Nuclear experts get it wrong and Ontario’s Bruce Power gets it right – 2013 September

Nuclear experts get it wrong and Ontario’s Bruce Power gets it right – 2013 September

By: Donald Jones, P.Eng., retired nuclear industry engineer.
The Ontario power grid has around 13,000 MW of nuclear capacity but only 2,400 MW of nuclear flexibility and even that comes with operating limitations (reference 1). Most grid flexibility is provided by combined cycle gas turbine generators (coal is being phased out) and by a part of the total hydro generation. The large amount of nuclear, hydro and combined heat and power baseload leads to periods of surplus baseload generation (SBG) where supply exceeds demand. The SBG is exacerbated by over 2,000 MW of installed wind/solar, soon to increase by several thousand more MW. When demand is low and wind generation is high this has led to shutdown of vital nuclear units. Changes made by the grid operator, the Independent Electricity System Operator (IESO), now allow it to dispatch down wind generation to reduce the frequency of nuclear shutdowns. The 2,400 MW of nuclear flexibility is provided by the eight units operated by Bruce Power and is much appreciated by the IESO since it enables the nuclear units to reduce power to accommodate increases in wind generation without having to shutdown and then be unavailable for two to three days. Wind generation does not need to be curtailed until the nuclear flexibility has been used up (gas and hydro generation would have already been minimized and exports maximized), maximizing wind generation.  More nuclear flexibility should be welcomed to cater for the intermittent and variable wind/solar on the grid. However there appears to be some reticence  amongst pro-nuclear organizations about promoting nuclear flexibility to support wind/solar generation on the power grid. Let’s take a look at what the experts say.

From the Canadian Nuclear Association’s (CNA) Nuclear Facts,

“Nuclear has a role to play in Canada as part of our energy mix because of its very small carbon footprint, and its important role in medical research and applications, and food safety, and its contributions to other industries, and the Canadian economy.  Nuclear also enables renewable energy sources (wind, solar) by being a safe and reliable base load electricity provider” (author’s highlighting).

Wrong. In fact the presence of large amounts of baseload nuclear leaves less room for wind/solar on the grid.

From an interview with the Canadian Nuclear Association (CNA) President in IPPSO FACTO, the magazine of the Association of Power Producers of Ontario (APPrO), 2012 August, 

“We are proud that we make a big contribution to mitigating this country’s carbon emissions in two ways – not only are our own operations providing affordable clean air energy, but their presence also enables the grid to accept more and more renewables” (author’s highlighting). 

Wrong. In fact the presence of large amounts of baseload nuclear leaves less room for wind/solar on the grid.

From the Canadian Nuclear Society (CNS) input to Ontario’s 2013 Long-Term Energy Plan (LTEP),

“The presence of the nuclear fleet in Ontario has provided stability for electricity rates in the province, and provided a foundation for the development of non-dispatchable renewable technology like wind and solar” (author’s highlighting).

Wrong. In fact the presence of large amounts of baseload nuclear leaves less room for wind/solar on the grid.

From World Nuclear News (WNN) Daily of 2013 Sept. 13 reporting on the World Nuclear Association (WNA) 2013 Annual Symposium, panel discussion on energy and nuclear power, 

“Nuclear should be seen as complementary to rather than in competition with renewables, the panellists felt. Nuclear could play a vital role in providing affordable baseload power to support the intermittent nature of many renewables, (author’s highlighting) in the absence of a truly effective and affordable means of storing electricity.”

Wrong. In fact the presence of large amounts of baseload nuclear leaves less room for wind/solar on the grid.

From the website of the Organizations of Canadian Nuclear Industries (OCI), Nuclear Power in Canada: Perception and Promise    

“As a provider of stable, cost-effective electricity for society’s “baseload” needs (i.e. the 24/7 supply that tends to stay relatively constant), nuclear power also provides a foundation for intermittent renewable expansion, such as wind and solar (author’s highlghting). Far from being in competition, as often portrayed by the media, these technologies work together to provide diverse, low-emission electricity options to fossil fuels”. 

Wrong. In fact the presence of large amounts of baseload nuclear leaves less room for wind/solar on the grid.

Finally, Bruce Power gets it right. It understands the need for “flexible nuclear”, not baseload nuclear, to support wind/solar on the grid. From page 15 of, 

“Bruce Power is owner of Ontario’s first commercial wind farm called Huron Wind. Renewables such as wind and solar provide a clean source of electricity but need to be augmented with more consistent generation to ensure around-the-clock system availability. Bruce Power has provided the market with 2,400 MW of flexible capability from our eight nuclear units as we work with renewables to provide the people of Ontario a coal-free energy mix (author’s highlighting). Natural gas also has a role to play but gas prices are known to fluctuate. Stability of electricity costs is important to Ontario’s families and businesses, so natural gas can only be relied on to work alongside sources that have more stable operating costs such as nuclear and renewables.”

However even if manoeuvring nuclear down can allow more wind on the grid it still does not make any environmental, economic or technical sense to do so. Manoeuvring nuclear does make sense if it makes way for more nuclear (reference 2) to eventually lead to a greenhouse gas-free Ontario grid supplied by a mix of nuclear and hydro. Let’s follow the lead of France and Sweden.

Presently only Bruce A and B have this nuclear flexibility, Darlington and Pickering operate baseload and do not. The Enhanced CANDU 6 (EC6), proposed for new build at Darlington, will be very flexible due to its 100 percent steam bypass capability and reactor manoeuvring capability (reference 3). Pro-nuclear organizations should have been the first to promote nuclear flexibility since there are enough anti-nuclear voices saying that nuclear is inflexible baseload.   SBG has been a problem on the grid for many years so it is surprising that our pro-nuclear organizations have not been active in promoting the benefits of flexible nuclear. Let’s hear more flexible nuclear and no more baseload nuclear. Cheers, Bruce Power, even if they do have a wind farm.



1. Ontario’s already “flexible nuclear” CANDU even better by satisfying IESO requirements to replace flexible coal, Don Jones, 2012 October, see item 18 of

2.  An alternative Long-Term Energy Plan for Ontario – Greenhouse gas-free electricity by 2045, Don Jones, 2011 May, see item 2 of

3. Candu Energy Inc. says Enhanced CANDU 6 is flexible – so revise the boilerplate, Don Jones, 2013 August, see item 29 of


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