does that meanan in congo we dot hahave problems? youou know.at would be lying. >> it's sunday in rubaya. a day off, and a chance to go to church. the day is sacred for mathis too.o.it's thehe k where the miners can pray and rejoice without fear. doing something to resist violence and giving the democratic republic of the congo a chance, certificication appears s to bt least one effective first step towards justice in the minerals trade. >> and now to our global ideas series, where we meet people committed to preserving our planet's climate, flora and fauna. islands that live off tourism often lack the resources to meet their own energy requirements. grenada in the caribbean wants to reduce its dependency on fossil fuels, and promote renewable energy. our reporter k katja dohne tooa closer look at biogas production there. >> ricichmond-hill pririson in grenada. some 450 inmates are incarceratated here. a a few are allolowed outside;e biogas plant needs a new load of liquid manure. the prison has been producing its own biogas for several months.