Wind Energy – Innovative Installation
Ecowende, in collaboration with CAPE Holland and GBM Works, is pioneering innovative installation techniques for XXL monopiles at the Ecowende offshore wind farm.
The project focuses on vibro-based technologies designed to reduce underwater noise and minimise impacts on marine life during monopile installation.
As offshore wind turbines grow larger, so do their monopiles. Traditional impact pile driving produces powerful underwater sound waves that can disturb marine mammals, such as harbour porpoises. Even with mitigation measures like bubble curtains and resonator arrays, underwater noise remains a concern.
Ecowende and partners have therefore explored alternative and innovative installation methods with the aim of reducing the ecological footprint of wind farm construction. These innovative methods will soon be demonstrated at our wind farm, where Van Oord’s offshore installation vessel Boreas began construction on 3 December.
Ecowende demonstrates two cutting-edge methods:
1. Vibro Technology
The CAPE VLT-640 Quad uses vertical vibrations to temporarily reduce soil resistance, allowing monopiles to sink under their own weight. The CAPE Vibro Lifting Tool (CAPE VLT) has already been successfully deployed to install hundreds of monopiles on recent large-scale offshore wind projects on both sides of the Atlantic, establishing it as a proven, commercially mature technology for specific site conditions.
CAPE Holland will supply and operate the CAPE VLT to Van Oord, who is planning to use it to drive the monopiles into the seabed with the Boreas installation vessel at six selected test locations. In the Dutch North Sea, the relatively dense sands present a major challenge to install the monopile by vibro-driving – making the Ecowende project an ideal setting to assess the capabilities of vibro-based methods in the most demanding ground conditions.
2. VibroJet Technology
At three of the test locations, VibroJet is planned to be applied, including the Vibro Technology. This approach combines vertical vibrations with controlled water jets inside the monopile, fluidising the soil inside the monopile to further lower soil resistance. This increases the likelihood of achieving full depth while potentially generating lower underwater noise than conventional impact hammers.
“Noise regulations for offshore wind projects are becoming increasingly strict, while wind turbines continue to grow and monopiles become heavier, generating more underwater noise,” explained Dick van Wijngaarden, Business Development Manager at CAPE Holland.
“Vibro Technology has already demonstrated its capability and significant ecological benefits in commercial projects, but we need to fully understand how the technology performs in dense to very dense soils to apply it reliably and effectively and to continue its development for future projects. The innovative combination of Vibro Technology with VibroJet Technology represents an important step toward reliably installing monopiles to full depth with minimal noise generation.”
