Central Toronto was frequently covered in smog before the state of Ontario shut down coal power stations. James MacDonald

In a shift hailed by public health experts, Ontario's electricity generation from coal went from 19 per cent to zero, from less than 1 per cent renewables to 9 per cent, from 51 per cent nuclear to 58 per cent, from 8 per cent gas to 10 per cent, and from 22 per cent hydro to 23 per cent.

"Just a few years ago, people of all ages became prisoners in their own homes on hot summer days," said the president of the Asthma Society of Canada, Vanessa Foran, after the shift.

"They feared for their health when smothering, polluted air descended upon their city. Today, they enjoy a better quality of life outdoors with a much lower risk of an asthma attack or a trip to the emergency room."

After the switch from coal, smoggy days in Toronto fell to almost zero. Wire

Ironically, Toronto's clean air is likely to be facilitated, in part, by a country with a nuclear power ban. As the third-biggest seller of uranium, Australia fuels nuclear reactors around the world.

Nuclear power has widespread community support in Canada, which is a party to the Nuclear Non-Proliferation Treaty and has a reputation for high standards of nuclear-industry regulation and operation.

As the Australian Parliament begins an inquiry into nuclear energy, Canadians look quizzically at a nation with abundant renewable energy yet dependent on climate-warming coal for 75 per cent of its electricity.


"The benefits are just amazing when you go to clean energy," Sawyer says. "By using nuclear power you address CO2 emissions and any health issues caused by CO2."

All developed economies - including post-coal Britain, where 1 million homes lost power two weeks ago - are discovering that the challenge of the shift to renewables is securing reliable backup.

The Australian government is operating on the assumption that for every kilowatt of potential electricity from wind and solar, between 0.8 and 1 kilowatt will be needed from sources that are available at any time.

Step in a new generation of nuclear. Sawyer is now president of ARC Nuclear Canada, which is designing a compact power plant designed to be located next to wind and solar farms and to kick in when they aren't operating.

At an estimated cost of $C450 million ($500 million) and an output of 100 megawatts, the reactor needs to be refuelled every 20 years and is designed to automatically shut down if the core temperature starts to rise.

ARC is going through the process of securing permission to build a reactor in New Brunswick that could be operating by 2028. ARC's design is so much cheaper than regular nuclear plants - which can cost more than $10 billion - because it will use one-twelfth the cement and will be mostly built in a factory, where it is easier to reach the high standards required for advanced engineering.

The ARC design is one of many small modular reactors in planning around the world. In April, the Canadian nuclear regular received the first application for one of the plants, a 5 megawatt reactor on Chalk River in Ontario.