A look inside Idaho Falls Power’s underwater turbine

Water normally flows through the underwater turbine located underneath the Snake River in downtown Idaho Falls at about 6,000 cubic feet per second. But this turbine is currently off for about 10 days. Every five years, Idaho Falls Power takes turns shutting down its plants for inspections and cleaning.

“We started Monday with dewater of the plant,” said Jason Cooper, hydromechanic foreman and chief dam safety coordinator for Idaho Falls Power. “That’s installing the stop locks, the front and then the back. Draining all of the water out of the machine.”

This turbine was completed in the 1980s, so it is important to keep up with the maintenance to ensure it is sustaining its efficiency. Engineers look at the wear and condition of the machines to see if they need to do any work now or schedule some for the future. One area they look at is the blades of the turbine.

“The runner blades, the clearance, the tolerance between those blades and the wearing or the draft tube, we have to check those,” Cooper said. “If we get too far out of clearance, then our efficiency drops. And, of course, we don’t want the blades to hit the housing.”

Even though the city plant is shut down, it won’t affect any power for Idaho Falls. The city’s other plants keep everything running.

“Power prices are low right now and that’s why we timed it during this time of year,” Cooper said. “We have high river flows, which help us out. Generation at our other three dams and four power houses. And so this is an optimal time to take this down and do the inspection and maintenance repair.”

Idaho Falls Power says the first inspections and measurements show everything looking good, so far.