National Grid’s Welsh grid upgrade clears planning validation hurdle

National Grid has had four planning applications validated for a major electricity network upgrade in North Wales, as it seeks to reinforce the existing high-voltage route between Pentir and Trawsfynydd and unlock more capacity to move low-carbon power to homes and businesses.

National Grid said the proposals, part of its wider Great Grid Upgrade programme, are intended to relieve pressure on the existing network and support Wales’ clean power and energy security ambitions, as electricity demand rises.

North Wales is expected to become a growing hub for clean power generation, with plans for an SMR at Wylfa, growing generation from offshore wind assets in the Irish Sea, and a new test bed for tidal energy off the coast of Anglesey. That will make reinforcing the grid critical to ensure that power can get where it needs to go – with the Pentir and Trawsfynydd cited as a common pinch point at this moment in time. 

To that end, National Grid submitted planning applications to upgrade the network in early December to Gwynedd Council (three applications) and to the Eryri National Park Authority (one application). National Grid has now confirmed each has been validated by the relevant local planning authority, meaning the submissions have passed an initial check that the paperwork is complete and can be formally processed.

While validation is not planning permission, it is a key administrative step that moves the project into the next phase of scrutiny, including consultation and assessment by planners.

John Lamb, Director for Pentir to Trawsfynydd, noted, “We are pleased to have reached a significant milestone for our Pentir to Trawsfynydd project.

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

What’s being proposed

The planning submissions cover four main elements along the existing corridor, mixing works within existing substation sites with new infrastructure and cabling replacement. National Grid’s applications seek consent for:

• Installing new and replacement underground cables and other equipment within the existing substation site at Pentir
• Replacing 5.8km of underground cables 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

While they’re not exactly bold plans – they will enable North Wales to reliably grow as a centre for generating clean energy. That should have a knock on benefit for local households, which could benefit from access to greener and cheaper electricity. 

That doesn’t mean that the application process will be smooth, however. National Grid will be hoping that its previous community engagement will help the project maintain momentum through scrutiny and consultation, allowing it to receive final consent that aligns with its target to start work in summer 2026.