Frequently Asked Questions
What is Greenlink?
Greenlink is a planned electricity interconnector linking the power markets in Ireland and Great Britain. The project has a nominal capacity of 500MW and comprises a subsea and underground cable and associated converter stations to connect EirGrid’s Great Island transmission substation in County Wexford (Ireland) and National Grid’s Pembroke transmission substation in Pembrokeshire (Wales).
Why is it needed?
Interconnectors allow electricity to flow between different national transmission networks – from where it is generated to where it is needed - improving the security and reliability of our power supplies and supporting the integration of green, low carbon energy sources in an affordable way.
Of particular importance is Greenlink’s ability to maximise the integration of green energy generated in both Ireland and Great Britain by exporting surplus electricity between the two countries. The climate crisis is a serious matter of concern for many people - and most governments, communities and businesses recognise the need to take action to reduce carbon emissions from our energy production and use. Interconnection has an important role to play in meeting renewable energy targets and supporting the decarbonisation of
our economies, whilst at the same time bringing forward jobs and investment.
Greenlink has been named a ‘Project of Common Interest’, making it one of Europe’s priority energy infrastructure projects. It will have strategic importance by doubling the interconnection capacity between Ireland and Great Britain. Construction will bring regional investment and jobs in both countries and, once operational, Greenlink will create downward pressure on consumers’ electricity bills.
Who is behind the project?
How is it being funded?
Greenlink is privately financed by Partners Group. The project represents €500 million/£420* million of private capital investment in Ireland and Wales. The project has also been successful in sourcing some funding from the European Union Connecting Europe Facility (CEF).
*Approximate figure, based on value and conversion rate as at October 2021
When will it become operational?
A large infrastructure project like Greenlink takes several years from development to construction, including technical design, obtaining the relevant permits and consultation with a variety of stakeholders. Once all the necessary permits are in place, the three-year construction process will commence and the interconnector is expected to become fully operational in 2024.
What technology does it use?
The interconnector comprises two High Voltage Direct Current (HVDC) electricity cables and a fibre optic cable stretching approximately 190km beneath the Irish Sea and underground connecting the two converter stations.
HVDC is more efficient for the transportation of electricity over long distances, particularly subsea. The cables have lower electricity losses than comparable AC cables and negligible heating effects, and are therefore suitable for undergrounding both onshore and offshore. Accordingly, there will be no overground cables between the two converter stations. One of the other benefits of HVDC cables is the relatively small footprint required to install them underground onshore. HVDC technology has the added benefit of enabling two grids to be connected successfully despite not being synchronised.
At the converter stations the Direct Current (DC) electricity in the HVDC cables is converted to Alternating Current (AC) so that it can connect to the substation and be used within the national transmission and distribution networks. A fibre optic cable provides communication between the converter stations for system monitoring, control and safety purposes.
Where will the interconnector be located?
In Wales, Greenlink will connect to the Pembroke 400kV substation in Pembrokeshire. In Ireland, it will connect to the Great Island 220kV substation in County Wexford. These were identified as the connection points following assessments and consultation with National Grid and EirGrid respectively.
The proposed cable landfalls are Freshwater West beach in Pembrokeshire and Baginbun Beach in County Wexford. The landfalls were selected after a review of potential sites in the regions.
A preferred subsea cable route has been identified following the conclusion of subsea surveys and consultation with stakeholders.
Onshore, the preferred underground cable routes and converter stations sites have been identified following consultation and technical and environmental assessments. A map of these, along with other onshore cable routes considered, can be found in the latest brochure here.
Where will the cables come ashore?
The cable landfalls are Freshwater West beach in Pembrokeshire and Baginbun Beach in County Wexford. The landfalls were selected after a review of potential sites in the regions. At both locations we will be using a Horizontal Directional Drilling technique to install the cable under the beach and dunes and thus avoid impacts on the local environment or beach users.
How will the cables be laid?
