The demand and need for alternative obstruction marking has become a significant challenge for the wind power development in Sweden. While the development of wind turbines pushes for higher heights, the need to denote them as possible obstacles for aviation increase. To reduce undesired effects of the aviation warning lights in the landscape, various technologies for reducing the light emitted have been developed. One of these technologies control the lights’ output by dimming them based on measurements of the prevailing visibility in the vicinity of the wind farm.Visibility controlled obstruction lighting has not yet been used in Swedish wind farms. This thesis will investigate how a system can be applied from different viewpoints and what would be gained in a wind farm in northern Sweden.By reviewing literature, interviewing key-persons, studying a case with application of Finnish regulations and estimating the performance during different conditions, and discussing the results, conclusions could be drawn. The findings are general recommendations for acceptance, an aviation risk that need to be considered, indications of preferable regulation applications and approximations of the performance and possible gain.

The overall purpose of the study was to examine the aesthetic impacts of wind farm obstruction lighting. The research problems investigated in this study were; aviation safety regulations for wind farm obstruction lighting in different countries, obstruction lighting technology, and the public attitudes towards wind farming. The research was designed taking into account the research problems, questions, and the researcher experience. Hence, mixed method approach was employed to collect as much, and as diverse data as possible. The sample was drawn focusing wind energy project developers, operators, and the owners. Seeking to build a detailed narrative, a web-based survey was conducted to gather the thoughts, and opinions of the sample population, in addition, to a thorough literature review conducted earlier. The key findings of this study are that the lighting system should be efficient to operate in terms of technology with least aesthetic impacts. Out-dated wind farm obstruction lighting systems are annoying, and contributes to overall aesthetic impacts that triggers nagetive attitudes towards wind farming. In addition, for wind farms near any aerodrome, infrared integrated into light emitting diodes obstruction lighting have minimal aesthetic impacts. Whereas, the radar-activated obstruction lighting is a better choice for wind farms further away from aerodromes. The study argued that understanding the affecting components of attitudes would give various stakeholders a realistic understanding about attitudes towards wind farming. This study concludes that the optimization of lighting angle, intensity, color, and luminance will help reducing the aesthetic impacts under the prevailing regulations, and mapping affective components of attitudes will help in better understanding the public support towards wind farming.