Wisconsin Electric Power d/b/a We Energies applied Oct. 23 at the Public Service Commission of Wisconsin for approval on $12.5m worth of repairs and upgrades at the gas-fired Port Washington power plant.
The utility is seeking a Certificate of Authority to replace the desuperheater portions of the Hot Reheat (HR) and Superheat (SH) piping with redesigned components on Block 1 (HRSG 11 and 12) and Block 2 (HRSG 21 and 22) at the Port Washington Generating Station (PWGS) located in Ozaukee County, Wisc.
PWGS is a combined-cycle power plant which consists of two fossil-fueled generating units, each with two natural gas-fired heat recovery steam generator (HRSG) boilers and one steam turbine generator. PWGS Block 2 was placed in service in 2005, with PWGS Block 1 following in 2008. Each unit has a net rating of 545 MW.
The proposed project will replace the desuperheater portions of the HR and SH piping of the four PWGS HRSG units at an estimated cost of $12.5m.
The hot reheat and superheater components of HRSG 21 and 22 on PWGS Block 2 are original equipment and were placed in service in 2005. Likewise, the hot reheat and superheater components of HRSG 11 and 12 on PWGS Block 1 are original equipment and were placed in service in 2008. Each of the HRSGs has experienced HR and SH manifold link cracking damage since their first year of operation. The plant’s HRSGs were designed and supplied by Alstom Power.
The HR and SH headers and manifold link pipes have experienced cracking problems from mechanical and thermal stresses caused by HRSG cycling events (about 125 start-up/shutdowns and 1000 thermal cycles between minimum and maximum load per year). Cracking at the HR and SH link manifolds was first identified in 2006 and 2008 for Blocks 2 and 1, respectively. Significant manifold link cracking in HRSG 21 and 22 in December 2010 resulted in through wall leaks and a six-week forced outage for repairs.
To meet the desired initial installation date of April 2014, the company told the commission it will need to release the remainder of the material and fabrication contracts in early February 2014. For this reason, it requested a commission decision no later than Feb. 1, 2014, so that orders to proceed with, or cancel, material and fabrication contracts can be issued in a timely manner.