Minnesota Power's Thomson Hydro Station, capable of generating 72 MW of hydroelectricity, is nearing the end of its restoration, according to the utility. The 106-year-old hydropower asset, located on the St. Louis River, was taken offline June 20, 2012 because of flood damage.
The facility, which is Minnesota Power's largest hydropower generator, will be partially restored to service by the end of 2013 and completely rehabilitated by 2014.
Although the integrity of the hydropower dams was maintained during the flood, the volume of water flooded the six turbines at Thomas, overtopped the reservoir and breached a portion of the earthen dike at the forebay, according to Power Engineering.
Repairs to the forebay are estimated at $25 million, and the company is investing about $35 million in improvements to provide protection against future flooding as well as maintenance and rehabilitation of facilities that would have required extended outages within the next several years.
Minnesota Power is a division of ALLETE Inc.