Power is not transmitted through the ground, the neutral conductor serves this purpose. Ground is used as a universal voltage reference, the neutral conductor is connected to it at many nodes to ensure a constant voltage along its entire length.
Locally, ground also serves the purpose of being an infinite current sink, someplace to put all the current you want and still make it 0V. Obviously, local soil condition dictate on how well it works for this purpose.
As to VLF, I doubt its easy to get an FCC licence to experiment, especially since it makes ones head explode. (see below for proof )
From
http://www.themareks.com/xf/1998.shtml
Entering California, a highway patrol officer on motorcycle hands Mulder a cell phone. Scully tells Mulder that she has learned that the Navy has part of an underground transmitting array for an ultra low frequency radio system (used to communicate with submarines) running under the Crump property. They had a power surge that morning that disrupted television in four states. Scully theorizes that the surge created a condition in the inner ear that is somehow eased by speed along magnetic lines of force, or some such reason. She will fly ahead of Mulder and meet the car where the highway ends, inserting a needle into Crump's ear to relieve the pressure. Crump agrees, as his only way to survive. But when the car actually arrives, Crump's ear has already exploded and he is dead.