The number of offshore installations for expanding the use of renewable energy and the construction of coastal infrastructure has grown rapidly in recent years. As a result, demand for economical and environmentally friendly installation technologies for offshore foundations has increased. These are needed for wind turbines, substations, tidal power plants and bridges as well as for harbor infrastructure such as quay walls, breakwaters and jetties.
The newly developed Herrenknecht OFD technology uses a full-face drilling concept and a drive behind the cutterhead to overcome the limits of conventional methods. This applies in particular to difficult ground conditions unsuitable for pile driving and where established pile driving methods would cause critical noise emissions.
The first project to employ the OFD technology is the Saint-Nazaire wind farm off the North Sea coast of France. In June 2021 the first mechanized excavation for the installation of large-diameter monopiles for wind turbines was successfully completed in water depths between 12 and 25 meters. In total, 73 monopile foundations have to be excavated with a diameter of 7,700 millimeters and with drilling depths of between 6 and 24 meters. The Saint-Nazaire offshore wind farm is the first in the world to use mechanized drilling for the construction of large-diameter monopile foundations.