candles and flowerpots
http://www.naturalcuresnotmedicine.com/2013/11/heat-your-room-for-15-cents-day.html
Superflux biogas from atle dung - Tanzania
http://superflex.net/tools/supergas/image/5#g
Making a Run at Alternative and Free Energy By Wade Frazier
http://www.ahealedplanet.net/energy1.htm#new