Case Study Overview
The Consortium Jan De Nul and LS Cable (JLC) was awarded the supply and installation of high voltage cables for the grid connection of the Dutch offshore wind farms Hollandse Kust Noord and West Alpha. The connection consists of four cable systems with a total length of 210km that connect the wind farms to the onshore Dutch power grid near Beverwijk, just north of the Port of Ijmuiden.
At a glance
- Location: Hollandse Kust Offshore Windfarm, Netherlands
- Plant used: 400T Haven SeaSeven
- What we did: Red7Marine supported Jan De Nul with the offshore windfarm cable landing at Hollandse Kust.
CHALLENGE
Jan De Nul Group chartered Red7Marine’s 400t Haven SeaSeven jack-up barge for the export cable installation to act as a tensioner station to reduce the total export cable tension.
Red7Marine’s in-house team of engineers carried out a full vessel site specific assessment and leg penetration assessments for the project completed to ISO19905 standards.
The barge was mobilised in the Port of Tilbury and towed into the Port of Ijmuiden ahead of operations commencing. Red7Marine also supplied Barge crew throughout the duration of the project.
SOLUTION
Red7Marine began working with Jan De Nul early in 2021 and as a part of the project, our in-house team designed, fabricated and installed a cantilever platform and cable highway system which was welded on to the barge in Tilbury before its departure to support the tensioning operations.
On-site works began in April 2022. The SeaSeven was positioned in the nearshore intertidal area and supported the HDD system from landside to the beach with Jan De Nul using its trenching vehicle the ‘moonfish’ to trench the cable 5m below seabed.
The barge worked alongside MPI Offshore‘s Adventurer cable laying ship which was being used to winch the cable back to shore.
SEE RELATED CASE STUDIES
Brighton Marina
Phase 2
In order to accommodate a new luxury apartment block in Brighton, part of the marina needed to be reclaimed using sheet piled cofferdams. This would enable the water to be kept out and foundations to be built for the stunning seafront properties. Red7Marine supported the installation of a sheet pile twin wall cofferdam.
Oldbury
Red7Marine installed replacement Active Effluent Discharge Lines at Oldbury power station as part of the on-going care and maintenance works. Red7Marine’s previous project experience on similar projects consisting of works on subsea pipeline and outfalls at Bradwell and Sizewell nuclear power stations, positioned the company as the ideal marine partner for client, Magnox.
Emirates Cable Car
The Emirates cable car was installed to provide a pedestrian link across the River Thames between the Royal Docks and the Greenwich peninsula. Red7Marine worked with Bachy Soletanche in a joint venture to install the foundations for the one-kilometre long cable car using marine rotary bored piling.
Battersea River Pier
Red7Marine secured a contract at Battersea in December 2016 to install new tubular driven steel mooring piles for the Battersea Power Station river bus pontoon installation which is planned to be operational in Autumn 2017. Transport for London (TFL) decided to extend the river bus service after the number of housing developments at Battersea began to increase.
Middleton Sands Navigation Marker
This fast turn-around marine construction project involved the installation of a new tubular steel navigation marker pile at Middleton Sands, Barrow-in-Furness in 2017. The navigation marker was required to identify the sub surface obstructions and enable other vessels in the area to operate safely.
Liverpool 2 Deep Water Port Extension
Red7Marine was the marine partner of choice for BAM Nuttall when they constructed a piled combi-wall as part of the Liverpool 2 Dock Expansion that began in 2014. The construction of the container terminal was supported by four of Red7Marine’s jack up barges; the Haven Seariser 1, Haven Seariser 2 and the Haven Seariser 3 and the Haven Seajack as it carried out rock socket piling works.
Weston-Super-Mare
The Red7Marine team was chosen to provide specialist marine plant and personnel to aid the redevelopment of the Weston-super-Mare Grand Pier after it was destroyed in a fire in 2008. Red7Marine supplied the Haven Seajack 4 assisted in the pier construction works. Its previous experience in pier and marina construction works made it the ideal project partner for this development.
Bradwell Power Station Barrier Wall Removal
Red7Marine is a leading provider of equipment for marine demolition and is skilled in dismantling structures that are beyond the reach of ordinary demolition contractors. In 2012, Red7Marine removed approximately 800 tonnes of steel in the Blackwater Estuary from the Bradwell nuclear power station water intake structure.
Fingringhoe Firing Ranges
Red7Marine installed scour protection and provided remediation on damaged sections of the flood defences to preserve areas of the salt marsh at the Fingringhoe firing ranges in Essex. Scour protection and remediation techniques are used to control erosion in both estuarine and the offshore environments.
