Hydropower Station Rehabilitation
Four generating units rebuilt one at a time behind cofferdams, while the station kept sending clean power to the grid.
- Owner
- Confidential
- Location
- U.S.
- Market
- Renewable Energy
- Delivery
- EPC
- Scale
- 4 units / 120 MW
- Completed
- 2025
Four 1950s generating units rebuilt one at a time behind cofferdams, so the station kept producing power and every unit returned to the grid stronger than it left.
The station’s four units were more than 70 years old and losing efficiency. Each had to be dewatered, dismantled, rebuilt with a new turbine, generator and controls, and returned to service while the other units kept running. The work happened inside a dam, with river flows, fish passage rules and environmental permits setting the window for every outage.
The approach.
- 01
Cofferdams and dewatering
Each unit was isolated with stoplogs and a cofferdam and pumped dry, with instruments watching seepage and structure throughout.
- 02
One unit at a time
Only one unit was ever out of service, so the station kept producing power for the whole program.
- 03
Heavy lifts inside the powerhouse
The powerhouse crane was refurbished and load-tested first, then used to pull and set rotors, runners and stator sections.
- 04
Returned to the grid tested
Each rebuilt unit went through wet testing, balancing and load rejection tests before release back to the operator.
The outcome.
“We took apart a 70-year-old machine and put back a new one, and the river never knew we were there.”
Mechanical superintendent, PerryWester
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