Issaquah Reliability and Capacity Improvements

Issaquah area reliability and capacity improvements

Project overview

Puget Sound Energy (PSE) is updating Issaquah’s power grid to provide more reliable energy to homes and businesses and increase electric capacity for the entire community.

We’re building a new substation in the Issaquah Highlands area, called Grand Ridge, which will deliver power through an underground distribution system.

The Grand Ridge substation will make Issaquah’s power grid more resilient and will enable us to better serve you now and in the future.

We’re addressing Issaquah’s energy needs with reliable, long-term solutions

Issaquah needs more reliable power: Customers in Issaquah Highlands experience longer and more frequent power outages. This can be attributed to the current grid layout and substation locations, along with dense vegetation which can fall on overhead power lines.

Issaquah needs access to more energy: As Issaquah has grown, more people in the area are using more energy. We serve nearly 40,000 residents and businesses in Issaquah, and while customers are doing their best to conserve energy, it’s not enough to meet the area’s increased energy needs — particularly during high demand times like cold winter nights or hot summer days.

Our solutions: We’re building a fifth substation to improve Issaquah’s power grid and increase electric capacity. This will enable us to meet Issaquah’s changing energy needs in the most cost-effective way with the least impact on the community.

You can look forward to:

Experiencing fewer outages: We will pull the new power lines through existing underground electrical conduits installed years ago in anticipation of future needs. This will minimize power outages from falling tree limbs.
Having a more flexible and resilient power grid: With a fifth substation, we can redirect power along additional pathways during outages or periods of high demand. This helps us keep the power on for everyone in Issaquah.
Being closer to the point of energy distribution: Energy from the new substation doesn’t have to travel far underground to reach Highland residents. This will cause fewer disruptions from outages elsewhere in Issaquah.

We plan on building the new substation in the existing PSE-owned easement near the Bonneville Power Administration (BPA)’s transmission corridor. The Issaquah Highlands master-planned community has already designated this site for a substation in anticipation of future growth. We will connect the new substation to the BPA transmission corridor with a short transmission line within the PSE-owned easement. This site is located on Park Drive, near the Vista community gardens.

This ideal location allows us to:

Connect the transmission to the substation in just a few feet.
Make minimal changes to the surrounding area, including fewer impacts to trees and vegetation.
Easily shift load capacity from other substations because the new substation will be near the middle of the grid.
Use existing conduit from the site to install the new underground distribution system in most locations. This will cause fewer construction impacts.

The new substation site is within an existing PSE-owned easement. These renderings show what the substation could look like.

Next steps

We are currently in the project design and permitting phase. We plan to start building the distribution line in spring 2026 and begin substation construction in summer 2026. We anticipate finishing substation construction and energizing the new substation in fall 2027.

This schedule could change depending on the permitting and construction progress. Check the project webpage to stay updated on the project status or contact us with questions.

Grandridge Substation Project Process