Growing up, my grandparents' house had a biogas plant, powered by cowdung (they had anywhere between 6 and 8 cows and bulls at the time). Looked something like

Growing up, my grandparents' house had a biogas plant, powered by cowdung (they had anywhere between 6 and 8 cows and bulls at the time). Looked something like this: https://www.peda.gov.in/nnbomp https://www.peda.gov.in/nnbomp Most of the cooking and some of the lighting for the house was done using this thing. Most of the bigger houses in the village had one.