What happens when a wind turbine malfunctions?

Several readers have asked about a number of wind turbines throughout Adair County that either are not operating like they should, or they aren’t operating at all.

Readers reported a turbine a half-mile west of Richland, which is at 310th Street and Jordan Avenue, had mangled blades in late March. This is after a turbine about two miles away lost blades two years ago.

Additionally, residents in areas south of Fontanelle and Greenfield heard what they described as an explosion and saw smoke coming from a turbine last October. This was the same week that another turbine, south of Menlo, caught fire. Fortunately, crops in the field below the turbine that caught fire had already been harvested.

At the time, Geoff Greenwood, Media Relations Manager with MidAmerican Energy Company, which built Adair County’s wind turbines in both the Arbor Hill and Orient Wind Farms, called a fire like the one south of Menlo an “extremely rare occurrence.” He said officials have since learned the cause of that fire was likely electrical.

“Some turbines house certain electrical equipment, including a transformer and connected components, inside the nacelle at the top of the turbine (the nacelle is the structure behind the turbine blades, and inside it are important components) while other models house that same equipment on the ground outside the tower,” Greenwood said. “For those turbines that house this electrical equipment internally at the top, we’re evaluating the feasibility of purchasing and outfitting them with fire supression systems.”

Greenwood said that a “relatively small number” of wind turbines in Adair County are temporarily not working for various reasons.

“Depending on the individual turbine, the issue may involve performing a routine inspection, maintenance, or perhaps there’s a need for a larger repair,” Greenwood said.

Inspections, which are conducted regularly, stop blades for safety reasons. Routine maintenance includes lubricating key mechanical components, changing oil or filters, making adjustments, cleaning, updating software or making sure components inside the nacelle are working. Minor repairs can include replacing sensors or switches while major repairs can include repairing or replacing key components on equipment like the gearbox, generator or the turbine’s blades. Major repairs often require a crane with a associated highly-specialized crews.

Greenwood explained MidAmerican has full-time technicians and supervisors who are assigned to each wind farm. Wind technicians are turbine manufacturer employees are under contract with MidAmerican who are specially trained on the equipment they oversee and repair. There are operations and engineering support teams and resources are at the ready for more major repairs, when they’re needed.

When asked about dismantling or replacing idled wind turbines, Greenwood instead said that inspections or maintenance will be made and each turbine will be returned to service.

“In each case, the timeframe depends on the issue,” he said.

Greenwood said MidAmerican’s priorities are returning any idled wind turbine to service as quickly and safely as possible so it can resume generating wind energy to customers.