Abstract
Offshore wind is a growing industry. In the near future, a lot more offshore wind farms will be constructed, most of them in the North Sea. Those windfarms will probably be placed further offshore and generally the turbines will be larger and have a higher capacity.
There are several offshore foundation types. Currently the foundation most applied is the monopile (65%), followed by gravity based foundations (25%) and jackets (8%) (V.d. Walle, 2011).
Monopiles are generally being driven in the seafloor by a large hammer. This technique produces high-level underwater sound. These sound waves could have a large negative impact on marine life, especially if several large offshore wind farms will be constructed simultaneously.
Internationally there is awareness that the underwater sound of piling can cause serious problems. NGOs are concerned about the impact. Scientists conduct research to find out what the impact of piling is on the marine life. Governments put restrictions to the piling of offshore wind parks. These could lead to a delay in construction of future parks. Companies are therefore looking for engineering mitigation solutions or alternative construction methods.