Energy output of Willmar wind turbines improves over last three years
WILLMAR — Energy produced by Willmar Municipal Utilities’ two wind turbines has been increasing since the turbines were commissioned in September 2009, according to a status report given to the Municipal Utilities Commission this week.
Jon Folkedahl, supervisor of power production, presented monthly and annual production figures for 2010 through 2012. Combined output increased from 6,616,964 kilowatt-hours in 2010 and 7,703,769 kilowatt-hours in 2011 to 8,339,767 kilowatt-hours in 2012.
“That’s a nice improving trend,’’ said Folkedahl. He attributed the increase to improved availability and to technicians from turbine manufacturer DeWind who are “gradually working out a lot of the little bugs that are constant in these turbines.’’
Folkedahl said the turbines are still not perfect, but any lost production is covered under warranty up to 95 percent availability.
“The wind turbines themselves are good turbines. They’re in good condition. There are just a lot of small issues that tend to crop up,’’ Folkedahl said.
For example, recent short outages are due mainly to cold temperatures. But Folkedahl said he’s working with DeWind to improve those conditions and said work is under way on the heaters.
Last week, he said, technicians were here and insulated the control cabinets in the blade hubs. Folkedahl said he sent the technicians downtown to get some water heater blankets, which were shrink-wrapped around the control cabinets.
Folkedahl said the temperature was just a few degrees off. He said there just was not quite enough heat in the control cabinets on those cold-snap days, “and we could see the difference immediately.’’
The two turbines are located just north of Willmar Senior High School.
Folkedahl said the north turbine was not turning last weekend because technicians were unable to get to replacing 12 hydraulic accumulator heating blankets. He said the existing blankets were half burned out and technicians were scheduled to replace those this week.
“They’re similar to the heating blanket that you might use in your home,’’ Folkedahl said.
Technicians are also scheduled to do the annual service work starting this week, he said.
Commissioner Jerry Gesch asked if the utility has been using the warranty.
Utility assistant engineer Jeron Smith said the turbines’ first warranty covered two years and the commission extended the warranty three more years. He said DeWind’s warranty payment will be calculated at the end of 2013.
Commission President Steve Salzer asked why production goes down in the summer months such as July and August. Folkedahl said spring and fall are the windiest months. He said summer is always the lowest.
Smith said monthly production numbers are posted on the utility’s website. Smith said he believes DeWind becomes responsible when availability is under 95 percent. The percentage was around 90 percent in 2012.
Gesch said it would be interesting to see DeWind’s payment number.
In other business this week, the commission voted to invite companies to submit bids to repair the mobile substation transformer. The commission has budgeted $350,000 for the work.
Smith said the mobile substation was used in February 2012 while the power plant substation was repaired. Smith said routine maintenance is performed on all substation transformers.
He said an oil sample taken from the mobile unit indicated repair was needed. He said bids will be opened Feb. 19 and will be considered by the commission Feb. 25.
Commissioners asked Smith how cost comparisons will be obtained and the scope of work determined.
Smith said there is a chance the mobile transformer will need only minor repair, but the sample indicated that repairs will be more extensive.
Bid proposals will include the cost of shipping the transformer to and from the vendor’s shop, Smith said. He said Willmar does not have its own fallback mobile transformer in the event of a failure, but he said another could be obtained under mutual aid from other organizations.