Assessing energy sources for powering “evakuula”

Technologies that are appropriate, affordable, and sustainable are needed to increase incomes and resilience among sub-Saharan African smallholder farmers. A combination of thermization and low-cost evaporative cooling, termed Evakuuling, was developed to enable rural smallholder dairy farmers to preserve their evening milk in the absence of grid-electricity. The "EvaKuula" was configured to be powered by biogas. Biogas is used for the thermization process of the system. The evaporative cooling component is powered by wind. Use of biogas from domestic biogas plants add circularity value to smallholder farms. However, domestic biogas plant set-ups are relatively high capital investments and as such, a financial barrier to co-adoption with the EvaKuula. To lower this barrier, other energy sources have been considered. The purpose of this study was to assess alternative energy sources to power the thermization component of the EvaKuula. The list of energy sources considered included biogas, butane, kerosene, charcoal, and firewood. These energy sources were assessed with respect to the sum of the social and market costs. The product of a unit of fuel cost and the units consumed represented the "market cost." The product of the long-term social carbon cost and total carbon dioxide emission equivalence represented the "social cost." Regular and improved stoves were included in the charcoal and firewood analysis. As expected, biogas ranked on top of the list, followed by butane and kerosene. However, butane and kerosene are not easily accessible in rural setting. Approximated 76% of farmers in rural sub-Saharan Africa rely on firewood to meet domestic needs like cooking. Butane and kerosene are the fuel sources predominantly used in urban and peri-urban areas, due to accessibility and affordability. Incomes are typically higher among urban dwellers. Therefore, with butane and kerosene not readily available to the target EvaKuula users, the next best option was firewood, provided it is combusted in improved efficient stoves such as Lorena type.