How Are Wind Turbine Blades Made?

Blades are among the most important elements of a turbine.

Wind turbine blades must be strong, light and capable of operating for decades without much, if any, maintenance. And of course, they must be capable of handling the nuances of the wind over a long period of time.

Fiberglass

Fiberglass is also used in the manufacture of boats.

Fiberglass is one of the main components of many large-scale wind turbine blades. Fiberglass is a woven glass material made with glass and resin. The material is used because it is lightweight, easily shaped and not too expensive. Believe it or not, turbine blades are between 70 and 75 percent glass. Fiberglass has been used extensively in the manufacture of wind turbine blades since the 1970s.

Carbon-Fiber and Other Materials

Carbon fiber can help enhance stiffness in long blades.

Another material used in longer turbine blades is carbon fiber. This material is too expensive to use throughout the blades, but on the longer blades it's used to help reinforce them because of its stiffness and lightness. Since fiberglass is less expensive, it is used more often than carbon fiber. Blades can be filled with honeycomb materials or foam to help enhance stiffness.

Making the Blade

The wind turbine blades are formed in two halves. Separate molds are made for each half of the turbine blade. Then the halves are formed using sheets of fiberglass. After they are formed, they are removed from the mold and glued together.

Shaping the Blades

Most utility-scale turbine blades are made using vacuum infusion. Sheets of fiberglass are laid out in a mold, then a vacuum bag is attached, the air is sucked out and resin is pumped in. After that, all air is pumped out, ensuring that no air bubbles can get in to damage the fiberglass. This process can take up to 24 hours for larger blades.

Sanding and Finishing

Like this window frame, turbine blades need to be sanded until smooth.

After the mold is removed, the blade is checked for imperfections. Then it is sanded down until smooth and finally painted with special paints to ensure that the blade is resistant to UV rays and weather.

References

• Plastics Technology: Composites Wind Power Blades Energize Composites Manufacturing
• YouTube: Vacuum infusion of small Wind Turbine Blade