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Breathe a bit easier: nuclear power’s clean credentials

Do you remember smog days?

I think I’m too young to appreciate the impact of what my, let’s just say, more mature coworkers describe: thick, soupy air… not being able to see the CN Tower as they drove through Toronto… one even told me of family members with asthma unable to go outside on certain days of the summer because the air was too hard on their lungs.

These realities can’t be overstated—air quality has serious effects on public health. The World Health Organization (WHO) estimates that around seven million people die every year from exposure to fine particles in polluted air that lead to diseases such as stroke, heart disease and lung cancer.

In 2005, the province of Ontario declared 53 smog days due in large part to the burning of fossil fuels for electricity generation like coal-fired power plants. But by 2015, smog days were eliminated in Ontario.


As in, we fixed them.

Today not only can we see the CN Tower, but people with respiratory problems now can literally breathe easier on hot days in July and August.

So, how did we do it?

Day in and day out, Canada’s 19 nuclear reactors steadily produce 15% of Canada’s electricity without emitting greenhouse gasses (GHGs). In fact, it’s Canada’s second largest source of GHG-free electricity. In Ontario, nuclear power plays an even greater role—where more than half of the province’s electricity comes from nuclear.

Because those smog days didn’t disappear by accident: every year, Canada’s nuclear power plants displace 80 million tonnes of GHG emissions. That’s equal to taking 15 million cars off the road.

As you’ll see below, as nuclear power increased and displaced coal-fired electricity generation in the 2000s and 2010s, Ontario’s carbon emissions decreased.

Nuclear up—smog days down.

Nuclear energy is clean energy

How is nuclear energy clean?

My colleague Dr. Eric Johnston, Chief Innovation Officer at the Nuclear Innovation Institute (NII) compares nuclear reactors to big and very powerful kettles:

“Nuclear power plants generate electricity by splitting atoms of uranium in a process called nuclear fission. The fission process produces heat that is then used to generate steam—like a big kettle—which spins turbines to generate electricity.”

He says:

“Just like wind, solar, and hydroelectric power do not produce any carbon dioxide, methane, or other GHGs, generating electricity using nuclear power is also carbon free.”

And it gets better.

Digging into nuclear’s entire lifecycle and factoring in activities like plant operations, mining, etc., nuclear power remains one of the lowest carbon-intensive sources of electricity generation.

In fact, at only 5.6 kg of GHGs per megawatt-hour of electricity generated, nuclear is the best-performing source of electricity generation globally. This low lifecycle carbon intensity performs better than other clean sources of generation, including onshore wind (11 kg of CO2/MWh), solar PV (16 kg/MWh), and hydroelectric power (117 kg/MWh).

More nuclear means more forests and farmland

If you’ve ever gone on a road trip in Canada, you understand: Canada’s really big.

But our status as the second largest country in the world doesn’t mean that size considerations shouldn’t factor in to how we use our land. For every acre of new solar or large-scale wind farms, that’s an acre of land that can’t grow carbon-capturing trees or food to feed our families.

Which is why it’s pretty great that nuclear power plants require a comparatively small amount of land compared to other forms of clean electricity generation.

In fact, my coworkers here at NII ran the numbers on what it would take to build out just over 430 terawatt hours (TWh) of new electricity generation—about the amount of electricity Canada believes it will need to create a clean hydrogen economy by 2050.

It should come as no surprise that relying only on sources of generation like wind and grid-scale solar would require millions and millions of acres of land to be converted into energy generation sites.

Meanwhile, the land required to meet this same capacity with nuclear power is much less. Like, way less.

Take a look at all those acres nuclear doesn’t need to use:

For too long, we haven’t given nuclear power’s clean credentials the recognition they deserve for their role in keeping our air clean and our land usable.

The truth is Canada’s CANDU nuclear generating stations are doing this heavy lifting now—and they’ll continue to do so as we seek to achieve net zero. Nuclear has an incredibly low environmental impact while providing some hugely important environmental benefits.

So, once more for the people in the back: Nuclear energy is clean energy.


Jordan Durrer is a Program Coordinator at the Nuclear Innovation Institute.


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