Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

Kuo-Chi Chang; Noel Hagumimana; Jishi Zheng; Godwin Norense Osarumwense Asemota; Jean De Dieu Niyonteze; Walter Nsengiyumva; Aphrodis Nduwamungu; Samuel Bimenyimana

doi:10.1155/2021/1211953

Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

Chang, Kuo-Chi;Hagumimana, Noel;Zheng, Jishi;Asemota, Godwin Norense Osarumwense;Niyonteze, Jean De Dieu;Nsengiyumva, Walter;Nduwamungu, Aphrodis;Bimenyimana, Samuel 2021-10-05 00:00:00 Hindawi International Journal of Photoenergy Volume 2021, Article ID 1211953, 22 pages https://doi.org/10.1155/2021/1211953 Research Article Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study 1,2,3 4 4 Kuo-Chi Chang , Noel Hagumimana , Jishi Zheng, 5 6 Godwin Norense Osarumwense Asemota , Jean De Dieu Niyonteze , 7 5 8,9 Walter Nsengiyumva , Aphrodis Nduwamungu , and Samuel Bimenyimana Department of Applied Intelligent Mechanical and Electrical Engineering, Yu Da University of Science and Technology, Miaoli County, Taiwan Department of Business Administration, North Borneo University College, Sabah, Malaysia School of Electronic, Electrical and Physics, Fujian University of Technology, Fuzhou, China Fujian Province Key Laboratory of Automotive Electronics and Electric Drive, Fujian University of Technology, Fuzhou 350118, China University of Rwanda, African Centre of Excellence in Energy for Sustainable Development, Kigali 4285, Rwanda Carnegie Mellon University Africa, Kigali, Rwanda Laboratory of Optics, Terahertz and Non-destructive Testing, School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China Huaqiao University, Intelligence and Automation in Construction Provincial Higher-Educational Engineering Research Centre, 361021 Xiamen, China Hello Renewables Ltd., Kigali, Rwanda Correspondence should be addressed to Kuo-Chi Chang; albertchangxuite@gmail.com and Noel Hagumimana; hagumanoel@gmail.com Received 3 May 2021; Revised 26 July 2021; Accepted 6 September 2021; Published 5 October 2021 Academic Editor: James Connolly Copyright © 2021 Kuo-Chi Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In recent years, several factors such as environmental pollution, declining fossil fuel supplies, and product price volatility have led to most countries investing in renewable energy sources. In particular, the development of photovoltaic (PV) microgrids, which can be standalone, oﬀ-grid connected or grid-connected, is seen as one of the most viable solutions that could help developing countries such as Rwanda to minimize problems related to energy shortage. The country’s current electriﬁcation rate is estimated to be 59.7%, and hydropower remains Rwanda’s primary source of energy (with over 43.8% of its total energy supplies) despite advances in solar technology. In order to provide aﬀordable electricity to low-income households, the government of Rwanda has pledged to achieve 48% of its overal electriﬁcation goals from oﬀ-grid solar systems by 2024. In this paper, we develop a cost-eﬀective power generation model for a solar PV system to power households in rural areas in Rwanda at a reduced cost. A performance comparison between a single household and a microgrid PV system is conducted by developing eﬃcient and low-cost oﬀ-grid PV systems. The battery model for these two systems is 1.6 kWh daily load with 0.30 kW peak load for a single household and 193.05 kWh/day with 20.64 kW peak load for an oﬀ-grid PV microgrid. The hybrid optimization model for electric renewable (HOMER) software is used to determine the system size and its life cycle cost including the levelized cost of energy (LCOE) and net present cost (NPC) for each of these power generation models. The analysis shows that the optimal system’s NPC, LCOE, electricity production, and operating cost are estimated to 1,166,898.0 USD, 1.28 (USD/kWh), 221, and 715.0 (kWh per year, 37,965.91 (USD per year), respectively, for microgrid and 9284.4(USD), 1.23 (USD/kWh), and 2426.0 (kWh per year, 428.08 (USD per year), respectively, for a single household (standalone). The LCOE of a standalone PV system of an independent household was found to be cost-eﬀective compared with a microgrid PV system that supplies electricity to a rural community in Rwanda. 2 International Journal of Photoenergy renewable energy is much less costly [7]. Given that many of 1. Introduction Africa’s rural areas are plagued by an unsustainable energy Small electricity systems that can run independently, known system, building standalone, minigrid can solve energy prob- as oﬀ-grid microgrids, could play a pivotal role in the devel- lems for scattered people [8]. In developing nations like opment of electricity systems based on decentralized renew- Rwanda, where power outages are common, implementing able energy (RE) technologies. These networks are more supportable energy development and clean energy needs cost-eﬀective than stretching transmission lines to rural extensive preparation, particularly given the ﬁnancial impacts. places [1, 2], thereby providing the possibility to produce As a result, the HOMER (hybrid optimization model of elec- suﬃcient electricity in countries where the national demand tric renewable) Pro software can design, prepare, and simulate surpasses the regular production. In East Africa, for exam- the model in a variety of environments, including restrained ple, the energy deﬁciency is a signiﬁcant impediment to and unrestrained systems, standalone, grid systems, and/or social and economic growth. The capital expenses of wide storage. The microgrid system design has advantages that lead grids can be incredibly expensive for developing countries to eﬃcient source loading for microgrids and facilitate power leading to a shortage of roads and utilities [3–5]. To this systems operators. HOMER’s beneﬁts lie in the features used end, community-based microgrids are considered the best in the design, planning, and simulation of the microgrid option that would help rural areas in developing countries model discussed in [9, 10]. In contrast to African countries, to reap the beneﬁts of geospeciﬁc renewable energy sources. developed countries like the United States, China, and Japan The people who are not connected to nor served by the have increased their investment in renewable energy by bil- public or private power grid are referred to as “oﬀ-grid lions of dollars. Researchers are attempting to produce more users.” According to the authors’ deﬁnition in Ref. [6], the electricity from cost-eﬀective resources that are not detrimen- term “oﬀ-grid” refers to a system and way of life that allows tally impacting the environment [11]. people to function without the assistance of remote infra- HOMER was used to examining selected rural places in structure, including an electrical grid. It is a method of gain- Nigeria based on the availability of wind and solar energies ing access to electricity that is used in countries and areas so that healthcare centers or clinics in isolated regions can where there is limited access to electricity due to a dispersed provide quick delivery of medical services to the people or remote population. It corresponds to living without rely- who need them. It uses the best technical and economic ing on one or more public services, commonly referred to as design and sizing of hybrid electric power system compo- electrical grids. Oﬀ-grid users are people who live oﬀ the nents like wind, PV, battery, and inverter systems, where grid, and those systems can be categorized as standalone PV/wind/diesel/battery hybrid setup is best for rural health power systems, minigrids, and microgrids, which should centers, while PV/diesel/battery hybrid systems are best for typically provide energy to a smaller community. In this Port Harcourt considering the quality of renewable energy research, the HOMER software (HOMER Pro, version potential [12]. 