Underwater noise during the construction phase of offshore wind farms

The potential of offshore wind energy within the energy transition is growing rapidly. The construction phases of offshore wind farms generate harmful underwater noise, but the impacts of this noise on the marine environment have not been fully understood.

Underwater noise can affect marine animals by masking important environmental sounds and communication and by causing stress, behavioural changes, hearing damage, and other physical injuries. The characteristics and levels of underwater noise vary depending on the construction phase. Pile driving and explosions generate loud impulsive noise, while increased vessel traffic raises continuous low-frequency noise throughout the construction process. At its most severe, underwater noise can cause direct or indirect mortality in marine animals. However, mitigation measures can reduce construction phase noise levels and minimize their impact on the marine environment.

The aim of this report was to gather current knowledge through a literature review on the noise levels during the construction phases of offshore wind farms and the effects of underwater noise on the marine environment. Based on the literature review, an assessment was conducted to estimate the construction phase impacts of the Navakka Offshore wind farm project on the marine environment.