Scenario: Aliens gift humanity some mega power plant that runs off a black hole or some shit. Maybe it’s a quantum time battery or perpetual motion machine, whatever.
If we plopped it somewhere on Earth, could humanity build infrastructure across the globe to provide everyone with near unlimited clean electricity?
Yeah. If you have a magic generator, you can pretty much do whatever.
Powerlines work really well all things considered, esp if you dont have to care about transmission losses. You could run an atmospheric processor to crack C0² and water back into hydrocarbon fuels and run a carbon-neutral ICE engine. If you wanna get scifi with it (and really dont give a shit about losses) you can beam power with masers and rectennas.
Unless of course it was destroyed in the fight to control it, or as an act of sabotage to avoid undervaluing barrels of oil or whatever.