When planning Ontario’s future electricity supply mix we have to answer the question, what should we be aiming for 35 to 40 years from now, and how are we going to get there? 35-40 years because that’s when our 10,000 MW of “to be refurbished” nuclear will be decommissioned and new generation would have to take its place. With fossil fuels in decline, and with climate change possibly making hydro generation less reliable, the obvious answer is that Ontario will have to increase its nuclear capacity.
This would make Ontario independent of outside jurisdictions, including long costly and unreliable transmission lines, and give us a clean reliable power supply at stable prices well into the future. Nuclear would supply around 80 percent of generation, up from the current ~ 50 percent, with hydro supplying the balance.
For nuclear to achieve 80 percent of generation would mean that all new nuclear build must be capable of load cycling using changes in reactor power with steam bypass as necessary, and of load following using steam bypass followed up with changes in reactor power. Automatic Generation Control would also be possible using steam bypass.
The Ministry of Energy has already made load following a requirement for nuclear new build at Darlington. However, 80 percent nuclear penetration on the grid would mean that the new build nuclear in operation after 2045 (including the proposed 2,000 MW of Darlington new build) would have to have substantially better night time turndown than anything seen up to now in Ontario. It would also have to use a combination of reactor power reduction together with steam bypass to bring unit output down to around 40 percent of full power.
So, until around 2045-50 the province would have to rely on a generation supply mix of around 50 percent nuclear, 25 percent hydro and 25 percent gas with wind playing interference. The limit of 50 percent on nuclear generation is because the present nuclear plants do not have the capability to reduce reactor power (load cycling) during the periods of surplus baseload generation (SBG) that usually occur in the spring and fall.
Bruce B has been, and is, called upon to reduce station output when necessary. However, plant operators do this by bypassing steam that would normally be used to generate power, not by reducing reactor power. Other Ontario nuclear stations do not power maneuver, they are either on or off. It is doubtful how long the four units of Bruce B can go on using steam bypass since the original design was that any maneuvering was to be done by the reactor. The bypass system was not designed for the wear and tear from this kind of frequent use.
The gap between where we are now and where we want to be 35 years or so from now could be filled by more nuclear instead of by natural gas if the present 10,000 MW of nuclear slated for refurbishment could be made more flexible. Improving reactor maneuverability may not be practical since it is complex and impinges on reactor safety, which means this would depend on the Canadian Nuclear Safety Commission giving it the green light. So it may be easier (all relative, nothing is easy) to improve the steam bypass capability of the units so that, at least, load cycling is possible.
This would allow the output of the units to be reduced during periods of SBG, and overnight and on weekends, without any changes to the reactor power output. It would also accommodate much more new nuclear on the grid than the 2,000 MW limit set in Ontario’s November 2010 Long Term Energy Plan.
Doing this would reduce Ontario’s dependence on conventional natural gas and on the increasing amounts of controversial shale gas that is offsetting the drop in conventional gas supply. Cost and life-cycle greenhouse gas emissions are concerns with shale gas. Life cycle greenhouse gas emissions may be worse than those from coal and costs are sure to go up as demand increases elsewhere in North America for power generation and many other uses.
There is still a lot of life left in the coal-fired units at Nanticoke and Lambton. Indeed they should be kept operating, burning coal, to be available through the long nuclear refurbishment program. Coal generation will be a lot cheaper than gas generation and, being much more flexible than gas, it is a better partner for wind if that totally unnecessary energy source is to be continued with.
The health risks associated with burning coal at Nanticoke and Lambton have been greatly exaggerated to say the least, to the benefit of the gas industry (just like the hysteria associated with low doses of radiation) and not to the benefit of the nuclear industry since present nuclear cannot compete with coal on maneuverability. Two units at Nanticoke and two at Lambton have flue-gas clean up systems and need not be converted to expensive gas-firing or biomass-firing or a combination of both.
Expensive flue-gas clean up systems are not even necessary on the other coal-fired units since emissions from those plants pose little health risks. These assets belong to the people of Ontario and should be kept in operational readiness.
If the refurbishment of the 10,000 MW of nuclear does not include the improvements that would make the units more flexible, then flexible coal-fired units can be used instead to protect Ontarians from gas price hikes over the next 35 to 40 years. Having coal generation available to compete with gas may keep non-utility gas generation costs in check and reduce the large amount of contracted gas generation that has led to the present surplus and the need to export electricity at subsidized prices.
Since the long term outlook for wind and gas is bleak, the billions of dollars being invested in the so called “smart grid” should instead be put into improving the reliability of the existing centralized grid to get it ready for the increased centralized nuclear generation after 2045. Distributed generation based on many small wind and gas installations, and their necessary expensive transmission connections and “smart” grid, does not have a long term future. With a future grid powered by nuclear and hydro, wind has no place. It makes little environmental, economic, or technical sense to maneuver multi-billion dollar nuclear power plants and hydro facilities, with attendant wear and tear, to accommodate the vagaries of wind generation.
In summary. Ontario should start planning now to get off fossil fuel use by 2045-50. A new Long Term Energy Plan is needed. The supplier of Ontario’s new reactors should be made aware of the stringent requirements for load cycling and load following if Ontario is to wean itself off fossil fuels after 2045. Money should be put into improving the existing centralized grid rather than into the so called “smart” grid. Since it is unlikely that Bruce Power and Ontario Power Generation will include steam bypass improvements in their refurbishment plans if left to their own devices, it will be necessary for the Minister of Energy, through the Ontario Power Authority, to mandate that they do so.
This means delays in the refurbishment schedule and extra costs that the nuclear-electric generators would be unwilling to accept. Contracts with these generators would have to resolve this issue, bearing in mind the benefits to be obtained by a significant reduction in fossil fuel use up to 2045-50 when the refurbished nuclear units are replaced by new nuclear build.
All this has to be initiated now, now, now!
Donald Jones, P.Eng.
Retired nuclear industry engineer