And well, if you can have a heat battery then why not a cold battery too ? Winter cold spells in southern Finland can hang at around -20C (subzero F), so you could store that for summer use.
Years ago there was a meme that when Helsinki's snow removal created giant piles of the stuff ("lumikasat"), sometimes a pile lasted thru the summer - greatly diminished, but extant. It was a fun meme but then it disappeared from the mediascape: maybe the city thought it was bad PR for tourism.
https://northwiseproject.com/nbis-stock-mantsala-data-center...
It is a great solution for places where heating is the primary use of electricity and I hope it finds broader applications.