Xcel Energy Inc. says it will cost as much as $200 million to repair the damage from a catastrophic turbine failure at Minnesota’s largest power plant last November.

Sherco plant director Ron Brevig says Xcel still hasn’t determined exactly why turbine broke up, sending debris and metal flying and sparking a fire. Nobody was injured. He says consultants are expected to finish the investigation around the end of this year.

Brevig says most repair costs will be covered by insurance. He told reporters Wednesday that Xcel and contractors are working around the clock to complete the repairs so Unit 3 can restart in the first quarter of 2013.

Utilities that use Sherco 3 say they haven’t had to raise rates because replacement power has been available at a reasonable cost.