Explanation using my half forgotten physics course: Apparently they are using the overhead wire as waveguide, with high frequency, using only its capacitance, thus avoiding ohmic losses. There are losses only from dielectric polarization, which they claim to be much less than ohmic loss in standard transmission.
Thanks for spending the time but can you give me the 3rd grade explanation?
Gets energy from the power plant to your light bulb without heating up stuff along the way quite as much.