Monthly Archives: April 2015


When is the Best Time to Take a Nuclear Power Plant Offline?

By Erin Polka
Communications Officer
Canadian Nuclear Association

What happens to greenhouse gas emissions when a nuclear power plant goes offline? Let’s look at the Bruce Power complex in Kincardine, Ontario. On April 15, Bruce Power shut down the four reactors in its B building to enable a vacuum building outage (VBO). The vacuum building, which is an essential safety feature, needs regular maintenance that should last about a month.

Shutting down Bruce B means some 3,268 MW of generating capacity needs to be replaced with some combination of hydro, gas and wind. Which combination is better for the environment?

Hydro capacity is highest in the spring, as winter snows melt and rivers run high. So it stands to reason that hydro power will make up for some of the shortage. (And, yes, the VBO was timed to match the availability of hydro.)

What about wind? Not as much help. Wind provides only four percent of Ontario’s electricity on average. Whether it could provide more would depend on whether the wind blows longer and stronger. Maybe it will, and maybe it won’t – hardly the reliability needed to replace the steady nuclear workhorse.

And then there’s gas. It can be fired up quickly and easily, it runs reliably, and it doesn’t cost all that much more than nuclear power – about twice as much.

In the best-case scenario, hydro would replace the power from the four Bruce B reactors. It’s the best case because hydro, like nuclear, generates no greenhouse gases. But there’s a problem. Hydro in Ontario is quite limited as a result of the province’s geography, and the province lacks sufficient transmission lines to import replacement power from Quebec. Also, even if the lines did exist, Quebec doesn’t have a spare hydro dam to match the output from the four reactors.

The next-best scenario would use all the available hydro power, keeping cost and emissions down, and use gas for the rest. Very likely, hydro could replace half the nuclear energy from Bruce B, and natural gas would replace the other half.

Is that a problem? After all, Ontario businesses and residents will still get steady, reliable electricity – just as they did with the Bruce reactors. But here’s the thing – natural gas emits greenhouse gases, especially carbon dioxide, which is primarily responsible for climate change.

GiraffesReplacing half the nuclear output with gas means the province’s gas plants will emit an additional 295,095 tonnes of carbon dioxide. For perspective, that’s the weight equivalent of about 300,000 adult giraffes.

What else would produce 295,095 tonnes of CO2?

  • Driving a car 35,563 times around the Earth’s equator
  • Taking 82,394 round-trip flights from Toronto to Sydney

And that’s not all. Unlike nuclear and hydro, gas also emits nitrogen oxides (NOx), sulphur oxides (SOx), and particulate matter (PM) during operation. These “other” greenhouse gases cause lung and heart disease, and make these conditions worse. They can also harm plants and animals on land and in the sea. And they can even cause building materials to deteriorate and weaken.

Drive around the worldOf course, if hydro weren’t able to stand in for the offline nuclear plants, then Ontario would need to use gas alone. And that would mean the weight of another 300,000 giraffes in greenhouse gas emissions, or another 35,563 trips around the world (“Are we there yet?”), or another 82,394 round trips to Sydney.

So, timing is everything. Scheduling the VBO in spring, when hydro reaches its peak performance, was a wise decision. Just how much hydro will be available, and how much gas is actually used, remains to be seen.

You can track the results on the CNA website, if you like. Check our emissions tracking.


The 2015 Canadian Nuclear Factbook is Here!

CNA Factbook Cover Page

The Canadian Nuclear Factbook’s 2015 edition is now available!

Packed with up-to-date information about Canadian nuclear technology, the new Factbook is an ideal pocket-sized reference guide.

And not only is it new – it’s improved! Compared to the previous edition, this year’s Factbook features a sleek, perfect bind, as well as enhanced sections on:

  • the environment and climate change;
  • how nuclear works;
  • radiation safety;
  • nuclear science and technology; and
  • nuclear medicine.

And did we mention you can order free copies? Just email us at! (Shipping charges may apply for international orders.)

You can also download a PDF version on the CNA website.

**A French version of the Factbook will be available in May.


Ontario Nuclear Sets Monthly Output Record

By Erin Polka
Communications Officer
Canadian Nuclear Association

Ontario nuclear set another monthly output record – 8.72 billion kWh for March, beating out January’s 8.46 billion kWh, and more than any other month since 2010.


