The controversy concerns between 200 and 300 NEG Micon 750 kW turbines equipped with a Jahnel Kestermann model PSC-1000 gear unit. About 100 of these turbines are in Denmark, with the remainder in operation abroad.
A year ago the owners association established that gear units in about 30% of the turbines in Denmark had been replaced -- half of these because of defective bearings. The replacement unit, PSC-1001, is an improved version in which one of the bearings has been strengthened. But the association's technical consultant, Strange Skriver, has discovered that not all the gear bearings that were damaged in the old gear unit have been strengthened in the new one that Vestas is now offering customers.
In several meetings with Vestas, Skriver has pointed out that the new PSC-1001 gear unit does not live up to normal quality standards and will likely have a short lifetime. Vestas insists the unit is good enough. It has given wind turbine owners three choices if their Jahnel Kestermann gear unit or one of its bearings fails: a retrofit of the failed bearing for EUR 8270; a replacement of the original PSC-1000 unit with a PSC-1001 unit for EUR 76,640; or replacement of the Jahnel Kestermann gear unit with a PEAC 4300.5 from Flender/Windergy with a price tag of EUR 78,330.
The owners association has taken the unusual step of publicly warning its members not to accept either of the two cheapest solutions. "We find it incomprehensible that Vestas is offering a gear unit which the company knows does not to live up to the operating lifetime requirements expected of a wind turbine. In selling such an expensive component with such a poor operational life, we find that Vestas has relaxed its quality standards," states Skriver.
Vestas executive vice president and former head of NEG Micon before its recent merger with Vestas, Torben Bjerre-Madsen, says Vestas has no further comments on the matter.