I was playing 7DTD (Vanila, no mods), and my home electricity was randomly turned off, game wasn't saved.
Today I continue my playing and observed that base lights are not working, then I saw that ALL batery cars and Solar Panels were removed from appropriate slots in banks.
You were not lucky. The game was saving when you lost electricity, so it messed up the save.
You should go in the creative menu and get your stuff back... It's fair in this case.