If we don't need anything except the cleaner alternatives, we should start by banning and issuing laws against burning fossil fuel for connecting to the energy grid. This naturally include imports, as buying energy generated by burning fossil fuel outside the nations borders is just as bad as if the burning occurred inside.

At that point people can choose between all the non-fossil fuel alternatives and pick what attributes they favor.

In Czechia, we don't have enough wind or sun for generating much power, and the available space for hydro isn't ideal either.

The only cleaner alternative with fully predictable and controllable power delivery is hydro.