Seven Sisters Generating Station

Photo of Seven Sisters Generating Station

Seven Sisters Generating Station is Manitoba Hydro’s largest producer of electricity on the Winnipeg River. Located about 90 km northeast of the City of Winnipeg, it is fondly and respectfully described by engineers who designed and built it as the river’s mightiest generating station.

Seven Sisters, which is about 72 km from Lake Winnipeg, was built in 2 stages. The first stage, begun in July 1929, featured the construction of a powerhouse. When completed in August 1931, it housed the first 3 of 6 turbine generators (called units) which produced a total of 75 MW.

Stage two began later, in 1948, 3 years after World War II had ended. In 1952, the sixth and final unit was placed in service. These additional units doubled the generating station’s total megawatt production.


  • Construction started 1929;
  • Construction completed 1952;
  • Capacity 165 MW;
  • Average annual generation 990 million kWh;
  • Waterfall drop 18.6 metres;
  • Powerhouse 128 metres long;
  • 6 turbine generators (units) (units 1 to 3 turn at 138.5 rpm, units 4 to 6 at 128.6 rpm);
  • First unit in service 1931;
  • Units’ discharge capacity 1,146 m3 of water;
  • Forebay area 21 km2;
  • Forebay’s normal water level 274.2 metres;
  • Spillway length 225 metres (Seven Sisters has 2 spillways with 27 bays, divided by a sluiceway with 2 bays);
  • Spillway’s discharge capacity 1,030 m3 of water;
  • Transmission lines:
    • 5 115-kV lines to Winnipeg;
    • 1 115-kV line each to Whiteshell area and Kenora, Ontario.