http://www.newenergyworldnetwork.com/renewable-energy-news/by-technology/wind/wind-turbines-up-to-20mw-are-feasible-report.html

Ultra large 20MW wind turbines are feasible, according to a new report from the European Union-funded UpWind project, despite their mammoth size and obvious weight issues.

The project, which explored the design limitations of upscaling wind turbines to 20MW, found they would have a rotor diameter of about 200 metres, compared to the 120 metres often seen in 5MW models.
The researchers said such a turbine would be a solution to the rapidly evolving offshore wind sector.
The European Wind Energy Association has forecast that wind energy will meet between 26 per cent and 34 per cent of Europe’s electricity power demand by 2030, with offshore wind accounting for almost as much output as the more established onshore wind parks/
Jos Beurskens of the Netherlands’ Energy Research Centre, who led the project along with the UpWind coordinator Peter Hjuler Jensen from the Danish Technical University Risoe DTU, said, ‘UpWind found that making a 20MW machine is not as simple as just upscaling today’s 5MW turbines. We identified key innovations to the design, materials and way the turbine is operated.’
Among the innovations are lowering fatigue loads on blades to allow lighter blades to be built, using individual blade control and adapting the turbines pitch and position to allow for higher overall wind farm efficiency.