The interconnector cable will be under the sea or below ground for its entire length between the substation in Ireland and the substation in Wales. The marine cable is buried under the seabed (or laid on the seabed with a protective cover, where this isn’t possible) using purpose-built ships with cable laying tools.
To minimise disruption to beach users and respect the sensitive environments at the landfalls, we are planning to install the cable using Horizontal Directional Drilling (HDD). HDD is a widely used modern technique to install cables underground and avoid open trenching. Following extensive studies, a cable route is determined for the HDD and drilled. The resulting hollow is tubed with an inert pipe and the cables laid within. The cable is jointed behind the beach and dunes underground and will be buried all the way to each substation. This methodology will avoid any requirement for beach closures during installation.
Onshore the cables will be laid in trenches with a depth of cover of at least 850mm deep. It is usual to increase the depth of cover in agricultural land to avoid impacts on agricultural practices. A specific design will need to be engineered for any utility crossings, watercourses and any other areas where the ordinary depth of cover cannot be achieved.
The precise route and how much of the underground cabling will follow existing roads will differ in Wales and Ireland due to different circumstances (overall length, landownership, etc.) but the same fundamental routing principles have been applied in both jurisdictions.
Where will the cable connect to the grid?
At the National Grid Pembroke substation in Pembrokeshire and at EirGrid’s Great Island substation in County Wexford.
Will there be any overhead cables?
All the onshore cables will be buried underground and the offshore cables will be buried in the seabed or, where this is not possible, laid on the seabed with a protective cover.
Will the interconnector be visible?
All the cabling between the two converter stations will be underground and, once installation is complete, there will be no permanent visual impacts from the cables (for example, any necessary vegetation clearance will be temporary and will be restored). There will be no fencing or permanent structures on Freshwater West beach or Baginbun beach. Link boxes (small cabinets) could be located at strategic locations along the cable route. These will be small in number (circa one every 6km) and located within field boundaries to minimise any visual impact.
The converter stations near Pembroke and Great Island substations will be visible. The converter station site footprint will be circa 1.85 hectares (185m x 100m).
A converter station consists of various components. These include a converter hall, converter transformers, AC switchgear and busbars, harmonic filters (if required), lightning towers, ancillary plant such as cooling bank and stand-by back-up emergency generators, and a control building. Typically the tallest components are the lightning towers at circa 26 metres high and the converter hall, which will be approximately 17 metres high at its apex.
We have conducted a visual impact assessment and produced visualisations from viewpoints agreed with Pembrokeshire County Council and Wexford County Council. The visual impact of the converter stations will be carefully considered and suitable mitigation, such as landscaping and building finishes, will be incorporated.
How safe is it?
All the cabling will be buried under the ground or under the seabed (or laid on top of the seabed with protection where this isn’t possible). The electricity cables are in protective armoured casing and on land they will be buried to a depth of at least 850mm with a protective cover and warning tape. Marker posts will be installed at regular intervals at ground level.
The HVDC cables we are using emit lower levels of electromagnetic fields (EMF) than HVAC cables and both technologies adhere to World Health Organisation guidelines. Greenlink has engaged expert consultants and has committed to undertake EMF assessments to provide further confidence where required.
The lowest limit for static magnetic fields referenced by ICNIRP (International Commission on Non-Ionizing Radiation Protection) is 500 microtesla to protect wearers of implantable electronic medical devices. From a human health point of view the EU recommends a limit of 40 milli tesla (40,000 microtesla). (EMF Recommendation 1999/519/EC).
The maximum level from the proposed cable will be experienced directly above the cable. Under full load conditions the DC magnetic field will be 17 microtesla. To put this into context the earth’s magnetic field, which is exactly the same type of field, is approximately 47 microtesla in Ireland. As such, the magnetic field produced by the cable will be lower than the existing background level.
At 5m from the cable the level will have reduced to 2.5 microtesla. In effect, this level will be very low with respect to the earth’s magnetic field. This is 160 times below the 500 microtesla guideline limit.
As such, the emissions from the cable comply with the ICNIRP and EU recommended limits by a wide margin.
