What does "battery capacity to the tune of 10% of their maximum output" mean?
Battery capacity = energy (e.g. in Wh); power output is power (in W).
So is it 10% of annual energy output? Daily output? These are VERY different.
Solar electricity may be interesting because of a relatively low carbon footprint (although around 4x larger than wind and 10x larger than nuclear).
Adding batteries increases carbon footprint a lot.