National Grid has confirmed that four planning applications to upgrade the electricity network between Pentir and Trawsfynydd in North Wales have been validated by Gwynedd Council and Eryri (Snowdonia) National Park Authority.

The submissions, made in early December, cover works to reinforce and refurbish parts of the existing high-voltage network.

Validation is the first step in the planning process, where local authorities check applications are complete and correctly prepared before formal consideration.

The scheme forms part of The Great Grid Upgrade, a nationwide programme to modernise the UK's electricity system. In North Wales, the proposals aim to meet rising demand, relieve pressure on existing infrastructure, support Wales's clean power and energy security objectives, and reduce constraint costs — the additional expense incurred when grid capacity cannot carry power to where it is needed. The upgrades are expected to stimulate local economies, create jobs and strengthen the resilience of supplies, helping to connect cleaner, more affordable energy to homes and businesses.

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John Lamb, Director for Pentir to Trawsfynydd, said: "We are pleased to have reached a significant milestone for our Pentir to Trawsfynydd project."

He added: "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."

The applications cover four main elements: installing new and replacement underground cables and associated equipment within the existing Pentir substation; replacing 5.8km of underground cables beneath the Glaslyn Estuary at Porthmadog from Wern to Minffordd; constructing a new substation south of Bryncir; and installing new and replacement underground cables and equipment within the existing Trawsfynydd substation.

Ahead of submission, National Grid held public information events in May to brief local communities and answer questions. In line with Welsh Government requirements, a 28‑day statutory pre-application consultation took place in September, with feedback used to refine the plans.

Decisions on the applications are expected early next year. Subject to approval, construction is scheduled to start in Summer 2026, with the project due to be fully operational in 2030.