Dam Love Means Rehabilitation and Replacement

Hydro Review presents information on several rehabilitation projects in North America ranging in price from US$10 million to $1.3 billion that are either in the planning stage or already undergoing much-needed repair.

By Gregory B. Poindexter

Gregory Poindexter is associate editor of Hydro Review.

I am a neophyte with regard to all things related to generating hydroelectricity, especially rehabilitation and refurbishment of powerhouses. Since coming aboard Hydro Review in October 2014, I have asked myself, “Does North America really need to spend millions or billions of dollars to rehabilitate and refurbish its hydroelectric power plants?”

I know now the answer is, “Yes.” But, rehabilitation and refurbishment depend on several factors because each scheme at a dam site is unique. Conversely, there is also a sameness at each and every North American scheme — all equipment within hydroelectric generating facilities will eventually bow to time in-service.

The oldest scheme in this snapshot of rehabilitation projects began service in 1932, while the youngest facility began generating power in 1977. The majority of the 12 featured hydroelectric facilities in this article are owned and operated by the U.S. Army Corps of Engineers and have been producing energy since the 1960s.

Since the execution of a 2004 Memorandum of Agreement signed by the Corps’ Nashville District, the Southeastern Power Administration and power customers, a US$1.2 billion funding stream exists to rehabilitate 28 hydroelectric generating units located at nine hydropower plants operated by the district in the Cumberland River Basin.

The list on the following pages is by no means comprehensive. I encourage Hydro Review readers to send information on North American projects undergoing rehab work to gregp@pennwell.com. I plan to compile an additional list on rehabilitation projects in the coming months.

Beauharnois

Owner: Hydro-Quebec
Location: Quebec, Canada
River: Saint-Lawrence
Capacity: 1,755 MW
Original On-Line Date: 1932
Description of Work: Rehabilitation is intended to extend the service life of Quebec’s fifth largest power station. Work on the project began in 1994 and is scheduled to be complete in 2019. The work involves overhauling the 36 generating units, constructing new buildings and rehabilitating the existing buildings, and rehabilitating the 120-kV transmission lines.
Value of Work: C$1.6 billion (US$1.3 billion)
Expected Completion Date: 2019
Service & Product Suppliers Involved: Alstom Hydro Canada Inc., Cegerco Inc., Dessau, Hydro-Mecanique Inc., SNC-Lavalin, Voith Hydro Corp.

Blue Mesa

Owner: U.S. Department of Interior’s Bureau of Reclamation
Location: Colorado
River: Gunnison
Capacity: 86.4 MW
Original On-Line Date: 1967
Description of Work: Rehabilitation and upgrades are planned for two Francis turbines that are controlled by 156-inch butterfly valves. The units’ initial combined generating capacity of 60 MW was increased to 86.4 MW in 1988. The above-ground power plant will see its generator receive new air coolers, to include new cooling water and air vent piping and valves. The units will be provided with new lower and upper guide/thrust bearing oil coolers, new cooling water piping and valves for the upper and lower guide/thrust bearing coolers. Babbitt metal will be serviced in each generator’s bearing shoes, along with rehabilitating the thrust runner, flushing bearing oil pipes and installing new bearing oil. Each unit’s stator frame, stator core and armature winding will be replaced. The generator field poles will be refurbished and the rotating excitation system will be upgraded with a digital exciter.
Value of Work: US$15 million
Expected Completion Date: 2020
Service & Product Suppliers Involved: Reclamation is in the process of seeking bids for this work.

Center Hill

Owner: U.S. Army Corps of Engineers
Location: Tennessee
River: Caney Fork
Capacity: 135 MW
Original On-Line Date: 1951
Description of Work: Refurbishing Units 1, 2 and 3 in the Center Hill Dam powerhouse, which began operation in 1950 and 1951, includes a newly designed turbine tested in October 2014. Work will include replacement of runners, wicket gates and generator stator windings; refurbishment of servomotors and the unit braking system; restacking existing generator iron; and installing vibration monitoring and high-pressure thrust bearing oil lift systems. Auto venting features are incorporated into the design of the new turbines. Openings in the edge of the turbine blades will introduce air into the water as it flows through the unit. The venting feature will elevate dissolved oxygen levels in the water, which benefits aquatic wildlife, by introducing air into the water as it flows through the turbine.
Value of Work: US$47.2 million
Expected Completion Date: Unknown
Service & Product Supplier Involved: Voith Hydro Corp.

