Canada's Energy Mix


Nuclear power has been an important part of Canada’s energy mix since the 1960s. As the second-largest producer and exporter of uranium in the world, nuclear energy and uranium play an important part in Canada’s energy story.

JasonParis, Frenchman's Bay (Pickering - Bay Ridges),, (CC BY 2.0)

What is nuclear energy and how is it produced?

Nuclear energy is a type of thermal energy that uses uranium to generate electricity

Nuclear power generation is perhaps one of the most complex energy production processes. It creates a lot of energy from a relatively small amount of a radioactive element called uranium (a heavy metal). The mineral uranium has to first be mined and milled, then processed into a usable fuel source before it can finally be used for nuclear energy production. When the uranium ore is extracted from the earth, it is crushed and chemical processes are used to remove impurities.

Through a process called fission, uranium atoms are split apart, which releases a lot of energy and causes more atoms to split apart (this chain of events is called a nuclear reaction). The entire process takes place inside a nuclear reactor. Water is used as a moderator (to slow down the reaction) and nuclear reactors have something called control rods to control the process and the rate at which fission occurs. The heat from this process converts regular water into steam, which then passes through a turbine (creating mechanical energy) to generate electricity. 

This process produces no sulphur dioxide, nitrous oxides or carbon dioxide emissions, which are major components of greenhouse gases (i.e., nuclear energy production doesn’t directly contribute to climate change). However, radioactive waste from uranium mining and processing must be stored for anywhere from a few months to a few thousand years until the radiation levels of the waste have dropped to safe levels.

Nuclear Regulatory Commission, NRC Chairman visits Darlington Nuclear Plant in Canada,, (CC BY 2.0)

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

To get to the end user, electricity generated from nuclear power plants first goes to a transformer, boosting it to a higher voltage so it can be transmitted long distances along transmission lines to local communities.

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 the electricity used for?

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.

Canadian Nuclear Safety Commission, Bruce A Nuclear Generating Station,

How does nuclear energy production impact the environment?

Nuclear power doesn’t directly produce greenhouse gases, but it can pose a risk to the environment with the challenge of ensuring safe long-term storage of hazardous waste. Radioactive materials need to be stored in containers that are leak-proof (which need to be stored in sealed facilities) to ensure they do not get into the groundwater because they can remain radioactive for thousands of years. Spent fuel rods are the most dangerous to safely store in the long-term because of their very long radioactive decay.

There are also greenhouse gas emissions and environmental impacts when it comes to the mining of uranium for use in power generation and the construction of nuclear power plants. Nuclear power is the most water-intensive method of power generation (water is used in any type of thermal power generation, with coal being the second most intensive energy for water use). Water is boiled to produce steam to turn a turbine to produce electricity, and then this water needs to be cooled down before it can be released back into the environment—warmer water can harm wildlife and kill aquatic plant life.

Other environmental concerns about nuclear energy include incidents like the 2011 tsunami in Japan, which damaged the Fukushima Daiichi Nuclear Power Plant, causing hydrogen gas explosions and radiation leaks.

Mdf / CC BY-SA (

Where do we find nuclear energy production in Canada?

Canada has the world’s largest deposits of high-grade uranium located in the Athabasca Basin of northern Saskatchewan. Saskatchewan’s mines produce all of Canada’s uranium, three-quarters of which is exported and the rest is used for nuclear energy production in Canada. 

Ontario has three nuclear power plants: Bruce, Darlington and Pickering. New Brunswick is the only province outside of Ontario that produces nuclear energy, at the Point Lepreau Generating Station.

Did you know?

  • Canada is the sixth-largest producer of nuclear energy in the world, and about 15 per cent of electricity generated in the country is from nuclear power.
  • Canada has developed its own nuclear reactor technology called Canada Deuterium Uranium, CANDU for short. CANDU is used around the world and has been exported to India, Pakistan, Argentina, South Korea, Romania and China.
  • Canada exports three-quarters of its uranium, mainly for nuclear energy production. Canadian policy dictates that Canadian uranium can be used only for peaceful purposes, such as in medicine or energy production (not for the production of nuclear weapons).
  • The Canadian Nuclear Safety Commission regulates and monitors Canada’s nuclear industry to protect the health and safety of Canadians and the environment, to uphold international commitments to the peaceful use of nuclear energy, as well as to keep the public informed about what goes on in the industry.