First REpower turbine goes up at Germany's 60MW Alpha Ventus

The first of six REpower 5M turbines to be erected at Germany’s Alpha Ventus offshore project has gone up, with the full 60-megawatt (MW) wind farm on track to be exporting electricity by the end of the year, according to its developers.

The €250m ($366m) Alpha Ventus is unusual in that it will use six turbines made by REpower and six by Multibrid, a subsidiary of French nuclear giant Areva. Its developers are using it as a way of testing the durability and efficiency of two types of turbines and foundations in the harshest and deepest conditions ever seen for an offshore wind farm.

Since early September Norwegian contractor Norwind has been using the crane ship Thialf to install the six jacket-style foundations that will hold the REpower turbines in place in the North Sea.

The jacket foundations, built in Scotland, were adapted from the design of the OWEC Tower showcased at the Beatrice Demonstrator put up in the UK’s North Sea in 2007.

While the REpower turbines are being installed onto jacket foundations, the Multibrid M5000 units have been installed onto tripod-style foundations by the jack-up barge Odin. In August, the first three Multibrid turbines began flowing juice to Germany’s grid.

Alpha Ventus is being developed by Deutsche Offshore-Testfeld und Infrastruktur (DOTI) – a consortium comprising Vattenfall, E.ON and EWE.

Wilfried Hube, general project manager at Alpha Ventus, says that while things are running more or less on schedule, “we’re in the final sprint to finish the wind farm by the end of the year”.

The first REpower turbine put up at Alpha Ventus stretches 155 metres above sea level to the tip of its blade. It is one of only 18 of REpower’s 5M turbines to be installed worldwide, and the ninth to be put up at sea.

After being built at REpower’s new manufacturing hub in Bremerhaven, Germany, the hub and three rotor blades were pre-assembled in the Dutch port of Eemshaven. The components were then transported to the offshore site on the JB-114 jack-up barge.

On 16 September Germany’s cabinet approved plans for 40 massive offshore wind farms – 30 in the North Sea, and another 10 in the Baltic Sea. Of these, 25 have already been approved. The approval comes as part of a new strategy meant to double the country’s wind capacity by 2020, and create a foothold in the rapidly emerging offshore wind industry.