Assessing Light Environmental Impact in Offshore Wind Farm: A Case Study of Aphae and Jangbogo Areas in South Korea

Renewable energies, particularly solar and wind power, are gaining prominence in the shift towards a carbon-neutral climate. however, challenges for wind power include ecological disruption, coastal landscape degradation, and visual impact due to offshore turbine installation. Technological limitations currently dictate offshore wind turbines' placement 10 to 30 kilometers inland, raising concerns about light environmental changes affecting nearby coastal areas. This raises concerns about the potential impact of light environmental changes such as the effects of aviation obstruction lights on wind turbines and blade movements on inland areas close to the coastline.  Therefore, developing offshore wind farm plans analyzing the impact of light environment changes and proposing mitigation measures is crucial.
In this study, we analyze the light environmental impact of wind power and propose mitigation measures to minimize its effects on the planned offshore wind farms in the South Sea's Aphae area, surrounded on three sides by sea and offering favorable conditions for marine renewable energy development, and the West Sea's Jangbogo area in South Korea.
The assessment utilized 2022 Day and Night Band (DNB) satellite imagery from the VIIRS sensor to evaluate light pollution. QGIS was subsequently employed to analyze visible frequency, turbine shadow impact range, and distance from the power generation site, resulting in a light environment value assessment map. Key points were identified on the map, and the study further examined the influence of turbine blade movements on aviation obstruction lights and shadow flickering using QGIS and WINDPRO.
As a result of measurements using VIIRS satellite images, the light pollution levels at the Aphae and Jangbogo sites were found to be approximately 0.631542 × 10-9 W/cm²sr and 0.38 × 10-9 W/cm²sr, respectively. In Aphae, the impact of light pollution was generally minimal, less than 0.002 cd/m², but it did have an impact in the northern coastal area. Jang Bogo measured less than 0.002 cd/m², indicating a low impact on island residents.
As a result of light pollution analysis, it was found that shadow flickering occurs for 30 to 60 minutes a day for more than 120 days a year in the northern coastal area of Aphae. Jangbogo showed very limited shadow flickering, less than 10 hours per year and less than 10 minutes per day in certain areas. The impact of light pollution is expected to be minimal in Jang Bogo, and mitigation measures are needed to alleviate pressure damage. Recommendations may include adjustments to the layout of offshore wind farms or changes to the coordination of offshore wind operations.
This study is significant in analyzing the impact of light environmental changes caused by offshore wind power on inland areas and proposing mitigation measures. Furthermore, the findings of this research can be applicable to environmental studies for the development of offshore wind farms in other regions in the future.

Acknowledgement

This research was supported by “Development of Advanced Science and Technology for Marine Environmental Impact Assessment” of Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (20210427)