Engineers in Technical and Humanitarian Opportunities of Service (ETHOS) is a non-profit organization for appropriate technology that holds annual conference on Clean Cookstoves.  Most of their presentations for last 10 years are online and are maybe the best single site for learning fast about the challenge of a billion people using dirty inefficient stoves.   Hydrobee CEO Burt Hamner presented the Firebee stove at the January 2017 conference near Seattle.  He fired it up in the conference room and charged phones with fire while giving his talk.