Abstract
In this study we assessed the possible impact on marine mammals of noise from the Hywind Tampen wind turbines. Measured data from Hywind 1 were used as the basis of the assessment. The sound from Hywind 1 was measured over a period of several month being representative for a variety of weather and operational conditions. The sound was measured at 150m distance from Hywind 1 and at a control station about 10k away with otherwise quite similar conditions. The work at Hywind 1 was analysed and reported by a renowned third-party consultant called JASCO. It was not easy to detect sound from Hywind 1 in the surrounding of other natural and anthropogenic noises, a clear sign that Hywind 1 only created a relatively low sound level. Sound at low frequencies, 25Hz, 50Hz and 125Hz, was detected that was attributed to the revolution of the rotor and the gear. For this study a scaling factor was used to account for the more powerful wind turbines that will be used at Hywind Tampen. Suggestions made in a report assessing the noise input from Hywind Scotland by consultant company Xodus were followed. At Hywind 1 a short transient sound was detected, most probably originating from the mooring system, it was describes as a “snapping” broadband sound that occurred occasionally. This transient sound was clearly detectable at Hywind 1 but is not known if this sound also occurs on other Hywind installations with a modified design. For completeness it has been included in this study.