The MaresConnect 750MW HVDC Interconnector System

MaresConnect Limited is procuring separate Engineering, Procurement and Construction (EPC) turnkey contracts for the development of a 750 MW, 320 kV bi‑directional high‑voltage direct current (HVDC) interconnector linking Denbighshire, Wales to North County Dublin, Ireland. The project will comprise two converter stations, an Irish 400 kV AC tail substation, and a 240 km subsea and underground HCDC cable system with associated high‑voltage AC underground cabling in both the UK and Ireland. The contracts are divided into four lots (LOT 1A, LOT 1B, LOT 2A, LOT 2B) with mandatory bid combinations, allowing a single EPC contractor per lot to provide design, construction, commissioning and associated maintenance services. The procurement follows the FIDIC “Silver Book” for EPC/Turnkey projects, with particular conditions tailored to each lot and full risk allocation to the successful contractors. The project aims to enhance energy security, market integration and renewable electricity utilization across the Irish and UK grids.

The technical configuration of the interconnector is a symmetrical monopole Hot‑Voltage Source Converter (VSC) system operating at ± 320 kV rated DC voltage, providing a 750 MW bi‑directional power transfer capability between the Irish and GB grids via the subsea‑underground cable pathway.

The MaresConnect Project is a proposed 750 MW, 320 kV High Voltage Direct Current (HVDC) electricity interconnector linking Denbighshire, Wales and North County Dublin, Ireland. Developed by MaresConnect Limited, a joint venture between Foresight Group Holdings Ltd and Etchea Energy Nominees Ltd, the project will transmit electricity via approximately 240 km of subsea and underground cables between new converter stations on each side. It aims to enhance security of supply, market integration, and renewable energy utilisation between the Irish and GB grids. MaresConnect shall utilise Voltage Source Converter (VSC) technology and the configuration shall be a Symmetrical Monopole. The rated DC voltage shall be +/-320 kV. The link shall be bi-directional and shall have a rated power (receiving end) of 750 MW. The project is being procured as separate EPC (Turnkey) contracts, divided into four lots: LOT 1A: EPC for two HVDC Converter Stations; LOT 1B: EPC for one Irish 400kV AC Tail Substation; LOT 2A: EPC for the HVDC subsea and underground cable system, and for the HVAC underground cable system in Wales (Bodelwyddan); LOT 2B: EPC for the supply and installation of HVAC cable system in Ireland (Dublin). The contract model for the lots will be amended FIDIC Conditions of Contract for EPC/Turnkey Projects (Silver Book). MaresConnect has conducted Preliminary Market Engagement prior to publication of this Contract Notice and encourages further collaboration between OEMs and Construction Contractors to establish bidding arrangements in time for the next step of the Procurement Process (notably the Pre-Qualification Questionnaire).
Additional information: Lot combinations: bidders for LOT 1A are also required to bid for LOT 1B, and bidders for LOT 1B are also required to bid for LOT 1A. Bidders for LOT 2A are also required to bid for LOT 2B, and bidders for LOT 2B are also required to bid for LOT 2A. The procurement process in respect of each of the Lots may result in a single contract being awarded to the successful contractor in that Lot (i.e. a single EPC contract which encompasses all elements of the project in that Lot). Alternatively, a number of different contracts may be awarded to the (same) successful contractor in the Lot, each covering a specific element(s) of the project. By way of example, in Lots 1A and 1B, the successful EPC contractor may be awarded a specific Long Term Service Agreement. Similarly, in Lots 2A and 2B, the successful EPC contractor may be awarded a specific Inspection, Maintenance and Repair Contract. In all of the Lots, the successful EPC contractor may be awarded a specific early works contract(s), which may for example encompass Front End Engineering Design and/or civil and structural enabling works. MCL is not a regulated utility for the purposes of Irish/UK/EU procurement law, and this procurement is therefore not subject to such rules. MCL intends to voluntarily follow Irish procurement rules in part but fully reserves its right to deviate from those rules. The publication of this notice does not make MCL and/or this procurement subject to any procurement rules. Form of Contract: The contracts to be awarded for all lots will be based on the FIDIC Conditions of Contract for EPC/Turnkey Projects, Second Edition 2017 (the 'Silver Book'). The FIDIC Silver Book will be amended and supplemented by Particular Conditions (specific to each lot), which are included in the procurement documents. Risk Allocation: Tenderers are explicitly advised that, in line with the EPC/Turnkey (FIDIC Silver Book) model, the successful contractor for each lot will assume full responsibility for the design and execution of their respective works. Requests to participate: a 'request to participate' is made by submitting a completed Pre-Qualification Questionnaire by the stated deadline. Variant tenders: Variant tenders may be submitted; however, this is at MCL's sole discretion and will only be permitted where the form and content of such variant tender has been agreed in principle with MCL in advance.
Place of performance: North County Dublin, Ireland

Lot: LOT-0001
Title: LOT 1A: EPC for HVDC Converter Stations

Lot: LOT-0002
Title: LOT 1B: EPC for Irish 400kV AC Tail Substation

Lot: LOT-0003
Title: LOT 2A: EPC for the HVDC Subsea and Underground Cable System, and for the associated HVAC Underground Cable System

Lot: LOT-0004
Title: LOT 2B: EPC for the HVAC underground cable system in Ireland (Dublin)