On 21 August 2018, the first of two N149/4.0-4.5 wind turbines with a nominal output of 4.5 megawatt was installed at the Wennerstorf II wind farm located roughly 30 kilometres south of Hamburg. “We are pleased to have completed this beacon project in time for the commencement of WindEnergy Hamburg 2018. In addition to our turbines at the port of Hamburg, the N149/4.0-4.5 in the vicinity of the Nordex main office in Hamburg is another impressive project with which we can demonstrate the Nordex Group’s state-of-the-art technology to our customers,” says Jörg Hempel, who is in charge of German business at Nordex Group.
The turbines in Wennerstorf II are just the beginning. Says Karsten Brüggemann, Head of Global Sales at Nordex Group: “We have received very favourable feedback from our customers. Many customers in Europe and other parts of the world have already included the turbines in the necessary approval procedures”.
Originally, the Wennerstorf wind farm consisted of four turbines, each with a nominal output of 1.3 megawatts, which had been producing electricity since 2003. In 2015 the developer ABO Wind decided to repower this site with the latest technology by replacing the old turbines with new ones. In doing so, it opted for the first turbine from the Delta4000 product series, the N149/4.0-4.5: With a total installed output of 9 megawatts, the capacity of the Wennerstorf II wind farm will increase by 73 percent.
New turbines must undergo extensive independent testing to obtain all relevant certificates. The site meets the requirements of IEC 61400 and offers wind conditions of approx. 6.5 meters per second on average. Consequently, it offers a good possibility to carry out the planned measurements of power performance, sound and electrical characteristics as well as the validation of the mechanical loads in the power mode with the maximum output of 4.5 megawatts.
The turbines are going to be equipped with radar-controlled aviation obstruction lighting due to their total construction height of 200 meters. The obstruction lights are only activated when an aircraft flying at an altitude of below 600 metres approaches the turbines within a radius of four kilometres. This avoids the need for continuous obstruction lighting during the night.
The N149 turbines are also well designed in terms of acoustics for increasing citizen acceptance, with a sound emission level of less than 106.1 dB(A) even when operating at full load. In addition, they can be operated in a variety of sound-optimized modes which can be set according to wind direction and the time of day to keep noise levels as low as possible.
Smart logistics solution for the transportation of the almost 73 meter rotor blades
Produced by Nordex itself, the single-piece rotor blade of the N149/4.0-4.5 measures almost 73 meters in length. The rotor diameter of 149 meters contributes significantly to the very low cost of energy and the high turbine yield. As with the predecessor models, the rotor blades of the N149 are made of carbon and glass fibre.
A sophisticated logistics solution for the transportation of rotor blades also celebrated its Nordex premiere with the installation of the new turbines at Wennerstorf II: in view of the length of the one-piece rotor blades, a dolly transporter was used in which the rotor blade, as the sole connecting element between the front and rear axles, also performed the function of a conventional low-loader. In this way, the rotor blades completed the 330-kilometre trip from the Rostock production facility to the discharge point close to the wind farm. There they were loaded onto a self-propelled multi-wheel – a steerable vehicle equipped with a tilting device that can elevate each rotor blade at an angle of up to 60 degrees. In this way, it was possible to manoeuvre the turbines at walking speed and remotely controlled past the dense forest to the construction site without any problems.
Nordex plans to commence series production of N149/4.0-4.5 in 2019.