[aaronmdjones]

> How does one transport energy over such a long distance ? Wouldn't there be massive loss in form of heat due to the fact that cables are not perfect conductor ?

Losses in power transmission are a function of the current (P = I^2 R; power dissipated = current squared multiplied by cable resistance). Using a thicker cable reduces its resistance, lowering losses. HVDC transmits power at -- as its name implies -- a much higher voltage; increasing the voltage means you need to draw less current in order to consume the same amount of power, lowering losses again.

It's why electrical grid transmission networks within countries run at a couple hundred kV. The UK uses 275kV and 400kV for transmission for example, stepping it down to 33kV and 11kV at substations, before it is finally stepped down to 230V for light commercial and residential consumption.

EDIT: A fantastic demonstration: https://www.youtube.com/watch?v=qjY31x0m3d8

[LorenPechtel]

You are describing what happens with thermal losses, which as you say can be addressed by running up the voltage. But corona loss goes entirely at voltage and will come to dominate if you try kicking the voltage too much above current levels.