Will it be noisy?
Our environmental and technical surveys include an assessment of noise and vibration. Most of the noise and vibration impact will be during construction of the converter station and the burial of the cable and will therefore be temporary and at isolated locations. However, we will work to ensure that this is kept to a minimum. There will be noise from the electrical and mechanical plant during operation of the converter station, but this will mostly be located indoors in the converter hall and at lower levels than the neighbouring power stations and substations in both Ireland and Wales. All noise was fully assessed within the planning application documents.
How will it affect wildlife and the natural environment?
The Greenlink interconnector will have minimal impact on the local wildlife and natural environment. We have worked closely with independent experts on a range of environmental and technical surveys, the results of which have helped us to design the project sensitively and minimise impacts. We voluntarily conducted a full Environmental Impact Assessment, which allowed detailed scrutiny from stakeholders. Our surveys and assessments were verified by Natural Resources Wales (Wales) and the National Parks and Wildlife Service (Ireland), for example.
For more information on the studies and assessments carried out in Ireland and Wales, please click here
How will it affect Freshwater West in Wales and Baginbun Beach in Ireland?
We fully appreciate the beauty of both Freshwater West beach and Baginbun beaches and their value to local residents, visitors and wildlife. We recognise that some might have concerns about potential damage during construction. It is for this reason that we have consulted with independent experts and stakeholders, including Natural Resources Wales and the National Parks and Wildlife Service, to design the project sensitively and we have conducted a range of environmental and technical surveys.
To minimise environmental impacts, it is currently proposed that the cables between the landfalls and the sea will be installed by drilling underneath the beaches (known as Horizontal Direct Drilling or HDD).
Regarding potential disruption to beach users, the installation of cables is likely to last no more than 3 months with a temporary compound located on the fields behind the beach and there will be no access restriction to the beaches or dunes during this process. Work will be scheduled to take place outside of the peak summer period. Once this is complete, the cabling will be invisible and there will be no fencing or any other permanent structures restricting access.
What about traffic impacts?
We will work hard to limit the impact of traffic and transport on local residents and businesses as much as possible during construction. The project is expected to temporarily give rise to additional traffic on the local road network. Installation of the cables may require partial or full road closures and road users may have to use alternative routes. We continue to consult closely with Wexford County Council and Pembrokeshire County Council to minimise these impacts, including through Traffic Assessments and the production of Traffic Management Plans.
We will comply with the requirements of Wexford County Council and Pembrokeshire County Council with regard to reinstatement of the roads.
Which organisations/bodies are you consulting with?
During the development of the project, we have consulted widely with a range of statutory consultees, NGOs and government bodies.
In Wales these have included (but not been limited to):
- Pembrokeshire County Council
- Pembrokeshire Coast National Park Authority
- Natural Resources Wales
- Milford Haven Port Authority
- Local councils
- Castlemartin Firing Range
In Ireland these have included (but not been limited to):
- An Bord Pleanála,
- Wexford County Council,
- Commission for Regulation of Utilities
- Government departments
- The National Parks and Wildlife Service
What is the status of the planning applications and who were they submitted to?
In Wales, planning applications were submitted to Pembrokeshire County Council and Pembrokeshire Coast National Park Authority for the onshore components of the project in early 2020 and were unanimously consented by both authorities in July 2020. In Ireland, a planning application was submitted to An Bord Pleanála for the onshore components of the project in December 2020 and has now been approved.
The marine applications were submitted to Natural Resources Wales and to the Department of Housing, Planning and Local Government (Foreshore Unit) in Ireland in Autumn 2019.
NRW approved the application in Wales in March 2021.
For more information and documents pertaining to planning, please click here.
What are the local and regional benefits for Wales and Ireland?
Greenlink will provide additional network capacity, reinforcing the electricity grids in Ireland and southernWales and make a positive contribution to the regional security of electricity supply.
