We're talking about Ontario. I live in Ontario. The sky is overcast 8 months of the year. We're not building enough storage to charge for 4 months and drain for 8.
Overcast winter days tend to be very calm as well. These are periods of minimal solar+wind generation and maximal heating demand.
Having a grid with no baseload generation and only storage is going to spell disaster during extended cold+calm periods. Rolling blackouts when it’s -30C outside…