South Brittany network strengthening project

The South Brittany project involves strengthening the natural gas transmission network by installing a new 98 km pipeline between Pluvigner (Morbihan area) et Pleyben (Finistère area).
South Brittany project

Securing the energy supply for South Brittany

This project forms part of Brittany’s electricity pact and aims to secure the region’s energy supply.

The new natural gas transmission capacities will also provide development opportunities for industrial companies, as well as new energy alternatives for private individuals in the region.

General map and municipal-level scale diagram

What’s new?

Entête de la plaquette d'information n°11 du projet Bretagne Sud

After seven months of construction, the network reinforcement project comes to an end. To find out all about the restoration of the land crossed and the filling of the pipeline with gas, consult the newsletter:

 Newsletter No.10 - Bretagne Sud project

The safety of structures is at the heart of GRTgaz's concerns. The Bretagne Sud project is no exception to the rule. From site supervision, to hydraulic tests that check the compliance of the structure, discover all the processes in place to deliver a faultless structure.

 Lettre d'information du chaniter de Bretagne Sud - mai 2021

The completion of four directional drilling operations on the site marks a key step in its progress. Installation works over the 98 km route are moving forward at pace, while the delivery stations are preparing the for connection of a new pipeline.

Discover the site’s main activities before the rehabilitation work!

 Newsletter no.8 cover - January 2021

An exceptional worksite with outstanding organisation! Two GRTgaz teams are supervising two groups of companies working simultaneously on the main sections of the pipeline. Opening accesses, earthworks for platforms, directional drilling... more and more operations are taking place along the 98 km of future pipeline. Planning, players, and some big steps to come...

Pour tout savoir sur le chantier de pose :

>> Newsletter No. 8 - Morbihan - February 2021
>> Newsletter No. 8 - Britany - February 2021



The prefectures of Morbihan and Finistère grant GRTgaz the use of administrative servitudes.

Public meetings were initially scheduled in the four municipalities crossed by the pipeline. However, these had to be cancelled due to the health crisis. GRTgaz suggested live web conference as a digital alternative.

The Finistère Prefect issued a temporary occupancy decree for the municipalities of Châteauneuf-du-Faou (29) and Spezet (29) for the subsurface drilling of the River Aulne.

 Launch of the project’s first directed drilling operation. The pipeline extends 1.2 km between the municipalities of Berné and Plouay, reaching a depth of almost 18 meters under the River Scorff in Morbihan.

The procedure involves drilling the subsoils using a drill with an adjustable bit. Once the bit emerges, we expand the borehole by drilling successive bores into which the pipe will later be inserted. The equipment needed for the works will be installed from platforms located on both sides of the borehole. Directional drilling has the advantage of avoiding impacts on the valleys of these watercourses and their woodland areas, conserving their environmental stability.

As part of the project, three other subsurface directional drilling operations are being prepared for the River Blavet, the River Aulne and the River Aër – the three main watercourses crossed by the pipeline.

First specialist works on the alignment of the pipeline

Project schedule

  • 2022: repair work and finishing touches
  • 2021: construction and commissioning of the pipeline
  • 2020: preparatory works and specialist works
  • 2019: soil surveys and archaeological diagnostics
  • 2018: preliminary studies
  • 2015: obtaining a Declaration of Public Utility and Ministerial Authorisation




2017 - 2018

2014 - 2015



Plan décennal de développement 2018 - 2027

GRTgaz’s ten-year development plan 2018-2027

Protocole entre la Profession Agricole et GRTgaz

Protocol between the Agricultural Profession and GRTgaz

Contact details for more information

  • By post:
    GRTgaz Direction des Projets et de l'Ingénierie
    Projet Bretagne Sud
    7 rue du 19 mars 1962
    92622 Gennevilliers cedex
  • By e-mail : arteres-de-bretagne(at)
  • By telephone: +33 (0)1 56 04 01 83