hello there! so i have a question about electricity. i have a character, senku, from a canon in which the major thrust of the plot involves using scientific techniques and principles to slowly reinvent all the technology that was lost when a mysterious calamity petrified humanity for 3700 years. one of the earliest developments is senku reinventing electricity using solely the low-tech items available in the stone age. initially they build a hand-crank generator and eventually develop a rudimentary form of hydroelectric power using a waterfall.

would that kind of thing still be possible or does the setting block any access to electrical power outside auroras and batteries?