With 49 hours of peak pricing so far this winter (out of a maximum of 100), I've learned a few things.
First, my basic consumption runs between 4 and 5 kW, as shown in the first two screen grabs from my account on Hydro's web page. The little bump every evening is likely hot water for the shower.
Second, I have been preheating the house prior to a peak event, possibly more than necessary. But the real cost is turning everything back up all at once, with peaks as high as 11 kW. This next screenshot illustrates an extreme example, where the average during the day was about 5.5 kW, but 8 kW in the evening. The 11 kW load right after the evening peak event was due to the house being quite cold, and I will probably not turn everything down so low in the future.
Third, the 2 kW impact of running an oven at 450F for 45 minutes at 18:00 is obvious in this next screenshot.
Finally I have discovered that several of my thermostats and their associated baseboard heaters never really come into play, at least in the range of outside temperatures encountered so far this year. These are in rooms connected to my large open living area where the doors tend to be open. So rather than 10 thermostats, I really only need to worry about 5. These are the ductless heat pump; a convection unit in the living area; the heated floors in the kitchen and bathroom; and the study, which is in what was originally an unheated coal storage shed and which has two walls exposed to the outside. Leaving the others at 14C does not seem to impact the final temperature in those rooms; and furthermore I can simply shut the doors during a peak event and let the heat pump do it's job on re-opening.
In other news I have been informed by a colleague of the existence of Hydro-Québec's Hilo program. This offers programmable thermostats that are controllable at a distance via an app on my smart phone. While not relying on Google or Amazon, I would be relying on Hydro's web services remaining functional. As well, it seems they do not yet have remote controllers for heat pumps or for convection units with built-in thermostats; and their system may not be able to control heated floors. So I may only be able to benefit for the single thermostat with baseboard, in the study area. I will dig and report. Stay tuned!