Industrial wind turbines can well exceed 400 feet and as a result, can post a hazard to aviation. The Federal Aviation Authority regulates aviation hazards in the United States. Generally speaking, the FAA requires that developers of structures over 200 feet file a Notice of Proposed Construction (Form 7460-1).
Wind project terrain and configuration factor into lighting requirements. It is not the case that every turbine for every project will be required to be lighted; indeed minimal lighting (which still guarantees safety) will likely be found to be desirable, if not required, by the surrounding community.
More from the FAA may be found here. Additional guidance may be found in the FAA OE/AAA [Obstruction Evaluation / Airport Airspace Analysis] Advisory Circular AC 70/7460-1K Obstruction Marking and Lighting.
History buffs will enjoy a 2005 preliminary report, “Development of Obstruction Lighting Standards for Wind Turbine Farms,” in which the FAA stated:
“The lighting concept for wind turbine farms includes the use of red, simultaneously flashing lights positioned on the outer perimeter of the wind turbine farm, each spaced no more than one-half statute mile from each other, and requires only one fixture per turbine. As long as the wind turbines are painted white in color, daytime illumination is not required.
“A test site was established in Lawton, Oklahoma, to validate the new lighting concept. Research personnel conducted repeated evaluation flights of the test site, and confirmed that the proposed lighting concept provided approaching aircraft ample warning that the wind turbine farm was a single, very large obstruction that should be avoided.” Only 17 of 43 turbines at Lawton were so lighted.