PUD Working on Significant Maintenance Project at Jackson Powerhouse 

The PUD’s Jackson Powerhouse is undergoing a significant maintenance project to rebuild the power nozzles on both generation units.

Nozzles, similar to the much smaller ones found on the ends of garden hoses, shoot a pressurized spray of water at spoon-shaped rotating portions of the turbine, which capture the energy produced by the water’s flow. The pressure can be controlled by needle valves in the nozzle’s opening.

The project is incredibly labor-intensive, requiring crews to disassemble components and lift them out of the powerhouse using a large overhead crane. Typically, this maintenance process happens every 15 to 20 years. The needle valves have worked properly since being installed in the mid-1980s at Jackson, so they have been in action more than 40 years without needing significant repairs.

The complete assembly weighs 8,000 pounds with six nozzles per unit. There is a similar set up at Alaska Energy Authority’s Bradley Lake Hydroelectric Plant near Homer, Alaska. AEA has performed similar maintenance three times since 2001 because its water conditions lead to more sediment and equipment wear and tear. The PUD hired its consultant to help guide us through our first needle valve replacement.

Our Generation team has been preparing for this work for about two years, and got a head start on procuring equipment needed for the repairs. Work started on April 27, and is on schedule to be completed in October. Since the unit is shut down, the Generation team is taking the opportunity to perform additional maintenance to ensure all is functioning as efficiently as possible when it’s turned back on.

As soon as repairs on Unit 1 are complete, the team will start needle valve repairs on Unit 2. Each unit will take about two-and-a-half months to complete.

The repairs have led to an extensive first project for new Generation Superintendent Bryan Baze. Bryan noted that a ton of folks have been instrumental to the project from multiple departments, including Jason Cohn, Robin Berry, Gary Stutheit, Scott Spahr, Brian Parsley, Gaylin Larson, Josh Grisola, the crew at Jackson and lots of folks who have pitched in to help get the project done.

The PUD is also working with contractor JR Merit and Everett Engineering is helping with disassembly, part machining and re-assembly of the nozzles.

Jason praised everybody working on the project – and the fact that this kind of specialized work likely won’t happen again for a few more decades.

“Hopefully, this won’t happen in our careers again,” Jason said. “It’s a ton of work but everyone is doing a great job finding solutions so that we can get this to work for another 40 years.”