The Netherlands-based CAPE Holland has been awarded a contract by Seaway 7 to supply a vibro lifting tool (VLT) for the installation of the monopile foundations for the Kaskasi offshore windfarm
After years of development, this will be the first offshore wind project in which the monopiles will be driven into the seabed to final penetration using a vibro hammer alone.
A research project led by innogy has shown this installation method can reduce installation times and noise levels during construction.
Kaskasi will be the first offshore windfarm in the world using the vibro driving technique to install all of the monopile foundations.
Seaway 7 first used CAPE Holland vibro equipment in 2012 to drive the monopiles for the Riffgat offshore windfarm, although on this project the equipment was not used to drive the piles to full depth.
Since then, the vessel owner/operator has used vibro equipment on oil and gas projects and on an offshore wind project in Taiwan.
The equipment to be supplied by CAPE Holland combines the capabilities of an offshore lifting tool with the ability to upend and drive the piles, quickly and with reduced noise levels compared to conventional pile driving.
The VLT for the Kaskasi project will have multiple vibro hammers linked together to provide a total force of 1,920 kg, which makes this the most powerful vibro pile driver in the world.
A specially developed clamping system will be used to create the interface between the VLT and the flanged top of the monopiles.
The VLT is able to pick up a stored pile, upend into a vertical position, lift it to the correct position and drive it down, monitoring verticality while driving, in a single operation without needing a gripper or seabed installation frame.
Due to the modular design of the equipment it can be deployed to install a range of piles, from small anchor piles to XXL monopiles of up to 2,500 tonnes.