Nathaniel Washington Power Plant Overhaul Project
Project Update - Nathaniel Washington Power Plant Status Report – May 13, 2020
Mechanical Overhaul of Units G-22, G-23, G-24: Construction phase work on this current contract continues; Unit G-24 was overhauled and returned to service in April of 2016; Unit G-23’s overhaul immediately followed and was returned to service on March 15th, 2019. Unit G-22 is currently wrapping up its component refurbishment portion of work in preparation of reassembly and will be completed by the end of the year. Significant challenges with the refurbishment of each of these of these 805 MW units has extended the duration of this contract, which was originally scheduled to be complete at the end of 2017. Major wear on components including the wicket gates, shaft assemblies, thrust bearing, rotor, outer head cover, and embedded components have all contributed to additional work for the government and its Contractor. We have implemented a variety of lessons learned on this project and are on track to complete work on the last unit within a 2-year outage window, an improvement of approximately one year over each of the other units.
Overhaul of Units G-19, G-20, G-21: Originally, the plan for Units G-19, G-20, and G-21 was to overhaul, similar to the G-22, G-23, and G24 Contract. Because of lessons learned on G-22, G-23, and G-24 and what Reclamation has observed from a maintenance perspective on G-19, G-20, and G-21, the work plan for these three older units has evolved into a modernization-minded project over the past few years. The ultimate goal for this project is to ensure reliability and provide three modernized units that will operate with more flexibility and durability over the next 40+ years.
A cost and schedule risk analysis on a variety of modernization options was completed in 2019. The final scope of work remains to be determined and may include up to full replacement of unit(s). Currently, Reclamation is working with the Bonneville Power Administration and the Army Corps of Engineers to develop an optimization study, which will help show the best overall hydro-related modernization for future operations at Grand Coulee. We believe that this study will also determine the ultimate work scope that is best for the G-19 through G-21 Project. It is anticipated that this product will be in the works for the next 2-3 years, so final design and subsequent procurement of the G-19 through G-21 Modernization Project will likely wait until then.
As part of the Nathaniel Washington Power Plant Overhaul Project, the contractor 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 >>
Grand Coulee Visitor Center