Seeing as I am depressive, no fun and literal -
Really a steampunk clock should use no electricity at all. That's the idea behind steampunk; a Victorian era that never goes electric. E.g. in Nabokov's ADA, there is no electricity - it's a forbidden word - telephones are hydraulic and vehicles use steam or Diesel engines (which need no electricity). Putting in a microcontroller makes me feel the way I feel about watches that try to look mechanical but need batteries. I mean, none of my mechanical watches are that accurate at telling time, but they have real springs.
Now I'll go and have a rant somewhere about skeuomorphism and how it's a lazy and self-referential way to avoid coming up with new design languages.
(Mind you, the machinery is nice.)