National Grid has had four planning applications validated for proposals to reinforce and refurbish the electricity network between Pentir and Trawsfynydd in North Wales.
The applications were submitted in early December to Gwynedd Council and Eryri National Park Authority and have now passed the initial checks confirming they are complete, said the company.
The upgrades form part of the Great Grid Upgrade and are required to meet rising electricity demand, added the developer.
National Grid stated that the work will support Wales’ clean power and energy security goals and help lower constraint costs.
The plans cover new and replacement equipment at the existing substation sites at Pentir and Trawsfynydd, 5.8km of replacement underground cables beneath the Glaslyn Estuary at Porthmadog, and construction of a new substation south of Bryncir.
The applications follow public information events in May and 28-day statutory pre-application consultations held in September.
National Grid anticipates decisions early next year.
Subject to approval, construction is due to begin in summer 2026 with the project scheduled to be fully operational in 2030.
John Lamb, director for Pentir to Trawsfynydd, said: “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.”