Dong turbine strategy based on 6-8MW machines

Rotor diameter of 150-180m needed to be competitive

Wind turbines with a 6-8MW capacity and a rotor diameter of 150-180m are what the world's largest offshore wind developer, Dong Energy, is looking for as it plans its future turbine purchase agreements.

"We think this is what will be needed to be competitive," Uffe Jørgensen, Dong senior director for concepts and technology, told Windpower Offshore.

Dong signalled its commitment to increase turbine size at its future offshore projects last summer, when it announced a 300-unit framework agreement with Siemens for the latter's new 6MW 154m machine to be deployed in UK waters.

The relationship with Siemens is not exclusive. "Dong scouts all relevant turbine suppliers," said Jørgensen. "Yes, we have spoken with Chinese manufacturers, but so far their turbines are at a relatively early stage of development."

Talks with Chinese and other Asian suppliers of array cable technology are more advanced. Dong has recently received tenders for the supply of 66kV inter array cables from Asian suppliers, confirmed Jørgensen. Increasing the voltage and reducing the cost of inter-array cabling is a high priority for Dong, he added.