Abstract: When planning and setting up wind power installations, the visual detractions to be expected on the part of the wind power installation on the environment play an increasingly important part in approval and acceptance. The shadow casting caused by the wind power installation on the adjoining properties is often perceived by the residents as being very troublesome. A wind power installation is provided by means of which shadow casting regulation is improved. That is achieved by a method of operating a wind power installation wherein a first light intensity is detected in a region of direct light irradiation and a second light intensity is detected in a shadowed region, and wherein the wind power installation is shut down if the difference between the first light intensity and the second light intensity is greater than a predetermined value.