Monthly Ontario nuclear output


Most likely, it’s the highest monthly output in Ontario’s history, however reliable data sources are hard to find.

According to the Independent Electricity System Operator (IESO), nuclear’s output is usually highest in mid-winter and mid-summer. This is due to the increased electrical demand as a result of heating and cooling.

But March isn’t typically a high-demand month, which makes this record all the more impressive.

The more Ontario relies on nuclear energy, the fewer greenhouse gases the province releases into the atmosphere.

Over the entire lifecycle, including construction, transportation, operation and decommissioning, nuclear is one of the cleanest options available, emitting about 16 grams of CO2 per kWh. It compares favorably with hydro (4 grams), wind (12 grams) and solar (46 grams), and is a vast improvement over gas (469 grams).

This past March, gas only contributed 1.09 billion kWh, which is less than usual, and translates into less air pollution.


Energy in Ontario – by the Numbers

By Erin Polka
Communications Officer
Canadian Nuclear Association

Curious how much nuclear power is being generated in Ontario on any given day? What about any given hour?

If so, you may want to check out the CNA’s new ‘Energy in Ontario’ web app, which shows daily and hourly energy generation by selected fuels – and related lifecycle pollution emissions.

Energy in Ontario - Table 1

Energy in Ontario - Table 2

You can see how much power was generated from nuclear, gas and wind, as well as how many tons of carbon dioxide (CO2), and kilograms of particulate matter (PM), oxides of nitrogen (NOx), and oxides of sulfur (SOx) each source emitted.

A nifty feature also shows you what the environmental impact would have been had a combination of wind and gas replaced the power that nuclear generated. On average, carbon emissions would have been five to eight times higher than what they actually were.

What’s important to note about the CNA’s emission data, and is different from some of the other data out there, is that we’ve considered lifecycle factors, such as construction, transportation, operation and decommissioning. This is why nuclear, for example, appears to be generating emissions on a regular basis.

What’s next?

We’re working on adding all of Ontario’s current fuel types, including hydro, solar, and biofuel, as well as distinguishing between simple and rankine cycle gas.

We’re also developing a historical overview, showing yearly energy output and emissions, by fuel type, dating back to 2008.

All of this information is important in trying to show the effect that nuclear power has in curbing air pollution in Ontario. If not for the significant ramp-up in nuclear output, the province would be facing much more serious health and environmental problems.

Check out the live data on the CNA website, under ‘Resources,’ or click here.


Essential Energy: Part 2

By Peter Poruks
Manager of Regulatory Affairs
Canadian Nuclear Association

In an earlier post I described my thoughts on how critically important energy is to us and our society. I outlined how it can become a matter of life or death if you do not have a reliable supply of, or access to, energy. I hope that I have gone at least a little way in convincing you that energy is important. But I didn’t answer the obvious next question; how do we produce, harness and store our power?

There are a host of options when we start to think about how we power our lives. Let’s limit the conversation a bit by looking at the large scale: how we supply our cities, factories, offices, hospitals, and homes. Oil, coal, natural gas, hydroelectricity, and nuclear all come to mind. Increasingly we hear about renewables such as wind, solar, tidal or biomass. Each has their own strengths and challenges. The simple truth is that there is no easy answer when it comes to producing energy. If there were, we wouldn’t be having this conversation.

There is mounting evidence about the effects of greenhouse gases on climate. By burning fossil fuels, we are increasing the carbon in our atmosphere, increasing average global temperatures, raising sea levels, and altering weather patterns across the planet. The United Nations, among many others, is advocating for strict measures to limit global temperature increases to 2 degrees. At this point, there is concern that we do not have the regulations or the global will to meet these targets. If you agree that it is important to reduce carbon emissions, then limiting our consumption of fossil fuels becomes almost automatic.

To reduce our carbon emissions, we need to look at low emitting sources of electricity: nuclear, hydro and renewables. Hydroelectric power, generating electricity by moving water, is an attractive option. It is used widely in Canada; most provinces have significant generating capacity in hydroelectricity, and as a country we are world leaders in hydro generation. 60% of Canadian electricity comes from hydro!

