Category Archives: Harmon GS

Harmon Generating Station, Mattagami River

The Lower Mattagami Project is a hydroelectric project that includes the addition of a new third generating unit to the existing two-unit Harmon Generating Station.

Existing Facility

The existing Harmon facility includes two vertical propeller turbine-generator sets, penstocks and draft tubes, and three existing single-phase transformers. Harmon has been in-service since the mid-1960’s.

Located 90 km north of Kapuskasing, Ontario, the facility is operated remotely from OPG’s Northeast Control Centre located at the Porcupine Transformer Station in Timmins, Ontario.


The expansion includes one vertical propeller turbine-generator set, penstocks and draft tubes, and one new three-phase transformer. The addition of the new generating unit adds 78.3 MW to the existing capacity for a total site capacity of 219.3 MW at a head of 31.1 metres. Continue reading