I got opportunity to visit Det Nationale Testcenter for store Vindmøller (The national test center for large windmills) as part of INFRASTAR 3# training week held at Aalborg University.
This is a test center in northwest part of Denmark 7 kilometres from North Sea in a place named Østerild. The location is chosen close to seacoast to simulate the conditions at offshore, however the location should be easily/cheaply accessible for technicians for improving the performance of prototypes. These multi-megawatt turbines, if installed at sea, it would be difficult access and to install them. However, on land they can be installed easily by gigantic land cranes specially designed for this purpose at very cheap cost.
To test large wind turbines there is need to atleast 8m/s (~30kmph) wind speed at 100 m height above sea level. Which is available here owing to the flat topography of the area.
This is the only place in the world big enough to test next generation wind turbines. This place can be visited by tourists, school going children. At office of the test center they have very nice prototypes of wind turbines, a lot of videos showing how a wind turbine is installed answering all queries.
Also they placed a small wind testing tunnel for a layman to understand how models of wind turbine are tested in laboratory.
This specific wind turbine in test center is equipped with direct drive technology where gear box is not present and main shaft is directly attached to generator saving a lot of maintainance cost where this industry observe a lot of failures in gearboxes.
However, this direct drive technology comes up with heavy weight of Nacelle putting more load on tower structure. Here concrete tower is used to support the wind turbine to save cost as steel tower would be a costly affair.
I am very happy that I am working as an ESR for INFRASTAR project where I get opportunity to work in Denmark (world leader for wind turbine technology). Keep following my blog for all recent updates.