[QUOTE=Balthisar]
This is in no way harnessing geothermal energy. I have to believe that all definitions of geothermal energy mean harnessing the energy for doing useful work.
[/quote]
Huh? Heating and cooling your home isn’t doing useful work?
This makes no sense. Do you think that heating or cooling your home doesn’t require energy? Geothermal doesn’t work because ‘it’s a more efficient exchange medium than the air’ - it works because it’s a different temperature than the air. The air is heating or cooling your home. It takes energy to counteract this. Since the ground is at a temperature closer to what you want, you run water through it and extract the energy resulting from the temperature differential and use that to heat or cool your home. Energy is energy.
I have no idea what your point is now. Electric vehicles aren’t desirable because they are cheap to drive, they are desirable because you can run them without burning fossil fuels and without giving off emissions. The point about plug-in hybrids is that they do this nearly as well for a fraction of the cost and without having to change the infrastructure. And OF COURSE if gas were dirt cheap there would be no market for these. But gas isn’t dirt cheap, and therefore people will switch to them out of self-interest because it will save them money.