Project overview

Construction of the power line is underway.

Hydro-Québec began the Integrated Enhancement Program (IEP) application process with eligible organizations in September 2016.

Chamouchouane substation in Saguenay–Lac-Saint-Jean.

The optimal solution for ensuring the reliability of Hydro-Québec’s transmission system

Hydro-Québec’s transmission system, the largest in North America, carries the power produced by generating facilities located primarily in the Baie-James region and Manicouagan-Outardes corridor, in northern Québec, to load centres in southern Québec.

The grid is constantly evolving according to changing transmission needs and the increase in power consumption. The demands placed on the 735-kV lines are growing steadily.

Video: Hydro-Québec transmission system, the largest in North America [in French only]

Jean-Pierre Giroux, Director of transmission system planning at Hydro-Québec, talks about the high-voltage transmission system that connects large generating facilities, located mainly in northern Québec, with major load centres, concentrated in the south.

He describes how the system has evolved, from the commissioning of the first high-voltage lines in the 1950s until today.

Funnel effect around Chamouchouane and Saguenay substations

In the Lac-Saint-Jean region, four transmission lines bring power to the Chamouchouane and Saguenay substations from the north (from Baie-James on one side, and Côte-Nord on the other), while only three run southwards. This creates a funnel effect and limits the system’s capacity to bring power to the south, where the major load centres are located.

As a result, the transmission system must be reinforced between Chamouchouane substation and the Montréal metropolitan loop to counter the funnel effect and reduce pressure on the entire system.

In addition, the Chamouchouane–Bout-de-l’Île project will considerably reduce electrical losses on the system and increase operating flexibility, benefiting all Hydro-Québec customers.

Area where the energy transmission corridors from the Baie-James and the Côte-Nord meet.

Video: Chamouchouane–Bout-de-l’Île, an essential project for the transmission system [in French only]

Jean-Pierre Giroux, Director of transmission system planning at Hydro-Québec, talks about the 735-kV Chamouchouane–Bout-de-l’Île project, which is essential to the power transmission system.

Growing electricity needs in the Laurentides region

In the Terrebonne area, the demand for electricity is experiencing strong growth, due in large part to the Urbanova major residential development and the new Train de l’Est.

The Laurentides region is experiencing the greatest rate of growth in Québec, at 1.2% a year. Moreover, the expected growth rate for the Mille-Îles area for 2013 to 2027 is 1.6% a year, the highest in the region.

The capacity of certain substations in Mascouche and Terrebonne will be exceeded in the near or short term, and several 120-kV lines between Duvernay and Laval’s north shore are facing the same situation.

Hydro-Québec must thus expand its transmission system with additional infrastructure to meet this increasing demand.

Plans to build a new line

Based on environmental studies, technical studies and the meetings it has held to date in the project’s host community, Hydro-Québec is proposing the following:

  • Construction of a 406-km 735-kV line between Chamouchouane substation in Saguenay–Lac-Saint-Jean and the Montréal metropolitan loop. In light of concerns expressed by the community during the public consultation, Hydro-Québec proposed a new route located to the west of the initial route. At the same time, it was studying power needs in the Terrebonne and Mascouche areas (see Judith-Jasmin substation). Moving the route of the Chamouchouane substation line farther west made it possible to combine the 735-kV line project with plans to build a new substation servicing Terrebonne and Mascouche. As a result, the new Judith-Jasmin substation will be built in Terrebonne.
  • Diverting a section of an existing 735-kV line over 19 km. This line will supply Bout-de-l’Île substation rather than Duvernay substation, to which it is currently connected.

To learn more about the steps in building a power transmission line

Nouvelle ligne du Saguenay–Lac-Saint-Jean à Montréal et poste Judith-Jasmin (400 km) [interactive map – in French only]
Déviation de Lanaudière à Montréal (19 km) [interactive map – in French only]

Major economic spinoffs for Québec

The project’s economic spinoffs for Québec are estimated at $1.1 billion, representing more than 80% of the total investment. The project will create the equivalent of more than 1,000 full-time jobs over a five-year period. During peak periods (2017–2018), more than 1,500 workers will be employed on the project.

Projects carried out in collaboration with affected communities

To develop the best possible power transmission project, Hydro-Québec works together with affected publics every step of the way, from the time the project is first announced to the facility’s commissioning.

For every project, Hydro-Québec sets up a public participation program to explain it, respond to stakeholders’ information needs and hear community concerns. Hydro-Québec also communicates with representatives of various levels of government, official representatives of the communities involved, property owners, residents, community organizations, contractors, suppliers and regional media.

This process helps ensure that projects are integrated harmoniously into their environment and raises the level of community acceptance. Discussions with stakeholders are helpful in determining the line route that will have the smallest social, environmental, technological and economic impact. They also contribute to ensuring that projects meet the needs and expectations of the host community.

To learn more about the public consultation process [pdf — 1.4 MB]

Bout-de-l’Île substation, Montréal.