Twenty-megawatt wind turbines are feasible, according to a new report from the European Union-funded UpWind project and published at the European Wind Energy Association (EWEA) 2011 conference in Brussels.
The UpWind project explored the design limits of upscaling wind turbines to 20 MW and found that they would have rotor diameters of around 200 meters, compared to some 120 meters on today's 5 MW turbines.
Such turbines could be a solution for expanding Europe's offshore wind energy capacity, providing several times more electricity at lower costs than today's turbines. EWEA forecasts that wind energy will meet 26% to 34% of Europe's electricity demand power by 2030, with almost as much electricity coming from offshore turbines as from those onshore.
Twenty-megawatt machines could be a cost-efficient way of reaching these levels of production. However, according to the UpWind report, the 20 MW turbine requires a new, innovative and tailored design to make it work.
‘UpWind found that making a 20 MW machine is not as simple as just upscaling today's 5 MW turbines,’ says Jos Beurskens of the Netherlands' Energy Research Centre (ECN), who led the project along with UpWind coordinator Peter Hjuler Jensen from the Danish Technical University Risoe DTU.
Beurskens believes that 20 MW turbines could be in operation by 2020 but that significant research is still needed. For example, fatigue loads on blades would have to be lowered in order to build longer and lighter blades. This can be achieved by doing the following:
– Fore-bending blades and using more flexible materials could lower fatigue loads by 10%;
– Using individual blade control could lower fatigue loads by 20% to 30%; and
– Putting the blade in two sections, allowing each to be controlled separately, could lower fatigue loads by 15%. It also makes it easier to transport the blade.
SOURCE: European Wind Energy Association