Greenlink is an electricity interconnector linking the power markets in Ireland and Great Britain. The project consists of a subsea and underground cable and associated converter stations, with 500 MW nominal capacity.

It connects EirGrid's Great Island substation in County Wexford (Ireland) to National Grid's Pembroke substation in Pembrokeshire (Wales).

Interconnectors allow electricity to flow between different national transmission networks — from where it is generated to where it is needed — improving security and reliability of supply, and supporting integration of green, low‑carbon energy.

Greenlink can export surplus electricity between Ireland and Great Britain, which helps meet renewable energy targets, reduce carbon emissions, and brings jobs and investment to both regions.

Construction began in January 2022 and became operational in February 2025.

The interconnector uses two High Voltage Direct Current (HVDC) electricity cables plus a fibre‑optic cable. These run about 190 km beneath the Irish Sea and underground.

HVDC is more efficient for long‑distance (especially subsea) transmission than AC, with lower electricity losses and minimal heating effect — suitable for underground/onshore routing.

At converter stations, DC is converted to Alternating Current (AC) for connection to national grids. The fibre‑optic cable enables communication between converter stations for monitoring, control, and safety.

In Wales: connects to the Pembroke 400 kV substation (Pembrokeshire).

In Ireland: connects to the Great Island 220 kV substation (County Wexford).

Landfall sites are at Freshwater West beach (Pembrokeshire) and Baginbun Beach (County Wexford), chosen after assessments and consultations. Onshore cable routes and converter station sites were identified after environmental and technical assessments.

Freshwater West beach in Pembrokeshire, and Baginbun Beach in County Wexford. Horizontal Directional Drilling (HDD) was used to install the cable under the beach and dunes — avoiding impacts on the environment or beach users.

Offshore: The marine cable was buried beneath the seabed (or laid on the seabed with protective cover where burial was not possible), using purpose built cable laying ships.

At landfalls (beaches): Horizontal Directional Drilling was used under dunes and beaches, so there was no open trenching or disruption to beach users; the cable was then jointed and buried underground.

Onshore: Cables were laid in trenches with a minimum depth of cover of 850 mm. In agricultural land, a deeper cover was provided for farming safety. Any utility crossings, watercourses, etc. were subject to custom engineering solutions. The underground route sometimes followed existing roads depending on land ownership and other constraints.

At National Grid's Pembroke substation (Wales) and at EirGrid's Great Island substation (County Wexford, Ireland).

No. All onshore cables were buried underground; offshore cables were buried under the seabed (or covered where burial was not possible).

Cables: No — because they were entirely underground or subsea, resulting in no permanent visual impact. Any necessary vegetation clearance was temporary and was restored. There was no fencing or permanent structures at Freshwater West or Baginbun beaches.

There were small link boxes (cabinets) along the route — approximately one every 6 km — located inside field boundaries to minimise visual impact.

Converter stations: Yes — converter station buildings are visible. Their footprint is approximately 1.85 hectares (about 185 m × 100 m). Components included the converter hall, transformers, AC switchgear, filters, lightning towers (approximately 26 m high), a control building, a cooling plant, and standby generators. The converter hall apex is approximately 17 m high. Visual impact was assessed, and mitigation included landscaping and building finishes

All cabling is buried (underground or seabed) in protective armoured casing; on land at least 850 mm deep with protective cover and warning markers.

HVDC cables emit lower electromagnetic fields (EMF) than AC cables; they comply with guidelines from World Health Organization (WHO) and the relevant EU standard (ICNIRP/EU Recommendation 1999/519/EC).

Under full load, magnetic field directly above the cable is approx. 17 microtesla (µT). By comparison, Earth's magnetic field in Ireland is ~ 47 µT. So the cable's emissions are well below guideline limits. At 5 m away from cable, magnetic field drops to ~ 2.5 µT — ~160 times below the 500 µT guideline limit.

Noise from electrical and mechanical plant is expected — but mostly located indoors within the converter hall and at lower levels than nearby existing power stations/substations.

The Interconnector project had minimal environmental impact. A full Environmental Impact Assessment was voluntarily conducted. Independent experts carried out environmental and technical surveys to shape the design to minimise impacts.

The resulting assessments were verified by Natural Resources Wales (for Wales) and the National Parks and Wildlife Service (for Ireland).