I understand how "on the grid" power generation works...to a certain degree. If I remember the info during the tour of the Niagra Generating station, I seem to recall the guide stating that in off peak hours, they shut down generators and or divert water away from them.....so at 1 am, on a tuesday, in June, for the past 10 years demand has been 100 MW, why would you run every generator at every generating station at 100%? A sane person would say "to meet that demand I have to run 25% of my generating capacity therefore I can shut down 65% of my generators, I'll keep the extra 40% capacity JIC.....then when demand increases at 5 am, at 3 I'll start to spool up all my generators to be ready when that demand hits.
WHat is 100% LUDICROUS is to keep all your generators running at 100% capacity then sell that excess energy at a LOSS. Then because either I'm an idiot, or the system is flawed, I'll charge all my customers a premium because I have a system that is inefficient.
See, the biggest issue with electricity generation, least in Ontario, is there is NO competition. A "supplier" is given carte blanche to do whatever the hell they want, with NO recourse...
I'll tell you one clue that the system is flawed: back in the day when generating your own electricity was as rare as an albino raccoon, a guy in Kingston Ontario built himself some windmills to power his farm. He disconnected from the grid (for the most part) and then...what the hell is this? He got a bill from Ontario Hydro for the electricity HE was generating....he got a lawyer and discovered that Ontario Hydro had a monopoly contract (which is illegal in Canada) to recoup the revenue from ALL electricity generated in Ontario, whether they made it or not....Well, the bills piled up, and he took Ontario Hydro to court....FINALLY a judge with common sense ruled that Hydro One was operating an illegal monopoly, made them pay the farmer's legal bills, AND pay him 6 cents per KWH for every KWH of energy HE generated which he fed back into the grid....So now, if you DO have solar, wind or geo-thermal electricity generation and you're connected to the grid, Hydro One (the new name) has to pay YOU for that electricity....