The privately financed €500/£420 million project represents valuable investment in Ireland and Wales andwill lead to direct jobs. During construction there will be around 250 direct jobs on each side and furtherknock-on economic benefits in each region. Once the project is operational there are expected to be up to 5 permanent jobs in Pembrokeshire and up to 20 in Ireland, with many of these in the Great Island area of Co.Wexford.
We are committed to maximising the use of locally based contractors and personnel during the construction and operational phases of the projects. The significant amount of work due to take place at the landfall,cable and converter station sites will require skills and experience available from contractors in the area.
If you are a local business interested in the project, please visit our Suppliers & Procurement page for more details of goods and services that might be required and how to make contact.
Where the design and route of the project offers opportunities to the local community, we will explore those (see question on community benefit below).
Please view our Project Benefits page for more information.
How can local people have their say?
We are very keen to hear people’s views on the project. Since May 2108, our consultation process has included a number of public exhibitions (you can see the full list of events here) and meetings with statutory authorities, community representatives and local organisations in Pembrokeshire and Co. Wexford.
To date, there have been four rounds of public exhibitions as follows:
May 2018: Pembroke Dock, Hundleton and Angle
December 2018: Pembroke Dock, Hundleton and Angle
June 2019: Pembroke, Angle, Pembroke Dock and Hundleton
December 2019: Hundleton, Angle, Pembroke Dock and Pembroke
June 2018: Fethard on Sea and New Ross
August 2018: Duncannon
January 2019: Fethard on Sea, New Ross and Duncannon
March 2019: Ramsgrange
December 2019: Ramsgrange, Duncannon and Fethard on Sea
Our local engagement will continue and we encourage local people to to discuss any concerns with the team. We also encourage local businesses and suppliers to get in touch to discuss the opportunities to be involved in the project.We can be contacted at any time by email at firstname.lastname@example.org and all the latest information on the project,including a regularly-updated downloadable brochure and exhibition boards, is available on our website - please view our pages here.
For future events, please check our events page here.
Why is the subsea cable route in Ireland not coming up the Estuary directly into Great Island?
This route was considered but not deemed to be optimal following consultation with the Port of Waterford. The estuary plays an important role within the local economy and concerns were raised regarding potential sterilisation of the waterway due to interaction between the cables and ongoing dredging activities.
Can the HVDC cables be converted to run as HVAC at the flick of a switch?
The cable configuration for HVAC is different (three cables instead of two), so no.
The cables also run between AC/DC converter stations and therefore are required to be HVDC.
What is the impact on sites of local historic value?
We assessed the potential effects of Greenlink on designated and non-designated local archaeology and cultural heritage assets.
To mitigate any potential impacts, we considered the predicted impacts of the proposed scheme and aimed to avoid adverse effects. Wherever possible, mitigation was designed to deliver benefits, such as maintaining the visual setting of historic assets. We aimed to avoid undisturbed archaeological remains and preserve them in situ. Where this is not possible, preservation by record will be proposed as mitigation.
Will the onshore cable-laying damage the roads? Will they be fully re-surfaced after construction?
The installation will follow best practice and ensure that the resultant road surface is of the standard required by the Highways Authority.
What engagement have you had with fisheries in Ireland and Wales?
Consultation had a direct impact on the delivery of subsea surveys undertaken as part of the development work. Existing fishing areas were identified, and relevant fishing interests were kept informed of planned survey work to minimise impacts.
What community benefit are you providing?
Where the design and route of the project offers opportunities to the local community, we will explore these. These might include local infrastructure improvements.
Once the major contracts have been awarded, we will be looking to maximise the use of locally based contractors and personnel and this will also lead to knock-on economic benefits in the area (for shops, B&B providers etc). We are looking at holding a meet-the-buyer event locally where these can be discussed.
Are you going to provide a community fund to be spent by local organisations, like you get with wind farms?
We are not providing an annual community fund of the type typically provided at renewable energy projects because Greenlink is not an energy generating project. However, we will hear people’s views and listen to suggestions, for example for how the design can bring about infrastructure improvements that benefit the local community (see above).