Antwerp, Belgium, November 13, 2015 – During the building of offshore wind turbines, a lot of noise is produced under water, which is harmful for marine life. To protect sea mammals a bubble curtain is placed around the site. The oil-free air needed for this curtain is supplied by Atlas Copco Rental. Recently 13 oil-free air compressors were used during the Gode Wind project in the North Sea.
Building offshore wind parks: a noisy business
The building of these wind turbines requires a firm and stable foundation. This because the offshore turbines are exposed to extreme weather conditions such as heavy wind and strong current. For the foundation of one wind turbine, 3 to 4 piles have to be driven into the seabed. Each pile weighs 250 to 420 tons and has a length of 86 m, of which 35 to 40 m needs to be hammered into the ground. During hammering the underwater noise level is more than 160 dB (A) with a speed of up to 1500 m/s.
Air bubbles reduce underwater noise level with over 90%
These sound levels are five times higher than in open air, and can harm and even kill sea life. Even little increases of the underwater sound level can disorient dolphins and whales, who communicate through ultrasound, making them drift away from the waters where they find their food and feed their young. To reduce the underwater noise levels, a so called “bubble curtain” is placed at the bottom of the sea, around the construction site. This bubble curtain can reduce the noise levels by more than 90%, thus protecting sea life.
100% oil-free air to produce bubbles
The air to produce the bubbles is supplied by 100% oil-free air compressors of Atlas Copco Rental. Before installation of the hammer, a perforated hose is placed around each pile on the seabed. This hose is connected to an compressor. When it starts up, small air bubbles are released from the perforated hose, creating a bubble curtain from the seabed to the surface.
13 oil-free air compressors for Gode Wind project in North Sea
100% oil-free air produces high-quality bubbles and guarantees no oil pollution of the sea water. In total, 10 to 16 mobile oil-free air compressors of the type PTS 1600 are installed on a Semi-Submersible Crane Vessel. They are offshore certified and placed in a 20 feet offshore frame, in accordance with the DNV 2.7-1 directions, making sure the compressors can be moved safely also offshore. Recently we supplied 13 oil-free units to the Gode Wind project in the North Sea, where they provide air for the bubble curtain around the Semi-Submersible Crane Vessel “Hermod” of Heerema Marine Contractors.
Atlas Copco is a world-leading provider of sustainable productivity solutions. The Group serves customers with innovative compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. Atlas Copco develops products and service focused on productivity, energy efficiency, safety and ergonomics. The company was founded in 1873, is based in Stockholm, Sweden, and has a global reach spanning more than 180 countries. In 2015, Atlas Copco had revenues of BSEK 102 (BEUR 11) and more than 43 000 employees.
Specialty Rental is a division within Atlas Copco’s Construction Technique business area. It serves customers in the industry segments around the world with temporary air, nitrogen, steam and power rental solutions. The specialty rental services are offered under several brands. The divisional headquarters is located in Houston, USA.