Please refrain from unnecessary, unsubstantiated insults. Rgbrenner's point that geothermal is costly for the same reasons that oil is costly - that is, it takes work to transport the energy in usable form - is valid. You're right that geothermal has a humongously deep supply curve, but that doesn't mean its price will be zero.
The point was that if you want energy in your home, you either (1) have to transport energy to your home or (2) place your home at the source of the energy. Since placing your home next to a large temperature differential is difficult, then the future will continue to rely on option (1), transporting energy to your home. And if energy has to be transported, its final price will not be zero, even if its wholesale price is.
Nothing will ever be truly zero cost, but those costs can be minimal.
A geothermal system for your house involves "transporting energy to your home" but the distances involved are so minimal that once installed it's next to nothing.
> Since placing your home next to a large temperature differential is difficult...
Well, that's wrong. Every house sits on top of a significant temperature differential which is why geothermal systems work. In large parts of the continental US the ground deep beneath the house maintains a consistent temperature year round. This can be used as a thermal sink in the summer, and a source of heat in the winter.
A friend of mine just got geothermal for his very ordinary house in a major metropolitan area. It was cheaper than the solar on my house was a bunch of years ago. Your point seems very bogus to me.
