Hydroacoustic measurements of the radiated noise from Wave Energy Converters in the Lysekil project and project WESA

• Field measurements of the hydroacoustic noise from Wave Energy Converters (WECs) in the Lysekil project at Uppsala University and the Project WESA (joint effort between Uppsala University (Lead Partner), Ålands Teknikkluster r.f. and University of Turku) are presented. Anthropogenic noise is increasing in the oceans world wide and wave energy conversion may contribute to this noise, but to what extent? The main objective in this study is to examine the noise from full scale operating WECs in the Lysekil and project WESA. Acoustic measurements were made in order to be able to estimate potential environmental impact. Submersible recording devices (SRD) were deployed at 1 m from WECs at a depth of approximately 24 meters. Both WECs are a full scale point absorber with a directly driven linear generator, placed on gravitation foundations at the seabed with a connected buoy at the surface that absorbs energy from the heaving waves. The SRDs used to measure the noise from the WECs, consists of a SM2-recorder from Wildlife Acoustics and hydrophones from High Tech Inc. (HTI 96 MIN and HTI 99 HF). Measurements at in the Lysekil project were carried out in the spring of 2013 and in the project WESA in Jan-Feb of 2012. Preliminary results show that the main operating noise radiated from the WEC are short transients with instant rise time when the translator moves past the stator and when the stator hits the end stop springs of the generator. Most of the power in the noise is between 20 – 1000 Hz.

Nyckelord

Wave Energy Converter

Underwater noise

renewable energy

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