In the pursuit of a greener and cleaner planet, there's been an almost religious focus on whether a new piece of tech or innovation is environmentally sustainable in the long run. Hence, we've now ended up with electric cars, hydrogen fuel cells, more efficient plastic recycling, and materials that are friendlier to the planet. It's all pretty positive and forward-thinking, but at times, you get something that's completely unexpected. For example, a way to convert your stinky sweat into usable electrical energy.