Rotor blade coating



Project DKL-WEA

The availability of energy is a basic requirement for light, heat and motion. During the Stone Age, the discovery of fire led to continuous development of the human kind. Later, the growing demand was covered by fossil and therefore limited energy sources like coal and crude oil.
Nowadays, renewable sources like wind, solar or hydro energy open alternative approaches in order to cover the further increasing energy demand of the global population. In this context, particularly wind energy plays a major role. In 2015, nearly 4 % of the global power demand was covered by high-tech wind power stations.

At present, the amount of onshore plants is thereby predominating over offshore-ones. However, the decreasing amount of available onshore locations will cause a strongly increasing market for the offshore sector.

 

Besides the greater and more constant availability of the resource wind on the oceans, the onshore found negative disturbances like noise and shadowing get in the background for the offshore counterparts. This allows the planning and construction of bigger power plants for offshore deployment.

 

Offshore - obvious benefits but also challenges:

With increasing size of the rotor blade diameter, also the requirements with respect to the materials load capacity increase. In the case of failure, the repairing costs occurring offshore are a multiple over those onshore. Therefore, the costs of energy produced offshore are more than doubled when compared to onshore energy generation.
One main reason is attributed to the difficulty of accessibility, as many possible disturbing factors (waves, wind, additionally required equipment like ships with cranes etc.) complicate the planning and implementation of maintenance. This leads to a considerable amount of logistics and costs even for minor repair works.

 

Goal of development: Reduced maintenance costs by increased lifetime. Longer periods without maintenance mean an effective contribution to cost reduction!

The rotor blades utilized nowadays with length of more than 70 m can reach up to 350 km/h at the front, especially the edges are affected. The influence of erosion as a result of rain, salt, sand or hail is disastrous at such high speeds. To solve these problems, a durable and long-term stable coating was therefore developed within the research-project DKL-WEA. During this project, 3 partners from industry were working together with the faculty of engineering of the University of Kiel as research center.

 

The Phi-Stone AG (formerly FUMT R&D Functional Materials GmbH) and its project partners were able to develop a coating material with particular high load-bearing capacity. The polymer composite DKL-WEA is a solvent-free rotor blade coating system which bears onshore requirements, but which in particular resists the extreme demands for offshore-wind turbines.

 

The interaction of specially structured micro particles (CSP - Core Spike Particles) and additives with an extremely stable and UV-resistant full-solid polymeric matrix leads to an end product, which strongly exceeds the lifetime of conventional rotor blade coatings.

 

In order to guarantee the quality and lifetime of the DKL-WEA coatings, a testing method was established in collaboration with the company IRATEC GmbH which simulates offshore conditions on a laboratory scale. Besides conventional erosion and abrasion analysis, this method allows the depiction of a water droplet which impinges on the rotor blade or its edges at speeds of more than 800 km/h.