According to a report from the National Renewable Energy Laboratory (Table 30), depending on make and model wind turbines are predominantly made of steel (66-79% of total turbine mass); fiberglass, resin or plastic (11-16%); iron or cast iron (5-17%); copper (1%); and aluminum (0-2%).
Many turbine components are domestically sourced and manufactured in the United States. According to the Land-Based Wind Market Report by the Office of Energy Efficiency & Renewable Energy, wind turbine towers are 60-75% domestically sourced, blade and hub components are 30-50% domestic, and nacelle assemblies are over 85% domestically sourced. However, many internal parts such as pitch and yaw systems, bearings, bolts, and controllers are typically imported.
Learn more: Wind Energy