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This paper looks at an islanded complementary power system in Sierra Leone's South-eastern region. It presents a method for assessing or evaluating the performance of an existing complementary hybrid energy system (Bo-Kenema power network) in an urban environment, taking seasonal variability into consideration. The proposed method attempts to assess the feasibility of establishing either a new hybrid system without current sources or a hybrid system that includes both existing and new sources. A comprehensive techno-economic-environmental optimization analysis was carried out in which 13 scenarios were evaluated and compared. With a net present cost (NPC) of $50.4 million (M) and a cost of energy (COE) of $0.211/kWh, Case 1 (Solar photovoltaics (PV)/generator 1 (G1)/generator 2 (G2)/generator 3 (G3)/battery/hydro/converter) was found to be the most cost-effective and sustainable scenario. The sensitivity analysis performed on Case 1 (optimum scenario) revealed that the total system cost was heavily reliant on turbine efficiency, PV and battery capital prices. Furthermore, adding two extra high-efficiency turbines (75%) to the optimum scenario eliminated the PV component and reduced the COE and NPC by 38.9% (from $0.211/kWh to $0.129/kWh) and 39.1% (from $50.4M to $30.7M) respectively, while increasing CO 2 emissions by 49.9%. This elimination led to a change in the configuration of Case 1 (G1/G2/G3/hydro). The preference of the governing authorities determines whether the previous or later optimal design is to be implemented. By implementing this strategy, the optimum scenario can provide cost-effective and long-term electricity for the selected region. [ABSTRACT FROM AUTHOR]

For off-grid electrification, hybrid renewable energy power systems have evolved as a more reliable alternative. Solar tracking systems boost PV power generation but come at a high cost, necessitating a thorough investigation of one's goals before deciding on the type of PV module and power generation approach. A hybrid energy configuration's optimum design and capacity scaling also necessitates the evaluation of numerous factors, making the choice process extremely complicated. The goal of this research is to conduct a feasibility analysis and design an optimum power system considering a two-step approach, capable of electrifying a rural community in Sierra Leone. In the first step, Hybrid Optimization Model of Multiple Energy Resources (HOMER) software is used to assess feasibility and optimally design the various scenarios, while Multi-attribute Decision Making [(MADM)-Combinative Distance-Based Assessment Algorithm (CODAS)] is used to rank and select the optimum scenario based on technical, economic, and environmental factors. With a net present cost (NPC) of ($471,993), cost of energy (COE)($0.376/kWh), and CO 2 of (1.32 kg/yr), SC#2 is the most cost-effective and sustainable scenario. It has a 107 kW PV system, a 30 kW biogas generator, a 38.4 kW converter, and 129 batteries. Results proved that a tracking system is not required for the specified location, and the Sharp ND-250QCS PV module is preferred to the CanadianSolar Dymond PV in attaining the research goal. The decision-making process is validated by comparing the results of three different MADM approaches; CODAS, The Weighted Aggregated Sum Product Assessment (WASPAS), and The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Sensitivity analyses revealed that the optimal scenario is superior and robust, and that its success or triumph is independent of the approach employed in assigning weights to the considered variables. • A techno-economic and environmental assessment is presented for optimum consideration. • PV modules with different manufacturing technologies. • Solar tracking strategy to boost power generation. [ABSTRACT FROM AUTHOR]

Providing quality and reliable power to grid-isolated areas has long been a difficulty in Africa, particularly in Sierra Leone, where government regulations are either weak or non-existent to assist the developing endeavour. Hybrid off-grid systems have grown in popularity as a way to offer electricity to people who live remote from power grids. This strategy, on the other hand, is capital demanding and prone to interruptions. This paper considers a decision-making process based on the Government of Sierra Leone's initiative to undertake a project to provide sustainable electricity to the people of Bo and Kenema in Sierra Leone's South-eastern region, with the assistance of the Africa Development Bank (ADB) and the Department for International Development (DFID). Two operating scenarios were modeled, and a comparative study was performed to determine which of the two should be considered. The results showed that the complementary scenario's proposed optimized hybrid configuration performed best in terms of technical, economic, and environmental features. Technically, it produced an excess energy of 2.29 %, compared to the combined total of the independent scenarios with 49.4 % (15.3 % excess energy from Bo and 34.1 % from Kenema). In terms of cost, it has a net present cost (NPC) of $45.6 million (M), compared to a combined NPC of $52 M ($37.8 M for Bo and $14.2 M for Kenema) for the independent networks. In terms of the environment, it generated 2,402,380 kg/yr of CO 2 which is 42 % less than the combined total produced by Bo and Kenema (3,408,018 kg/yr). Sensitivity analysis revealed that the overall system cost is heavily reliant on the diesel fuel price and average annual stream flow rate, as well as the hydro turbine's deplorable efficiency status, with the intention of project leaders' ignoring the impact of variations in the PV derating factor. • Design of a hybrid complementary power system is studied. • Seasonal variability has a great impact on renewable supply. • Diesel generator/photovoltaic/hydropower is a cost-effective and reliable hybrid option. • Joint-complementary system is superior to independent systems network. [ABSTRACT FROM AUTHOR]