and much of California is also a rich source for this kind of power..from one end to the other. Most faults are areas of geothermal energy, even if it's not visible at the surface. OTOH these are geologically unstable regions.
If you dig deep enough you can get this kind of energy almost anywhere in the US. The operative is "deep enough" and I believe in roughly this is shallow enough to be economically viable..
OTOH it's misleading to say their feed stocks are free because in all but a few spots they are very expensive to reach with large, deep wells.
Yes you can get back more energy than it took to make the cells, but the cost of the electricity from them, or rather the installation is far more than what the utilities charge.