What’s been done so far in Eryri, what is coming up and what will happen as the project progresses.
Autumn 2014
A section of overhead lines in the Eryri National Park that crosses the Dwyryd Estuary near Porthmadog was identified as having a significant landscape and visual impact.
Winter 2014 – Autumn 2015
National Grid and independent landscape consultants undertook further technical work and considered the detailed input from local stakeholders in Gwynedd and the National Park. This enabled the project’s Stakeholder Advisory Group to prioritise the section of transmission line as one of four to be taken forward in England and Wales in September 2015.
Spring 2015
National Grid, working with local partners, established a Stakeholder Reference Group. The following organisations regularly attend these technical meetings:
- Cadw
- Gwynedd Archaeological Planning Service
- Cyngor Gwynedd
- National Trust
- Natural Resources Wales
- Network Rail
- Eryri National Park Authority
Winter 2015 – Summer 2016
National Grid undertook environmental, transport and ecology surveys in the area around the line both within and outside the National Park boundary and engaging with technical stakeholders and members of the local community.
Autumn – Winter 2016
The VIP project’s Stakeholder Advisory Group reviewed the results of the environmental and engineering surveys, the stakeholder feedback and National Grid’s preferred options. The Group recommended that the project should proceed to further development work which would inform the preparation of a planning application.
2017 – 2018
Geotechnical surveys took place throughout 2017 and 2018; the results of which helped us to develop detailed engineering designs.
In November and December 2018, we carried out a formal consultation, with three days of events in Penrhyndeudraeth and Talsarnau.
Stakeholders and members of the public in Penrhyndeudraeth and the surrounding towns and villages were invited to public consultation events to find out more about our plans. This consultation also provided an opportunity to submit formal feedback on our proposals.
2019 – 2020
We undertook a pre-application consultation, including an event in December 2019 at the Eryri National Park office in Penrhyndeudraeth, and submitted a planning application in March 2020 in respect of the tunnel head house sites at each end of the project, and associated infrastructure.
In July 2020, we received planning permission subject to the discharge of a number of conditions from both the National Park Authority and Cyngor Gwynedd. Both planning committees were unanimous in their approval of the project.
2021
We held a tender event to identify and appoint the main contractor to deliver the project with National Grid.
2022
We announced Hochtief UK as our main contractor for the project and began survey work, detailed project design and site establishment.
2023
Full construction work started in February 2023, when we started setting up the main site construction sites in Garth and Llandecwyn.
In July 2023, the Eryri VIP project team moved from offices at Trawsfynydd substation into its new compound at Garth, the launch site for the tunnel boring machine (TBM) and the location for the equipment to process material taken out of the ground when building the shafts and the tunnel.
We also started creating the entrance for our site in Llandecwyn, the location of one of the tunnel headhouses.
2024
On the Garth site, we completed the lagoons to process the water used in tunnelling and started building workshops and treatment plant structures to support the TBM on its underground journey.
In anticipation of the TBM’s arrival, we held a naming competition for the machine, where we invited pupils to submit entries inspired by a figure of significance in Welsh STEM, culture or folklore. The winning name, Buddug, was submitted by Scarlett Katie Lebeau Harvey, from Ysgol Eifion Wyn, Porthmadog and means buddugoliaeth / victory and deallus / intelligent.”
Buddug was transported in sections and arrived as 27 different deliveries to the Garth site construction compound in November 2024.
2025
In May 2025, we launched Buddug from her starting point in Garth, Minffordd to begin her 3.4km journey tunnelling under the Dwyryd Estuary towards Llandecwyn. To mark the launch, we held a blessing ceremony for the TBM, a site visit from members of the Minffordd community and a stakeholder event with strategic partners and advisory group stakeholders.
By late October 2025, Buddug had tunnelled over 1,200 metres and installed over 1,000 rings, completing over a third of her journey to create the tunnel where we will install the new electricity cables.
At Llandecwyn, we continued constructing the reception shaft where we will lift Buddug out of the ground once she finishes tunnelling across the estuary. We completed the main ground treatment works for the shaft and made good progress with excavation works, which revealed a variety of rocks, sediment and even a few boulders.
2026 - 2029
Buddug is on track to finish tunnelling in 2026. We will then begin to insert the cables that will replace the overhead line and pylons crossing the Dwyryd Estuary.
Following this, the project team will start working on the construction of the tunnel headhouse and sealing end compound which will connect the underground cables to the existing overhead line.
Pylon and overhead line removal is due to be completed in 2029.