To be fair, there is a lot of grid scale solar (and wind) being built, largely because they are the cheapest way to add generation capacity right now. But they are not a simple pluggable replacement for gas, coal, or nuclear, because they deliver power to the utility grid when the weather dictates power is available, not when the utilities demand dictates they need it. Utilities struggle once the fraction of their power supplied by these "interruptible sources" gets over 1/4 or so of their total generation base. As far as I know, the only regional-scale grids that have gone completely to renewables are Tasmania and Iceland. South Australia is not far behind, and Scotland not far behind them. But each has special circumstances that make it an easier lift. Tasmania and Iceland have abundant hydro and geothermal, which are ideal complements to interruptible renewables, because they can be quickly throttled up and down as required, as the interruptibles wax and wane. South Australia has highly reliable sunshine and wind, and so have been able to bridge the stochasticity of these with relatively manageable sized batteries (and a couple of flywheel installations to provide very short term momentum based frequency control). Scotland has highly reliable wind, and is headed in the same direction as South Australia.