Just from looking at some government studies. This doesn’t necessarily compare longer-term costs, but it does give some direct comparisons between storage options.

I’m certainly no expert here, but just throwing out some rough estimates of battery degradation, it doesn’t seem to be cost-effective vs natural gas, which is already only slightly more expensive than solar. So solar plus battery storage seems to be significantly more expensive than natural gas.

It’s certainly more complex than that (i.e. you’d need less generation if battery backup is plentiful), but that’s the data I’m looking at.