Ketron Island Power Planning Study
Tacoma Power has received a grant from the Washington State Department of Commerce to study the long-term options for providing reliable, affordable, and clean energy to the island.
The proposed alternatives will be evaluated by Tacoma Power’s contractor, HDR, based on several criteria, including:
- Cost (capital, operational, fuel, environmental, emission credits, siting, and delivery),
- Risk (operational and technological maturity),
- Environmental impact (air emissions and the social cost of carbon),
- Reliability, and siting considerations such as land availability and permitting.
The report will not include an analysis or evaluation of the existing undersea cable arrangement or its potential replacement. However, Tacoma Power will evaluate this option internally to compare it with microgrid options.
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If you have questions about the project, please use our online form. Our team reviews all submissions.
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Tacoma Power has been serving the island with power since an undersea cable was installed in 1965. At the time of deployment, it was anticipated that significant real estate development would follow, and Ketron Island would grow to include 265 homes and other non-residential facilities, such as a church, library, and market. The cable providing power was designed to accommodate this projected growth. However, this development never occurred due to persistent issues with septic, freshwater, and ferry transportation. A little less than 20 homes were built over the years, and many are used only during the summer months. Ketron Island is currently zoned R-10 by Pierce County, which limits residential home development to 1 for every 10 acres.
In 2005, Tacoma Power performed cable injection to extend the life of the power cables’ insulation, but not the other cable components. Currently, the cable serving Ketron is nearing the end of its useful life, and the electrical testing required or the act of trying to inject the cable again could mean the end of the remaining life. Ketron Island residents should always plan ahead in the event of a power outage or if the undersea cable is unable to provide power to the island.
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4/3/2026
Tacoma Power continues to advance the Ketron Island Microgrid Non-Wires Alternative Study, which is exploring whether the island’s current and future electricity needs could be met with a self–contained microgrid rather than a new undersea cable.- The first two phases of the study — evaluating real estate and energy needs and examining available microgrid technologies — are now complete. Our engineering partner, HDR Inc., is finalizing documentation summaries of the first two phases.
- The team is currently analyzing several potential microgrid configurations as part of Phase 3, with initial modeling results expected in April.
- The study’s final phase, which will include a full report, is targeted for completion by June 30, 2026, though this timeline may be adjusted as work progresses.
We will also offer opportunities for community input as the study progresses. Details will be shared once finalized.
Separate from this study, Tacoma Power continues to explore a variety of distribution options, including remediation and replacement of the undersea cable, to better understand the costs and risks.
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Provide your Questions and feedback
Tacoma Power will provide an opportunity for residents to share input regarding the study and the draft findings near the completion of the study. If you have questions or comments you’d like to share before the input opportunity, please feel free to use our message form.No Immediate changes
This study is a planning effort. No decisions about the future power supply for Ketron Island will be made at the end of this study; only recommendations will be made. Those recommendations will be shared with the residents of Ketron Island.Transparency and updates
Tacoma Power will work to keep residents informed throughout the study and communicate the findings once the study is completed. This webpage will be updated as new information becomes available.You may see new faces
Residents may notice representatives from Tacoma Power and HDR Engineering, our contractor, on the island for a brief period, conducting an early field visit. This is expected to occur only once and last about one workday. -
- Why is Tacoma Power doing this study?
- The undersea cable serving Ketron Island is nearing the end of its useful life. This study aims to identify long-term, reliable, and affordable solutions for maintaining power service.
- Is this study about replacing the cable?
- The study focuses on exploring new local options, such as microgrids. Tacoma Power is also separately evaluating cable replacement, but this is not part of the current study.
- Will there be construction or immediate Changes?
- This is a planning effort. No decisions or construction will happen as part of this study.
- How will residents be involved?
- Residents will have opportunities to review draft findings and provide input later in the process. We’ll also keep the community updated throughout the study.
- Will Tacoma Power Staff or Contractors visit the island?
- Early in the process, a small team from our participating contractor, HDR, will visit the island for a brief, one-day, field assessment.
- Why is Tacoma Power doing this study?