> If the plan is to use solar and storage for _all generation_, though, that's the number that matters.
And that's the problem with these Internet discussions: that's almost never the plan, but commenters trying to make solar look bad assume it is (to your credit, you made it explicit; many commenters treat it as an unspoken assumption).
In real life, solar and batteries is almost always combined with other forms of generation (and other forms of storage like pumped hydro), in large part due to being added to an already existing large-scale grid. The numbers that matter are for a combination of existing generation (thermal power plants, large-scale hydro, etc) with solar plus storage. Adding batteries for just a few hours of solar power is enough to mitigate the most negative consequences of adding solar to the mix (non-peaking thermal power plants do not like being cycled too fast, but solar has a fast reduction of generation when the sun goes down; batteries can smooth that curve by releasing power they stored during the mid-day peak).
And that's the problem with these Internet discussions: that's almost never the plan, but commenters trying to make solar look bad assume it is (to your credit, you made it explicit; many commenters treat it as an unspoken assumption).
In real life, solar and batteries is almost always combined with other forms of generation (and other forms of storage like pumped hydro), in large part due to being added to an already existing large-scale grid. The numbers that matter are for a combination of existing generation (thermal power plants, large-scale hydro, etc) with solar plus storage. Adding batteries for just a few hours of solar power is enough to mitigate the most negative consequences of adding solar to the mix (non-peaking thermal power plants do not like being cycled too fast, but solar has a fast reduction of generation when the sun goes down; batteries can smooth that curve by releasing power they stored during the mid-day peak).