A Siemens spokeswoman was unable to give any details about the turbine or when it would be launched. However, she said it would be 6MW and direct drive.
However, according to reports and industry rumour, a prototype will be ready at the end of 2010 or early 2011. There is also speculation the turbine's capacity could be increased to a higher rating by the time it is ready for testing.
Manufacturers are arguably racing against each other to create bigger wind turbines. Proportionately higher O&M costs at involved using smaller capacity machines at sea make larger capacity machines more economical.
Among these, Repower recently launched its 6.15MW machine while Samsung is rumoured to be working on a 7.5MW product. Both of these will be dwarfed by Clipper Windpower's 10MW Britannia turbine and AMSC's 10MW SeaTitan.
With the output of offshore turbines continuing to rise, there is a question of whether the Siemens should be developing a larger capacity machine.
Garrad Hassan GL principal engineer Joseph Phillips said it is not necessarily a case of bigger is better when considering offshore. He said: "Both cost and risk need to be taken into account when determining the capacity of a new wind turbine product.
"With respect to the former, the most useful metric is some form of Cost of Energy, which takes account of capital and operational costs as well as energy production over a turbine's lifetime."
Phillips said Garrad Hassan believed the optimum offshore turbine capacity – when considering primary markets – was in the 5MW to 7MW range.
Other industry sources have said suggested Siemens is right to be conservative in its approach to the turbine's capacity. One view was that it would be less risky to make smaller steps in terms of product development by largely relying on tried and tested technology.
An alternative to this approach has been taken by Clipper, which is designing the 10MW Britannia turbine. Prior to this, its biggest product is the 2.5MW Liberty turbine.
