Willmar, Minn., turbines perform as projected, review shows
WILLMAR — Willmar Municipal Utilities’ two wind turbines have performed as projected, according to a performance review.
The review looked at energy production figures combined with warranty payments pending and received since the turbines were installed 3½ years ago.
During that time, energy production increased from 6,616,964 kilowatt-hours in 2010 to 7,703,769 kilowatt-hours in 2011. For 2012, production reached 8,339,767 kilowatt-hours, said Wesley Hompe, Willmar Utilities general manager.
Hompe presented the review to the council’s Public Works/Safety Committee last week and committee Chairman Ron Christianson noted the review in his report to the council Monday night.
Last year’s production coincides with the results of a wind speed study performed at Ridgewater College from 2002 through 2004 that predicted both turbines would have combined energy production of 8.3 million kilowatt-hours.
The turbines are located just north of the Willmar Senior High School. Hompe said the vast majority of initial turbine problems were hydraulic in nature.
He said the south turbine had a hydraulic leak that was difficult to find “because everything is coated in oil and you cannot be inside that turbine when it’s under pressure and operating. That’s a safety hazard. You’re not going to have somebody inside the hub as it’s spinning around.”
Hompe said the leak was repaired and the turbine’s availability to produce energy whether or not the wind blows improved as a result.
Hompe said additional heaters, which were installed by the utility and turbine manufacturer DeWind Company, considerably improved cold-weather performance. Also, various control system adjustments and tweaks improved energy production.
Hompe said the utilities commission has added three years to the original two-year warranty, and he said four utility employees have received basic maintenance training from DeWind.
“There are nine levels of training and we haven’t moved beyond the second level because of the time it takes to do the training and how often we’re able to work on them. They start losing that knowledge fairly quickly and we have basic knowledge and we’re able to do that,” Hompe said.
“But when you get beyond that with the two turbines, it would not be cost-effective training for our people to get beyond that. They are able to do some basic things on their own. If it gets beyond that, we can have our people go up there and troubleshoot and call the maintenance people who do know what needs to be done. It gets really complicated really quick inside there. I’d much rather have somebody who works on it every day,” Hompe said.
The commission approved an agreement Aug. 4, 2008, with DeWind of Round Rock, Texas, to buy two turbines, which were installed July 7 and commissioned Sept. 3, 2009.
Before approving the agreement, the utilities had a financial projection prepared by Folkedahl Consulting Inc., of Willmar, to estimate the cost of energy.
The projection determined the cost of electricity, when the turbines were installed and went into production in 2009 dollars, was 4.7 cents per kilowatt-hour over the 20-year life of the turbines.
Committee members asked Hompe if the utility had compared the cost of wind with the cost of coal and natural gas. Hompe said coal and natural gas are different fuels and do not fall under renewable energies.
The Minnesota renewable energy mandate requires renewable electricity account for 25 percent of retail electricity sales by 2025.
Hompe said the utility assumed it would be included in the state’s renewable energy mandate. “So that comparison was not made because we were trying to work our way toward satisfying that renewable energy mandate,” he said.
Hompe later clarified that Willmar is officially not yet required to operate under the mandate but is operating as if it were.
The mandate affects utilities that are members of a joint action agency. He said Willmar is among a handful of utilities that are independent and are not a member of such an agency.
A joint action agency provides power but also provides many other services to smaller utilities “that we in-house do ourselves,” Hompe said.
Hompe said Willmar has studied the possibility of joining a joint action agency, but so far has not come to the conclusion that membership would be economically or operationally advantageous.
Hompe was also asked about solar power during last week’s presentation. He said the utility conducted an in-depth investigation at the beginning of 2012 with a vendor who made a generous project offer. But Hompe said it did not make financial sense because solar is still relatively expensive even though the price has come down.
“If we were to put a lot of time and money into renewable energy, we probably would be best off going to dispatchable renewable energy such as biomass and that would be much easier to control when we need it, not just when it happens,” he said.