For most countries this will first happen with wind. The locations of power plants will still be used because they connect large parts of the grid. So if we hav

For most countries this will first happen with wind. The locations of power plants will still be used because they connect large parts of the grid. So if we have batteries that allow using purely renewables (capacity high enough to overcome days with little production), they could be placed at the former plant sites, probably easiest for the grid. Batteries would then of course also play a large role to control demand (in-house batteries to even out spikes), but there's likely still need for utility companies to balance out supply/demand for some parts of the day which would likely lead to large battery arrays at these locations.