First wind turbine for alpha ventus offshore wind farm installed

REpower wind turbine nacelles in Bremerhaven
REpower wind turbine nacelles in Bremerhaven

The REpower wind turbines have a blade tip height of 155 m above sea level. The first German offshore wind project is being built by a consortium of companies consisting of EWE, E.ON and Vattenfall. The alpha ventus offshore wind farm is located approximately 45 km north of the island of Borkum, Germany.

At the beginning of September 6 jacket foundations were anchored onto previously erected piles in water around 30 m deep. On one of these lattice structures, which are especially suitable for great water depths, the first REpower wind turbine was erected. Five additional wind turbines are scheduled to be installed by the end of the year.

“We expect that the first turbine will supply power to the electricity grid in the fourth quarter of this year," says Norbert Giese, Offshore Director of REpower Systems AG. "Of the 18 REpower 5M wind turbines already erected, we now have successfully installed 9 on the open seas, each in water up to 45 m deep.” Wilfried Hube, General Project Manager for the alpha ventus wind farm, adds: "Now that the first 6 wind energy turbines are already being placed into operation, we're in the final sprint to finish the wind farm by the end of the year."

The REpower 5M wind turbines have been specially developed for offshore installation. "We've placed a great emphasis on serviceability, for example. The components are generously designed and the turbines are intended to be serviced just once per year later," says Giese.

With optimum wind conditions, each of the 6 wind turbines is slated to supply the electricity grid with around 18 GWh of power per year.

Before erection on the open seas, the wind turbine hub and three rotor blades were first preassembled in the Dutch base harbour of Eemshaven to form a rotor star. Afterwards, all components of the first wind energy turbine – that is, two tower segments, one nacelle and the rotor star – were transported to the offshore construction site by means of a jack-up barge.

A new regional development plan was recently approved by the German federal cabinet. The resolution calls for the erection of 30 wind farms in the North Sea as well as 10 additional wind farms in the Baltic Sea. In total, the planned projects are targeted to have a capacity of around 12 GW, thus helping to achieve the climate protection targets of the Federal Government, which envisage that the percentage of power supplied by renewable energy will be increased to 30% by 2020 and around 25 GW of power will be supplied from offshore systems by 2030.