Meeting Ontario’s summertime heat load with zero-carbon energy means doubling the nuclear fleet

Yes, summertime heat load. You don’t usually think of using bulk artificial heat in the summer, what with outdoor temperatures pushing upward of 30° C. But in Ontario last July, we collectively bought 1.1 billion cubic meters of natural gas (see StatsCan CANSIM Table 129-0003). By my calculation about 320 million cubic meters of this were purchased by the 45 or so power plants in the province that burn natural gas to make electricity. This means about 796 million cubic meters were used for other applications.

In some of these applications natural gas was used as a raw material to manufacture other substances, including polyethylene, the most common plastic in the world. But most natural gas by far is used as energy. Let’s assume that 90 percent of the 796 million cubic meters of natural gas purchased in Ontario in July 2015 were used this way. That works out to 717 million cubic meters. This amount contained 7.1 billion kilowatt-hours of energy, and when that energy was released as heat it produced 1.3 million metric tons of carbon dioxide (CO2).

In all cases where natural gas was used for heat energy, that energy could have been provided by electricity. Considering the 1.3 million tons of CO2 that came with the gas-fired heat in July 2015, that energy should have been provided with electricity—Ontario electricity in that month was four times cleaner than gas.

That energy was used to heat water, as well as for cooking and baking. Some was used for air conditioning.

Now, Ontario electric power generators, including the gas-fired ones I mentioned above, collectively made about 13.3 billion kWh of energy. (The gas plants contributed 12 percent of that energy.) Collectively all power plants made 635,000 tons of CO2—but almost all of this pollution came from the aforementioned gas-fired plants.

Out of those 13.3 billion kWh, 8.3 billion—or 62 percent of the total—came from nuclear plants, which produce zero CO2.

In all cases where natural gas was used for heat energy, that energy could have been provided by electricity. Considering the 1.3 million tons of CO2 that came with the gas-fired heat, that energy should have been provided with electricity. Electricity in that month came with about 47 grams of CO2 per kWh, making electricity four times cleaner than gas.

How could we provide 7.1 billion kWh of electricity? With nuclear. We could double the size of our nuclear fleet, and that fleet could run pretty much flat out all year long—there would be no need to curtail nuclear output. July and August were the low demand months, remember. In January and February of 2015, natural gas use was triple what it was in July and August.

We currently have 12,500 megawatts of available nuclear capacity. Doubling that would give us 25,000 MW. It would also wipe 15 million tons of CO2 off of our provincial GHG inventory. It is the only way we can wipe out those 15 million tons.

We should get started on this.

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8 years ago

I cannot help but recall that the 19 MW(e), 62.5 MW(th) EBR-II had a core volume of less than a cubic meter.  A steel-lined concrete containment cell would be sufficient to isolate one from the environment, at very reasonable cost.  Many such plants could be placed in a metropolitan area such as Toronto, supplying both electricity and low-pressure steam to all buildings therein.  That would supply all heat, light, DHW and charging for electric vehicles that the residents would require.

A more reasonable reactor would not start with driver fuel at 67% enrichment; closer to 20%, perhaps.  That would require a larger core volume.  A substantial breeding blanket would be required to capture the escaping neutrons.  This grows the minimal system’s physical size, if not output power.  The big question:  how much spent nuclear fuel does Canada have sitting around, and what is its fraction of trans-uranics?  That tells you what you’ve got on hand to get the whole thing started.

8 years ago

Okay, 2e6 bundles at a nominal 19.2 kg UO2 each is about 34,000 tonnes heavy metal; .0038 of that is roughly 130 tonnes.  At 2.43 tons per core load and 3 core loads per unit, this would provide the initial fuel charge for about 17 S-PRISMs.  At 311 MW(e) apiece that is a tad over 5 GW.

Looks like a good start to me.

7 years ago
Reply to  Engineer-Poet

I’d trust IFR a lot more if it used molten lead instead of sodium to cool the thing. I’d go with any molten salt breeder (thorium or fertile uranium) over IFR though.

7 years ago
Reply to  Kyle

Lead is corrosive and requires protective coatings on metals lest it take them into solution.  Sodium is non-corrosive, and next-generation power conversion systems like supercritical CO2 turbines will eliminate the last concerns about water-sodium reactions.

Jim Baerg
7 years ago
Reply to  Kyle

I had that attitude too, until in the book _Plentiful Energy_ about the Integral Fast Reactor I saw mention of filling the containment building with argon.

If sodium is better in other ways than less flammable reactor coolants, filling the containment building with argon will make the flammability a non-issue.

8 years ago

There is an excellent Canadian solution to summer peak electrical demand problem. The iMSR from Terrestrial Energy is designed to be really cheap. It has a relitively brief core life time, although replacing the core is expected to be relatively inexpensive. ooperating iMSRs at a capacity factor of from 15% to 25%, typical for natural gas peak load natural gas generator systems, might offer an ideal solution to the peak load problem.

8 years ago
Reply to  Charles Barton

I have another solution:  set up all air conditioning as ice-storage systems, with the favored system in steam-service areas being ammonia-absorption cycles instead of vapor-compression cycles.  The A/C runs flat-out at night,when other electric demand is at a minimum.  Absorption cycle units remove their load from the grid except for circulating pumps and fans.

Voila, the peak can be re-sculpted into anything you want it to be.