Experts assume that the offshore wind power market will enter its first phase of maturity from 2015 onwards with annual sales volumes of more than five gigawatts (GW). Says Richterich: “We have been preparing for this for a good two years.” Thus, the company has hired an experienced team of experts in its new business unit Nordex Offshore GmbH, which covers the complete off-shore value chain.
The preliminary result is the N150/6000, which has been developed specially for offshore use and is being unveiled in Hannover. With a rotor diameter of 150 meters, it has an installed nominal output of six megawatts, making it one of the largest and most efficient in the offshore market. The specific weight of the tower head has been kept low thanks to the use of a new kind of direct drive. This impacts not only the costs but also the loads to which the entire system is exposed.
“Out at sea in particular, we must do everything we can to optimize the technical reliability of the wind turbine. With cost structures differing to those in the onshore market, we are able to implement a more complex drive system, namely a direct drive", explains Thomas Karst, CEO of the Offshore division. However, a special and substantially lighter version is to be used – a direct drive with a permanent magnet generator and a full power converter.
Nordex is engineering this drive design in conjunction with experienced suppliers and thus relying on proven technical details. Only system suppliers able to deliver the entire generator/converter system and who are market leaders in this area are being considered.
Thanks to the modular system design, assembly and servicing at sea are possible with the systems already available today. If necessary, components can be replaced simply, quickly and without dismantling the rotor. A condition monitoring system facilitates preemptive maintenance of critical parts. In addition, Nordex can fit out the N150/6000 with a helicopter platform if requested by the customer.
Nordex has participated in a reference project in the German part of the Baltic Sea to expedite market access. Up to 70 N150/6000 wind turbines are to be installed here from 2014/15 onwards. Explains Richerich: “We are able to extend the preliminary experience which we gained with smaller turbines within a relatively short space of time and offer our customers a mature product.”