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Minffordd Area

National Grid launches consultations on plans to upgrade the electricity network between Pentir and Trawsfynydd

18th September 2025
Press release
  • The proposals, part of The Great Grid Upgrade, are required to reinforce and refurbish parts of the high voltage power network in North Wales.
     
  • Upgrades are needed to the existing network between Pentir and Trawsfynydd, to reinforce the electricity transmission network in North Wales and boost local economy, creating jobs, and providing cleaner, home-grown, more secure energy.
     
  • National Grid is undertaking a 28-day statutory pre-application consultation, ahead of submitting four planning applications to both Gwynedd Council and Eryri National Park Authority.


Today, Thursday 18 September, National Grid begins four pre-application consultations on proposals to reinforce and refurbish the existing electricity network between Pentir and Trawsfynydd. The consultations are open until Wednesday 15 October. 

The way electricity is generated in the UK is changing rapidly to a cleaner, more affordable and more secure energy system for the future. To meet rising energy demand National Grid needs to reinforce and refurbish the existing electricity network between Pentir and Trawsfynydd in North Wales. These upgrades will help relieve pressure on the existing network, support the Welsh government’s energy security and clean power goals, and reduce constraint costs - which are the extra costs added to bills when there is not enough grid capacity to move power where it is needed. 

The project is part of the Great Grid Upgrade, the largest overhaul of the electricity grid in generations, and will help keep the network secure and resilient by enabling more clean energy to be delivered to homes and businesses. 

The consultations follow a series of public information events National Grid held in May, which gave local people an early opportunity to see its plans, ask questions and meet the project team. 

Suzanne Crouch, Portfolio Director for Pentir to Trawsfynydd, said:

“We will take into consideration the feedback received during this pre-application consultation to help refine our proposals before submitting our planning applications to Cyngor Gwynedd and Eryri National Park later this year.  

“To meet rising electricity demand and allow new sources of clean, home-grown energy to reach homes and businesses, we need to reinforce and refurbish the existing electricity network between Pentir and Trawsfynydd. This will help to make our energy supply more secure, independent and deliver long-term benefits to bill payers.” 

The statutory 28-day consultations give consultees the opportunity to feedback on the draft planning applications for the following four main elements of the project:   

  • Installing new and replacement underground cables and other equipment within the existing substation site at Pentir
  • Replacing 5.8km of underground cables that run beneath the Glaslyn Estuary at Porthmadog from Wern to Minffordd
  • Constructing a new substation south of Bryncir
  • Installing new and replacement underground cables and other equipment within the existing substation site at Trawsfynydd.  

Notices with information about the consultations are also being displayed on the application sites, and the draft applications are available to view on the National Grid website at www.nationalgrid.com/Pentir-Trawsfynydd  

Following consultation National Grid will carefully consider the comments received as it finalises its planning applications, prior to submission to Cyngor Gwynedd and Eryri National Park Authority later this year.  

Providing feedback 

To learn more about the consultations and how to get involved, members of the public can:    

The deadline for feedback is 11:59 pm on Wednesday 15 October 2025.