2 points
i have a sneaking suspicion that if 80%+ of energy is used on heating anyway then storing that heat at point of use and topping it up when excess energy is available is the easiest, least wasteful way to go
1 point
Heating/cooling probably, but renovation of older structures is generally expensive and complicated, whereas grid batteries can scale until newer construction (which should be more insulated) can keep up. It’s not an either or, but more of both that will compliment each other as time progresses.