3.13.1) had been used to model, simulate, and optimize Tourist destinations in the South China Sea, Malaysia potential renewable energy sources, as well as solutions to were at risk due to the widespread use of diesel generators ensure universal access to energy Rwandan for oﬀ-grid users. and pollutants from diesel-based power plants. HOMER HOMER has a built-in optimizer through the proprietary software was used for economic and technical analysis of derivative-free method that was adopted in Section 2. The the system. The best optimized standalone hybrid energy simulation models took place in Rwanda’s Western province system consists of PV, wind, diesel generator, converter, ° ° ′ ′ (Rutsiro, Rwanda, 1 56.3 S, 29 19.5 E). To optimize standa- and battery. The output has proved the diesel-only system lone solar systems, several site visits were conducted in the has a higher net present cost, cost of energy, and CO emis- Rutsiro district of Rwanda’s Western province, precisely to sion compared to the optimized hybrid renewable energy the location of the typical sample residential house used in system [13]. this section. The owner of the residential house listed his The study on decentralized power stations in Sabah, electric household items, along with their rated power and Malaysia [14], with a diverse combination of photovoltaic daily usage hours. For this study, a sample size of 121 resi- (PV), diesel generators, system converters, and storage batte- dential houses was chosen. ries. The impact of PV integration using HOMER was prop- erly quantiﬁed by analyzing the practical behaviors of diﬀerent PV penetration levels. The analysis based on tech- 2. Literature Review: A Comparative Analysis of nical, economic, and environmental constraints has resulted in satisfying the load demand with the minimum total net Standalone and Minigrid-Connected Solar present cost (NPC) and the levelized cost of energy (LCOE). Energy in a Rural Area The sensitivity analysis and the impact of diﬀerent PV pen- With the mounting consequences of global warming, pollu- etration levels on the system performance and the genera- tion, scarcity of fuel, and energy use, renewable energy sources tion of harmful emissions has been carried out. The (RES) is constantly getting more attention around the world. ﬁndings reveal an increase in the use of renewable energy (RE) sources in energy generation, as well as a decrease in Therefore, the need for renewable energy to plan and build a grid-connected or standalone, microgrid, the minigrid system the reliance on standalone diesel generators. has risen and will continue to increase. When the price of con- The ability to supply power for rural health clinics ventional energy is compared to the price of renewable energy, (RHC) in six geopolitical regions of Nigeria has also been International Journal of Photoenergy 3 Table 1: Summary of comparative analysis based on standalone, microgrid, on-grid, and oﬀ-grid results. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type M.K The objective is to Deshmukh, quantitatively estimate Street 1. Athokpam 2018 — Standalone Electrical HOMER energy losses due to the lighting Bharatbushan standalone operation Singh [23] mode The current method can work in various operating modes, and during U Villages, transient and steady-state On-grid and Hybrid PV battery with 2. Subramaniam 2020 — islands, and Electrical situations. With both oﬀ- oﬀ-grid controller et al. [24] hilly areas grid and on-grid situations, the suggested power management controls were approved. The study looked at the Comparative analysis economics of an islanded of the costs of a C Marino Standalone Residential PV project with two 3. 2020 Italy Electrical standalone and a grid- et al. [25] photovoltaic user conﬁgurations that networked PV system measure diminishing self- vs. grid distance suﬃciency. This review highlights the recent development of systems for generating MH grid-connected PV (GPV) Grid synchronization Mohamed Grid- Villages, involving many sub- 4. 2020 — Electrical and islanding detection Hariri et al. connected islands components, like DC-DC methods [26] converters, PV modules, maximum power point tracking (MPPT), and inverter technologies The aim was sizing and Hybrid photovoltaic FA Alturki, price reduction of islanded Saudi Remote (PV)/wind turbine 5. EM Awwad 2020 Standalone Electrical hybrid WT/PV/biomass/ Arabia community (WT)/biomass/pump [27] pump-hydro storage- hydro/storage energy systems This study provides a new approach to maximizing the scale of grid-connected renewable energy sources integrated with the salp swarm algorithm (SSA) T Wu et al. Grid- Salp swarm algorithm pumped storage system. 6. 2020 — Load serving Electrical [28] connected (SSA). This method enables diﬀerent energy sources to be explored and their combination to contact the base in the optimum conﬁguration of the hybrid system The research explores the viability of using wind and BE Türkay, Standalone solar energy. Using AYTelli 7. 2011 Turkey and grid- Pilot area Electrical HOMER hydrogen as storage in renewable connected combination with energy [29] traditional grid-based electricity to fulﬁll the 4 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type electricity needs of the pilot area The goal of this work is to bridge the absence of direct comparisons between the technoeconomic output of islanded and grid- Standalone Oﬃce D Mazzeo Hybrid renewable networked investigations 8. 2020 Koppen and grid- building Electrical et al. [30] system in the same operating connected district. environment, providing global technoeconomic mapping, and optimizing islanded and grid- networked PV-wind systems The research focused on the grid-connected development system’s A Chakir et al. Grid- 9. 2019 — Load serving Electrical MATLAB/Simulink management, connection [31] connected with the grid, and storage hybrid renewable energy system’s management The various cases were examined based on their location, design and year of development, as well as the power, the technology used, and performance Standalone that can help design a PV R Srivastava 10. 2020 — and grid- Load serving Electrical Review plant considering the et al. [32] connected achievements of the previously commissioned plant. The material of the PV module and panel tilt angle was found to be crucial for the design of a PV plant The study focused on a cost-beneﬁt analysis of grid-aﬃliated rooftop PV systems for private use. There was the suggestion AC Duman, Ö Grid- 11. 