Coal is a third of the US energy mix. It'll take decades to bring that to zero at present energy consumption using both NG and renewables. NG will continue to expand by necessity. We're about to switch over to electric vehicles, which will add a huge amount of new electricity demand to the grid. There's no scenario where we support that shift in the next ~30 years on renewables alone. More likely, circa 2050, we're going to see 30-40% NG with 50-60% renewables (maybe 10% nuclear).
It will take a lot less if the fuel cost differential between NG and coal looks permanent. Coal turbines will be converted to NG or shut down entirely.
