Very cool. Also a related possibility not currently being considered to think about. Tesla builds tunnels for about $1 B per mile. What if tunnels were built into mountains to funnel run off into tunnels that descend 300 feet or so to turbines, the water then to another tunnel etc. for say 1 mile. Would that be cheaper that building another boulder dam? Of course this only works where topology and weather patterns are optimal, but where cost effective this could be an interesting addition.