From an article by Tom Content in the Milwaukee Journal Sentinel:

State utility regulators are reviewing the extent of a steam-generator tube problem with the coal-fired power plant that opened last year near Wausau.

The power plant experienced unexpected shutdowns late last year and early this year, with more expected this year to address the problem, according to the state Public Service Commission.

Wisconsin Public Service Corp. opened the $773 million power plant, the first coal plant built in the state in a generation, in June 2008.

At issue is whether WPS is eligible to pass along the cost of power it had to purchase late last year when the coal plant wasn’t running.

Tim LeMonds, a spokesman for the Public Service Commission, said the steam generating tubes at the power plant have a tendency to clog, and the plant needs to take measures to keep the pipes clean to avoid future clogging.

Dennis Derricks, WPS director of electric regulatory policy, said the problem is a routine start-up issue that the company is addressing with the company that built the power plant, Babcock & Wilcox. According to Derricks, the power plant is still projected to operate 92% of the time, as the utility had projected when it proposed the plant.

The plant, one of two major coal plants built in the state, was recognized with industry awards including Plant of the Year by Power Magazine, an industry trade publication, and 2008 Best Coal-Fired Project by Power Engineering magazine.

Derricks said clogging isn’t the best way to describe the problem. The tubes have an exfoliation problem that is common across the industry and is expected to improve this year.

“The outages going forward are to manage the amount of material that flakes off,” he said. “The tubes are expected to season themselves and develop a coating over them” that helps address the problem, according to Derricks.