Ontario Power Generation
How Hydroelectric Generation Works
Hydroelectric generating stations are in essence factories that convert the energy of falling water into a flow of electrons called electricity. Learn more about how they work by watching the video and reading the text below.
Most hydroelectric stations use either the natural drop of a river, such as a waterfall or rapids, or a dam is built across a river to raise the water level, and provide the drop needed to create a driving force.
Water at the higher level is collected in the forebay. It flows through the station's intake into a pipe, called a penstock, which carries it down to a turbine. The turbine is a type of water wheel that is connected to a generator. As the water flows down the penstock the water pressure increases. It is this pressure and flow that causes the turbine to revolve which in turn spins a generator.
Inside the generator are large electromagnets attached to a rotor that is located within a coil of copper wires called the stator. As the generator rotor spins the magnets a flow of electrons is created in the coils of the stator.
This produces electricity that can be stepped up in voltage through the station’s transformers and sent across transmissions lines.
The falling water, having served its purpose, exits the generating station through what is called the tailrace, where it rejoins the main stream of the river.
Station Diagram
Click below to download a diagram of a hydroelectric generating station.
Stay Clear, Stay Safe
Download our Water Safety brochure for more
information on safety around dams and hydro stations.