International Journal of Engineering Trends and Technology Volume 70 Issue 9, 222-239, September 2022 ISSN: 2231 – 5381 / https://doi.org/10.14445/22315381/IJETT-V70I9P223 © 2022 Seventh Sense Research Group® This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Review Article The Optimization of Hybrid Renewables for Rural Electrification: Techniques and the Design Problem Chu Donatus Iweh 1 , Semassou Guy Clarence 2 , Ahouansou H. Roger 3 1,2,3 Laboratory of Energy and Applied Mechanics (LEMA), University of Abomey-Calavi, Benin. 1 Corresponding Author : iwehdona@gmail.com Received: 24 June 2022 Revised: 07 September 2022 Accepted: 26 September 2022 Published: 30 September 2022 Abstract - Presently, there is mounting pressure to decarbonize the power grid via the use of renewable energy (RE) sources. However, most of these sources could perhaps not easily replace conventional power plants due to the fact that they have nonlinear characteristics, and most of these issues still need to be resolved. In order to effectively manage the non-linearity of some RE sources and improve the energy harvesting capability of these systems, various methods have been adopted. Some of these techniques have one or more objective functions and commonly use commercial packages to minimize system cost and improve output power simultaneously. Rural electrification is still pitiably prohibitive, especially in Sub-Saharan Africa, and off-grid RE technologies remain a reliable way of meeting rural electricity needs. Exploiting these sources could help offset rural electricity demand sustainably while mitigating the negative impacts of using a diesel generator and other sources that are not environmentally friendly. This study reviews issues regarding the hybrid RE system design with insights on the most often conflicting constraints. Also highlighted are the recent trends in hybrid system optimization with RE technologies and the various considerations scholars use in hybrid applications. Moreover, the study has discussed the essential aspects of evaluating the performance of a hybrid RE system and its applicability in rural electrification. The study has explored various methods and concludes that hybrid techniques based on artificial intelligence (AI) offer better performance for system optimization. Keywords – Decarbonize, Power Grid, Energy Harvesting, Electricity, Constraints, Artificial Intelligence. 1. Introduction Increasing global electricity demand and the growing climate concerns have made the transition to renewable power a very popular topic among researchers. Even with the advancement in technological know-how in industrialized countries, approximately 1 billion of the world's population still lack electricity access, a greater percentage of which are in developing nations, especially Sub-Saharan Africa, South Asia and Latin America [1]. A greater percentage of the non-electrified communities are inaccessibly isolated areas, making grid extension uneconomical. Therefore, these distant communities, which are geographically constrained, must consider installing smaller off-grid systems [2]. The unavailability of electricity in communities could spur adverse conditions such as low- level economic development, poverty, hunger and gender inequality [3]. It also hinders economic growth and social progress, but it could also be a source of issues related to the quality of life in rural areas [4]. While diesel generators can be a salvation for these areas, empirical studies have shown that the operation and maintenance of the generators are high [5]. Besides, these generators emit gases, so their installation retards the global commitment to fight climate change. Thus, renewable energy (RE) through off-grid systems will continue to be a promising option for remote power communities far from the main electricity grid [6]. Indeed, the Sustainable Development Goal (SDG) 7 of UN Agenda 2030 has interesting ambitions regarding universal access to clean, reliable and affordable energy by 2030. While substantial progress has been made, the difficulties are enormous. Apart from improving rural energy access, renewable energy systems (RES) can also expand the income levels of rural inhabitants. Research from various regions has demonstrated that installed solar PV systems could improve rural dwellers' income levels since they will be engaged in income-generating activities [7-9]. A study conducted in Ghana on solar-based electrification installations showed that an extra revenue of $5 - $12 daily might well be gotten in a grocery business due to solar PV lighting [10]. Research on the income of shop owners in rural areas of Bangladesh showed that those who installed solar home systems increased sales revenue due to improved lighting from RES, attracting more clients [11]. The International Renewable Energy Agency (IRENA) had projected that solar pumps could increase the revenue generated in household income by 286 % for the extremely poor, 173 % for the poor and 47 % for the middle-income families in Zimbabwe [12].