GRAND COUEE, Wash. – Today, the Bureau of Reclamation and the Bonneville Power Administration announced the completion of the major overhaul of hydropower generating units 22, 23 and 24 inside the Nathaniel “Nat” Washington power plant in Grand Coulee dam. Located on the Columbia River about 90 miles west of Spokane, Washington, the Grand Coulee Dam is the largest power generation complex in the United States and the hydropower workhorse of the Columbia River. The dam can generate more than 6,800 megawatts and annually provides more than 20 billion kilowatt-hours of clean, renewable electricity to the region.
Planning for the project began in 2008, and in 2012, the contractor arrived on site to begin preparatory work for the project. As of March 2013, teardown was underway on G24, taking the first of three massive units offline to begin overhaul. G24 and G23 were brought back online in 2016 and 2019, respectively, and the last unit, G22, was returned to service on September 30, 2021.
The project involved the complete dismantling of each 805 megawatt hydroelectric unit, refurbishing each to ensure that all mechanical and electrical surfaces were restored and made to new condition. About 6.5 million pounds of steel were removed from each unit after every component up to the turbine wheel was completely disassembled. While the units were taken apart, each component was sandblasted, welded, ground, polished, and then repainted before reassembly. Restoration of mechanical and electrical components results in less friction. As a result, generator sets run with less wear and tear, making them more reliable and efficient.
“Revising something of this magnitude doesn’t happen overnight; it takes years of planning and strong partnerships to reach such a milestone ”, said Lorri Gray, regional director of Columbia-Pacific Northwest. “The overhaul of these units is essential to the accomplishment of Reclamation’s mission and represents one of the most significant infrastructure investments in the region’s recent history. This redesign allows us to optimize Coulee’s performance as one of the world’s most coveted clean energy assets.
Known as the jewel in the crown of the Pacific Northwest, the Grand Coulee Dam provides about a quarter of total hydroelectric power generation for the federal Columbia River grid.
The Grand Coulee Dam is one of 31 federal dams that produce more than half of the hydropower in the Northwest. BPA supplies electricity generated by federal dams, a non-federal nuclear power plant, and several small non-federal power plants to more than 140 Northwestern electric utilities, serving millions of consumers and businesses in Washington, DC. in Oregon, Idaho, western Montana and parts of California, Nevada, Utah and Wyoming. Hydropower is a key renewable resource and is essential in supporting the region as it moves towards a carbon-free energy future.
“I cannot overestimate the value of our taxpayers’ investment in this project”, said Suzanne Cooper, Senior Vice President of BPA Power Services. “Federal hydropower is the region’s original renewable energy source, and it is essential that we maintain the integrity of Grand Coulee, so that it can continue to provide the clean, reliable and sustainable energy that our region needs. “
Washington’s Nathaniel “Nat” Power Plant was built between 1967 and 1975 and is the largest of the four power plants. The plant contains six generators capable of producing more than 4,200 megawatts and contributes about 2/3 of the total power generated by the dam. Two of the generating units can supply a city the size of Seattle with all of its electricity needs for an entire year.
“As the region’s dependence on clean energy continues to grow, so does the need to maximize the hydropower generated by the dam” Gray added. “The success of the redesign allows us to continue providing clean, renewable, economical and reliable energy for another 30 years or more. “
Completed in 1941, the Grand Coulee Dam serves as a multipurpose facility, providing water for irrigation, hydroelectric power generation, flood control, fish and wildlife conservation, and recreation. The Grand Coulee power station consists of 33 generators distributed among three power stations, the John W. Keys III pump station and three switching stations.