Power plant work completed at Grand Coulee Dam

Major work on hydroelectric generating units has been completed on "one of the most coveted clean energy assets in the world" at the Grand Coulee Dam.

The U.S. Bureau of Reclamation, along with the Bonneville Power Administration, announced Monday that "the major overhaul of hydroelectric power generating units 22, 23 and 24" inside the third power plant, now known as the Nathaniel "Nat" Washington Power Plant, at the Grand Coulee Dam, had been completed. 

USBR Public Affairs Specialist Erika A. Lopez told The Star in an email that the total estimated cost of the project was $200 million. 

Project planning began in 2008. In 2012, the contractor arrived onsite to begin preparatory work. 

"Overhauling something of this magnitude does not happen overnight," said Columbia–Pacific Northwest Regional Director Lorri Gray.  "It takes years of planning and strong partnerships to complete such a milestone."

 "The overhaul of these units is key to accomplishing Reclamation's mission and represents one of the most significant infrastructure investments in the region's recent history," Gray said. "This overhaul enables us to optimize Coulee's performance as one of the most coveted clean energy assets in the world."

"By March 2013, disassembly was underway on G24, taking the first of the three massive units offline to begin the overhaul, G24 and G23 were back online by 2016 and 2019, respectively, with the final unit, G22, returning to service Sept. 30, 2021," a Dec. 20 news release announced.

Lopez said that work on the remaining generators in the powerplant, on generators 19, 20, and 21, has not yet begun.

The bureau says just two of those massive generating units can supply a city the size of Seattle with all its power needs for an entire year.

The six units in the power house are capable of producing more than 4,200 megawatts. They contribute about two-thirds of the total power generated by the dam.

Refurbishing them required an enormous amount of detailed work.

"The project involved complete disassembly of each 805-megawatt hydroelectric unit, refurbishing each to ensure all of the mechanical and electrical surfaces were restored and returned to like-new condition. Approximately 6.5 million pounds of steel were removed from each unit, once every component down to the turbine runner was fully taken apart. While the units were disassembled, each component was sandblasted, welded, ground, polished, and then repainted before reassembly. Restoring the mechanical and electrical components results in less friction. As a result, the generating units operate with less wear and tear, making them more reliable and efficient."

"I cannot overstate the value of our ratepayers' investment in this project," said Suzanne Cooper, senior vice president of BPA Power Services. "Federal hydropower is the region's original renewable energy resource, and it is critical that we maintain Grand Coulee's integrity, so it can continue to provide the clean, reliable and sustainable power our region requires."

"As the region's reliance on clean energy continues to grow, so does the need to maximize hydropower generated by the dam," added Gray. "The successful completion of the overhaul helps ensure we continue to provide clean, renewable, economical and reliable power for another 30 years or more."

The release also includes more details about the dam. "The Grand Coulee Dam is the largest power generating complex in the United States and the hydropower workhorse of the Columbia River. The dam can generate more than 6,800 megawatts and annually supplies more than 20 billion kilowatt hours of clean, renewable electricity to the region... Known as the crown jewel of the Pacific Northwest, Grand Coulee Dam provides about one-quarter of the total generation of hydroelectric power for the Federal Columbia River Power System." 

"Grand Coulee Dam is one of 31 federal dams that generate more than half of the hydropower in the Northwest," the release says. "BPA delivers power generated by the federal dams, one nonfederal nuclear plant and several small nonfederal power plants, to more than 140 Northwest electric utilities, serving millions of consumers and businesses in Washington, Oregon, Idaho, western Montana and parts of California, Nevada, Utah, and Wyoming. Hydropower is a key, renewable resource and is essential to support the region as it moves toward a carbon-free energy future."