Some future technologies that might make these concerns about renewables irrelevant in a few generations — but we need fission now!
Power Satellites — space-based solar power could be provided to the earth as a baseload reliable source of solar power.
Fusion — the holy grail of energy — may just be perfected in the next few generations.
Self-replication machines — if self-reps really arrive and start to deploy almost everything we need in some sort of Post Scarcity economy then today’s normal economic questions vanish. Who cares if you have to build the grid 5 or 6 times over, and all that storage, if the robots build it all for us — for free?