But you (and I) could have a seasonal thermal energy storage, cooling the solar array in summer and removing the need of external heating in winter. Doesn't work for power, but does for heat.
I do something far shorter: heating water in the sunny days to have it in the cloudy ones, but that's definitively far from sufficient for heating the entire house and to scale at the entire house needs well... It's cheaper run on grid electricity, even these days.