In this library you can view documents we’ve produced for the Pentir to Trawsfynydd reinforcement and refurbishment project.

In this library, you can view documents we’ve produced for the Pentir to Trawsfynydd reinforcement and refurbishment project.

We have now submitted our planning applications for the four main elements of the project.  

We have applied to Cyngor Gwynedd for permission to build a substation south of Bryncir; install replacement cables beneath the Glaslyn Estuary and complete other related work; and install new cables and other equipment within our existing Pentir Substation.  

You can view these three applications on Cyngor Gwynedd’s online planning portal:  

Pentir Substation Application

Bryncir Application

Glaslyn Cables Application 

We have submitted the application for work at Trawsfynydd Substation to Eryri National Park, because the substation is within the national park.  

You can view this application on Eryri National Park’s online portal:  

Trawsfynydd Application  

Please note: the draft application documents available below were presented during our Pre-Application Consultations in September and October 2025. These documents are provided as a record of the information shared at that time. Please use the links provided above to view our final application documents.  

If you have any questions about this information, or accessing any of our documents, please call or email us using the contact details on the right-hand side of this page.

We will continue to keep this library up to date as the project progresses.