Strong winds delay Horns Reef repairs

Unseasonably windy weather has slowed Vestas down on its retrofit of 80, 2 MW turbines at the Danish Horns Reef offshore wind farm. Half the turbines remain to be fixed, according to Søren Vestergaard of Danish utility Elsam, the plant owner.

With wind turbines offline for longer than expected, production losses are mounting. New talks are being held between Vestas and Elsam over compensation payments for Elsam's lost income. Production was guaranteed by Vestas in the turbine supply contract. The company will not necessarily feel the full economic impact of the delays. The contract contains a force majeure clause, also covering the weather, and Vestas is expected to have accounted for the risk of losses in its insurance.

The exact sum involved is not being revealed by either Vestas or Elsam, but the estimated annual production of each wind turbine is four million kilowatt hours. If each turbine is out of operation for a month of average winds, the loss amounts to 26 million kWh, worth about $1.5 million. Added to that is the cost of the retrofit.

The timetable began to slip in September, when winds blew 20-25% harder than usual for that month -- a factor which increased the earnings lost by turbines not online. Completion of repairs has been reset for the end of the year -- depending on the weather -- about two months later than originally planned.

Vestas began the retrofit operation in July. The rotor and nacelle of each turbine are taken down and shipped to shore, with the nacelle further transported to one of two of Vestas' works in Denmark, either close by at Ringkøbing or across the country at Nakskov. Repairs or replacement of faulty components are carried out in co-operation with Vestas' suppliers -- mainly ABB. It made the faulty transformers and generators. Once the work is complete, the nacelle and blades are shipped back to the Horns Reef site and remounted on the tower.