Ontario nuclear performance in the recent heat wave

Anybody who followed the output of Ontario’s electric generators during last week’s heat wave would have noticed the nuclear fleet’s stellar performance. During the entire week, the sixteen nuclear units—with a total electricity generating capacity of around 11,500 megawatts—ran at just over 96 percent. Through the week of July 1 to July 7, they generated over 1.8 billion kilowatt-hours of rock-steady cooling power to fight the heat wave.

By contrast, the performance of the much-vaunted wind turbine fleet was dismal. The fifteen provincial wind farms scattered all across southern Ontario contain nearly a thousand individual turbines, and have a collective (fleet) capacity of around 1,700 megawatts. Over the same July 1 to July 7 period their actual output represented less than 14 percent of that capacity. They collectively produced less than 38 million kWh—about one-fiftieth of the nuclear fleet’s output.

Put another way, the nuclear fleet, the capacity of which is only 6.7 times that of the wind fleet, produced nearly 50 times as much actual electricity.

That’s called clutch hitting. When Ontario needed cooling power to fight the heat wave, nuclear stepped up and delivered it.

It is also called bang for the buck. Those 1.8 billion kWhs of nuclear electricity each cost around 6 cents. Each of the less-than-38-million wind generated kWhs cost at least 11 cents.

That is to say, Ontario rate payers paid less money for nuclear power, which—as last week proved—is by far the more reliable power source.

Moreover, nuclear is the only reliable carbon-free power source. People think wind is carbon-free. It’s not. Because wind is so unreliable, it must be paired with a backup source that is capable of delivering power on demand. In Ontario, the preferred backup source is natural gas.

Well, natural gas is mostly methane (CH4). React CH4 with oxygen—i.e., burn it—and you create a lot of carbon dioxide (CO2) to go with the heat. That CO2 gets dumped into our atmosphere, where it swirls around for centuries before dissolving in ocean water and turning that water more acidic.

From an environmental point of view, the sheer unreliability of wind power during last week’s heat wave should come as a sobering wake-up call. If Ontario’s wind fleet only produced power at 14 percent capacity during a period when every megawatt of capacity was needed, then what produced the other 86 percent? The answer: natural gas. Gas is a carbon-emitting fossil fuel.

0 0 votes
Article Rating
Notify of

Newest Most Voted
Inline Feedbacks
View all comments
11 years ago

Right on Steve. the capacities of the various fleets are usually provided when making comparisons, not their actual energy output. It is interesting to see in the recent ETP 2012 published by the IEA that even with a drop of about 20% in demand going from the based scenario to the 2 degree (low carbon) scenario, total capacity increases due to the low capacity factors of renewables. I have discussed this in my most recent blog (if you haven’t seen it, it is here http://bit.ly/MJIUOE )

11 years ago

True enough … Ontario has had a surplus of baseload generation as it prepares for regularly scheduled shutdowns, mothballing of coal plants, and maintenance upgrades. The additional capacity provided from renewables should help better balance the energy grid in Ontario and lower costs on a poor performing wholesale market (with renewables paying their fair share, and negotiated contracts helping to pay down long standing debt from artificially low energy prices).


“Over the past several years, and continuing for the next 18 months, new sources of generation have been – and continue to be – brought into service to meet future supply needs and replace coal-fired capacity. The incorporation of this supply, coupled with declining demand during off-peak periods, has caused periods of surplus baseload generation (SBG) which the IESO will continue to manage.”

No supply shortfalls during the current heat wave, or projected for the future.