It’s not easy being green: A wind turbine update 

It has been over a year since Chaska’s wind turbine went up next to the Pioneer Ridge Middle School. But what was supposed to be a “visible commitment to renewable energy” has certainly provided its fair share of headaches in the last 12 months.

The Chaska City Council received a progress report on the turbine at its Dec. 20 meeting. To date, the 160 kilowatt turbine has generated 118,000 kilowatt hours.

“It’s produced enough energy to power 15 homes,” noted City Administrator Matt Podhradsky.

That figure is slightly less than the 20 homes the city had anticipated. The turbine is currently operating at 12 percent capacity.

“Over time that’s going to increase,” said Podhradsky. “But it’s pretty typical of wind turbines – primarily because you see peaks and valleys.”

Renewable

Last October, Chaska was one of 11 member cities to receive an 80-foot, 160 kilowatt wind turbine as part of the Minnesota Municipal Power Agency’s (MMPA) Hometown Wind Power Program. The refurbished turbines were shipped to Minnesota from California and cost $300,000 each. The MMPA purchased the turbines using a no-interest loan from the federal government.

“It wasn’t local tax dollars that went into the project,” said Podhradsky. “It’s really supported directly by rates.”

The turbines are part of the MMPA’s attempts to meet state mandates for renewable energy. By 2012, 12 percent of energy must come from renewable resources like wind. That figure jumps to 25 percent by 2025.

In cities like Chaska, though, the turbines serve more as symbols of renewable energy than major energy producers.

“The biggest impact will be the Oak Glen Wind Farm in Blooming Prairie,” said Podhradsky. “Those are the big turbines.”

The 100-acre wind farm will generate enough energy to power 14,000 homes annually.

“That’s going to have a significant impact with us meeting our goals by 2012,” said Podhradsky. To that end, the MMPA is also developing a biofuel energy plant in Le Sueur.

Trouble

The energy produced by Chaska’s turbine has been spotty, mostly due to long periods of inactivity. Though the turbine was delivered and installed late last fall, it didn’t begin producing energy until March.

After installation, all 12 of the refurbished turbines needed work before they could begin producing energy. The MMPA took over the turbine work from original contractor Henkels & McCoy in February. By mid-February, Chaska’s turbine had been commissioned to spin, but was creating loud noises, necessitating more work to fix.

Then, in May, the turbine was rendered inoperable again when a malfunctioning brake at the Faribault site triggered the shutdown of all the MMPA turbines. Chaska’s turbine was inspected and new brake pads were installed.

“It certainly was inordinate when we had it installed,” said Podhradsky when asked about the problems incurred with the turbine.

The turbine was also shut down this December while crews waited for an ordered part to be delivered.

“They are down for maintenance every once in awhile,” said Podhradsky.

Numbers

When it has been spinning, Chaska’s turbine has produced an average of 20 kilowatts an hour. At full output, the blades can spin 1.5 times every two seconds.

According to Chaska’s Electrical Director Dan Geiger, the turbine has reached its 160 kilowatt capacity on a number of occasions. Its record high output is just under 240 kilowatts. The turbine has experienced a high wind speed of 18 meters per second.

Typically, Chaska’s turbine starts spinning when the wind is blowing a steady 8 mph, noted Geiger in an e-mail. “Electricity is produced at about 12 mph,” he wrote. “As the wind blows harder, it produces more electricity.”

Podhradsky told the council that he thought the 11-member cities were largely on par with one another in terms of output, save for the East Grand Forks site, which has vastly different terrain than the remainder of the sites in central and south-central Minnesota.

“I don’t think any city has outperformed another,” he said.

December was not a particularly windy month in Chaska. According to Geiger, “the only two days this month that we’ve had sustainable winds greater than 12 miles per hour were the 11th and 12th. Last month we had 10 days with sustained winds greater than 12 miles per hour.“So the wind turbine doesn’t produce electricity every day,” he wrote. “Only when it’s windy enough.”