The first test installation of the new turbines took place last month at the onshore Westre windfarm in Germany near the German-Danish border. The three units erected stand at 100 metres high and will be extensively tested and subjected to a type certification for offshore deployment at a later stage.
"The load validation on our three test systems recently erected on the German-Danish border shows that the 6M is designed for operation with a continuous power output of 6,150 kW," said Matthias Schubert, REpower's chief technical officer. "These values have now been verified externally so that the REpower 6M, with its increase in rated power of 150 kW, is currently the most powerful turbine in the world."
The 6M has a rotor diameter of 126 metres with a hub height of 80-95 metres in offshore installations and 100-117 metres in onshore installations. For installations on the open seas, REpower claimed that 6M can supply power for up to 5,400 households.
The 6M has been constructed using the same dimensions as the REpower 5M turbines, allowing them to be used in all the projects that the 5M models have been allocated for. The 6M, like the 5M, will be produced in the Offshore and Logistics Centre in Bremerhaven, and from there, directly shipped to offshore installation locations. The 5M series was the world's most powerful turbine at 5 MW when it was first introduced in 2005 and, to date, they are used at 17 offshore installations.
"The REpower 6M will guarantee a bigger yield and therefore a better use of good wind sites," said Norbert Giese, Director of Offshore Unit of REpower, speaking to Industrial Info Resources about the benefits of the 6M over the 5M series. "A second target will be the higher economic efficiency compared to the REpower 5M. Improved technology better supports higher grid code requirements. We are looking for more onshore test sites for the zero series of REpower 6M."
Regarding compatibility, Giese said: "The transportation and installation of REpower 5M and 6M (turbines) are more or less the same. Because of the same dimensions in hub height, rotor diameter and dimension of the frame of the nacelle they could still be replaced (swapped out with each other) in the development phase."
It's likely the 6M turbines will be supplied in numbers to RWE Innogy, the renewables arm of German power producer RWE AG. REpower recently signed a major framework agreement with RWE Innogy to supply 250 5M and 6M offshore wind energy units between now and 2015. REpower will deliver the first 30 5M units by 2011 in a deal estimated to be worth $2.5 billion.
Most of the first 5M units will be installed at the offshore Innogy Nordsee 1 windfarm in Germany, which will boast between 150 and 180 turbines when it is finished. When operational, it will generate up to 1,000MW of power.