This work describes a progressive strategy to achieve 100% penetration of intermittent renewables at minimal cost. The strategy works to optimally transform variable renewable energy (RE) into firm, effectively dispatchable generation. This functional dispatchability enables large-scale displacement of conventional generation at equal or lower production cost.By way of this strategy, we delineate a pathway for a full renewable energy transition of the Italian electric mix. In order to achieve 100% renewables in any grid, the fundamental imbalance between the supply of the resource and demand must be alleviated. We propose a transition that starts by addressing net load forecast imbalances resulting from renewables' prediction errors and end...