LS Cable & System and Jan De Nul Group on Monday announced the completion of the construction of the first batch of subsea power cables in South Korea for TenneT’s offshore projects Hollandse Kust (noord) and (west Alpha) in the Netherlands.
Grid-operator TenneT is constructing two offshore platforms, one for Hollandse Kust (noord) and one for Hollandse Kust (west Alpha). These platforms will gather the wind energy generated by the corresponding wind farms and transform this energy from a voltage of 66kV to 220kV.
With the Hollandse Kust (north) and (west Alpha) projects, TenneT takes care of the connection of the wind farms in the North Sea to the national electricity grid (Grid at Sea), and of the wind farms to be constructed in the North Sea to the national electricity grid.
As for the subsea cables complete in South Korea, Jan De Nul’s cable-laying vessel Isaac Newton will load the 220 kV AC cables from LS Cable’s factory in Donghae, South Korea, and transport them to the project for installation in April 2022.
"This first lot consists of the complete cables for Hollandse Kust (noord) (HKn) and the nearshore section for the Hollandse Kust (west Alpha) (HKwA). In total, this is more than 90 km of cables, weighing 7,160 tonnes and having very large cross-sections resulting in an overall cable diameter of more than 25 cm," Jan De Nul said.
Jan De Nul Group and LS Cable & System are jointly responsible for the design, supply, installation, protection and testing of the 210 km of submarine power cables for HKn and HKwA of TenneT.
Delivery of the Hollandse Kust (noord) project is anticipated by the end of 2022. The Hollandse Kust (west Alpha)project is planned to be finished by the end of 2023. Both offshore wind farms have an installed capacity of 700 MW. This means they will together generate enough electricity to power 1.4 million Dutch households.
Jeroen Devos, Project Manager at Jan De Nul Group: “The successful delivery of the first 90 km of cables is the first major milestone for our project. We look forward to installing these cables in Q2 2022 by means of our custom-built tracked vertical injector Moonfish and our offshore installation vessels Isaac Newton and Adhémar de Saint-Venant.”
Myung Sun Kim, Project Manager at LS Cable & System: “We are delighted to announce that we successfully manufactured and tested the first 90 km of submarine cable for the Hollandse Kust (noord) and (west Alpha) wind farms. The manufacturing and testing is well ahead for the planned load-out onto Jan De Nul’s vessel Isaac Newton in the course of Q1 2022. We are confident and looking forward to proceeding with this first load-out together with the Jan De Nul team.”
The cable laying vessel Isaac Newton will install the cables on the seabed. In the nearshore area, JDN's in-house developed tracked vertical injector Moonfish will bury the cables up to 8 m below the seabed level.
The burial offshore is taken care of by the trencher UTV1200, supported by the multipurpose vessel Adhémar de Saint-Venant. Jan De Nul will also install multiple cable protection systems and rock berms at the cable crossings along the route.
Jan De Nul’s scope includes the transport and installation of the submarine power cables. LS Cable is responsible for the design, manufacturing, termination and testing of the submarine power cables, as well as for the 10.5 km of land cables and approximately 1 km of platform cables. The land and platform cables were already successfully manufactured and transported to the project site earlier in 2021.