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1999
Conference Paper
Titel
Reliability assessment of wind turbines in Germany
Titel Supplements
Results of the national "250 MW Wind" programme
Abstract
Plausible evaluations concerning the reliability and operating costs of Wind Turbines (WTs) can be determined only after several years of operation. The German subsidy measure "250 MW Wind" is accompanied by a scientific programme, which evaluates the technical and financial experiences of the supported WTs. The programme began in 1989, so that the long experience of several turbines is now available. In the following, it is shown that technical availability of WTs increased significantly in the first operational years. Down times, following malfunctions of certain components, were especially reduced by improved service. The increasing availability, however, can also be traced to decreasing failure rates in early operation. The annual number of malfunctions in the fifth year of operation, is only half as high as in the first year. Obviously, insufficient constructions and faulty fabrications could be corrected in this time. Operating costs, however, do not follow this tendency. With expiry of guarantee periods, after the second operational year, the repair costs particularly increase. The total operating costs are doubled in this time.