Oct 21 Xcel Energy Inc's 860-megawatt
Unit 3 at the Sherburne County coal-fired power plant in
Minnesota has returned to service after a nearly two-year
outage, the company said on Monday.
The unit shut in November 2011 during turbine testing as it
was restarted after a maintenance outage. The failure caused
extensive damage to the turbine, generator and associated plant
systems, Xcel said.
"An investigation by external experts found extensive
cracking in one row of turbine blades due to stress corrosion.
The problem was a function of the original design and was not
related to how the plant has been operated or maintained," Xcel
The utility expects much of $200 million repair bill to be
reimbursed by insurance.
"Restoration following such a significant event on such a
large unit was extremely complex," said Dave Sparby, president
of Xcel's Northern States Power-Minnesota.
The three-unit plant, called Sherco, is Xcel Energy's largest
Midwest power plant, generating 2,400 MW to serve more than 2
million Minnesota homes and businesses.
Sherco 3 is jointly owned by Xcel Energy and Southern
Minnesota Municipal Power Agency, which holds a 41 percent