Apparently this company called Alphabet Energy, has built a cheaper thermo electric system that should be 6 times cheaper than existing stuff and 10% better. Themo electric is converting heat to electricity. This would be cool since you could power stuff with candles, campfire, etc at a much lower cost than current stuff out there. Of course it could be a year or two, or more before we start seeing it.
http://www.technologyreview.com/news/528841/thermoelectric-material-to-hit-market-later-this-year/