Spring - time to build turbines

The wind turbine building season is here again and the Härnösand dock is full of part towers and huge blades.  They arrive here by specialist boat, (See extra) coming from Denmark or Germany and are stored on the dock until their specialist transport lorries can take them to their hilltop, usually in the middle of the night. 
Wings always leave eddies in their wake, especially near the tips, and this reduces efficiency. Eagles and vultures have a collection of feathers fanning out from their wing tips to reduce these swirling eddies. The sawtooth edge on the end section of the rotor blades does the same job, as well as making for a more interesting photo.