Construction at Bainbridge Island substations

Project overview


In the coming years, PSE will upgrade our three substations on Bainbridge Island to improve electric reliability and capacity. To provide safe, reliable energy during construction, we will work on one substation at a time. We plan to follow this general construction schedule: 

  • Port Madison Substation (2023/24)
  • Murden Cove Substation (2025/26)
  • Winslow Substation (2028)

We will schedule the construction work at the substations during the non-storm season, typically from late-spring to fall. This schedule could change, depending on permit approvals and the progress of construction. Please read on for more information about construction at each substation. 

Port Madison Substation

Serving approximately 4,140 customers

Originally built in 1954

New transmission line and improvements in 2000

Port Madison Substation (2023/24)

Starting in spring 2023, we’ll replace aging equipment and complete some upgrades at the Port Madison Substation. This work will start as soon as late April and continue through this fall. We’ll continue to provide safe, reliable energy during construction and will minimize community impacts as much as possible.

To prepare for this work, we’ll trim some trees along the existing transmission lines that serve Bainbridge Island. You can expect some traffic impacts from time to time as we bring in and remove equipment at the substation.

Murden Cove Substation

Serving approximately 4,850 customers

Originally built in 1979

Murden Cove Substation (2025/26)

We plan to work on the Murden Cove Substation in 2025 and 2026. The Murden Cove Substation upgrades will support the Battery Energry Storage System (BESS) as well as the new Murden Cove – Winslow 115 kV transmission line.

In addition, we’ll coordinate with Washington State Ferries (WSF) to help electrify WSF’s Bainbridge to Seattle ferry run. This work will include connecting the Bainbridge Island ferry terminal to our electric system. We anticipate building a power line from the ferry terminal to the Murden Cove Substation to support this effort.

The schedule for these activities could change. We will provide more information as construction approaches.

Winslow Substation

Serving approximately 3,980 customers

Originally built in 1960

Winslow Substation (2028)

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

See the Bainbridge Island substations and map of existing power grid here.