Techno-economic analysis of a cogeneration system for post-harvest loss reduction: A case study in sub-Saharan rural community

Abstract

Over 90% of global yam production is from West Africa where it provides food and income for above 300 million smallholders’ farmers. However, the major challenge of yam is 10–40% post-harvest losses due to the lack of appropriate storage facilities. This paper assesses a biogas-driven cogeneration system, which could supply electricity and cold storage for ‘yam bank’ within a rural community. Considering 200 households’ Nigerian village as a case study, crop residues are used as anaerobic digestion feedstock to produce biogas, which is subsequently used to power an internal combustion engine. Result shows that the system could store 3.6 tonnes of yam tubers each year and provide enough electricity for domestic and commercial activities. At the current electricity tariff of USD0.013·kWh −1 for rural areas, the system is unable to payback during its life span. The proposed USD0.42·kWh −1 by Nigerian Rural Electrification Agency seems good with less than 3 years discounted payback period but brings about extra burden on poor rural households. Based on the income from cold storage, electricity tariff of USD0.105·kWh −1 with an interest rate of 4% is suggested to be reasonable which results in 6.84 years discounted payback period especially considering non-monetary benefits of renewable energy system.