Comment by bluGill
Depending on which one, most of them don't have airplane warning lights. There have been extensive study, and if done right you can only light up a small number but because the lights are synchronized that is a better stay away indication than having a light one them all. (lights not synchronized is a disaster - too many lights to keep track of)
At first I questioned your assertion, but after reading the most recent FAA AC revision (https://www.faa.gov/documentLibrary/media/Advisory_Circular/...) I found:
13.5.3 In most cases, not all wind turbine units within a wind turbine farm need to be lighted. Obstruction lights should be placed along the perimeter of the wind turbine farm so that there are no unlit separations or gaps more than 1/2 SM (0.80 km) (see Figure A-26). Wind turbines within a grid or cluster should not have an unlighted separation or gap of more than 1 SM (1.61 km) across the interior of a grid or cluster of turbines