Danish wind energy giant Ørsted has piloted a new low-noise installation method for offshore wind turbine monopile foundations which the company believes “represents one of the greatest advancements yet in offshore wind foundation installation methodology.”
Ørsted successfully tested the new installation method on three monopile foundations during construction at the 253MW German offshore wind farm Gode Wind 3.
According to Ørsted, the noise mitigation method involves a “patented jetting technology attached to the monopile, which lowers the resistance of the surrounding sandy soil, effectively allowing the foundation to sink into the seabed – completely replacing conventional installation methods such as pile driving.”
The water jetting technology employs high-pressure water jets attached to the monopile to disturb the sandy seabed, minimising the resistance as the monopile is sunk into the ground.
A new monopile installation method may sound a strange contender for “one of the greatest advancements yet in offshore wind foundation installation methodology” but, as more and more offshore wind farms are built around the globe, ensuring the environmental stability of the surrounding ecosystems becomes increasingly vital.
Traditional installation methods such as pile driving create significant disturbances as the massive steel pipes are hammered into the seabed to serve as a foundation for the turbine.
The repetitive and blunt-forced nature of pile driving creates audible reverberations that can disorient and harm local wildlife, as well as physically disturbing the seabed.
Ørsted claims that the implementation of their new installation technology results in a substantial decrease in underwater noises, with a reduction of 34 decibels relative to commonly used installation methods.
Moreover, and without additional mitigation, noise levels using the new installation method were reduced by over 99 per cent to a level “just marginally above the ambient noise found in the German Bight in the North Sea.”
It is also hoped that, once adopted at scale, this new installation technology will allow for more efficient and cost-effective installations of offshore wind farms.
“Ørsted has been at the forefront of offshore wind innovation and marine protections for 30 years, and we continue to push the envelope on new innovative solutions,” said Patrick Harnett, executive vice president and chief operating officer at Ørsted.
“This new technology is a potential game changer for how we build offshore wind.
“Once industrialised, it could not only be cheaper, faster, and far quieter – without additional mitigation – than any other monopile installation technology, it also has the potential to make next-generation foundations lighter as they won’t need to be designed for conventional installation process.”
