The most reliable grids in the world are made up of a large number of small generators rather than a single source which when taken down takes down the entire grid.
If you were to start a new city disconnected from the rest of society then a combination of wind, solar, hydro, and batteries is the cheapest and most reliable system to power that city.
If you were to start a new city disconnected from the rest of society then a combination of wind, solar, hydro, and batteries is the cheapest and most reliable system to power that city.