This metallic case holds the fuel capsule for the National Ignition Facility fusion experiments. The target is precisely positioned and cooled to cryogenic temperatures (18 kelvins, or -427°F) so that a fusion reaction is more easily achieved. (Photo by Eduard Dewald/LLNL)
The notion of generating power by our natural activities is very appealing. However, I can't help but observe that 1 to 5µW/cm2 is a tiny amount of power when solar cells can generate (according to http://www.solamonenergy.com/about-solamon-energy/history) 10,000 µW/cm2 (10 mW/cm2). Since people require light to see and navigate, are we better off just putting solar cells on our cloths for the time being?