Techno-economic analysis of a low-cost biogas fed combined heat and power system for African villages

Abstract

The increasing depletion of fossil fuels and the imperative of environmental sustainability have compelled the adoption of renewable energy sources (RES). Particularly, the utilization of renewable resources is crucial in African countries where challenges persist in accessing electricity and modern cooking fuels. Conventional electricity generation systems have proven inadequate to meet the growing energy demands within African villages due to the scarcity of fossil fuels. Consequently, this study examines the viability of alternative energy sources, focusing on the conversion of biomass into biogas through anaerobic digestion technology. Many African nations possess abundant biomass resources, making them potential feedstock for biogas production through commercial biogas plants. However, challenges such as startup finances and equipment shortages have hindered the full exploitation of these resources. This research addresses the feasibility of using anaerobic digestion to convert household and poultry waste from rural areas in Limpopo and Western Cape province, South Africa, into biogas for cooking, and lighting. The study employs two simulation models, one for the anaerobic digestion process and another for the subsequent power generation. Anaerobic digestion, a well-established technology for organic waste treatment, proves promising in this context. Research outcomes indicate that anaerobic digestion of kitchen and animal waste is a viable method for biogas production. Food waste amounting to 668 kg and 467.5 kg from Madombidzha village and Walladecene area produced a biogas volume of about 522.3 m3 and 365.2 m3, respectively while poultry waste amounting to 418 kg from Madombidzha village produced a volume of about 209 m3. The results reveal that the more the waste the more biogas volume production. Employing the HOMER Pro hybrid microgrid system for electric power generation, the study demonstrates that the biomass from these rural areas can also be used in a biogas generator to generate electrical power. The estimated electric power production from the biogas generator in Madombidzha village and Wallacedene area amounts to about 109,508 kWh/year and 199,000 kWh/year, respectively. This investigation underscores the potential of anaerobic digestion as a sustainable energy solution, paving the way for the wider adoption of biogas technology in rural African communities.