Solar and wind do need storage, but if their levelized cost of energy is low enough they still beat nuclear. Remember not to use batteries for annual load leveling, which some dishonest analysts try to do.
For seasonal storage and rare event backup: hydrogen burned in a combined cycle plant. Hydrogen can be stored underground for maybe $1/kWh of storage capacity.
High voltage dc interconnects? Importing Danish wind energy is one of the projects supposed to keep the lights on after an exit from nuclear in Belgium.
