24 Mar 2011 10:03:23
20 MW turbines the way of the future
20 MW wind turbines are feasible and such turbines could be a solution for expanding Europe's offshore wind energy capacity, according to a new report from the EU-funded UpWind project. The association has projected that wind energy will meet 26–34% of Europe's electricity demand power by 2030, and says 20 MW machines would be a cost-efficient way of reaching these levels of production.
However, building a 20 MW machine is not simply a matter of up-scaling today's 5 MW turbines, says to Jos Beurskens of the Netherlands' Energy Research Centre (ECN), who led the project along with the UpWind coordinator Peter Hjuler Jensen from the Danish Technical University Risoe DTU. But Beurskens says that if the following design issues are addressed, the industry could see 20 MW turbines in operation by 2020.
Lowering fatigue loads on blades allows longer and lighter blades to be built. Loads can be lowered in the ways listed below:
• Fore-bending blades and using more flexible materials – this could lower fatigue loads by 10%.
• Using individual blade control – this could lower fatigue loads by 20–30%.
• Putting the blade in two sections (like an aeroplane wing), allowing each to be controlled separately – this could lower fatigue loads by 15%. It also makes it easier to transport the blade.
• The future smart wind turbine would be able to adapt its position and the pitch of its blade to local wind conditions.
• Wind farm layout.
• Lowering the power output of the first row of turbines allows for higher overall wind farm efficiency.
• Control and maintenance
• Putting sensors on one wind turbine allows the fatigue loading on the other turbines to be estimated if the relationship of fatigue loading between the wind turbines is known.
• Loads can be alleviated preventatively by evaluating the upcoming gust before it arrives at the turbine. A nacelle-mounted LIDAR is sufficiently accurate for wind energy applications.