Early off-shore unreliability and availability

The first large offshore wind farm in the world, consisting of 80 Vestas V80-2MW wind turbines each of 5,027-m2 swept area, was completed in 2002 in 6-14 m of water in the North Sea at Horns Rev, 14-20 km off the West Jutland coast of Denmark. The project was managed by the West Danish utility Elsam, then DONG Energy, now Oersted and the wind farm is connected via an offshore substation using 30-kV AC collector cables and to shore from the substation via a 150-kV AC export cable. Maintenance of the wind farm was conceived on the basis of using helicopters' access to individual wind turbine nacelles via specially designed access platforms built onto the nacelles to accommodate drops and lifts from the Eurocopter EC135.