- Reclamation
- CPN Region
- Grand Coulee Dam
- Nathaniel Washington Power Plant
- Overhaul Project
Nathaniel "Nat" Washington Power Plant Overhaul Project
Project Update - Nathaniel "Nat" Washington Power Plant Status Report – Nov. 2021
Mechanical overhaul of units G22—24: The Nathaniel “Nat” Washington Power Plant Overhaul project for generating units G22–24 was successfully overhauled and modernized. Unit G24 was overhauled and returned to service in April 2016, and unit G23 was overhauled and returned to service in March 2019. Unit G22 was overhauled and returned to commercial service on Sept. 30, 2021. Significant challenges with the refurbishment of each of the 805-megawatt units extended the duration of the contract to an additional four years than originally planned. Challenges included major wear on components, including the wicket gates, shaft assemblies, thrust bearing, rotor, outer head cover, and embedded components.
Overhaul of units G19, G20, G21: Originally, the plan for units G19–G21 was to conduct an overhaul similar to the G22, G23, and G24 contract. Because of lessons learned on the first three units and what Reclamation has observed from a maintenance perspective on G19–G21, the work plan for these three older units have evolved into a modernization-minded project. The successful completion of these units will ensure a reliable generating source and provide three modernized units that will operate with more flexibility and durability over the next four decades or more.
Cost and schedule risk analyses for this project were completed in 2019. Due to new energy market demands and climate change, we learned that the overall scope of the project may require a review at a wider range of alternatives. The final scope of work remains to be determined and may include full replacement of some or all generating units. Reclamation is working with the Bonneville Power Administration and the U.S. Army Corps of Engineers to develop an optimization study for an overall hydro-related modernization of future operations at Grand Coulee. The study also will determine the scope of work for units G19–G21. The final design and subsequent procurement of units G19–G21 is projected for 2026.
Visualization of the disassembly process during the G22–24 overhaul:
As part of the Nathaniel “Nat” Washington Power Plant Overhaul project, the contractor Architect Engineer has prepared a simulation of the base scenario showing step-by-step how the units will be disassembled and placed in various locations. The animation was prepared using CAD files and other types of software listed in the credits. There is no audio in this version of the animation.
This interactive PDF showcases a 3D model of a generator and allows you to take it apart, rotate it, and view it in detail. Download the 9 mb PDF >>
Contact
Grand Coulee Visitor Center
(509) 633-9265
pninfo@usbr.gov
