Ontario Electricity Generation on a Hot Day

Today is a hot day in Toronto. The temperature is 34 degrees and it is only 2 pm. Toronto's Medical Officer has upgraded the heat alert to an extreme heat alert. Cities across the province are finding it very hot as well.
On hot days like today, demand for air conditioning swells. Air conditioning requires electricity, so what fuel sources are being used to generate electricity?

Source	MW	%
Nuclear	10857	45.31
Hydro	4658	19.44
Gas	5410	22.58
Coal	1722	7.19
Wind	441	1.84
Other	873	3.64
Total	23961	100
source:http://www.ieso.ca/
Fuels used to meet demand Jun. 20 - 12:00-13:00

Nuclear is the most important fuel. Nuclear, hydro and natural gas provide 87.3% of the fuel. Other refers to wood waste, biogas, solar, etc. Electricity generation in Ontario is very dependent on nuclear. For the year to date, nuclear has accounted for 56.9% of the fuel used to generate electricity in Ontario. Renewables make up a relatively small proportion of total fuel source. Notice that coal, which used to be a big fuel source, now accounts for just 2.7% of total fuel usage.

Today's electricity demand is projected to peak is 24,267 MW at 5 pm.
The summer record was 27,005 MW on August 1, 2006.