Fast Facts

  • Up until the late 1950s all of Ontario’s energy needs were met by hydroelectric generation.
  • Waterpower was responsible for the electrification of Ontario and is the energy engine that built the province’s original economic prosperity. 
  • In countless towns and cities across the province, the very identity of the community is inextricably linked with the generation of electricity from falling water. 
  • There are 224 waterpower facilities across Ontario, many of which have been in operation for more than a century.
  • Waterpower generation accounts for 24% of the province’s supply mix.
  • Currently, there is 9,000 MW of existing waterpower in Ontario.
  • The OWA has identified more than 5,000 MW of untapped potential in Ontario.
  • As early as 2030, the Independent Electricity System Operator (IESO) has identified that the province will need an additional 6,000 MW in new capacity.
  • New hydroelectric generation can help address the growing long-term electricity needs in Ontario and partnerships with Northern and Indigenous communities is critical in advancing hydropower in the province. 

There are 224 operating waterpower facilities in Ontario

more than 40 of Ontario's waterpower facilities have been in operation for 100+ years

Currently there is 9,000 MW of existing waterpower in Ontario

approximately 5000 MW of additional untapped waterpower potential has been identified


24% of all of Ontario's electricity needs comes from waterpower generation

greater than 6,000 MW of additional capacity will be needed by 2030

How does waterpower work?

In order to convert the potential energy of water to electricity, waterpower facilities use either a natural drop in elevation like at Niagara Falls or create a drop using dams. The amount of electricity generated depends on the vertical distance of the waterfall and the volume of water. Water from the river or reservoir behind the dam flows in through an opening called the intake. From the intake, water flows under pressure through a pipe called the penstock. A turbine is located at the end of the penstock. The force of the water turns the blades of the turbine which then turns the shaft inside the turbine. The shaft inside the turbine is connected to a generator, which generates electricity. Once the water passes the turbine it flows through a draft tube out of the station and back into the river.