EDITED:

Initially I posted this to ask about implementing underground power, because the circuit connector only mentions red and green circuits, and when you check the power network underground it doesn't show any production or usage. But after some more testing it does look like the power connections work. It's just a bit misleading when you read the tooltip, and then see no power underground.

I think that should be fixable, though. I'm not sure off the top of my head, but I think Factorissimo showed power usage from the whole base even while inside a factory building.