2020 Turkey Load serving Electrical HOMER to increase the number of Güler [33] connected private PV incentives and cultivate a regional support system, considering solar diﬀerences among regions The purpose of the research was to provide a thorough analysis of the recent progress in the HM Ridha Standalone Remote 12. 2020 — Electrical Review design of standalone PV et al. [34] photovoltaic areas systems. Multiobjective optimization (MOO) and multicriteria decision- making (MCDM) International Journal of Photoenergy 5 Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type methodologies, including the mathematical models used to measure the PV module power output and storage battery Grid-connected, ground- mounted technoeconomic optimization of genetic algorithm-based photovoltaic power plants MJ Mayer Hungarian Grid- 13. 2019 Load serving Electrical use Mathematical model on a comprehensive et al. [35] region connected mathematical model. The target function is the internal rate of return and a genetic algorithm performs the optimization Dust is one major parameter aﬀecting photovoltaic eﬃciency, yield, and proﬁtability X-ray diﬀraction HA Kazem Grid- Load linked to the grid. The 14. 2020 Oman Electrical (XRD) and X-ray et al. [36] connected management proposed model in the ﬂuorescence (XRF) paper took account of the dust on the grid-aﬃliated photovoltaic output power innovatively The research focused on technology, cost-beneﬁt, and environmental analyses of grid-aﬃliated hybrid wind/PV/biomass systems, Marmara Marmara Grid- E Aykut, ÜK University, Goztepe 15. 2020 University, connected Load serving Electrical HOMER Terzi [37] campus. The performance Turkey hybrid of the hybrid electricity system was assessed using both the net present cost (NPC) and cost of energy (COE) and found to be cheaper This research speciﬁes the optimum solar capacity for grid-aﬃliated households, R Khezri et al. Grid- Households photovoltaic (PV), and 16. 2020 Australia Electrical [38] connected serving battery energy storage (BES) to minimize the net present cost of electric power networks The study sized an islanded and grid-aﬃliated solar PV electricity Standalone provision to a small 17. BK Das [39] 2020 Bangladesh and grid- Load serving Electrical HOMER neighborhood. The result connected reﬂects major cost savings through the incorporation of the PV module into the grid 6 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type This study provided a layout for a grid-aﬃliated PV system and an islanded PV system. Factors inﬂuencing device design Grid- Open distribution and size were also ALM Maher connected Industrial 18. 2019 Palestine Electrical source simulator described and analyzed. [40] and zone (OpenDSS) The results showed a good standalone improvement in the overall energy losses and voltage proﬁle concerning load and capacity production It provided a precise Buck- Boost DC-DC converter design powered by the fuzzy logic controller HA Attia, F United Remote (FLC). The research 19. delAma 2018 Arab Standalone Electrical Fuzzy logic control building concentrated on Gonzalo [41] Emirates suggesting a suitable solar PV panel model conﬁguration and attachment Thermal modeling of a typical Pakistani rural house was performed using BEopt throughout this research to assess the A Iqbal, MT Standalone 20. 2019 Pakistan Rural area Electrical HOMER Pro hourly load proﬁle. System Iqbal [42] PV studies indicated that such a system can primarily reinforce the lighting and loading of appliances in a rural household The study tracked how the maximum power point (MPP) transferred the Y Chaibi et al. Standalone Sliding mode MPPT/ 21. 2019 — Load serving Electrical maximum available power [43] PV MATLAB Simulink to the load. The control fed the AC load by a sinusoidal output current The study proposed a viable solution to the problem of energy output in the private dwellings MA Omar, Grid- Unconventional PV sector using unpredictable MM connected Residential 22. 2018 Palestine Electrical system/MATLAB PV systems operating in Mahmoud and sector software islanded and grid-aﬃliated [44] standalone modes. The battery storage framework enables private dwellings to secure stable energy operations This paper brieﬂy PK Grid- discusses the modeling, 23. Bonthagorla, S 2020 — connected/ Load serving Electrical MATLAB/Simulink simulation, and Mikkili [45] standalone performance evaluation of hybrid and conventional International Journal of Photoenergy 7 Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type array conﬁgurations during diﬀerent PSCs in MATLAB/Simulink environment A fresh concept to active modeling and locked-loop Hybrid control of hybrid grid- M Salimi et al. 24. 2021 — grid- Load serving Electrical MATLAB/Simulink aﬃliated multi-input [46] connected multioutput (MIMO) renewable energy systems was addressed A hybrid system associated Grid- with the grid was connected described in the study. The M Dali et al. 25. 2010 — and Load serving Electrical Standalone inverter experimental ﬁndings [47] standalone show that the system can modes operate parallel to or independent of the grid A multiobjective optimization design Non-dominated accounted for lossy load MI Hlal et al. Oﬀ-grid or Load separating genetic likelihood (LLP), energy 26. 2019 Malaysia Electrical [48] standalone management algorithm (NSGA-II) cost (COE), price of method battery life loss, and cost of service, substitution, and repair. The study is based on the evaluation of economic KNB Akshai, Household Simulation software 27. 2020 — Standalone Electrical expenses of grid-aﬃliated R Senthil [49] electricity PVsyst and islanded photovoltaic systems using PVsyst This research proposes a hybrid system consisting of an array of photovoltaic S Odeh et al. (PV) and rechargeable 28. 2019 Palestinian Standalone Load serving Electrical PVsyst software [50] batteries integrated into the distribution grid to share loads with the grid system The research resolved the power grid stability and control problems. The PV J Kumar et al. Residential System advisor model grid system consists of an 29. 2020 — PV grid-tied Electrical [51] load serving (SAM) software 8.0 kW PV array and battery energy storage unit connected to the power grid over AC or DC links This study mainly explores the design features of a solar photovoltaic device based on a grid Grid- 30. J Kumar [52] 2020 — Island Electrical PVsyst software connection. The analysis connected sheds light on various subjects like creating Sankey energy loss diagrams, eﬃciency 8 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type proportion, and total photovoltaic plant capacity A water-pumping double- deck converter and inverter for a single-phase islanded PV system were ZB Duranay, Load Water investigated. The single- 31. H Guldemir 2019 — Standalone MATLAB/Simulink management pumping phase islanded PV system [53] was modeled using insolation and temperature values as simulation data The study was a technoeconomic evaluation of grid- aﬃliated residential construction applications photovoltaic (PV) systems. Y Cui et al. Grid- Domestic 32. 