Reported wind turbine blade separation lands in Iowa cornfield

What happened

A letter to the editor in the Jacksonville Journal-Courier reports that a blade from a wind turbine in Adair County, Iowa, separated and was found in a cornfield. The letter cites a KCCI-TV report made before 18 September 2020 and describes the blade as 177 feet long and weighing 18,000 pounds, as stated by the letter writer. Nobody knew exactly when the blade separated. The letter calls this the third blade failure for MidAmerican Energy, with the two earlier failures attributed to lightning.

The letter puts questions about setbacks, lightning protection, landowner compensation and remote monitoring to the Lincoln Land Wind/Apex project. No operator response, official finding or cause for this separation is reported in the source.

Contributing factors

The letter states that two earlier blade failures for the same operator were attributed to lightning, and asks why lightning damaged a blade. No cause for this separation is reported in the source.

Lessons learned

1. Set turbine setbacks against a worst-case blade separation, not only normal operating loads.
2. Where earlier blade failures are linked to lightning, check lightning protection across the fleet, not only on the failed turbine.
3. Confirm that remote condition monitoring raises an alarm promptly when a sudden imbalance follows a blade separation.
4. Clarify compensation and insurance arrangements for neighbouring landowners and tenant farmers before an incident.

More lessons on structural integrity and turbines, weather and external hazards, emergency response and public communication, from every incident on the register.

Source

myjournalcourier.com