Using Acoustic Deterrent Devices (ADDs) during offshore wind farm construction is as an effective method for protection of minke whales, according to a study conducted through a joint industry project.
Previous studies have demonstrated that ADDs effectively deter seals and harbour porpoise, however, until now there has been little research into the use of ADDs as a deterrent for minke whales.
The Offshore Renewables Joint industry Programme (ORJIP), with funding from innogy, Ørsted, and Statoil and managed by the Carbon Trust, confirmed that minke whales showed a clear response to the tested ADD, demonstrating the effectiveness of the technology. During the field research whales were observed to display a clear and sustained movement away from the ADD deployment site, adopting faster swim speeds with more directed movement.
The detection of marine mammals is currently carried out by marine mammal observers posted offshore, or passive acoustic monitoring (PAM). If a marine mammal is detected close to an offshore wind construction site, piling for foundation installation will not commence until it is deemed that there are no longer marine mammals within the predefined zone.
The ability to use active acoustic systems to create a temporary safety exclusion zone around the turbine is a useful addition to the suite of mitigation options for wind farms developers. In particular, it increases confidence that marine mammals are adequately protected when operating in harsh conditions or poor visibility, and also avoids the need to unnecessarily delay construction operations, the Carbon Trust said.