2020 — Electricity @risk software The system met the [54] connected building residential electricity demand from April to October and the 1530.23 kWh excess electricity was supplied to the grid The research developed grid-connected PV system sensitivity and reliability models. For PV cell and DC-DC converters, Pareto analysis and N Gupta et al. Grid- analytical relationships of 33. 2017 — Load serving Electrical logic gate [55] connected ﬁrst-order sensitivity are representations formed and the developed models can be implemented to any PV system for better performance For an islanded PV- battery energy storage (BES) hybrid device, a power management control strategy is suggested in the research. MP Bonkile, V The evaluation shows that Load Physics-based Single-particle model 34. Ramadesigan 2019 — Standalone the power management management battery (SPM) [56] design was successful and met many islanded PV- BES hybrid systems goals, without overcharging, no output excess power generation, and no power transfer to the dump load The research concept of this paper includes the SS Dheeban Load mathematical simulation 35. 2019 — Standalone Electrical MATLAB Simulink et al. [57] management of the solar panels and a battery backup study of the standalone unit International Journal of Photoenergy 9 Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type The emphasis of the research was on the eﬃciency of a grid- Performance ratio aﬃliated PV system in E (PR), yield factor (YF), Central Greece that was Roumpakias, Grid- reference yield (YR), 36. 2019 Greece Load serving Electrical operational for six years. A Stamatelos connected capacity factor (CF), The study indicates a [58] and an array to capture slight eﬃciency reduction losses (LC) over the years, which declined between 1 and 4 percent This research recommends Sub-maximum power a single-phase linear PV BR VS, GG 37. 2019 — Standalone Load serving Electrical point tracking (S- default scheduler system. Devadhas [59] MPPT) It initializes any device to zero in the shortest period The primary target of the research was to build a sun-based PV plant at two diverse campuses. The specialized feasibility used Photovoltaic the open rack or free stand N Manoj geographical mounting position Grid 38. Kumar et al. 2017 Malaysia Load serving Electrical information systems crystalline innovation- connected [60] (PVGIS) and Watts PV based PV plant utilizing software the PVGIS and PV Watts software. The specialized presentation acquired through PVGIS is very similar to the PV Watts results In the study, an instinctive control procedure dependent on ‘ﬁfth-order general integrator (FOGI)’ N Kumar et al. Grid- Fifth-order general 39. 2019 — Load serving Electrical was proposed for [61] connected integrator (FOGI) framework-associated sun-powered photovoltaic (PV) energy conversion system (SECS) The study assessed a hybrid renewable energy system linked to the power grid with 15000.0 kW daily load demand and YZ Alharthi Grid- 40. 2019 — Load serving Electrical HOMER 2395.3 kW peak load. The et al. [62] connected net present cost (NPC), levelized energy cost (LCOE), and system environmental eﬀects were examined The eﬃciency of a DC grid-aﬃliated PV device E Kurt et al. Grid- under insolation and 41. 2019 — Load serving Electrical PSCAD [63] connected temperature variations was investigated in the study. The DC-DC boost 10 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type converter was constructed to increase the system’s performance An optimal islanded irrigation solar PV battery system (BS) for Al Minya, Egypt, was used in the study paper. The energy H Rezk et al. 42. 2019 Egypt Standalone Irrigation Electrical HOMER costs obtained were lower [64] than those previously reported due to the correct selection of PV size and shape, as well as the correct selection of the site achieved by hybrid optimization model for electric renew- demand and supply [19]. Sustainable power sources to replace able (HOMER). At the selected sites, the technoeconomic fossil fuels have been prioritized throughout the world for feasibility of using hybrid photovoltaic/wind/diesel with bat- both economic and environmental reasons. The authors in tery storage systems to match the load of a typical rural [20, 21], conﬁrmed the feasibility of a stable standalone elec- healthcare center was evaluated. The system is based on tricity generation system for oﬀ-grid users using HOMER to long-term daily meteorological data ranging between 18 model, evaluate, and optimize sustainable power sources that and 39 years in this study. The ﬁndings of HOMER simula- replace traditional energy sources. Table 1 below summarizes tions show that the hybrid system is the best solution for all the successfully implemented researches made on a standa- of the study’s locations. Since the diesel-only system pro- lone, microgrid, and grid-connected solar systems in diﬀerent vides the highest COE and emits CO2, the hybrid systems parts of the world and their results prove to be viable. involving PV/diesel/battery are considered ideal for RHC This study gives a complete comparison of the state-of- at remote locations within Iseyin and Port-Harcourt, due the-art deterministic methodology to build a minigrid, to the quality of renewable energy potential [15]. including the inﬂuence of operating strategies to provide Fossil fuels like oil and gas are still playing a role in energy recommendations on conceptual models and operating generation though people are now considering an alternative strategies to researchers, developers, and professionals in that provides energy demand by reducing it via energy eﬃ- the ﬁeld. The standalone like, home lighting system (HLS) ciency and environment-friendly use of that energy resources. requires no major maintenance, and consumers could use Since transport consumes a lot of conventional energy and it without being subjected to any inﬂuences, whereas mini- generates greenhouse gases, therefore, the proposed measure grids are administered by cooperative societies founded by to alter this issue is to use electric transportation. The HOMER local governments and beneﬁciaries. In order to provide program was used in this study [16] to develop and optimize a minigrid services in underdeveloped countries, it is neces- wind-solar hybrid energy charging station that will be beneﬁ- sary to establish an appropriate business strategy. The com- cial for supplying power from renewable resources eﬀectively parison as explained in literature, and Table 1 below was and sustainably, managing grid load, and establishing addi- mainly based on consumer characteristics, net present cost, tional charging stations. and the cost of energy, where it will depend on the quantity PV systems have used distributed microgrids as eﬃcient of the consumer as well as the diﬀerent components avail- local electricity sources in regulated environments for energy able to be used in each household. Therefore, the result of consumers and inexhaustible energy generation. The global the method adopted in our research compared to the elec- deployment of PV microgrids has expanded while taking tricity tariﬀ in Rwanda is much more viable. the beneﬁt of daily unrestricted solar insolation. In