Not energising the ground. Even if energised you still couldn't produce eletricity because you wont have the 0 for ele to flow to it. So you would still need cables to go back to power station.
From what I know he worked on trensmision of electric energy. Basicly wireless powering of machines.

The problem with the lack of the notes is if I remember correctly is that he rarely made any real experiments where he would see if his idea would start working. All the thinking he would do in his head and then conduce an experiment which would in majority of attempts succed.