If you need to build a complete parallel power generation infrastructure which must be capable of satisfying peak power demand on its own then it's almost irrelevant whether that infrastructure is battery powered or coal powered (from an economics standpoint). Not to mention that nobody's created anything even remotely capable of being used to generate peak (or even base) power loads using only stored energy.
This tidy infographic makes it seem like we could start the switch to PV power tomorrow if only we really cared to do so. However, the truth is far different. Not only do we lack the manufacturing capacity, by orders of magnitude, to produce enough PV panels, we do not have the operational experience in creating the sort of power storage systems that would be necessary if PV sources dominated base electrical power generation. This is not a solved problem.
This tidy infographic makes it seem like we could start the switch to PV power tomorrow if only we really cared to do so. However, the truth is far different. Not only do we lack the manufacturing capacity, by orders of magnitude, to produce enough PV panels, we do not have the operational experience in creating the sort of power storage systems that would be necessary if PV sources dominated base electrical power generation. This is not a solved problem.