Renewables, such as wind or solar, are another alternative, producing very low greenhouse gas emissions. However, an inescapable trait is intermittency, meaning that they do not work all the time – the wind isn’t always blowing and the sun isn’t always shining. Options for storage exist, but as of today they are unable to meet large scale demand. A renewables-based electricity system needs a back-up source of power, often natural gas. A recent study showed that because of this need to back-up wind with natural gas, the total carbon footprint (calculated though Life Cycle Analysis) of wind is only marginally better than gas on its own.

To my mind, nuclear power presents the strongest case. It isn’t intermittent, so it can provide “base load” power. It doesn’t emit greenhouse gases when operating, and over its life cycle, it compares very closely to wind power.

Questions are correctly raised concerning the management of spent nuclear fuel. Currently all of Canada’s spent fuel is safely housed in intermediate-term storage facilities at the power stations. An independent group, the Nuclear Waste Management Organization (NWMO), is tasked with finding a permanent long term management solution. The current thinking is to situate the spent fuel in safe underground storage facilities, much akin to a custom built mine (known as a Geologic Repository). The NWMO is working with communities across Canada to explore options to develop and build such a facility.

Some people criticize nuclear on its cost, saying it is too expensive. But when you consider the cost over the life of a plant (30 to 60 years) nuclear comes out as one of the most cost-effective energy sources there is.

We all use and need energy. We have always lived with the trade-offs between different technologies, but today the stakes are such that we can’t continue to dump carbon into the atmosphere without thinking of the consequences. Since each choice comes with some pros and cons, the solution probably will look like some combination of hydroelectricity, nuclear, and renewables with natural gas providing back up at times of peak demand. When you start to look into it, it is awfully hard not to consider nuclear power as an important and environmentally sound way to meet the globe’s increasing energy needs.


Essential Energy: Part 1

By Peter Poruks
Manager of Regulatory Affairs
Canadian Nuclear Association


In 1981, the movie Quest For Fire was released. Set in prehistoric times, it showed a trio of early humans on an epic search for fire. Their tribe had been able to capture fire after a lightning strike, but they lacked the knowledge of how to create fire themselves. After fending off an attack from a rival group and being chased into a swamp by wolves, the tribe’s carefully guarded fire becomes extinguished. So three adventurous scouts are sent out to find a new source of fire and encounter sabre tooth tigers, mastodons, and murderous rivals along the way.

While it may seem odd to us today that anyone would assume such risks, it starts to make sense when you consider that harnessing fire is quite literally a matter of life and death. Fire kept them warm, it illuminated the darkness, cooked their food, making it more nutritious, and kept threatening creatures at bay. Long before there were societies with written or even spoken words, humans would risk everything for energy. The knowledge of energy, and especially our ability to harness it, is a hallmark of the human condition.

Indeed, humanity’s quest for fire has only increased in intensity. We have dammed rivers and flooded thousands of square kilometres of arable land. We have deforested vast expanses of Europe and the Middle East, cutting lumber to feed our insatiable appetite for more and more energy. And today we burn billions of tons of coal, oil, and natural gas, all the while emitting climate-altering greenhouse gases.

So much for escaping the sabre tooth tigers; we’ve got out of the pot and climbed into the frying pan! We have radically altered our natural landscape, and now we appear on an irreversible course to altering our climate and the temperature of our globe.

Yet simply cutting back on energy consumption is not the answer. Yes, conservation and efficiency have an important role to play. But energy has an incredibly positive benefit to our lives and we should not shrink away from it. History has shown an ever increasing quality of life tied directly to an ever increasing energy usage density. The most advanced societies – countries with top tier health care, literacy rates, environmental stewardship, industrial output, and consumer luxuries – are precisely those countries that use energy the most intensively.

I am a firm proponent of the ability of science and technology to harness energy constructively, and apply it to the betterment of our world. We can readily find information and debate on financial inequality, such as the Occupy rallies of 2012, but the disparity of energy among populations is just as stark and, I don’t believe, nearly as well articulated. And just as it was for the heroes in Quest for Fire, access to energy remains a matter of life and death for billions of people. Energy brings potable water, light, heat, hygiene, growing crops and cooking food. It underpins every aspect of every activity we engage in. It would be no small injustice to condemn billions to poverty when we have myriad technologies available to produce the energy required to meet their needs. The question is not one of “if” but rather one of “how” to do so, in a fair and sustainable manner.