Canada's Energy Mix

Hydroelectricity

Water is such a big part of our lives—we drink it, bathe in it, use it for cooking and washing up—but have you thought about how we use water to create electricity?

Douglas Sprott, Churchill Falls Labrador 11 — Muskrat Falls, https://www.flickr.com/photos/dugspr/6954233084/, (CC BY-NC 2.0)

What is hydroelectricity and how is it produced?

Water had been used for thousands of years in water wheels to grind grain and corn. Since the late 19th century, water has been used to generate electricity. Hydroelectricity is electricity that is produced from moving water, which is referred to as hydro power. Hydroelectricity is now the world’s largest source of renewable energy.

The most common way to produce a lot of hydroelectricity is to use a dam. Dams are large-scale facilities built on rivers or estuaries to hold back the flow of water. By damming a river, a reservoir is created, which stores water (this is potential energy). As the water is released, it moves through the dam (the motion of the water is kinetic energy) and strikes the blades of a turbine (producing mechanical energy), which is attached to a generator to create electricity. Once the water has gone through the turbine, it returns to the body of water through pipes.

In some places, dams and falling water aren’t used to generate electricity. Instead, fast-moving rivers are diverted through a turbine in the river or off to the side. This is called run-of-the-river hydroelectricity.

If there is an increased electricity demand, plant operators can release more water from dams. Similarly, if demand is low, operators can store water for future use. Hydroelectric power plant operators can also store surplus water during high flows, to be used during the low season.

Douglas Sprott, Churchill Falls Labrador 12, https://www.flickr.com/photos/dugspr/7100296319/, (CC BY-NC 2.0)

How does the electricity travel to where it needs to go?

Hydroelectricity is distributed along power lines to cities and towns. Many hydroelectric facilities are in remote locations where there is good water flow, so transmission lines from the plants often span great distances.

There are three stages in the electricity system—generation, transmission, and distribution. Generation is about producing electricity, transmission is about moving it, and distribution is about delivering it to individual customers.

Transmission lines carry electricity from generating stations to end users or consumers. When electricity is running through these lines, some electricity is lost due to resistance and dissipates as heat. To reduce the amount of electricity lost in transit, these transmission lines carry high voltage electricity.

Power generators produce low voltage electricity and in order for this electricity to be transported to where it needs to go, the voltage has to be increased. A “step up” transformer is used to convert it to a higher voltage that the transmission lines can carry. Once the electricity reaches its destination, a substation “step down” transformer converts it back to a lower voltage so that it can be used by consumers.

The last part of the electricity grid is the distribution network, which is essentially the network of wires that takes the electricity from the transformers and carries it to the end-users. Electric utilities are private companies or government organizations that handle the production, transmission and distribution of electricity. Managing the electricity grid is a complicated process and an important responsibility.

Canada is connected to the United States through an international network called the North American Power Grid. Along the U.S. border there are more than 35 transmission connections, which allow for a flexible and mutually beneficial trade in electricity between Canada and its neighbour.

What is hydroelectricity used for?

Hydroelectricity, like all types of electricity, is widely used in almost all aspects of our daily lives. Electricity is used in our homes and businesses for things like lighting, heating and cooling, and powering appliances and electronic devices. We live in a world dependent on electricity. From the refrigerator in your kitchen to the computer that you’re using to access this website, electricity is the thing that makes possible most of our modern-day conveniences.

Kimon Berlin, Sir Adam Beck Power Station, https://www.flickr.com/photos/kimon/7234650340/, (CC BY-SA 2.0)

How does the production of hydroelectricity impact the environment?

Large hydroelectric installations such as dam reservoirs require significant areas of land, causing long-term changes to the surrounding landscape and river ecosystems, which can affect wildlife by fragmenting habitats. This has a direct effect on the migration of fish species, reducing their populations. There are some ways to mitigate the negative impact on wildlife, such as with fish ladders that allow fish to migrate around obstacles. Dams can also affect habitats downstream by causing rivers to run dry, which is why most hydroelectric utility companies are required to release water periodically to maintain the natural balance.

To create large hydroelectric facilities, reservoirs need to be created by flooding the land. An issue that arises from this is the decomposition of vegetation in dam reservoirs (whether that’s forests or fields or an excess of algae), which releases methane gas when it rots underwater, contributing to climate change. However, estimates for hydroelectric power plant life-cycle emissions are about half of that of natural gas and less than a third of coal emissions. 

ray_explores, Fish Ladder, Nimbus Fish Hatchery, https://www.flickr.com/photos/raybouk/10871622936/, (CC BY 2.0)

Where do we find hydroelectricity production in Canada?

Hydroelectric facilities have been built in Canada wherever the geography and hydrography were favourable and they exist all over Canada. However, some provinces produce far more of their electricity through hydro power than others.

  • Yukon, British Columbia, Manitoba, Quebec, and Newfoundland and Labrador all rely on hydroelectricity for more than 90 per cent of their electricity needs.
  • Quebec is the largest producer of hydroelectricity in Canada and is home to the largest power plant in the country, the Robert-Bourassa hydroelectric facility in the northern part of the province. British Columbia is the second-largest producer of hydroelectricity.

Did you know?

Hydroelectricity is a major energy source in Canada, providing about 60 per cent of the total electricity generated in the country. Canada is the world’s second-largest producer of hydroelectricity.