Several parameters influence the resulting noise levels such as pile diameter, water depth, soil structure and blow energy. The more energy is required to drive larger piles into the substrate, the less likely it is that existing mitigation methods alone will be suited to meet current noise standards in the future. For this reason the Geman Federal Agency for Nature Conservation organised an international conference on Noise mitigation for the construction of increasingly large offshore wind turbines - Technical options for complying with noise limits which took place in Berlin from November 22 to 23, 2018.
The aim of the conference and this report is to revisit the issue of underwater noise mitigation in the light of an anticipated further increase in turbine size. We describe and analyse the effectiveness of existing noise mitigation measures and readyness for use with increasingly large monopiles. Monopiles have by far the most extensive experience in the construction of offshore wind farms. Thus, they form the basis for comparative considerations. More experience is needed and explicitly desired with foundation types other than the monopile in order to make them a reliable, safe and economically viable alternative to the standard monopile and provide a benefit for the marine environment. This report gives a general view on the suitablity of existing noise mitigation methods for the piling of socalled “XXL monopiles” and alternative low-noise foundations for increasingly large turbines.