Investigative study on energy solutions systems for cereals milling in Sub-Saharan rural areas based on an optimal design using multi-objective NSGA-II

Sub-Saharan rural areas mostly use cereals diesel milling because of lack of electricity. However diesel engine operation is very polluting. Using an alternative energy source for cereals milling could be beneficial both environmentally and economically. In this regard, a comparative analysis based on a multi-objective NSGA-II is carried out between diesel and electric milling of cereals. Different electrical energy sources including photovoltaic solar energy are proposed and investigated. The concept of cost of mechanical energy (COME) is introduced for the economic comparison between diesel and electric milling. The obtained results have shown that for 0% DPSP (Deficit of power supply probability), the COME of PV/Batt/EM, Grid/EM, DG/EM, and DE systems, are respectively 0.2455 $ kWh⁻¹, 0.1905 $ kWh⁻¹, 0.5649 $ kWh⁻¹ and 0.4982 $ kWh⁻¹. The corresponding cost of electrical energy (COEE) of PV/Batt, Grid and DG systems, are respectively 0.2051$ kWh⁻¹, 0.158 $ kWh⁻¹, and 0.4785 $ kWh⁻¹. The cost of milling (COM) for the optimal systems designed are 0.0106 $ kg⁻¹, 0.0091 $ kg⁻¹, 0.0194 $ kg⁻¹, and 0.0175 $ kg⁻¹, respectively for PV/Batt/EM, Grid/EM, DG/EM, and DE systems. However, when the PV solar energy losses are sold, then the COME, the COEE, and the COM of the PV milling system become respectively 0.1854 $ kWh⁻¹, 0.1215 $ kWh⁻¹, and 0.0079 $ kWh⁻¹. The calculated CO₂ emissions (CO₂e) per year of PV/Batt/EM, Grid/EM, DG/EM, and DE systems, are respectively 3191 kgCO₂e, 6906.8 kgCO₂e, 14484 kgCO₂e, and 8963.8 kgCO₂e. The outcomes of this study show that, the electric milling based PV energy could be the best techno-economic and environmental option to adopt in grid and non-grid connected rural areas.