This previous post on Canada’s new commitment to generate 90% of its electricity from sources that do not emit greenhouse gasses by 2020 was a bit too wide-ranging, since it sought to consider all possible mixes that satisfied the 90% criterion. A more reasonable approach is to consider two plausible scenarios.

In the first scenario, electricity demand rises by 10%. Assuming that means 10% more generating capacity is required, that means increasing Canada’s electrical capacity to 132 gigawatts. Doing so while achieving the 90% target would mean scrapping 20.4 gigawatts of emitting capacity (about three times the capacity of all of Ontario’s coal plants) and building 32.4 gigawatts of non-emitting capacity (six giant dams or about thirty five nuclear reactors).

In the second scenario, energetic conservation efforts cause demand to fall by 10%. As such, we would be able to cut our total generating capacity to 99 gigawatts. Producing that while reaching the 90% target would mean scrapping 23.1 gigawatts of emitting capacity (3.5 times Ontario’s coal plants) and building 23.1 gigawatts of non-emitting capacity (under five giant dams, or about twenty five nuclear reactors).

The numbers might work out a bit differently if you did the calculations based on terawatt-hours of electricity use, rather than gigawatts of installed capacity.

{ 5 comments… read them below or add one }

I found your analysis easy to understand. I was somewhat struck that the difference in increasing 0r decreasing electrical consumption by 10% results in a difference between the need to build 6 giant dams instead of 5. I would have thought there would have been more of a difference.

I was wondering between the option of nuclear reactors and dams, which you would recommend and why given the present or future anticipated technologies.

Here is the analysis using terawatt-hours and some more recent statistics.

TWH is probably the more accurate way to go, since no power plant produces 100% of its capacity all the time and some are actually quite variable in output.

The difference between the gigawatts of capacity and terawatt-hours of output figures comes down to the different statistics used for the calculations.

The GW figures were based on Canada having about 120 GW of installed capacity, about 70% of which is non-emitting.

The more recent and authoritative TWH numbers are based on Canada producing 583 TWH of electricity, about 78.8% of which is non-emitting.

Using the TWH figures and a scenario where electricity demand rises about 10%, about 14-16 new large nuclear reactors would be required, or alternative sources of non-emitting energy with the same output. In a scenario where demand falls 10%, only 2 new reactors would be needed.

Note that this assumes that all existing non-emitting capacity continues to operate.

Does Canada even have the option of building more ‘giant dams?’ I thought all the good sites in developed states had basically been used.

Also, 32.4 gigawatts divided by five dams means 6,480 megawatts per dam. The W. A. C. Bennett Dam has a capacity of just 2,730 megawatts.

Electricity generated from coal – Total electricity generated (2006)

Canada: 97,625 gigawatt-hours (GWH)

Nova Scotia: 7,054 GWH

New Brunswick: 3,513 GWH

Ontario: 28,494 GWH

Manitoba: 352 GWH

Saskatchewan: 11,620 GWH

Alberta: 46,592 GWH

From:

Report on Energy Supply-demand in Canada (2006)

Catalogue no. 57-003-X