I don't think anyone who actually bothers to run the numbers suggests that solar will meet 100% of a buildings energy needs. However, even at 100 residents per

I don't think anyone who actually bothers to run the numbers suggests that solar will meet 100% of a buildings energy needs. However, even at 100 residents per acre[0], it's utterly possible to put about 4-6kw of panels and a solar water heater on every house. Having both of those on a duplex, I can tell you that my power bill is basically nothing now. Naturally, that power output will differ by location, but it's doable. [0] Based on my local area, this is a mix of row-houses, semi-detached, and fully detached housing.