What is the most important number in clean electricity? It is the carbon intensity per kilowatt-hour (CIPK): the total amount of carbon dioxide, or CO2, in metric tons, emitted by the emitting generators feeding the grid, divided by the total amount of electricity generated, in kilowatt-hours. As you can see in Table 1 on the left-hand sidebar, total grid generation in Ontario in the last hour was 16,986 megawatt-hours, and total carbon emissions were 984 metric tons. Therefore, the CIPK is 57.9 grams CO2 per kilowatt-hour. (To do this calculation, first convert total megawatts, or MW, to kilowatts by multiplying by 1,000; and convert total metric tons CO2 to grams by multiplying by 1,000,000. Then divide the total grams of CO2 by the total kilowatts.) As you can see in Table 1, there are two main CO2-emitting fuel types contributing to Ontario’s grid, gas and coal. Gas and coal are mainly why the CIPK is above zero.
And as you can also see, the three main zero-emitting fuel types are nuclear, hydro, and wind. Of these, nuclear contributes by far most of the megawatts. Without nuclear, Ontario’s grid CIPK, and its hour-by-hour grid CO2 emissions, would be more than three times what they are right now. Item 1 on the upper right sidebar shows what Ontario’s hourly electricity CO2 would have been with allegedly “clean” natural gas.
Nuclear is therefore the biggest reason why, for example, subway and streetcar travel in Toronto is so clean. Subways and streetcars are electric powered. The cleaner the electricity, the cleaner the subway/streetcar ride. More nuclear means a cleaner subway or streetcar ride.
Now, the question is: would you like to see Ontario’s CIPK drop permanently? If so, from Table 1, it is obvious that more nuclear would achieve that.
I stumbled across a very interesting website page the other day. It is from the Toronto Environmental Alliance, and it gives an excellent rundown of the environmental benefits of electric light rail transit (LRT). At one point, however, the page says that electric rail vehicles produce “no local emissions, since they are powered by electricity, and can be run on renewable energy like wind and solar.” The first part of that quoted sentence is bang on, but the second is clearly not. Any electric transit must be powered by reliable sources of energy. Wind, as I mentioned a few weeks ago, stopped being commercially viable in the mid-1800s. It was because it was simply too unreliable. Little has changed with global wind patterns since the mid-1800s. Wind was not reliable then, and it is stil not reliable.
For LRT in Toronto to be clean and reliable, it must be nuclear powered. That means adding nuclear capacity to our grid, to force Ontario’s CIPK to go down. If we allow our nuclear fleet to languish, or if we shifted nuclear generation to gas (the “cleanest” fossil fuel), then our CIPK would nearly three times what it is now.
How did I arrive at that? I replaced the total CO2 in Table 1 with the figure in Item 1 in the upper-right sidebar, and then re-calculated the CIPK. Item 1 is a counterfactual, which represents the tons of CO2 that would have been dumped into the air in the last hour if Ontario’s nuclear fleet were replaced by gas, as some “environmentalists” have advocated.