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Project Update

Greenlink Interconnector, UK–Ireland [free access]

October 7, 2021

Developer: Greenlink Interconnector Limited, a subsidiary of Ireland’s Element Power


Project details and status: The project is a proposed 500 MW subsea and underground cable (UGC) electricity interconnector (with associated converter stations) between the electricity grids in UK and Ireland, allowing for electricity to flow both ways between the two countries. It will connect the Great Island substation in County Wexford (Ireland) to the Pembroke substation in South Wales (UK).


The 170-km-long (submarine length) high voltage direct current (HVDC) interconnection aims to benefit both countries in increased energy security, decarbonisation and downward pressure on consumer bills. Further, the project will connect about 40 wind farms in the midlands of Ireland to a regional collector node, to harness their combined energy in a single output. The energy will be transferred via underground cables to the Irish east coast and from there on to the UK through subsea cables.


The interconnection has secured a 500 MW connection agreement with the UK’s transmission system operator (TSO) National Grid in Wales along with a cap-and-floor decision from the British regulator, Office of Gas and Electricity Markets (Ofgem).


In February 2015, Ofgem granted Greenwire Transmission Pembroke Limited an interconnector licence. However, in March 2015, Ofgem announced that it could not award Greenlink a cap-and-floor regime as the project did not appear to be in the interests of the UK. Previously, in 2014, plans to set up the wind farms were stalled due to massive local concerns about large-scale farms being developed in Ireland to allow the UK to meet its renewable energy targets.


Later, in August 2016, Ofgem reversed its 'minded to' decision on the project and decided to consult on its revised view to grant a cap-and-floor regime for Greenlink.


In December 2016, Element Power announced that it had formally accepted an agreement for a new 500 MW connection to Pembroke substation as part of the Greenlink Interconnector, following a review process with National Grid. Previously, the Greenlink and Greenwire projects, both promoted by Element Power, shared a single 2,000 MW connection.


In October 2017, Irish Commission for Regulation of Utilities (CRU), formerly known as Commission for Energy Regulation, endorsed the project. The regulator instructed Ireland's transmission system operator EirGrid to progress to the next stage the developer’s grid application for the project. With the endorsement, it is expected the project will receive CRU priority for regulatory arrangements as well.


In March 2018, CRU commenced a detailed assessment of the proposed project. Herein, the regulator assessed the proposed 25-year cap-and-floor support scheme that Ofgem has awarded for 50 per cent of Greenlink's revenue.


In May 2018, the UK’s Intertek was appointed to provide marine environmental and planning support for the project. The scope of the contract involved providing a wider range of services including marine survey procurement, execution and reporting, coordination of pre-application consultation and consent compliance activities for Greenlink’s offshore infrastructure. Moreover, it also included delivering a marine licence application to Natural Resources Wales and a foreshore licence application to Ireland’s foreshore unit.


In September 2018, MMT, a Sweden-based marine survey company, initiated the subsea survey work for the project. The developer in August 2018 awarded MMT the contract for the Greenlink Marine Survey (GMS).


In October 2018, CRU determined that the project passed the public interest test to be part of the Irish transmission system and it will further consult on the cap-and-floor regime in the first half of 2019.


In February 2019, the project received funding of EUR3.6 million granted by the European Commission’s (EC) 2018 Connecting Europe Facility (CEF).


In March 2019, Switzerland-based Partners Group, a private markets investment manager, provided equity financing for the project. However, Greenlink Interconnector Limited and its owner Hudson Sustainable Investments will retain the remaining interest in the project.


Recently, in September 2021, the consortium of Siemens Energy and Sumitomo Electric signed a contract with Greenlink Interconnector Limited to deliver the HVDC converter system for the project. Siemens Energy will be responsible for the overall system design and the construction of two converter stations near the Great Island and the Pembroke substations. The stations will be linked via an HVDC XLPE (cross-linked polyethylene) cable system by Sumitomo, which will enable the low-loss transport of energy with a voltage of 320 kV. Siemens Energy’s scope of supply also includes a service and maintenance agreement with an initial duration of seven years.


Greenlink is one of Europe’s vital energy infrastructure projects, and the European Union has recognised its contribution to security of power supply and the environment by designating it as a `Project of Common Interest’.


Work on the project is expected to begin in early 2022 with commissioning scheduled for 2024.