There is a tradeoff between a better grid and more storage requirements (it's always windy somewhere, and with a sufficiently smart grid you can match demand to supply better). You probably only need a day or two of battery or hydro storage and can use power-to-gas for long winters. Strategic gas storage infrastructure is already available, and power to gas is a proven technology (with fairly terrible energy efficiency). But you need power-to-gas anyway, because replacing all the old gas infrastructure for heating with heat pumps will take too long.
If you speak German, there is a very informative interview with Prof. Quaschning of Scientists for Future here: https://www.youtube.com/watch?v=z3EoCKgzLo4