I was thinking about insulating a shipping container to live in and I came across the issue of the ribs on every surface. If they aren't insulated they generate tons of mini ovens pumping heat towards your insulation. I live in Texas so that's a bad thing.
I was thinking about using peltier cells to generate power using the sun. Hook the peltier cells in series to 18v, then in parallel to 35 amps and run that to a charge controller to charge a battery bank. You can get 60w nominal peltier cells shipped for about $4 These can generate UP TO 60w if the max thermal difference is achieved [100*C difference between the two sides], which it wont be under any normal circumstance. Normal power generation will probably be 1/4 of that so, 15w/$4 or $0.33 per watt. About on par with diy solar, but you dont need the sun to make heat, during the winter you could reverse the polarity and pump the exhaust heat into the ribs to generate power with your excess heat.
My shipping container home will be completely modular so if any of the cheap Chinese cells go out I can pull the wall out and get to them.