Economic and Environmental Analysis of Farm-Scale Biodigesters to Produce Energy for Kitchen Stove Use
Developing countries throughout the world currently fuel kitchen stoves for cooking by burning wood which is responsible for many health and environmental problems. Producing fuel for cooking via anaerobic digestion is a very ecofriendly and resourceful solution that is being explored. To determine the sustainability of anaerobic digestion throughout these regions, multiple biodigester designs were tested under conditions specific to various third-world countries; the countries tested were Nicaragua, Bolivia, Nigeria, India and Indonesia. Factors to be considered included the use of local biomass resources and building materials. Determining the fueling efficiency of anaerobic digestion in comparison to burning wood consisted of evaluating the production costs and environmental impacts. This was accomplished utilizing techno-economic analysis (TEA) and life cycle assessment (LCA). TEA results indicated that tube digesters are the most cost effective method of anaerobic digestion in all countries tested; tube digestion at a family scale ranged from approximately $0.24 per meal to $0.73 per meal. The LCA showed that operation of anaerobic digestion required much more water than previously considered which may cause it to not be a sustainable method. However, it did emit a much lower amount of carbon dioxide than burning wood. The CO2 emissions per meal ranged from 0.97 kg per meal to 1.29 kg per meal. The water impacts ranged from 76 L/meal to 100 L/meal. Comparing the two fueling methods proved that anaerobic digestion was a more economically and environmentally effective process.