Rwanda, HOMER is particularly well suited to assessing prospective the average daily solar irradiation is between 4.0 and electricity possibilities in rural areas, as well as investigating 5.0 kWh/m the technical and economical eﬀectiveness of hybrids provided /day [17]. The highest solar radiation for the selected site is seen in July where the value is a village load and energy resource availability. Therefore, this 5.87 kWh/m /day. Energy storage has been proposed, with means diﬀerent areas with diﬀerent solar resources will pro- the backup used during peak demand, power shortages, vide diﬀerent output solar powers where a minigrid supply blackouts, or some other power loss in grid-connected sys- system is being proposed for rural electriﬁcation programs. tems. Global studies show that the world’s total implemented When the obtained energy costs were compared to the exist- photovoltaic capacity has been steadily increasing [18]. ing, current costs of electricity in Rwanda, it was discovered Rwanda is educating private investors on how to implement that this was the most cost-eﬀective option. Previously, the solar energy projects and narrow the gap between electricity solar home system was a simple choice, which included the International Journal of Photoenergy 11 Site visit and data collection Cost parameter of PV Location of RE activity Solar data (initial capital, replacement, O&M) Cost parameter of batteries Load profile Power plant components (initial capital, replacement, O&M) Cost parameter of inverter Transmission and Available resources (initial capital, replacement, distribution system O&M) Selecting renewable System lifetime Concept of system constraint energy technology Simulation results and evaluation Electrical energy evaluation Economic evaluation Generation Consumption Net present cost Cost of energy Figure 1: Illustration of the framework for analysis of the study. Abbreviations: RE: renewable energy; O&M: operation and maintenance. System profile System analysis Results Optimal sizing Load components Sensitivity analysis Net present cost Battery storage • Cost of Optimization energy • Capital Converter module cost Simulation • Capacity shortage System module • Renewable Energy balance energy fraction System control, constraints Fuel consumption Figure 2: A detailed schematic representation of HOMER software. implementation of PV panels, batteries, charge controllers, causing market distortions, and necessitating research pro- and inverter units for every residence and business structure jects for new electric power plants. in the village that used roof areas [22]. The methodology of this study is depicted in Figure 1 below. All of the study requirements were conducted based on our team’s site visits and data collection. The data collected 3. Methodology include electricity load demand proﬁle, available resources, power plant production capacity, solar power plant compo- HOMER software analyzed the data gathered from govern- nents, and constraints. HOMER software performed the tech- noeconomic analyses in this research. The purpose of these mental energy organizations considering diﬀerent photovol- taic systems uses in Rwanda’s rural settlements [65]. technical and economic analyses was to develop a practicable oﬀ-grid photovoltaic system that would suit Rwanda’spower HOMER software created a variety of models that demon- sector at lower tariﬀs and maximum availability. strate how diﬀerent natural sustainable energy sources com- bine to produce green power in this study. In addition, we started working with power plant owners and operators 3.1. HOMER Pro Software. The HOMER Pro microgrid soft- throughout the research to ensure the study’s reliability. ware is the world’s standard software for optimizing micro- According to these experts, relevant guidelines for the rural grids, from community power and islet utility services to electriﬁcation planning process are lacking, posing risks, grid-aﬃliated sites, and army assets [65]. Figure 2 presents 12 International Journal of Photoenergy W E RWANDA AFRICA W E 0 30 60 Kilometers W E MUKUNGU Figure 3: Location map of the selected study area (Mukungu village). 6 0.7 a schematic representation of the HOMER software. Imita- tion, optimization, and sensitivity analysis are the three pri- 0.6 mary functions of HOMER. It can strengthen power balance 0.5 measurements, load proﬁling, location-speciﬁc tools, and 0.4 system components are all factors taken into consideration 0.3 by HOMER. 0.2 HOMER simulates feasible systems with device conﬁgu- 0.1 rations in the simulation model. After each simulation, there 0 0 is an optimization step. To achieve the best possible match, 123456789 10 11 12 all imitated systems are categorized and reﬁned according Month to speciﬁed parameters. Sensitivity analysis, on the other Daily radiation (kwh/m /day) hand, is an optional function that allows HOMER users to Clearness index model resource variables that are outside their control, like fuel prices and wind speeds. As a result, researchers can Figure 4: Solar energy proﬁle at the preferred site. see how the ideal system changes because of these modiﬁca- tions [66]. The optimization ellipsoid encircles the simula- tion ellipsoid, showing that an imitation consists of several simulations. The sensitivity analysis ellipsoid, encircles the consumption of people living in Rwanda’soﬀ-grid areas optimization ellipsoid, as in Figure 2. was calculated, as well as the energy needs of each house. As a result, this investigation is aimed at approximating 3.2. Data Collection. In this survey, data were collected consumer requests, which is a prerequisite for designing from 121 households in four Rwandan provinces, exclud- a power plant. ing Kigali city, using a specially designed questionnaire. Oﬀ-grid solar power deployment necessitates a year’s Residents in the area were asked a series of questions as worth of solar irradiation. The National Aeronautics and part of this study. The data were then summarized and Space Administration provided the input data for solar analyzed using the Statistical Package for the Social Sci- resources over a year in this case (NASA). Other data from ences (SPSS version 23.0). Consequently, the total energy the Rwanda Meteorology Agency was obtained and Daily radiation (kwh/m /day) Clearness index International Journal of Photoenergy 13 Table 2: The projected everyday electricity demand for 121 houses in the village. Equipment in 121 No. in Power consumption Total power consumption Hours of use/day (Hrs/ Watt-hours/ No. households use (W) (W) day) day 1 Lamps 891 10.0 8910.0 5.0 44550.0 2 Mobile phone 335 10.0 3350.0 8.0 26800.0 3 Ceiling fan 0 75.0 0.0 0.0 0.0 4 Radio 113 20.0 2260.0 5.0 11300.0 5 Television 49 120.0 5880.0 5.0 29400.0 6 Computer 4 100.0 400.0 5.0 2000.0 7 Refrigerator 5 500.0 2500.0 24.0 60000.0 8 Iron 19 1000.0 19000.0 1.0 19000.0 193,050.0 Watt-hours/day = Daily total energy consumption in 121 households 193.05kWh/day Abbreviations: W: Watt; kWh: kilowatt-hour; Hrs: hours. The temperature power coeﬃcient is zero if the temper- compared to NASA’s data to ensure that the solar resource data obtained was correct. All these data