Wind Energy will form an increasingly important part of our energy mix. Power generation via this exciting renewable technology will treble in the UK between 2012 and 2020 and it is estimated that there are already over 100,000 operating wind turbines in the World.
The coating system for the rotor blades provides a range of functions:
1) Coatings protect the composite substrate from moisture ingress which causes deterioration of epoxy resin matrices. Water ingress can also freeze and cause expansion cracking and failure of the composite. As rainwater can also contain dissolved chemicals such as SOX, NOX and acids; the coating protects the substrate from contact with these potentially harmful substances.
2) Coatings protect the epoxy substrate from UV degradation which would otherwise shorten the working life of the blade.
3) Coatings protect the composite blade from erosion damage caused by rain, hail, salt, grit and other airborne particles which would erode the composite substrate, eventually requiring significant repair or replacement of the blade.
4) A smooth surface promoting efficient airflow is essential to the efficient operation of the blade. Imperfections and unwanted surface profiles can interfere with air flow resulting in vibration and reduced efficiency. Surface fillers and coatings form a smooth and even surface for maximum efficiency. Harmonics and vibrations can affect the yaw system and gearbox, resulting in substantial inefficiency and potentially expensive service work. This is even more evident in larger blades.
5) Coatings allow the colour of the wind turbine to be controlled. Usually this allows an unobtrusive, even, (typically grey) colour to be selected, which minimises the visual aspect of the turbine. It also allows marking colours such as red to be applied where necessary as a warning.