Following the detection of overheating in one of the sliding bearings in two of the nacelles of the six M5000 turbines installed in alpha ventus, Germany’s first pilot wind park, AREVA and its customer DOTI decided to replace them all as a preventive measure in order to guarantee continued strong performance.
- The six nacelles were successfully replaced in a short time and all six turbines are now back in operation. AREVA Wind’s offshore logistics ensures rapid restart after complete M5000 nacelle replacement, and thorough and effective preparation keeps downtime to a minimum.
- With quick reconnection to the grid, the six turbines can resume their robust performance. The six turbines have generated more than 92 GW since they were installed and commissioned at the end of 2009.
“The suitable weather conditions and the competence of the AREVA Wind team meant that the specially-designed maintenance concept could be put into practice for the first time”, declares Michael Munder-Oschimek, Managing and Service Director of AREVA Wind.
Dr. Claus Burkhardt, Director of Offshore Operations, Energy and Environmental Engineering at EWE, DOTI Director and Overall Project Leader of alpha ventus: “As the operating company, we are very pleased that despite weather-related delays, the nacelle replacement could be completed successfully in a relatively short time. Unfortunately, we recently had only ten turbines available. Now all twelve can once again supply the grid with power.
The need for repair work so soon after construction and commissioning was not due to genuine offshore-related problems but to overheating of the sliding bearings. Naturally, the offshore conditions in general, along with the logistics and weather conditions at sea, continue to be our main challenge – not only for construction and commissioning but also for nacelle replacement. Together with the contractor, AREVA Wind, we implemented the know-how we acquired during the construction phase to facilitate an expedient offshore solution. We are treating this nacelle replacement as a learning experience that can be used in future offshore projects and, presumably, incorporated into the production and maintenance concepts of turbine manufacturers."
Based on its experience, AREVA Wind will be building a test bench in 2011 so that every turbine can be tested under full-load conditions before delivery.