Great Britain–Ireland interconnector

Great Britain–Ireland interconnector
Name	Great Britain–Ireland interconnector
Country	United Kingdom; Ireland
Starts	Pembroke (Wales)
Ends	County Wicklow (Ireland)
Owner	National Grid plc; EirGrid; SONI
Type	High-voltage direct current submarine power cable
Capacity	500 MW (initial)
Length km	258
Commissioning	2012

Great Britain–Ireland interconnector

The Great Britain–Ireland interconnector is a high-voltage direct current (HVDC) submarine electricity link between the islands of Great Britain and Ireland, designed to enable power transfers between the National Grid (Great Britain), EirGrid, and SONI. The project was promoted by market participants including EirGrid plc and National Grid plc, and construction involved contractors such as ABB Group, Siemens, and Alstom specialists. The interconnector connects converter stations near Pembroke Power Station in Pembrokeshire and Moneypoint/County Wicklow infrastructure, integrating with networks centered on Parkeston, Dublin Port, and other substations.

Overview

The link provides cross-border electricity exchange between the United Kingdom and the Republic of Ireland, enhancing energy security for regions served by EirGrid and National Grid ESO while interacting with markets governed by institutions like the Single Electricity Market and regulators such as the Commission for Regulation of Utilities (CRU) and the Ofgem. It participates in dispatch coordination with operators including ESB Group, SSE plc, Bord Gáis Energy, SSE Renewables, Iberdrola, and supports trading on venues like the EPEX SPOT and Nord Pool power exchanges. The interconnector interfaces with generation assets such as the Plant Bowen, Moyle Interconnector, and wind fleets including projects by Statkraft, Ørsted, Vattenfall, and Energia.

History and Development

Planning initiated amid European Union energy integration promoted by the European Commission and frameworks like the Third Energy Package and ENTSO-E. Feasibility studies involved consulting firms and institutions such as Arup, Black & Veatch, KPMG, and academic partners at Trinity College Dublin and Imperial College London. Financing included investment from entities like European Investment Bank and equity from utilities including ESB and SSE. Regulatory approvals were sought from authorities including An Bord Pleanála, Planning and Environment Decisions (Wales), and the UK Planning Inspectorate. Construction was influenced by precedents such as the NorNed cable, the BritNed interconnector, and the East–West Interconnector development programmes.

Technical Specifications

The link uses HVDC technology with converter stations employing voltage source converter or line-commutated converter equipment manufactured by firms like ABB, Siemens Energy, and General Electric. Cables consist of mass-impregnated or cross-linked polyethylene (XLPE) insulation, produced by manufacturers such as Prysmian Group and Nexans. Specifications reference standards from IEC and IEEE. Protection and control systems integrate relays from Schneider Electric, communications via Siemens PLM or Cisco Systems networks, and monitoring aligned with ENTSO-E codes. Thermal ratings, reactive compensation using synchronous condensers, and harmonic filtering are coordinated with synchronous areas including Ireland synchronous area and the Great Britain synchronous area.

Route and Infrastructure

The submarine cable follows a corridor across the Irish Sea with onshore approaches traversing counties including Pembrokeshire, Cardiff, County Wexford, and County Wicklow, linking to substations that tie into the transmission grids of Scotland, Wales, Northern Ireland, and the Republic of Ireland. Surveying and seabed works referenced methods used on Celtic Interconnector and ISLES studies; contractors coordinated with maritime authorities like the Maritime and Coastguard Agency and the Commissioners of Irish Lights. Landfall works required permits from bodies including Natural Resources Wales and National Parks and Wildlife Service (Ireland), and considered habitats catalogued by BirdWatch Ireland and RSPB.

Operation and Management

Operational control is shared between National Grid ESO, EirGrid plc, and SONI under agreed commercial arrangements and scheduling coordinated through capacity allocation mechanisms akin to those managed by ENTSO-E and visibility protocols used by TSOs across Europe. Maintenance contractors include Balfour Beatty, Van Oord, and ship operators like CTruk and DeepOcean. Market settlements follow rules from EirGrid Group Settlement System and BETTA-era trading customs, with dispute resolution via bodies such as the European Court of Justice or national courts where necessary.

Economic and Environmental Impact

The interconnector affects wholesale price convergence across regions served by EirGrid and National Grid ESO, influencing investment decisions by utilities like ESB, Iberdrola, SSE, and independent generators including Pelamis Wave Power successors and offshore developers such as SeaEnergy. It supports renewable integration for wind projects in the Irish Sea, Celtic Sea, and onshore portfolios by Coillte and Viridian Group, while enabling capacity markets and ancillary services procurement similar to mechanisms in Great Britain Capacity Market. Environmental assessments referenced directives like the EU Habitats Directive and influenced conservation stakeholders including An Taisce, National Trust, and Heritage Council (Ireland).

Future Projects and Upgrades

Planned enhancements consider increased capacity projects comparable to Greenlink, Celtic Interconnector, and Wales-IRE proposals, proposals from developers like Xlinks, ABO Wind, and multinational consortia including Statkraft and RWE. Technical upgrades may involve VSC-HVDC conversion, cable replacements by Nexans or Prysmian Group, and integration with grid-scale storage solutions like Pumped-storage hydroelectricity projects such as Cruachan Power Station or battery arrays by Tesla, Inc. and Fluence. Policy drivers include targets set by the European Green Deal, commitments under the Paris Agreement, and national strategies from the Department of Energy Security and Net Zero and Department of the Environment, Climate and Communications.

Category:Electric power infrastructure in the United Kingdom Category:Electric power infrastructure in the Republic of Ireland Category:Submarine power cables