US Army Corps of Engineers
Nashville District Website

Old Hickory Unit 4 Turbine-Generator Rehab Project

FACT SHEET (As of January 2015)

Published Jan. 21, 2015

 Old Hickory Unit 4 Turbine-Generator Rehab Project 



AUTHORIZATION: Section 212 of Water Resource Development Act of 2000 (WRDA 2000).


TYPE OF PROJECT: Hydropower turbine-generator rehabilitation


LOCATION: Old Hickory Powerhouse, Hendersonville, TN.


CONGRESSIONAL INTEREST:  Alexander (TN), Corker (TN), Black (TN-06)


NON-FEDERAL SPONSOR: Power Preference Customers



·        The four identical turbine-generator units at Old Hickory became operational in 1957.  They have outlived the 30-40 year life expectancy for hydropower turbine-generator units.   

·        On August 1, 2011, a long-term Memorandum of Agreement (LT MOA) between the Nashville District, Southeastern Power Administration, and 24 power customers was signed which yields funding on a monthly basis to perform rehab work, as authorized by Section 212 of WRDA 2000.  Under Section 212 of the Water Resources Development Act of 2000 (WRDA 2000), codified at 33 U.S.C. Section 2321a, the Corps “may accept and expend funds provided by preference customers under Federal law relating to the marketing of power” under certain conditions to perform rehab work.  

·        Unit #4 has been out of service since July 2013 because of an oil leak in the hub and because the turbine runner rubs against the discharge ring.  The only way to discover the cause of the oil leak is to disassemble the turbine. The turbine runner is in contact with the discharge ring because unit is misaligned, a result of structural concrete movement.  A study is underway to determine whether the concrete is continuing to move.  If the study finds that the concrete is still moving, a structural fix to stop the movement must be completed before Unit #4 is rehabbed..   

·        Unit #4 rehabilitation will include replacement of the wicket gates, stator windings, and the stator core, plus refurbishment of the servomotors, the turbine runner and the brake systems.  Vibration monitoring systems and high-pressure thrust bearing oil lift systems will be installed as part of the rehabilitation.

IMPORTANCE:  Rehabilitating Old Hickory Unit #4 is a priority because it is out of service.  When there is sufficient flow to run all four units, the water to operate the fourth unit must be spilled, resulting in a net loss of generated electricity.          



·        Plans and specifications for Unit #4 rehabilitation are being prepared jointly by the Nashville District Corps of Engineers and the Hydroelectric Design Center, a division of the Northwest District Corps of Engineers.

BUDGET ($): The total estimated cost of design and construction is approximately $25,000,000.




FY2014 Completed Work:  30% plans and specifications.

FY2015 Scheduled Work:  60% plans and specifications; 90% plans and specifications; Agency Technical Review of 90% plans and specifications; Bidability, Constructability, Operability, Environmental, and Sustainability (BCOES) plans and specifications; BCOES review.

COMPLETION: A future construction contract is currently scheduled to be completed in August 2018.


For more information regarding the Old Hickory Turbine-Generator Rehab project, contact Jeff Linkinhoker, CELRN-PM, phone: (615) 736-7843, email: