State regulators have ordered Xcel Energy to reimburse customers for costs related to a catastrophic failure at the Becker coal-fired power plant 13 years ago.

On November 19, 2011, a serious mechanical failure at the Sherco coal-fired power plant caused a fire and extensive damage. Repairs to Unit 3 cost more than $200 million and resulted in the unit being shut down for nearly two years.

During the outage, Xcel had to purchase backup power and additional fuel from alternative sources. The Minnesota Public Utilities Commission allowed Xcel to bill customers for the additional costs.

For the past decade, the PUC has held off on determining whether replacement costs were reasonable while Xcel waged litigation with turbine maker General Electric.

An administrative law judge recently found that Xcel's failure to prudently operate and maintain Unit 3 contributed to the accident.

Xcel will reimburse customers approximately $58 million in replacement power costs, less credits customers have already received for Xcel's settlement with GE. The final amount of refunds has yet to be calculated.