MacKay Generating Station (62 MW) - Montreal River

On January 1, 2015, the Ontario Power Authority merged with the Independent Electricity System Operator to create a new organization that combines the OPA and IESO mandates.

Please note that the information on this page is not current and will not be updated. A new format for contract data will be published soon.

The MacKay Generation Station is a three-unit hydroelectric station located on the Montreal River. The site was first developed in 1937 by constructing a concrete gravity dam and an adjoining earth fill structure. In 1957, the dam was raised to its current height. The station has an installed capacity of 62 MW at a head of 75.3 metres.

This station is the most upstream station along the Montreal River. The forebay of MacKay extends approximately 40 km upstream and features the largest reservoir on the Montreal River with a storage capacity of 4,952 m3/s*day.

MacKay has one penstock for each of the three units. Originally, this station had operating surge tanks used to relieve pressure during disturbances and start-ups, but are no longer in use. Each penstock is 3.4 metres in diameter.

MacKay is connected to the existing Hydro One 115kV line at MacKay #1 and #2 and connects to MacKay TS.

This hydroelectric generating station generates approximately 206,741 MWh of renewable energy per year.

River System: Montreal River
Nameplate Capacity: 62 MW
OPA Contracted Capacity: 62 MW
Operator: Brookfield
Technology: Hydroelectric
Turbines: Three Francis turbines
Originally Built: 1937
Coordinate: 84° 26' 12.01" W, 47° 16' 7.89" N
OPA Contract Term Commencement Date: December 1, 2009


Brookfield Renewable Energy Group

Project Contacts:

Ontario Power Authority

Media and Public Relations
T. 416-969-6307 or

Brookfield Renewable Energy Group

Zev Korman
Investor Relations and Communications
T. 416-359-1955