were accurate, ature eﬀects on the PV array are not modeled by HOMER and they satisfy the requirement to be used in our study. software. Equation (1) becomes [65] Finally, the obtained data helped us to evaluate and verify the integration of solar power systems into Rwanda’s power P = Y f : ð2Þ PV PV PV system. T,STC 3.3. Selected Site. Rwanda’s government had approved a rural electriﬁcation strategy in the termination of 2016, On the other hand, HOMER can deﬁne the monthly average clearness index K using the following [65]: in which the government, private industry, and relevant stakeholders collaborated to signiﬁcantly boost rural elec- triﬁcation and establish lofty potential targets. Thus, in H ave K = , ð3Þ Rwanda’s rural areas, pico/minihydropower, and minigrids o,ave from solar energy have been successfully implemented [67]. Mukungu village located in the Karongi District of where Y is the PV array rated capacity (kW), f is the PV PV PV Rwanda’s Western province was chosen for this study, discounting factor (%), G is the PV array incident solar ° ° ′ ′ with GPS coordinates of S 02 13.9310 and E 29 24.590 . 2 irradiation (kW/m ), G is the emitted radiation under T,STC In addition, the details of the chosen village location are normal assessment conditions (1 kW/m ), α is the temper- shown in Figure 3. This village has a picohydropower ature power coeﬃcient (%/ C), T is the PV cell temperature plant that provides energy to up to 400 households in ( C), T is the PV cell temperature standard test condi- c,STC the oﬀ-grid region, promoting economic development. tions (at 25 C); H is the normal monthly irradiation from ave Solar energy, fortunately, can also be used as an alternative the earth (kWh/m /day); and H is the extraterrestrial o,ave energy source in this situation. horizontal insolation (kWh/m /day). 3.4. Solar Resource Availability Evaluation. HOMER utilizes 3.5. Load Details of the Selected Site. All types of electrical four renewable energy sources: biomass, hydro, solar, and appliances at home, as well as the time that the appliances wind, as well as other fuels that the system’s equipment are used by the residents, determine energy consumption requires [65, 66]. Rwanda has abundant renewable energy [68]. The estimated load was determined in this study based resources, and it is attempting to electrify Rwanda’soﬀ- on a survey directed at various communities across the grid villages. The Mukungu village solar resources were country. Experienced judges tested a series of the developed extracted from the surface meteorology and solar website questionnaires for validity and used them to gather energy of NASA. The solar energy proﬁle at the preferred study site consumption data from respondents. Representatives from is depicted in Figure 4. 121 households completed the questionnaires about their Generally, the PV array’s power output is determined by household electrical devices and monthly power consump- the angle of incidence of the solar radiation on the earth. tion pattern in the research. Table 1 shows the summary of HOMER calculates the PV array output in Equation (1) results obtained through analysis of other studies and their below [65]: input data. The daily energy demand of 121 homes, as well as their respective power ratings, are shown in Table 2. The electricity demand in remote areas is lower than in P = Y f ½ 1+ αðÞ T − T : ð1Þ PV PV P c c,STC PV T,STC cities, according to a comprehensive energy consumption 14 International Journal of Photoenergy Daily profile Seasonal profile 0 3 6 9 12 15 18 21 Yearly profile 24 14 kW 11 kW 8.4 kW 5.6 kW 2.8 kW 0 kW 90 180 1 270 365 Day of year (a) Daily profile Seasonal profile 15 20 0 36 912 15 18 21 Yearly profile 20 kW 16 kW 12 kW 8.0 kW 4.0 kW 0 0 kW 90 180 1 270 365 Day of year (b) Figure 5: The daily, seasonal, and yearly load proﬁles: (a) electric load for the distinct oﬀ-grid household and (b) electric load for microgrids for a rural community in an oﬀ-grid area. survey conducted in Rwanda. Household appliances that use (iii) The project’s lifespan was decided based on the electricity include radios, light bulbs, mobile phones, ceiling component warranty, which was estimated to be fans, electric irons, refrigerators, and laptops. Within each around 25 years. The load proﬁle used in this survey hour of the year, we must measure the sum of primary load during imitation is shown in Figure 5 in kilowatts using HOMER, either by importing hourly data from a ﬁle or by permitting HOMER to create hourly data 3.6. System Design Components. We used various compo- from typical everyday load proﬁles. Consequently, HOMER nents in this research depending on the photovoltaic systems generates typical load results depending on the consumer’s we needed to simulate. Photovoltaic solar was the resource features of everyday load [65]. The photovoltaic systems in the HOMER analysis. In addition, electricity is stored were designed, and their performance was evaluated in this and converted using batteries and a converter. The eﬃciency study, taking into account the following suppositions: and cost of each of the system’s components have a signiﬁ- cant impact on the design outcomes. Data from Rwandan (i) 193.05 kWh per day is the primary load, and generating companies and private sector companies’ mini- 20.64 kW peak load was assumed for an outside- grid remote grids, as well as existing literature, were used grid PV microgrid for the rural society (121 to develop the study’s technical and cost parameters. households) Tables 2 and 3 show the performance and cost of each com- (ii) The prime load of 1.6 kWh per day and 0.30 kW ponent for an islanded PV system for a single home and an peak load were assumed for a remote grid solar outside-grid PV microgrid for a remote neighborhood, PV microgrid system in the rural community respectively. Hour of day kW Hour of day kW kW kW Jan Feb Jan Mar Feb Mar Apr Apr May May Jun Jun Jul Jul Aug Aug Sep Sep Oct Oct Nov Nov Dec Dec International Journal of Photoenergy 15 Table 3: System elements and their costs for an islanded PV of an individual home. Rated Capital cost Replacement cost O&M cost/year Lifetime No. Component capacity (USD) (USD) (USD) (years) 1 Converter (system converter) 1.0 kW 3000.00 2500.00 800.00 15 Batteries (generic 1.0 kWh lead 2 1.0 kWh each 300.00 2,00.00 40.00 10 acid) 3 PV (generic ﬂat plate) 1.0 kW 1500.00 1100.00 40.00 25 3.7. Design and Modeling of Selected PV Systems in Rwanda. imitate, and process available inexhaustible power genera- Rwanda has a large number of untapped renewable energy tion technologies to ensure everyone in Rwanda has access source sites. Electricity is generated using hydro, solar, meth- to sustainable energy. Importantly, several site visits to a del- ane, peat, geothermal, wind, and waste energy. According to egate of selected residential houses in Rutsiro district, West- Rwanda’s Environmental Management Agency (REMA) ern province, Rwanda, were made to design standalone solar Outlook report from 2007, there are approximately photovoltaic systems, eﬃciently. Moreover, the electrical 1200 MW of untapped power generation resources in devices, power rating, and hours