According to a report from the National Renewable Energy Laboratory, wind turbines are predominantly made of steel (71-79% 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 (Wind Technologies Market Report). Wind turbine towers are 65-85% domestically sourced, blade and hub components are 40-70% domestic, and nacelle assemblies are over 90% domestically sourced. However, many internal parts such as pitch and yaw systems, bearings, bolts, and controllers are typically imported.
Learn more: Wind Energy