> "Storage" can't do that for more than smoothing out daily peaks.

See the system described in the OP link at this thread:

https://news.ycombinator.com/item?id=45012942

Long term literally dirt cheap thermal storage coupled with extreme cost optimized PV that would provide 600 C heat 365/24/7 for as little as $3/GJ, on par with combustion of inexpensive natural gas. Complementary with diurnal storage from batteries, this would be a complete solution to the renewable intermittency problem.