Nuclear Power and the Environment

How do Canada’s energy choices affect the environment?

In every country, governments make choices about the “energy mix” for generating electrical power. This “mix” is a combination of power sources:

  • hydrocarbons (“fossil fuels”) such as oil, coal, and gas;
  • renewables such as solar, wind, and hydroelectric power; and
  • nuclear power.

By choosing among these sources, governments and utility companies must consider their environmental effects:

  • Will they damage the natural habitat of plants or animals?
  • Do they take up space that natural life could occupy?
  • Do they contribute to climate change?

Does nuclear power damage the environment?

There have been three main public concerns about the effects of normal nuclear power operations on the environment. These relate to lakes, tritium, and the land footprint of the industry.

Effects on lakes

Nuclear power plants draw in a lot of water. In early designs, power plants could trap fish in their intake systems. Modern plants are designed to avoid this. Nuclear power plants also heat the water, leading to concerns that the released water could be too hot for fish and aquatic plants. The plants now cool the water before returning it to lakes.


Nuclear power plants create radioactive tritium, which is dangerous in large amounts. However, the amounts released into the air and water are well within safe limits – usually no more than 1% of the amount allowed by Canada’s independent nuclear regulator. Even at the highest allowable amount of tritium in water, the radiation would be 20-30 times less than the level of natural background radiation that comes from the ground, the sun, and the stars.

Land footprint

Nuclear power plants and uranium mines and mills take up space. Still, for the amount of power produced, they occupy less land than virtually any other power source.

This is because a small amount of uranium can generate a lot of power. To supply all the world’s electricity, nuclear operations would cover an area the size of Nova Scotia. For the same amount of energy, solar panels would cover an area larger than Alberta, and wind farms would cover an area the size of Quebec.


Does nuclear power contribute to climate change?

Climate change comes from the release of greenhouse gases. So, smart choices about the energy mix must take into account how much of these gases come from each power source.

This amount depends on the whole fuel cycle – not just gases from generating electricity, but also from building the plants and equipment, and from mining and transportation.

  • Fossil-based fuels release large amounts of carbon dioxide (CO2), a greenhouse gas.
  • Renewables release no greenhouse gases directly, but they use a lot of equipment to make a little power. Hydroelectric power is the cleanest renewable.
  • Nuclear power does not release any greenhouse gases while generating electricity. But plant construction does. So does uranium mining. Overall, however, nuclear compares closely with renewable sources – and is well ahead of hydrocarbons.


Canadian Nuclear Association,