Wind turbine blades are exposed to strong winds, rain and UV radiation, while spinning at high speed, all of which impose heavy demands on the blade coatings. Pär Jörgensen, Technical Market Development Manager at Perstorp, explains how Capa™ can help reduce the need for costly, time-consuming recoating.
Which demands are wind turbine blades subjected to?
Windmill blades are typically very long and rotate at high speeds. The radius can be as much as 60-80 metres and in strong winds the tip of the blade can rotate at a speed of up to 300 km/h. At the same time, the blades are also exposed to gruelling weather conditions, such as rain and hail, as well as temperatures well below freezing.
Why is a good coating important?
It is estimated that the cost of recoating a wind turbine after assembly onsite is ten times higher than the cost of the original coat. The reasons for this are obvious: coating in the factory is in a controlled environment where the blades are lying down, whereas coating onsite is complicated and risky. So, if you can prolong the lifetime of the coating, it makes a huge difference and enables a significant amount of money to be saved.
What properties make a good coating for wind turbines?
Mechanical properties like abrasion resistance, impact resistance and flexibility are very important, especially in tough conditions. The coating should also have good UV resistance, as sunshine will eventually degrade it.
How can Capa™ help?
Capa™ can improve impact resistance and flexibility and, because of its low Tg, it is able to maintain these properties at low temperatures. Capa™ has also performed very well in the rain erosion test – an industry standard test that depends on both excellent impact and abrasion resistance.