Nordex N90 Offshore exceeding annual energy yield expectations by 9 percent

Erected in summer 2003 off the Danish port of Frederikshavn in Kattegatt, the first offshore turbine to be built by a German manufacturer has generated roughly 8,000 MWh of wind power in its second year of operation, thus exceeding the expectations of the customer Elsam A/S. “In a normal wind year with an average wind speed of 7.8 m/s Elsam has estimated the annual production of the turbine at 7,800 MWh (at Grid). When taking the energy content of the wind for the production of the second year into consideration it corresponds to a production of 8,500 MWh in a normal wind year, i.a. approximately 9 % larger production than estimated” says Axel A. Petersen, project development management Wind at the utility Elsam A/S. At the moment, the turbine is even outperforming more powerful turbines in the same test field.

Since connecting the 2.3 MW turbine to the grid in June 2003, Nor-dex has been testing and continuously optimizing all the components used in the turbine as well as its overall response under realistic maritime weather conditions. Thus, in the past few months, the pilot turbine’s pitch and gearbox, among other things, have been modified to steadily increase availability. “The availability of the turbine has been continuously above 95 % in the second year. In general we are very pleased with the design, quality and function of the turbine. Also the installation of the emergency diesel generator ensures a fast and flawless restart of the turbine“, resumes Axel A. Petersen of Elsam.

Nordex has been plowing all the experience gained from the offshore pilot turbine into optimizing its N80/2500 kW and N90/2300 kW on-shore turbines as well as the development of maritime versions of these models. Nordex’s head of development Dr. Eberhard Voss is satisfied with the performance of the N90 in Denmark: “With the pro-gress made with the N90 range in Frederikshavn, we are able to offer our customers even more efficient multi-megawatt wind turbines. In fact, we will be unveiling a new-generation of the N90 with a greater installed capacity at the Husumwind fair in September 2005.”