Meeting the electricity needs of today and tomorrow while supporting economic and social development
To meet the sector’s growing electricity needs, Hydro-Québec will be investing over $500 million to upgrade its transmission system in the north-south axis of the island of Montréal, between the boroughs of Saint-Laurent and LaSalle. As the system’s equipment is aging, it must be replaced.
This project also aims to maintain the reliability of electricity supply and ensure continuity of service over the long term for all the region’s residents.
Hydro-Québec will add approximately 500 MW of capacity to support economic and social development in the following sectors:
- Commercial and residential development projects
- Public transit projects such as a Réseau express métropolitain (REM) station and Société de transport de Montréal (STM) garages for recharging electric buses
- Manufacturing projects
- Data centers and greenhouses
> $500 M invested
≈ 500 MW of planned capacity
18 km of transmission line to convert
3 substations to convert
Electrical system upgrade between Aqueduc and Saraguay substations
The project includes:
- rebuilding the existing 120-kV Aqueduc–Saraguay overhead transmission line at 315 kV over a distance of 18 km from Saint-Laurent to LaSalle. The line will be rebuilt it in the existing right-of-way, but the route may be optimized at a later stage to mitigate its impacts according to technical, economic, environmental and social criteria.
- converting three transformer substations — Rockfield substation (in Lachine), Hampstead substation (in Côte Saint-Luc) and Laurent substation (in Saint-Laurent) from 120 kV to 315 kV.
Hydro-Québec will also conduct a preliminary study for the construction of a new substation in the Dorval area as well as the associated supply line.
The line right-of-way for the project is situated in an urban environment that is very dense in places. To harmonize its project with the development approach of each of its municipal partners, Hydro-Québec is working in close collaboration with the towns, boroughs, organizations and residents concerned.
Harmonization with the project to upgrade the transmission system on the island of Montréal
This project is part of a broader plan to upgrade the transmission system on the island of Montréal, where the voltage is being increased from 120 kV to 315 kV.
The conversion of substations and transmission lines to 315 kV began in the eastern part of the island in 2009 (in light green on the map). The conversion project is continuing downtown and in the western part of the island. Projects under study or under construction are shown in dark green.
The next step is to complete an upgrade of the line in the Aqueduc–Saraguay axis and to convert the Laurent, Hampstead and Rockfield substations to 315 kV.
Saraguay substation
Saraguay substation is the northernmost point of the line that will undergo conversion. It is located in an industrial area and was commissioned in 1959. It supplies power to residences, businesses and industrial operations in Pierrefonds-Roxboro, Dollard-Des-Ormeaux and Saint-Laurent.
Although the substation does not need to be rebuilt, some adjustments must be carried out in order for the line to be converted. A reconfiguration of the towers around the substation and the replacement of equipment inside it are planned.
Diaporama
Following content is a slideshow of: Saraguay substation.
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1954: Land use around the substation, which was commissioned in 1959 -
1975 Land use around the substation -
2015 Land use around the substation
Saraguay‑Laurent segment
There are two overhead transmission lines in this line corridor, both operated at 120 kV. One of the lines will be dismantled and rebuilt at 315 kV on the same route.
Diaporama
Following content is a slideshow of: Saraguay‑Laurent segment
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1981 : Hydro-Québec transmission line segment between Saraguay and Laurent.
Source : Archives d’Hydro-Québec. -
2018 : Transmission line segment between Saraguay and Laurent substations.
Laurent substation
Laurent substation is located in an industrial and commercial area near the IKEA store in Saint-Laurent. Commissioned in 1962, it reduces the voltage from 120 kV to 12 kV or 25 kV. The electricity then supplies residences, businesses and industrial customers in the Saint-Laurent and Lachine boroughs and the town of Mont-Royal via the distribution system.
As part of the project, new 315-kV, 120-kV and 25-kV equipment will be installed at Laurent substation.
Diaporama
Following content is a slideshow of: Laurent substation
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1954 : Land use around the substation, which was commissioned in 1962 -
1973 : Land use around the substation -
2015 : Land use around the substation
Laurent‑Hampstead segment
This line corridor contains an overhead transmission line operated at 120 kV. It will be dismantled and rebuilt at 315 kV. The exact route of the line is currently under study. It will be the subject of consultations with the community.
Transmission line segment between the Laurent and Hampstead substations in 2018.
Hampstead substation
Hampstead substation is located in a residential area. Commissioned in 1955, it reduces the voltage of electricity from 120 kV to 12 kV or 25 kV. The electricity then supplies residences, businesses and industrial customers in Côte Saint-Luc, Hampstead, Montréal-Ouest, Côte-des-Neiges–Notre-Dame-de-Grâce and Lachine via the distribution system.
As part of the project, new 315-kV equipment will be installed at Hampstead substation.
Diaporama
Following content is a slideshow of: Hampstead substation
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1954 : Land use around the substation, which was commissioned the following year -
1973 : Land use around the substation -
2015 : Land use around the substation
Hampstead–Rockfield segment
This line corridor contains an overhead transmission line operated at 120 kV. It will be dismantled and rebuilt at 315 kV. The exact route of the line is currently under study. It will be the subject of consultations with the community.
Transmission line segment between Hampstead and Rockfield substations in 2018.
Rockfield substation
Rockfield substation is located in an industrial area. Commissioned in 1947, it reduces the voltage of electricity from 120 kV to 12 kV or 25 kV. The electricity then supplies residences, businesses and industrial customers in Lachine, LaSalle and Montréal-Ouest via the distribution system.
Rockfield substation will be rebuilt at a voltage of 315 kV.
Diaporama
Following content is a slideshow of: Rockfield substation
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1954 : Land use around the substation, which was commissioned in 1947 -
1973 : Land use around the substation -
2015 : Land use around the substation
Rockfield–Aqueduc segment
The overhead transmission line between Rockfield and Aqueduc substations travels through the boroughs of Lachine and LaSalle at a voltage of 120 kV. It will be rebuilt at 315 kV.
Transmission line segment between Rockfield and Aqueduc substations in 2018.
Aqueduc substation
Located in the borough of LaSalle, the Aqueduc substation is the end point of the line that will undergo conversion to 315 kV.
Although the substation does not need to be rebuilt, it requires certain adjustments in order for the line to be converted. A reconfiguration of the towers around the substation and the adjustment of equipment inside it are planned.
Diaporama
Following content is a slideshow of: Aqueduc substation.
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1954 : Land use around the substation, which was commissioned in 1971 -
1973 : Land use around the substation -
2015 : Land use around the substation