Things start to get interesting when you get into alternative power sources. I have also been researching solar/hydro power as an option for my next home. Hydro sounds like the best alternative if you have a stream, but solar technology keeps getting better and better. Solar energy is most effective at heating.
If you are trying to go completely off grid you would probably be better suited to use geothermal heating/cooling. These systems use much less electricity than traditional heating and cooling and they are cheaper to install if the geothermal coils are placed in the depths of a pond.
