. >> the average price for a wonderbag is 25 u.s. dollars -- well beyond these women's means. tuyishime and his ministry are trying to get rwandan villages to save enough energy for the country to be able to sell carbon emission credits. >> carbon finance helps to cut down the price. the wonderbag is very expensive for people to afford, but through carbon finance, carbon money comes to subsidize these wonderbags so people can access them free of charge. >> back to anastase tabaro in nasho. he's looking forward to returning to his home village -- around 300 kilometers away. he also has a dream for the whole of rwanda. >> i'm old now. i'd like to teach the next generation how to build small hydro-electric power plants. i'd like them to continue my work and use all the water power that rwanda has at its disposal. >> before anastase tabaro sets off back home, he takes one last look -- and one last picture -- of the power plant. that way he can show other villages how easily the facility works. >> when the global financial crisis hit in 2009, it put only a slight dent in the demand