Greenlink is a proposed subsea and underground electricity interconnector cable (with associated converter stations) linking the existing electricity grids in Ireland and Great Britain (GB), and has a nominal capacity of 500MW. Greenlink will provide a new grid connection between EirGrid’s Great Island substation in County Wexford (Ireland) and National Grid’s Pembroke substation in Pembrokeshire (Wales). The power will be able to flow in either direction, depending on supply and demand in each country.
Greenlink has key strategic importance, as it will provide significant additional interconnection between Ireland and Great Britain, with onward connections to continental Europe. The construction and development of Greenlink will deliver increased energy security, regional investment and value for money to consumers, and will enable the further integration of low carbon renewable energy sources.
The Greenlink proposal alongside other existing and proposed interconnectors in Ireland, UK and continental Europe.
Greenlink will consist of two converter stations - one located close to the Great Island substation in County Wexford and the other close to the Pembroke substation in Pembrokeshire - connected by two High Voltage Direct Current (HVDC) cables under the Irish Sea. A converter station converts electricity from Alternating Current (AC) to Direct Current (DC) and vice versa.
DC electricity is typically used for the transmission of electricity over long distances because it has lower losses, negligible heating effects and is therefore suitable to be buried underground. Accordingly, there will be no overhead lines between the two converter stations. Onshore, the cables will be buried underground and offshore the cables will be buried in the seabed or laid on the seabed with protection, if burial is not practicable.
Greenlink is planned for commissioning in 2023
The project requires planning permission in Ireland and Wales. Constructing and commissioning an interconnector requires the completion of a thorough programme of environmental and technical assessment to ensure that the final interconnector design fully considers the environment in which it is built.
Greenlink Interconnector Limited has undertaken a voluntary Environmental Impact Assessment (EIA), meaning the application documents facing an increased level of scrutiny from stakeholders.
A large infrastructure project such as Greenlink takes several years from concept to construction, including technical design, obtaining the relevant permits and consultation with a variety of stakeholders.
Technical and environmental constraints have to be identified and fully assessed to ensure that they are considered within the final design of an infrastructure project. Detailed environmental and technical assessment surveys commenced in 2018. This followed the completion of desk-based assessments and consultation with statutory consultees.
Once a detailed proposal and design are completed, permits and licences need to be obtained from: Pembrokeshire County Council, Pembrokeshire Coast National Park Authority, Natural Resources Wales (NRW) and Milford Haven Port Authority, in Wales; and An Bord Pleanála and the Department of Housing, Planning and Local Government – Foreshore Unit and the Commission for the Regulation of Utilities, in Ireland.
Once the appropriate permits and licences have been obtained, the scheme will be constructed, which is expected to take approximately three years from start to finish.