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Construction on Bainbridge Island substations

Current project phase: Ongoing

Project Manager: Molly Reed

Project overview

Murden Cove – Winslow 115 kV transmission line. To provide safe, reliable energy during construction, we are working on one substation at a time. We plan to follow this general construction schedule:  

  • Port Madison Substation (2023 – 2024) – Complete
  • Murden Cove Substation (2025 – 2026)
  • Winslow Substation (2028 – 2029)

This schedule could change, depending on permit approvals and the progress of construction. Please read on for more information about construction at each substation. 

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Port Madison Substation (2023 – 2024)

COMPLETE

In 2023 and 2024, we replaced aging equipment at the Port Madison Substation to improve reliability, better protect equipment and allow for remote control of the distribution system.

Substation facts:

  • Serving approximately 4,700 customers
  • Originally built in 1954
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Murden Cove Substation (2025 – 2026)

In 2025 and 2026, we are upgrading the Murden Cove Substation to support the new Murden Cove – Winslow 115 kV transmission line. These upgrades include installing a second transformer to provide electric capacity to meet the current and future energy needs of Bainbridge Island residents, businesses and Washington State Ferries.

Substation facts:

  • Serving approximately 5,300 customers

  • Originally built in 1979

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Winslow Substation (2028 – 2029)

We plan to upgrade the Winslow Substation in 2028 and 2029 to support the new Murden Cove-Winslow 115 kV transmission line. We will provide more information as construction approaches. 

Substation facts:

  • Serving approximately 4,500 customers
  • Originally built in 1960