of use variables were used Rwanda [67]. Unfortunately, so many of these resources during the studies. remain unexplored. Rwanda’s gross electricity generation The sketch of the islanded remote grid photovoltaic sys- was just 224.6 MW in 2019 [67]. tem for an individual household is shown in Figure 6(a). The HOMER is a sophisticated numerical modeling frame- distinct islanded solar home system, comprises the PV panel, work that oﬀers much more details than traditional statistical batteries storage, converter, DC, and AC buses, and electric modelers. It can perform imitation and responsiveness analy- load. As shown in Figure 6, the total load proﬁle was sis with modest data [69]. Better designs are produced for 1.6 kWh/day and 0.30 kW daily peak load. The estimated daily energy consumption for 121 residential houses in the likely inputs using net present cost (NPC), which is cost- eﬀective. In addition, it generates power balance equations village was 193.05 kWh/day, as demonstrated in Table 2 for every one of the 8760 hours annually, to simulate network above. So, the daily energy load average for one residential operations. Consequently, it helps to determine viable conﬁg- house in an oﬀ-grid area can be easily estimated to be urations and approximate the installation cost and implemen- 1.6 kWh/day per residential house. tation of the power system over the project’s life [69–71]. Previous researchers and experts in renewable energy HOMER computes the average annualized cost for every and minigrids or microgrids have provided insights on what item utilizing diversiﬁed costs and penalties for device pollut- hybrid systems are, why we need them, their uses, and appli- ants. This value is also used to calculate the overall net present cations for sustainable energy development. According to cost and the levelized energy cost (LCOE or COE) [65]. In the previous surveys and the outcome of this study, standa- HOMER software, the NPC can be evaluated using [65, 66] lone systems for one single household and a community are the ﬁrst-choice decision to be made while they may not be cost-eﬀective. iðÞ 1+ i CRF i, N = , ð4Þ ðÞ ðÞ 1+ i − 1 3.7.2. Oﬀ-Grid PV Microgrid System for Rural Community. The microgrid is important to intelligent power systems where i is the yearly actual interest rate and N is the dura- for increasing the distribution system’s energy supply reli- tion (years). Also, Equation (5) assesses the levelized energy ability and resilience. A microgrid is an interconnected col- cost [65, 66]: lection of distributed energy and demand entities that function in either grid-connected or island mode within ann,tot the network. Microgrids comprise small cell phone towers COE = ð5Þ E + E + E prim def grid,sales (as well as nanogrids), large commercial, industrial, and mil- itary facilities with generation capacities ranging from kilo- where C is the overall annualized cost, E and E watts to megawatts [72–75]. ann,tot prim def During our study, Figure 6(b) is the representation of the are the yearly overall basic and postponed load, respectively, oﬀ-grid solar photovoltaic microgrid system for rural areas. and E is the yearly power grid sales. grid,sales The average daily load for that rural area was 193.05 kWh 3.7.1. Standalone Solar Photovoltaic for a Single Residential per day and a daily 20.64 kW peak (for 121 households). In addition, the photovoltaic system provides DC, while the House. First and foremost, those who are unable to connect to and be assisted by the publicly or privately owned utility converter transforms DC to AC and vice versa, which is sup- plied to the battery storage facility. Undeniably, research on grids are known as “oﬀ-grid users” [6]. As a result, standalone PV, minigrids, and microgrids various conﬁgurations or architectures of microgrid systems can be used to provide electricity to such users. As previ- is gaining more attention to achieve the goals of carbon emission reduction. ously stated, this part used HOMER Pro software to design, 16 International Journal of Photoenergy AC DC AC DC Electrical load PV Electrical load PV 193.05 kW h/d 1.60 kWh/d 20.64 kW peak 0.30 kW peak Converter 1 kWh LA Converter 1 kWh LA (a) (b) Figure 6: Various types of photovoltaic solar systems: (a) the standalone photovoltaic for a single residential household and (b) the PV microgrid system for the rural community in the oﬀ-grid area. Table 4: Comparative simulation analysis for the proposed PV systems (we did not consider the sensitivity variables). Cost summaries Electricity production (kWh per year) Resource System architectures Total NPC LCOE (USD/ Operating cost (USD per (portion) (USD) kWh) year) Standalone (1 Solar 2426.0 9284.4 1.23 428.08 household) Microgrid Solar 221,715.0 1,166,898.0 1.28 37,965.91 (community) 4. Simulation and Optimization Results Using comprises 1.64 kW PV, 3 strings of batteries, and 0.262 kW of a system converter. The total operating cost and NPC Homer Pro Software for such photovoltaic systems are USD 428.08 and USD 9284.41 per year, respectively. HOMER’s micropower optimization model was used to pro- In contrast, the oﬀ-grid PV microgrid system for rural cess the modeling and simulation results. For each respon- communities has shown a high LCOE compared to the stan- siveness case it solves, HOMER imitates each system in the dalone PV for an individual household. It generates search space and rates all practicable systems in order of 221,715.0 kWh total yearly production and comprises decreasing net present cost. HOMER optimizes small power 150.0 kW PV, 443 strings of batteries, and 20.8 kW of system systems by simulating a variety of device options under dif- converter. For this photovoltaic system, the total NPC, ferent restrictions and stimuli. These systems are compared LCOE, and operating costs were also USD 1,166,898.00, using optimization tables. The optimization table contains USD 1.28 per kWh, and USD 37,965.91 per year, respec- information about each system’s architecture, such as the tively. In addition, PV output power and batteries’ charge number of batteries, converter size, and PV capacity. It also state (SOC) of the simulated photovoltaic systems are graph- includes information on costs like the levelized energy cost ically illustrated in Figure 7 below, where (a) is an islanded (LCOE), net present cost (NPC), running costs, preliminary solar PV system for a dwelling house and (b) is a PV micro- capital, and clean energy proportion. Also, two solar energy grid system for a remote neighborhood in the oﬀ-grid area. systems were designed in this research using a large number Because access to electricity is a key driver of develop- of hourly parameters in the HOMER software simulation. ment and welfare, Rwanda’s government has set a goal of The simulations and analyses took into account a variety providing electricity to 100 percent of all the population by of solar radiation values. Without taking into account the 2024. Rwanda has future prosperity of renewable resources, sensitivity variables, Table 4 illustrates the imitation and including wind, solar, geothermal, hydro, and methane gas, processing of two dissimilar remote grid solar PV for