Dec. 01–WENATCHEE — A key contractor for the Chelan County PUD will get started ahead of schedule manufacturing parts needed for turbine/generator unit upgrades in Rock Island Dam’s first powerhouse to lock in favorable prices and ensure the parts are ready when needed.
Commissioners Nov. 21 agreed to authorize PUD General Manager Steve Wright to give Andritz Hydro Corp. of North Carolina the go-ahead to manufacture $12.4 million in parts, even though some of them won’t be needed until mid-2019.
The schedule change and payment are part of a larger parts-manufacturing contract already in place with Andritz, to modernize the dam’s aged units.
Rock Island Dam was the first dam on the Columbia River. It began generating in the early 1930s. Some of the units slated for rehab contain original parts that are now broken or worn. The first powerhouse, where the work is taking place, is the one closest to the Columbia’s Douglas County shoreline.
Replacement parts for hydroelectric dams are not interchangeable. Each must be custom made to fit, and lead times to manufacture them can be long, Brett Bickford, the PUD’s director of engineering and project management, has said. Price tags are huge.
Moving up the manufacturing and payment schedule for these parts locks in favorable pricing, avoids manufacturing delays and ensures the parts will be on hand, allowing more flexibility in scheduling the future repairs, Bickford said.
Work to rehabilitate the 10 aged units at Rock Island Dam began in 2008 and has progressed in order of urgency:
— Two units, B10 and B9, were in the worst condition. They were rehabbed in 2008 and 2012 at a combined cost of about $60 million.
— B6 is now under construction.
— B7 will be next, with work set to begin in May.
— The dam’s four oldest units, B1 through B4, will be next in 2018 through 2020. These four are currently off line due to cracks discovered in their steel components.
— B5 and B8 will be rehabbed in 2021 and 2022, according to the current work schedule.
The cost to rehab these remaining eight units is $181 million.
The first powerhouse contains an 11th unit that is much smaller and used only to power to the plant if all the other units went down and more power was needed above what backup batteries can supply, Bickford said.
The second powerhouse, which is closer to the Columbia’s Chelan County shoreline, contains eight, more modern units.
The dam’s 19 units can generate a total of 624 megawatts, enough to power the city of Vancouver and surrounding Clark County.
A PUD staff analysis earlier this year revealed that all the units in the first powerhouse are still needed to generate power during the highest river flows and as backups when any of the dam’s larger units are down for repairs or maintenance.
The analysis concluded that the oldest units, B1 through B4, alone, add an estimated $46 million in revenue that the PUD wouldn’t otherwise receive if these units were permanently taken out of service.
Rehab often enables the units to generate more electricity with the same amount of water, making them more efficient, too, officials say.
Reach Christine Pratt at 509-665-1173 or email@example.com. Follow her on Twitter at @CPrattWW.