Vestas investigates fourth blade failure at Iowa wind farm since 2019

MidAmerican Energy halted 46 turbines at its Beaver Creek wind farm in Greene County, Iowa, on 15 October 2020 after a turbine blade broke away and fell into a harvested field. This was the fourth blade failure the utility experienced since October 2019, all involving blades manufactured by Vestas. The utility said the broken blades had been exposed to a direct or nearby lightning strike. The idled turbines, mostly rated at 2 MW each, meant more than 90 MW of generation was taken offline temporarily. Following inspection, most turbines were returned to service after confirming no blade damage, while some remained offline for blade repair or replacement. MidAmerican and Vestas said they were working together to determine the root cause and implement corrective measures. Injuries were not reported on in the source.

MidAmerican stated the affected blades had been exposed to a direct or nearby lightning strike. Vestas said it was inspecting turbines within proximity to significant lightning events under its established lightning inspection protocol, noting that while lightning protection systems normally prevent damage, some risk cannot be fully eliminated in severe events. The root cause analysis was still ongoing at the time of reporting.

1. Operators of wind fleets should maintain lightning inspection protocols that pause turbines during and after storms to check for blade damage before restarting.
2. Repeated blade failures sharing a common suspected cause warrant a formal root cause investigation involving both the operator and the original equipment manufacturer.
3. Falling blade debris, even in unpopulated areas, is a safety hazard that should inform site access controls and inspection triggers after severe weather.

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