Northern States Power, d/b/a Xcel Energy (NYSE: XEL), told the Minnesota Public Utilities Commission on May 3 that it is sticking with its previous prediction of Sept. 30 to bring back on-line the big, coal-fired Unit 3 at the Sherburne County (Sherco) power plant.
Unit 3 has been offline since November 2011 due to equipment problems.
“We previously reported that we expect Unit 3 to return to service on or before September 30, 2013,” the company reported. “Based on recent progress and current information, we affirm that return-to-service date. In our last update filed in April, we reported substantial completion of the on-site turbine and generator stator repairs, and that all major components that were being repaired off site had been returned to the plant.”
Updates the utility offered to the commission included:
- Generator Rotor and Stator (76% complete) – Assembly of the generator has begun. Various internal components have been installed and preparations are proceeding to allow the installation of the generator end shields (end bells) when they are returned to site at the end of May.
- High Pressure and Reheat Turbines (79% complete) – High pressure and reheat turbine grouting is complete and the inner and outer shells for both turbines have been set in place to allow pipe attachment welding to commence.
- Low Pressure Turbines (LP-A and LP-B) (81% complete) – Minor onsite repairs continue (for all parts of the turbine) as additional work is identified as the parts are fully assembled with each other. The LP turbines have been grouted. Final fit up, alignment, and installation of internal components has started. Assembly of the two low-pressure turbines is forecasted to be substantially complete by mid-August.
The 884-MW Unit 3 went off-line in November 2011 while being restarted after a repair shutdown. During the testing procedure after unit restart, specifically the overspeed test, the turbine and generator instrumentation showed vibration levels significantly above normal, and the unit was shut down. The vibration damaged many of the steam, oil, and hydrogen seals in the turbines and generator, and caused a fire.
Sherco is a three-unit, 2,400-MW plant. It burns low-sulfur Western coal from mines in Montana and Wyoming. The plant normally burns more than 9 million tons of coal a year.
Westmoreland Coal (NasdaqGM: WLB), which supplies Sherburne County out of its Absaloka strip mine in Montana, has had some hard times since Unit 3 went offline and said about this situation in its April 30 Form 10-Q report: “In November 2011, an explosion and subsequent fire occurred at Unit 3 of Xcel Energy’s Sherburne County Generating Station, or Unit 3, which is the largest customer of our Absaloka Mine. Xcel indicated that Unit 3 will be offline for an extended period while Xcel investigates the source of the explosion and the extent of the damage. Sherburne County Generating Station has indicated a start up date of September 2013. Westmoreland Resources, Inc., or WRI, our wholly owned subsidiary that operates the Absaloka Mine, maintains business interruption insurance coverage and submitted a notice of loss to its insurance carriers. Our insurance carriers have accepted liability under the policy for the business interruption claim. We recognize income as business interruption losses are incurred and reimbursement is virtually assured and have recognized $4.8 million of income and received $3.2 million of cash proceeds for the three months ended March 31, 2013.”