Abstract
Current (2023) and projected future (2030) underwater noise conditions were modelled for Danish marine waters, to understand the relative contribution of future offshore wind development on cumulative underwater noise levels. Underwater noise was modelled for three areas surrounding Denmark separately (North Sea, Western Baltic, and Bornholm) in two or three frequency bands centered at 125 Hz, 315 Hz and – for North Sea - 500 Hz. The results showed that expanding offshore wind energy in Danish marine waters is likely to negatively affect the indicators used to assess Good Environmental Status in the framework of the Danish Marine Strategy, thereby making it more difficult to achieve and/or maintain Good Environmental Status. Underwater noise from operation of offshore wind farms should be included in future assessments of new projects and appropriate measures to reduce the radiated noise levels, particularly from services vessels, should be considered. However, the main contributor to the continuous noise indicators is likely to remain commercial shipping.