Grand Coulee Line Replacement Project

The Grand Coulee Dam project originated with Bonneville Power Administration (BPA) being asked by the Bureau of Reclamation to design and construct six new 500-kV transmission lines at Grand Coulee Dam. The newly constructed lines replaced six existing underground lines. The previous lines consist of eighteen aging, oil-filled cables between Grand Coulee’s third powerhouse and the 500-kV spreading yard, both of which were operated and maintained by Reclamation. In the previous underground configuration, the cables were more susceptible to threats like fire, which would likely lead to multiple line failures. The newly installed overhead solution is less likely to experience multiple line failures, which helps ensure safe and reliable transmission of power from Grand Coulee Dam. The new lines transfer power that is generated at the third powerhouse, across the Columbia River to the visitor center area, and then proceed uphill where they connect to lines that transfer power from this area into the Regional power grid. Construction began in early 2012 and was completed at the end of 2012.

Project Sponsor Line Miles Voltage (kV) From State To State Year in Service
Bonneville Power Administration 1 500 WA WA 2012
Estimated Costs ($M) Voltage Type Project Status Project Group Origin Point Destination Point
2.6 Operating Grand Coulee Grand Coulee 500kV
Interstate Build Start NERC ISO/RTO Country Project Partners
2012 WECC US