Longmire substation (along Bald Hill Road near Vail Loop Road in Yelm) to a point along the Blumaer-Yelm 115 kV line along 123rd Avenue Southeast. We plan to replace the distribution poles along the route with taller poles to accommodate both the existing distribution lines and the new transmission line. As part of this project, we will also need to make upgrades at the existing Longmire substation (11623 Bald Hill Rd SE in Yelm) in order to accommodate the new line.

For customers who are served from our Longmire substation, the new transmission line will increase the electric reliability. Currently, the Longmire substation is served radially, which means it is served only by one transmission line. If the line serving the substation goes out, the substation and the customers served by it lose power. The new transmission line will create a "loop", which means each substation will be fed by two transmission lines. If one line goes out, the other line will still feed the substation to keep power on for our customers in the area. Construction of the new line is expected to begin in 2018.


St. Clair-Yelm transmission line

The St. Clair-Yelm transmission line project entails constructing 15-17 miles of new 115 kV transmission line from the St. Clair switching station (9512 Pacific Highway Southeast in Lacey) to a point along the Blumaer-Yelm 115 kV line near the intersection of State Route 507 and 123rd Avenue Southeast. Specific route alternatives are currently being evaluated, and we will construct the new line in existing utility corridors whenever possible. Construction of the new line is expected to begin in 2017.

Contact us:

For more information on this project, email Project Manager Doug Long at douglas.long@pse.com.

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.

What is a substation?

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

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 project milestones and construction will occur. We aim to complete the work with as little disruption as possible.

Download the information

Download the PDF files for more detail on PSE's Yelm transmission line and substation project.

Yelm transmission line and substation
Yelm substation outage notice, November 2011
Yelm outage map
Yelm construction notice, October 2010
Yelm vegetation management notice, September 2010
Yelm transmission line and substation map

Blumaer-Yelm transmission line rebuild
Blumaer-Yelm transmission line rebuild project map

Longmire transmission line
Longmire map

St. Clair-Yelm transmission line
St. Clair-Yelm fact sheet
St. Clair-Yelm map