In Denmark the government have allowed people who live along some of the largest underground powerlines to install geothermal equipment to heat their houses.
That might actually save the utility companies some power usage - the resistance of a material increases with temperature and the homeowners would be reducing the temperature of the ground.
It's very interesting. Do you have a link about this?
Anyway, this is very different.
In an electric wire part of the energy is always transformed into heat and wasted, so it's nice is someone can use it.
In this device, they add something to absorb part of the energy that otherwise would have traveled to your neighbor, so the transition tower must increase (slightly) the energy used.
It's like digging a hole and replacing a part of the high voltage cable with a device that makes more heat on purpose to heat your home.
seems like that's a win for both parties? the transmission line heating is a waste product, which increases resistance, which increases the waste. so if folks are willing to pump the heat out and productively use it, that's great.