With a new and innovative technology, it is now possible to comply with exciting legislation on noise reduction during installation of offshore wind turbines.
According to legislation from the EU the sound emissions from the installation of windmills at sea must be reduced so the threat to the marine mammals are minimised. Traditionally, the water borne noise from driving monopiles into the seabed has not been reduced. But with a new and innovative technology it is possible to reduce the noise with up to 25 dB in a radius of 750 m. The technology is based on a cofferdam (patent pending), which comply with the recommended requirements of maximum: 160 dB SEL and 190 dB Peak for underwater pile driving noise levels. So far, Germany is the only country having ratified the legislation, but the remaining EU countries are expected to follow Germany’s example.
The technology is developed by Lo-Noise, founded in cooperation between Kurt Thomsen, creator and founder of A2SEA (world leader in installation of offshore wind turbines), and OSK-ShipTech (consulting naval architects with extensive experience in offshore wind projects).
The visionary thinking enables an installation process almost without delay as well as ensuring that the costs does not increase significantly by using the cofferdam from Lo-Noise. In Europe, the preferred foundation for offshore wind turbines is monopiles, which could result in an industrial adventure for Lo-Noise and their new noise reduction technology.
From the 15th to the 20th of December the cofferdam was tested in the bay of Aarhus, Denmark with very positive results. The cofferdam is the only technology that lowers the noise level with 25 dB and meets the requirements of the EU legislation. The cofferdam test was performed with the following companies: Grundfos, Trelleborg, Nikon, DBB, Rambøll and OSK-ShipTech.
Offshore WIND staff, January 10, 2012; Image: osk-shiptech