Moyle Interconnector Limited is looking for a manufacturer led turnkey proposal for the design, manufacture, testing, supply, installation, jointing and commissioning of replacement subsea and land metallic return conductors.
There are two options currently under consideration. The first option is to install two discrete replacement metallic return conductors (MRC’s), one for each HVDC monopole that will be installed spanning between the converter stations positioned at Auchencrosh, Scotland and Ballycronan, Island Magee, Northern Ireland.
Each new MRC will involve the design, manufacture, testing, supply, installation, jointing and commissioning of approximately:
– 18 km of land cable – 2 x 3 km on the Northern Ireland side, and 2 x 6 km on the Scottish side,
– 106 km submarine cable – 2 x circuit crossing lengths of approximately 53 km with water depths of up to 150m.
Second option includes one discrete replacement metallic return conductor (MRC) which will be installed spanning between the converter stations positioned at Auchencrosh, Scotland and Ballycronan, Island Magee in Northern Ireland.
The converter stations would be reconfigured by others such that they would operate as a 500 MW Bipole with a single MRC. However the system, if necessary, would be able to revert to a 250 MW monopole under certain fault conditions.
This single new MRC will involve the design, manufacture, testing, supply, installation, jointing and commissioning of approximately:
– 9 km of land cable – 3 km on the Northern Ireland side, and 6km on the Scottish side,
– 53 km submarine cable – 1 circuit crossing length of approximately 53 km with water depths of up to 150m.
For either option, the works associated with subsea cable sections would involve:
– Design, manufacture and testing of the subsea cable system- Offloading the completed cables onto a suitable installation vessel,
– Delivery of the cable from the manufacturing facility to the installation site,
– The contractor must be willing to undertake a subsea burial assessment process to determine the optimal burial techniques to be utilized and to demonstrate an understanding of the soils on route and their effect on the cable protection methodology,
– Installation and protection of the cables via burial, or other suitable means, of the cables,
– Testing during loading, installation and post installation,
– Management of at least four (possibly five depending on timing) third party asset crossing positions,
– The supply of spares to facilitate any repairs.
For either option, the works associated with the land cable sections would involve:
– Design, manufacture and testing of the land cable system,
– Delivery, probably via road, to the installation sites in Northern Ireland and Scotland,
– Installation of the cables taking due care of the existing HVDC cables (if the cables are to be installed within the existing consented cable corridor),
– The supply, jointing and testing of accessories required in the cable lengths (transition joints, land joints and terminations),
– The client may choose to pre-install ducts at road crossings and other obstacles, therefore a willingness and agreement to work on client pre prepared land sections is required.
For either option, the contractor would be required to:
– Accept liability, and suitably mitigate against, any damage to the existing HVDC cables as a result of performing the works,
– Guarantee ‘on time’ delivery for the cable and installation programme,
– An on time delivery is required to ensure that critical network demands are met without the need to compromise strategic requirements of the existing network,
– Provide a level 1 (high level) manufacturing and installation schedule to establish a baseline for an ‘on time’ delivery of the manufactured cable and subsequent installation,
– To provide comprehensive as built report including drawings, and an operation and maintenance manual for the cables.
The contract has a value between £30,000,000 and £50,000,000, and the deadline for submission for tenders for the project is December 12, 2013.
Subsea World News Staff, November 22, 2013