Hills Creek

Owner: U.S. Army Corps of Engineers
Location: Oregon
River: Middle Fork Willamette
Capacity: 34.5 MW
Original On-Line Date: 1962
Description of Work: This work involves a turbine replacement and generator rewind. The hydro facility has two turbine-generator units and both will be rehabilitated.
Value of Work: US$20 million
Expected Completion Date: 2015
Service & Product Supplier Involved: Andritz Hydro Corp.

Originally commissioned in 1967, the 86.4-MW Blue Mesa hydroelectric facility generates power from waters of the Gunnison River in Cimarron, Colo.

 

Ice Harbor

Owner: U.S. Army Corps of Engineers
Location: Washington
River: Snake
Capacity: 603 MW
Original On-Line Date: 1962
Description of Work: Main Units 1 through 6 in this powerhouse will each receive a digital governor that will improve reliability, provide more versatile governor control, minimize torque stresses on the generators/turbines, and assure regional uniformity across the Corps. Units 1 through 3 rehabilitation are part of the turbine runner replacement project meant to develop the latest methods and technologies in turbine design as recommended by the Corp’s Columbia River Fish Mitigation Turbine Survival Program. A team of government agencies and a private contractor are developing the next generation of turbines designed to be safer for downstream passage of young fish, with installation of Unit 2 expected in 2016.
Value of Work: US$10 million
Expected Completion Date: 2018
Service & Product Supplier Involved: Voith Hydro Corp.

Lower Monumental

Owner: U.S. Army Corps of Engineers
Location: Washington
River: Snake
Capacity: 810 MW
Original On-Line Date: 1969
Description of Work: Work to be performed at Lower Monumental includes Unit 1 stator windings replacement and linkage and cavitation repair, as well as Unit 2 cavitation repair. The Unit 1 Kaplan turbine requires linkage repair to allow the blade angle to be adjusted, and the generator’s stator windings will be replaced.
Value of Work: Unknown
Expected Completion Date: 2016
Service & Product Supplier Involved: Contracts have not yet been awarded for this work.

Situated on the Middle Fork Willamette River in Oregon, the 34.5-MW Hills Creek hydroelectric facility began generating power in 1962.

McNary

Owner: U.S. Army Corps of Engineers
Location: Oregon
River: Columbia
Capacity: 980 MW
Original On-Line Date: 1953
Description of Work: A portion of the rehabilitation work to be performed at the powerhouse will include stator winding replacements for 10 generators to maintain reliable electric power generation. This project involves replacing the copper coil that transforms the mechanical power and torque of the turbine runner into electrical power. The new windings are capable of producing more electrical current — 100 MW instead of the original 80 MW — but the generator units are still rated at the original capacity for now because the turbine runners also need to be upgraded to increase the overall output. Replacing the turbine runners is a future project that is in the early planning stages and will finalize the unit upgrades to 100 MW. The second portion of the McNary rehabilitation work being performed includes upgrading the 4160/480 V powerhouse station service electrical distribution system, part of which involves the switchgear, substations and motor control centers.
Value of Work: US$115 million
Expected Completion Date: 2018
Service & Product Suppliers Involved: Andritz Hydro Corp., Olsson Industrial Electric

Priest Rapids

Owner: Public Utility District No. 2 of Grant County
Location: Washington
River: Columbia
Capacity: 955.6 MW
Original On-Line Date: 1956
Description of Work: The scope of the refurbishment work includes replacing bushings and linings for the wicket gates and wicket gate mechanism; replacing hub-shaft coupling hardware as well as the shaft sleeve and seal; refurbishing the draft tube liner, outer and intermediate head covers, stay ring, turbine bearing, wicket gate servomotor, shaft, Kaplan pipes, oil head and governor oil pressure system; and resurfacing the water passageway in the blade swept area. Upgrade to a new, modern, more efficient runner rather than refurbish and replace the inner head cover.
Value of Work: US$61.6 million
Expected Completion Date: 2026
Service & Product Supplier Involved: Voith Hydro Corp.

