Hydro‑Québec’s selected line route

In summer 2019, Hydro‑Québec filed an environmental impact assessment (in French only) with the Ministère de l’Environnement et de la Lutte contre les changements climatiques. The study presents the line route selected by Hydro‑Québec for the project.

See visual simulations

Description of line route selected

The line route selected is 100.9 km long and crosses both the Appalaches MRC (37.3 km) and Du Granit MRC (63.5 km), affecting eleven municipalities in all.

The future line will be paired with one or more existing lines along 73% of its route.

The crossing point, where the line will connect to the power system on the U.S. side, is located on private land northeast of ZEC Louise Gosford in the municipality of Frontenac.

Line route modified at Thetford Mines and Saint‑Joseph‑de‑Coleraine

Following a public consultation in spring 2020 and the BAPE hearing held the following summer, Hydro‑Québec modified the line route in the area of Thetford Mines and Saint‑Joseph‑de‑Coleraine.

The route variant submitted for consultation was adjusted and improved to respond as fully as possible to the concerns expressed by the communities, while taking into account the technical issues associated with the area to be crossed.

The line will therefore cross the old British Canadian mine and will meet up with Hydro‑Québec’s initial route at Lac Noir.

The route initially proposed ran along the right of way of an existing power line. The modification will move the new interconnection line farther away from the Black Lake residential sector in Thetford Mines, and will reduce the impacts on property owners in the mine area.

In Saint Joseph de Coleraine, the route was shifted west, close to the mining road.

The selected line route crosses these municipalities

MRC Les Appalaches
Municipality Length
Saint-Adrien-d’Irlande (M) 3.6 km
Thetford Mines (V) 10.2 km
Saint-Joseph-de-Coleraine (M) 13.2 km
Disraeli (P) 6.7 km
Sainte-Praxède (P) 3.6 km
Total: 37.3 km
MRC Le Granit
Municipality Length
Stratford (CT) 9.8 km
Stornoway (M) 14.8 km
Saint-Romain (M) 0.9 km
Nantes (M) 16.2 km
Sainte-Cécile-de-Whitton (M) 5.6 km
Frontenac (M) 16.3 km
Total: 63.6 km

Environmental approach and project optimization

Environmental approach

Our decision to select this route was made based on an environmental approach involving the following steps:

  • Describe the environment.
  • Analyze the technical and environmental constraints as well as the sensitive elements.
  • Develop a route.
  • Assess the impacts.
  • Identify appropriate mitigation measures.
  • Agree on the follow‑ups to be conducted once the new line has been commissioned.

These steps, which were carried out in collaboration with the host community helped us to develop a solution and then adjust and refine it based on specific regional realities

Project optimization

As a result of numerous exchanges with host communities, the following modifications have been made to the project so far:

  • A family of tubular towers has been developed to allow for the integration of a 3.5‑km segment of the new line near an urbanized area of the town of Thetford Mines.
  • The route of the approximately 24‑km segment of the new line in the Du Granit MRC has been relocated to protect woodlands or follow lot boundaries.
  • To the extent possible, the future tower sites have been determined in accordance with landowners’ requests, to avoid valued elements on their properties.
  • The line route has been adjusted to ensure the safe coexistence of the power line and the region’s extensive logging operations.
  • The commitment has been made to plant shrub species that are compatible with the future power line to limit the impact of land clearing operations on certain properties.
  • The project schedule has been adjusted to take the sugar bush season into account

Technical characteristics of the planned line

  • Hydro‑Québec has developed a new family of towers for this project: the conductors are located on one side only, thus reducing the width of the right-of-way to be cleared
  • Each tower will be made up of a positive pole (+320 kV) and a negative pole (−320 kV)
  • Each pole will be equipped with two conductors
  • The line will be supported by approximately 320 towers
  • The average distance between towers will be 325 m
  • The right‑of‑way to be cleared will be 43 m wide where the line runs alone (27 % of the line route) and 10 to 25 m wide where it is paired with an existing line (73 % of the line route).

Power line in a new corridor between Nantes and the crossing point

Power line in a new corridor between Nantes and the crossing point

Ongoing environmental and technical surveys

Hydro‑Québec is conducting environmental and technical field surveys to prepare for land-clearing work and construction of the future power line:

  • Geotechnical surveys related to siting of the future towers to determine the type of foundation to lay for each support structure.
  • Forest surveys on all properties affected to determine the type and volume of timber to be felled, the traffic strategy to be implemented and the mitigation measures to be applied during work near sensitive elements such as wetlands or watercourses.
  • Characterization of the watercourses over which temporary bridges may be installed.
  • Detailed inventories of wetlands affected by the work areas for certain towers.
  • Inventories of areas with archaeological potential identified along the line route selected.
  • All of the above preparatory work is carried out with the consent of the landowners

Visual simulations



  • Viewpoint
  • Planned tower
  • Line route selected
  • Tower for the line route variant
  • Appalaches substation
  • Crossing point

A new variant of the line route in Thetford Mines and Saint-Joseph-de-Coleraine is being considered.

The consultation period is now over. The results are available at Registre des évaluations environnementales du Ministère de l’Environnement et de la Lutte contre les changements climatiques. (in French only)

For more information on the new variant