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Assessment of utility generator aims for increased efficiency

WILLMAR — A federally mandated assessment aims to help Willmar Municipal Utilities increase efficiency and reduce fuel use for the main coal-fired generator at the downtown power plant.

The assessments will try to encourage electric utilities to find ways to operate boilers more efficiently, which will result in fewer emissions and less fuel used per kilowatt-hour of power produced, explains Jon Folkedahl, Willmar Utilities power production supervisor.

The one-time assessment is mandated by the U.S Environmental Protection Agency and carries the long title of National Emission Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers Area Sources.

The assessment will be performed on boiler No. 3, which produces hot water for customers of the district heating system and steam to turn a turbine generator to produce electricity. The boiler was installed in 1960 and the generator in 1970.

The boiler is quite important to the utility, according to Folkedahl. It runs pretty much 24 hours per day, 7 days per week about 11 months a year and produces about 12 percent of the city’s total megawatt needs.

The boiler is rated to produce 17.5 megawatts per hour. But due to restrictions on particulate matter — mainly soot — the utility can only run the boiler at about half-throttle, said Folkedahl.

“We can run it about 8 megawatts on coal before we bump up against the emission limits,’’ he said in an interview. The boiler can also operate on natural gas.

The assessment will be performed by Babcock and Wilcox Company of Charlotte, N.C., under a contract recommended by Folkedahl and approved Monday by the Municipal Utilities Commission.

Folkedahl recommended the contract proposed by Babcock and Wilcox because the firm manufactured Willmar’s boiler and because the firm will send to perform the assessment an engineer with 34 years of experience, including with this type of boiler.

Folkedahl said the engineer will spend four days in Willmar compared with a proposal from Wenck Associates of Minnesota whose representative would only spend one day in Willmar. Folkedahl said the assessment with satisfy both the EPA requirement and the utility’s insurance requirement for annual visual inspection.

“One of the EPA requirements is a visual inspection,’’ he said. “This will satisfy this requirement, and we do expect to get a lot of good information from the Babcock engineer on the operation of this boiler.’’

Folkedahl said the assessment deadline is March 21. The engineer will be here the week of March 10.

“He’s planning to crawl around inside and inspect everything and get up close and personal,’’ Folkedahl said. “That will take a day-and-a-half to two days. He’ll ask to fire it up and run it up to maximum, run it up and down, look at how all the controls operate, find means for us to operate in a more efficient manner.’’

The $12,367 contract includes inspection of boiler No. 2, which was converted from coal to natural gas 15 years ago. The utility will use information gleaned from the inspection in the utility’s power generation study.

No. 2 is a capacity boiler maintained in operational status for whenever there’s an unanticipated or emergency demand for power.

The plant also has a smaller “package’’ boiler, which is used only to service the heating district when No. 3 is not available.

David Little
David Little covers the Willmar City Council, Willmar Municipal Utilities and other city news.
(320) 235-1150