Rock Island

Owner: Public Utility District No. 1 of Chelan County
Location: Washington
River: Columbia
Capacity: 213 MW
Original On-Line Date: 1933
Description of Work: Modernization work will begin on a second Kaplan unit (installed in 1954) in April 2011. The work includes a new generator, turbine, wicket gates, high-pressure governor, exciter, and controls, as well as draft tube modifications. Turbine components have been designed with fish-friendly features and have greaseless bearings. Several years of performance testing have identified about a 10% gain in efficiency compared with the old unit. Major maintenance work is under way on the third of four Nagler units (installed in 1933). The work includes installing a new stator and environmental enhancements to turbine components, including greaseless bushings and water-lubricated bearings. Modernization of the balance of plant electrical and mechanical systems and installation of new cranes has already been completed.
Value of Work: US$200 million
Expected Completion Date: 2015
Service & Product Suppliers Involved: ABS Consulting, Andritz Hydro, Areva T&D, Brazil Quality Services, CE Power Solutions, Dix Corporation, DTA Consulting Engineers, Dunkin and Bush, Emagineered Solutions, Far West Iron Works, Gelco, H&H Engineering, Hyundai Heavy Industries, K&N Electric, Knight Construction, Konecranes, MRM Construction, MWH Global, NW Steel Fab, Okenite, Omega Morgan, Peer Technical, Pro-Cut, Technibus, Quality Resource Services, R.W. Beck, VanTran, Voith Hydro, WESCO, Western States

The 955.6-MW Priest Rapids hydroelectric project is owned and operated by Public Utility District No. 2 of Grant County, Washington.

Salina Pumped-Storage

Owner: Grand River Dam Authority
Location: Oklahoma
River: Grand and Saline creeks
Capacity: 260 MW
Original On-Line Date: In two stages — first completed 1968, second completed 1972|
Description of Work: GRDA is in the midst of a multi-year rewind project on five of the six pump-generator units inside the Salina Pumped-Storage Project powerhouse. The work includes a rewind of Units 6, 5, 3, 2, and 1, in that sequence. Currently, Unit 6 is being re-wound but is expected to return to service in late 2014 or early 2015.
Value of Work: US$11.3 million
Expected Completion: 2016
Service & Product Supplier Involved: Voith Hydro Corp.

Wanapum

Owner: Public Utility District No. 2 of Grant County
Location: Washington
River: Columbia
Capacity: 1,038 MW
Original On-Line Date: 1963
Description of Work: Turbines in all 10 units have been replaced with advanced turbines. The new turbines have six smaller blades instead of the five on the existing Kaplan turbine. The new runner reduces the pressure-versus-time and velocity-versus-distance gradients while minimizing clearances between the runner and discharge ring and maximizing the volume of flow passage. The servomotor that moves the blades is located near the top of the turbine shaft instead of at the hub. Each new turbine has 32 wicket gates instead of 20, and every other gate is aligned with one of the 16 stay vanes. The new blade centerline is lower. The new turbine is expected to have an overall efficiency gain of about 3% and an overall capacity gain of 15%. In addition, work recently began on the second phase of the rehab, installing 10 new generators at Wanapum.
Value of Work: US$195 million (turbines), US$161 million (generators)
Expected Completion Date: 2013 (turbines), 2018 (generators)
Service & Product Suppliers Involved: Alstom Hydro US, Devine Tarbell & Associates Inc.
For Further Details:Hydro Review Special Report: Spotlight on Wanapum and Priest Rapids,” Hydro Review, Volume 25, No. 2, April 2006.

Wells

Owner: Douglas County Public Utility District
Location: Washington
River: Columbia
Capacity: 840 MW
Original On-Line Date: 1967
Description of Work: Rebuilding generators and refurbishing turbine parts in all 10 units. The decision to begin rehabilitating the units originated from a February 2005 fault in Unit 1. Based on tests of Unit 1 and information indicating generator coils of the other nine units were approaching the end of their services lives, Douglas County PUD concluded it would be necessary to rebuild all ten generators. Generators are being rewound with new copper coils, and steel cores are being restacked with new laminations. Turbine components and water passages are being refurbished, replaced, or re-machined to extend the service life of each unit by 30 to 40 years. Site work began in the fall of 2008.
Value of Work: $151 million
Expected Completion Date: 2016
Service & Product Supplier Involved: Toshiba International Corp.

 
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