Materials in Wind Turbine Blades

As the technology and popularity of wind power increases, researchers work to find materials that can be used to create longer blades without sacrificing structural integrity. Many materials have been used, both for industrial wind power production and in small domestic applications. These include fiberglass, steel, aluminum, PVC, wood and polymer resin. Currently, most blades are glass-fiber reinforced plastic (GRP), a fiber-reinforced polymer composite with both a high tensile strength and a high compression strength.

Polyvinyl Chloride (PVC)

• PVC blades are an inexpensive blade option commonly used by do-it-yourself turbine builders. One advantage of the material is the ease with which the builder can shape it. It is also comparatively inexpensive, which makes it attractive to budget-constrained operations. However, when exposed to the elements, PVC constantly weakens until it becomes very brittle and forms tiny hairline cracks on the surface. The result is that an errant breeze could crack the blade and shut down the turbine.

Wood

• Wood is another common material for small, homemade, domestic windmills. While it is a readily available, inexpensive material, wood poses several problems for the home windmill builder. Wood requires a great deal of skill to shape accurately. If it is not properly treated, wood is extremely susceptible to weather, warping with moisture or becoming brittle in the sun. In addition, wood is not very resilient under lateral stress, so heavy winds can snap a wooden blade with little difficulty.

Aluminum

• Aluminum blades appeared soon after the domestic wind power industry exploded. Many manufacturers offer precision-built aluminum blades. While most large-scale generators do not use these blades, they are an excellent material for small turbines. While they are relatively heavy compared to plastics, aluminum blades are weather resistant, resilient and available from many suppliers. The down side is that they are more expensive than other options. Additionally, the maximum rotor diameter is strictly limited by the material's weight.

Composite Materials

• Composite materials, such as fiberglass and GRP, are currently the most commonly used materials in wind turbine construction. Fiberglass is generally only used for small, domestic applications, because fiberglass tends to be more fragile than other fiber-based materials. That makes fiberglass a liability for commercial purposes.

  GRP (glass-reinforced plastic) is similar to fiberglass in that engineers create it by layering multiple fiber meshes to create the shape of the blade. Generally, the GRP is used as a coating layer, with a filler inside the structure. It has the advantages of being lightweight, which assists in the movement of large rotor blades. It is also stronger than fiberglass, which allows for a wider rotor diameter without risking fractures at high wind speeds.