Tag Archives: CO2


Toronto To Host Climate Talks

Toronto will heat up in July. Amid the heat and humidity of summer, it will play host to two global events — the Pan-Am Games, and the Climate of the Americas Summit. More people will watch the games than the summit, but the talks may be the more important event.

In mid-June the Ontario government, led by Kathleen Wynne, touted the province’s track record on improving air quality.

Wynne tweeted out, “Ontario is leading the way in clean energy and the fight against climate change.”

It’s a good record. Ontario is the first North American jurisdiction to abandon coal as a source of electricity– an accomplishment made possible through its reliance on affordable, low-carbon nuclear energy.  In 2014, nuclear generators delivered 62.7 percent of the electricity carried on Ontario’s grid.

Nuclear’s clean-air contributions were confirmed recently by the International Atomic Energy Agency.


The report states:

The very low CO2 and GHG emissions on a life cycle basis make nuclear power an important technology option in climate change mitigation strategies for many countries. The figures demonstrate that nuclear power, together with hydropower and wind based electricity, remains one of the lowest emitters of GHGs in terms of  CO2-(equivalent) per unit of electricity generated.

If anything, Ontario’s nuclear experience offers an excellent case study for the climate-change summiteers. Nuclear energy provides a climate-stabilizing foundation for energy development. Between 2000 and 2013, nuclear power production in Ontario grew 20 percent while coal’s power production shrank.

Today, nuclear energy’s steady, reliable, around-the-clock performance enables Ontario’s experiments with renewable energy sources. If ever storage technologies advance sufficiently, the renewable energy sector may someday match nuclear’s proven grid-scale reliability. Until then, nuclear is Ontario’s best bet – and an excellent example for the summiteers to take home.






Nuclear Energy Delivers Clean Air for Ontario

Starting in the 1950s, coal made up a large part of Ontario’s power mix. Coal was inexpensive, and Ontario lacked sufficient alternatives such as hydroelectric power or natural gas. By the late 1990s, however, links between adverse health effects and air pollution were firmly established, and much of this could be traced to Ontario’s coal-powered plants.

In 2003, Ontario began to replace its coal-fired plants with nuclear energy, completing the switchover in 2014. Over that time, air quality improved significantly, reducing respiratory illnesses and deaths.


Ontario’s first electrical power supply came from a hydroelectric generating station on the Ottawa River in 1892. Hydro expanded rapidly across the province in the early 20th century. But it could not expand indefinitely: not every river can be dammed at places that are economically feasible and environmentally sensible. So, in the 1950s, Ontario added six coal-fired power stations to meet rising demand. Practical, large-scale nuclear power was not introduced in Ontario until the 1970s.

Coal remained an important part of this mix until the end of the 20th century, when it made up about a quarter of electricity generation in the province. By that time, the health risks of coal were becoming increasingly apparent.


As burners of carbon-based fossil fuels, Ontario’s coal-fired power plants were heavy emitters of greenhouse gases, which threaten to accelerate climate change. They also emitted pollutants that affect human health directly: mercury, several air-borne carcinogens, and sulphur dioxide, which can make asthma symptoms worse. Sulphur dioxide can also react with other substances to create particulate matter – small solids or liquid drops in the air that can damage lungs.

Burning coal also releases nitrogen oxide, which contributes ground-level ozone, a principal factor in smog, which has a devastating effect on public health.

In Toronto, airborne particulate matter commonly exceeded 20 μg/m3, the level at which adverse health effects can be demonstrated. It sometimes reached 75 μg/m3. Ground-level ozone often exceeded 80 parts per billion, far higher than the level of 31 ppb associated with increased hospitalization rates for asthma, lung disease, and respiratory infections.

The province attributed 1,800 premature deaths and 1,400 cardiac and respiratory hospital admissions each year to smog. Several studies and reports had also highlighted the connection between Ontario’s air quality and public health.

  • In 2004, Toronto’s health department estimated that 1,700 Toronto residents died prematurely and 6,000 Torontonians were admitted to hospitals because of air pollution each year.
  • A 2005 report by the Ontario Ministry of Energy concluded that coal contributed to 928 hospital admissions and 1,100 emergency-room visits each year.
  • In 2005, a report by the Ontario Medical Association identified several other costs of air pollution, including at least $150 million in additional healthcare costs, $128 million in lost productivity, and a total of $2.4 billion in economic damage.

