According to legislation from the European Union (EU), sound emissions from the installation of windmills at sea must be reduced so the threat to marine mammals is minimized. Until now, no efforts have been made to reduce the water-borne noise from driving monopiles into the seabed. With a new and innovative technology, it is possible to reduce the noise by up to 25 dB in a radius of 2,500 feet. The technology is based on a cofferdam that complies with the recommended requirements for underwater pile-driving noise levels. So far, Germany is the only country to have ratified the legislation, but the remaining EU countries are expected to follow suit.
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 A/S (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 do not increase significantly
by using the cofferdam system. In Europe, the
preferred foundation for offshore wind turbines is monopiles.
The cofferdam recently was tested in the bay of Aarhus,
with very positive results. The cofferdam is the only technology that lowers
the noise level by 25 dB and meets the requirements of the EU legislation. The
cofferdam test was performed together with the following companies: Grundfos,
Trelleborg, NICON Industries A/S, DBB, Rambøll and OSK-ShipTech.