When we were kids, we assumed that in the future everything would be powered by tiny nuclear fusion reactors: automobiles, toothbrushes, time machines (apparently we read a lot of sci-fi from the 1950s). The truth, as usual, is more mundane than all that: some of the more promising advances we've seen in green energy has been kinetic, taking the movement of automobiles or the tides and converting it into electricity. Pavegen, for example, can be set in public walkways to generate as much as 2.1 watts of electricity per hour from the footsteps of grizzl
