Around 8:50 pm, as the wind was gusting at over 100 km/h, the 6 turbines at a wind farm entered safety shutdown mode. On one of them, a blade became dislocated and slammed first into the tower then into another blade. Debris was strewn over a 160° radius up to 380 m, covering a 4.3-ha area. Travellers on the adjacent A16 motorway reported the accident at dawn. At the scene by 8:30 am, local police set up a safety perimeter. Driving speeds on the motorway were reduced to 90 km/h through the affected zone. The removal of damaged blades began on 9th January. The 5.4 tonnes of ordinary industrial waste, accounting for 35 m³, were evacuated using an appropriate service provider. A prefectural order required that all installations be shut off until repaired and subsequently tested to confirm their safety. Property losses were estimated at €800,000. The opportunity cost was evaluated at another €20,000 for each week of downtime.

Just prior to the accident, a 300-ms power supply outage on the 20-kV network caused extended shutdown of the site’s power station. This outage in turn triggered the turbines’ passive safety system (opening the solenoid valves controlling the hydraulic braking circuit). According to the site operator, the violent wind gusts (reaching 150 km/h) recorded on 3rd January were strong enough to damage the blade, generating forces that exceeded the tolerance threshold. The high mechanical stresses experienced when the blade abruptly stopped rotating led to its dislocation. The blade’s inner surface had become separated from the outer surface before striking the tower and then the other blade.

The destroyed turbine was the only one on the farm not equipped with a centrifugal force-driven, aerodynamic braking system installed at the end of the blade; it was properly equipped thereafter. This system mechanically protects the blades by reducing rotational speed before activating a hydraulic brake. Following this accident, the turbine clamping speed was temporarily lowered from 25 to 19 m/s.

This turbine model, installed in the early 2000’s, was involved in at least 2 other accidents (ARIA 29385, 38999).