The damaged turbine at the Alpha Ventus offshore wind farm is set to be repaired with a replacement nacelle.
Preparatory work on the turbine will begin soon; the cause of the damage will be examined in detail on land after completion of the work.
It has been noted that the retaining bolts of the nacelle are broken and torn, but the cause of which is currently unknown. Due to the damage large parts of the nacelle housing of the AV 07 (the roof, sides and floor) had fallen into the sea on the 6th April.
Since then, the wind farm's other five wind turbines have been in standby mode as a precautionary measure and are blocked for maintenance work.
Works are expected to begin soon. Firstly, access to the AV 07 will be made with the help of a Service Operation Vessel (SOV), which has a hydraulic gangway designed for offshore use. Industrial climbers will secure or remove the technical components located outside the machine carrier or drive train housing to protect against falling.
Subsequently, the parts of the nacelle housing which fell into the sea will be recovered from the seabed. The nacelle and the rotor are rotated to a position that allows disassembly of the rotor and replacement of the nacelle.
The collected components will be examined in Bremerhaven to deduce the cause of the damage. The evaluation of the data recorded by the Condition Monitoring System is already in progress. The visual inspections of the other five turbines started last week - when exactly they will be able to resume electricity production is currently unknown.
Alpha Ventus was one of the first German offshore wind farms to be built. Since it entered operation in 2010, the project has produced enough electricity to meet annual consumption of around 71,000 average households (3,500 kWh) in Germany.
The project is owned by EWE, E.ON and Vattenfall and the research and development results from Alpha Ventus have been incorporated into the design, construction and operation of additional offshore installations, including Riffgat (EWE), Amrumbank West (E.ON), and DanTysk (Vattenfall).
For more information follow the links provided. Click here to view the project on our interactive map.