Silent installation offshore

Offshore noise is a serious problem for the welfare of marine mammals, a problem that is increasing as the demand for wind farms increases. The gigantic piles for wind turbines have to be driven into the bed of the sea with great force. Due to the forces involved, thicker, and therefore more expensive, piles have to be used. At the moment, the companies that install the turbines reduce noise levels by, for example, installing a noise barrier of air bubbles to muffle the sound waves. Out at sea, that takes time, money, and effort.

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GBM Works B.V. has devised a quieter foundation technique for the offshore installation of monopiles. It was tested to scale in our geotechnical laboratory.

In a perspex tube 4.2 m long and 0.6 m in diameter, experiments were conducted with different combinations of sand densities and layers with varying flows in order to learn more about the process. The aim was to investigate whether the installation method, a combination of loosening up the bed through injection and vibrodriving the pile, is fast and efficient enough. The study was made possible in part by the Energy Top Sector schemes implemented by the Netherlands Enterprise Agency (RVO).