Adding Capacity to Sainte-Marguerite-3 Generating Station Project

Hydro-Québec is proposing to increase the capacity of the Sainte-Marguerite-3 hydroelectric power station on the Sainte-Marguerite River near Sept-Îles, Quebec. As proposed, the project would include the installation of a third generating unit in the existing power station, at the site earmarked for this purpose, as well as the construction of a 300-metre underground penstock linking the headrace tunnel to the future generating unit. The project would increase the capacity of the existing power station by at least 440 megawatts, for a total of 1,322 megawatts.

Latest update

July 18, 2025 — The Impact Assessment Agency of Canada issued an early decision for the project. The documents and list of factors considered can be found in the Notice of Impact Assessment Decision with Reasons.

At a glance

Planning

Planning

Completed 63/180 days

Key documents

Impact Statement

Impact Statement

Not applicable
Impact Assessment

Impact Assessment

Not applicable
Decision Making

Decision Making

Not applicable
Post Decision

Post Decision

Not applicable

Participate

Contacts

Impact Assessment Agency of Canada
160 Elgin Street, 22nd Floor
Ottawa, Ontario K1A 0H3
Telephone: 613-957-0700 or 1-866-582-1884
Fax: 613-957-0862
Email: information@iaac-aeic.gc.ca

Media Relations
Impact Assessment Agency of Canada
160 Elgin Street, 22nd Floor
Ottawa, Ontario K1A 0H3
Email: media@iaac-aeic.gc.ca


Disclaimer

This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.

  • Location

    • Sept-Îles (Quebec)

  • Nature of Activity

    • Hydroelectric Energy

  • Assessment Status

    Completed

  • Start Date

    2025-04-07

  • Proponent

    Hydro-Québec

  • Authorities

    • Impact Assessment Agency of Canada

  • Assessment Type

    Early decision - No further assessment required

  • Reference Number

    89403

Nearby assessments

...within 200 kilometres
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