Ontario's supply mix - 2000 vs. 2013 (2)CHANGING THE MIX

Pressure was building to improve air quality. In 1999, the Ontario Public Health Association called on the province to replace its coal-fired power plants with cleaner power sources. The Ontario Medical Association had already declared an air pollution crisis.

Phasing coal out

In 2007, the Government of Ontario adopted the Integrated Power System Plan, guiding the province’s energy choices over 20 years. The plan aimed to stabilize prices, double renewable energy, and increase conservation. Its central goal was to replace toxic coal with cleaner power.

Ontario closed four coal-fired plants in 2010, and the last one in 2014 – making Ontario the first jurisdiction in North America to shut down coal-fired generation.

Phasing nuclear in

Even with the conservation measures set out in the plan, Ontario would have to supply electricity to make up for the closures of the coal-fired plants. Hydro was not an option, as Ontario had reached nearly 75% of its hydro capacity. Renewables such as wind and solar showed promise – and the plan aimed to double their use – but represented only tiny fraction of Ontario’s power supply, and could not be scaled up easily. Furthermore, solar and wind do not produce steady power around the clock, which is necessary to prevent brownouts.

The Government of Ontario recognizes nuclear power as a reliable and safe supplier of electricity. Since 2003, investment in Ontario’s power infrastructure has modernized three reactors (Pickering A Unit 1 and Bruce Units 3 and 4) and returned them to service. Nuclear power, which made up 37% of Ontario’s power mix in 2000, stood at 62% in 2014.


Any change in the power mix has environmental consequences – which leads Ontarians to ask whether the transition from coal to nuclear power might simply involve changing types of air pollution.

To answer this question, it is important to look at a power plant’s emissions from cradle to grave – including its construction, its fuel source, its waste products, and its eventual shutdown and decommissioning.

Smog factors

All methods of power generation emit particulate matter and contribute to ground-level ozone. However, nuclear energy emits far less particulate matter per unit of electricity than any fossil fuel – and less than wind.

Greenhouse gases

Greenhouse gas emissions by nuclear power are surprisingly low, considering the amount of construction needed to build a nuclear power plant. But those plants operate for decades, and emit no greenhouse gases while generating electricity.

And because of the vast amount of power that can be extracted from a small amount of uranium (20,000 times that of coal, by weight), emissions from nuclear power compare favourably with renewable energy sources, and are well ahead of fossil fuels.

Carbon emissions per kWh


Today, Ontarians enjoy cleaner air. According to the provincial government, “Ontario’s air quality has improved steadily since 1988. We have good air quality approximately 90 per cent of the time.” With the exception of a spike in 2012, which included a serious drought, the number and duration of smog advisories across the province has dropped steadily since 2003.

Cleaner air means better health. In Toronto, premature deaths attributed to air pollution dropped from 1,700 to 1,300 between 2004 and 2014, while hospitalizations fell from 6,000 to 3,550.

Even with this progress, there is still much room for improvement – especially as Ontario’s population ages and more people are at higher risk of health effects from air pollution. And, as the economy grows, Ontario will need a reliable, clean-air power source that keeps prices stable and affordable. Nuclear power can meet this need, partly because Canadian-designed reactors can be refuelled without shutting down, and because they draw from a fuel source that is abundant in Canada.

Recognizing this value, the province also put primary focus on nuclear energy in its 2013 Long-Term Energy Plan. It decided to upgrade and replace key components at the Bruce Power and Darlington sites, so they can continue to provide clean power for decades.


Why Ontario Needs Nuclear

The following infographic shows the rationale for using nuclear energy in Ontario. Simply put, Ontario is the second largest energy polluter in Canada, and nuclear is the only reason the province isn’t worse off. Among the clean energy options, nuclear is one of the most affordable, and it’s readily available.

The seven points below make it clear why Ontario needs nuclear.

Why Ontario Needs Nuclear - Infographic


How Does Nuclear Energy Benefit Ontario?

Nuclear is the backbone of Ontario’s energy mix because it offers several advantages, including round-the-clock reliability, clean and environmentally-friendly operation, and affordability. The refurbishment project has also created thousands of jobs across the province.

The following infographic summarizes these advantages.

How Does Nuclear Energy Benefit Ontario - 2014

Click here to download your copy.


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.


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.