the all of which should be explored before making any decisions. selected survey site. This will undoubtedly encourage development projects, The simulation in this study considered diﬀerent photo- bringing the total capacity of electricity generation to voltaic systems. As illustrated in Table 5 above, the mini- 556.0 MW by 2024. Unquestionably, the ﬁndings of this mum levelized cost of energy (LCOE) found from the study show that for oﬀ-grid users, small solar standalone simulation results was USD 1.23 per kWh for a standalone systems for individual households are preferable because photovoltaic for an individual household. This standalone they can start providing energy more rapidly at a low price. system generates 2426 kWh total yearly production and International Journal of Photoenergy 17 Table 5: Structure items and their expense for oﬀ-grid PV microgrid systems for the rural community. Rated Capital cost Replacement cost O&M cost/year Lifetime No. Component capacity (USD) (USD) (USD) (years) 1 Converter (system converter) 10.0 kW 21,164.00 16,000.00 8000.00 15 Batteries (generic 1 kWh lead 2 1.0 kWh each 1702.00 1000.00 60.00 10 acid) 3 PV (generic ﬂat plate) 10.0 kW 18,500.00 15,000.00 20.00 25 PV power output 1.6 kW 1.3 kW 0.96 kW 0.64 kW 0.32 kW 0 kW 90 180 270 365 Day of year State of charge (SoC) 24 100% 88% 76% 64% 52% 40% 90 180 270 365 Day of year (a) PV power output 24 160 kW 128 kW 96 kW 64 kW 32 kW 0 kW 90 180 270 365 Day of year State of charge (SoC) 100% 88% 76% 64% 52% 40% 90 180 1 270 365 Day of year (b) Figure 7: PV power output and SOC of the simulated solar photovoltaic systems: (a) the standalone photovoltaic for a single residential house and (b) the oﬀ-grid solar photovoltaic microgrid system for the rural community. Hour of day Hour of day Hour of day Hour of day 18 International Journal of Photoenergy renewable resource availability, technological cost, and per- 5. Discussion formance which cause output power unstable. HOMER The electricity prices is constantly increasing due to the assesses diﬀerent designs using the levelized cost of electric- ity (LCOE), but it cannot assess diﬀerent ﬁnancial world’s fast growing population that needs access to sustain- able electricity to sustain modern life expectancy. In Sub- models [84]. Saharan Africa (SSA), for example, people living without Rural areas’ big issue is lacking consumer demand den- access energy remain a determining factor that contributes sity and generally consists of low-income groups; therefore, to persistent poverty [5]. In this area, urban communities project rate of return on investment is diﬃcult to achieve as planned. High costs, low energy eﬃciency, and a lack of are still served by ineﬃcient and unstable networks, while rural areas still lack access to electricity, except for power suitable rules and information are among issues that PV sys- given to fairly wealthy households by small/private genera- tems confront [85]. Unlike consumers in developed coun- tors. Using fossil fuels to produce energy has long been tries who can aﬀord the high upfront costs of installing regarded as unappealing due to the release of hothouse gases solar panels on their roofs to produce electricity, the number of Africans in stricken need of solar power cannot accom- into the environment that raises the overall carbon trail. The latter encompasses disastrous consequences including modate such an investment, despite the fact that solar power increased global warming as well as its related consequences has a positive economic and environmental case. The global [76, 77]. solar market is controlled by industrialized countries such as In the current era of accelerated development and glob- China, Europe, and the United States, making it diﬃcult for industry knowledge and skills to spread to local businesses. alization, countries all over the world are looking at the low-cost PV systems to replace their existing power genera- The state’s taxes and regulations have made solar-powered tion mix to ensure the reliability, aﬀordability, and sustain- town electriﬁcation prohibitively expensive [86]. Because ability of potential power systems [78]. In fact, most system functioning necessitates real-time measurements of governments have made renewable energy production a solar irradiation and ambient temperature data, the data col- lected is limited due to ﬂaws in the measuring equipment top priority, not only to minimize their overall carbon emis- sions and achieve international climate targets but also to [14]. Because minigrid payback times can easily exceed sev- gain wider socioeconomic beneﬁts. And as per the Interna- eral years, providing a regulatory environment that includes tional Energy Agency, 1.3 billion people everywhere in the valid agreements or subsidies is necessary to limit risks for world cannot have access to reliable electricity, particularly investors [87]. Long-term ﬁnancing for minigrid projects is frequently diﬃcult to come through due to inﬂation is either in the countryside of the developing world where the expan- sion of the utility grid is exceptionally diﬃcult [79]. With high or uncertain [88]. distributed and independent control solutions, the microgrid Challenges regarding policies are as follows: The neces- sity of policy support for oﬀ-grid electricity is critical where model has conﬁrmed to be one of the most realistic solutions that could be used to distribute inexhaustible energy sources mostly there is no long-term electriﬁcation strategy [89]. (DRES) and can mitigate the perceived complications of Licensing challenges are as follows: Retail or generation deployment with increased stability with natural catastro- licensing procedures that are complicated, costly, and time- phes, physical/cyberattacks, and cascading power black- consuming deter investors and businesses from starting outs [80]. minigrid initiatives [90]. Tariﬀ setting challenges are as fol- To date, conventional energy resources cannot provide lows: Tariﬀ design conﬂict is exacerbated by the fact that, enough energy to meet the demand and are generally not envi- in comparison to cheaper grid-based electricity, oﬀ-grid sys- ronmentally friendly. Solving this problem of the energy gap, tem developers must charge signiﬁcantly higher tariﬀsto solar energy can yield an adequate solution [81]. However, meet investment and operating costs [91]. The challenges due to every site requirement, they provide unpredictable are shown in Table 6. power generation. Renewable energy presents a challenge of The construction of a distributed power generation plant power quality, reliability, power system stability, and reactive with a transmission and distribution systems for the gener- power compensation. The intermittent nature of renewable ated power is typically the most cost-eﬀective solution in iso- energy like the solar, wind is less predictable and time- lated areas where grid expansion are considered expensive. variant. The inﬂuence of dust on PV panels in the UAE was Solar energy is an especially appealing renewable choice for researched, and it was discovered that after 5 weeks of outside most of the African countries because it is decentralized, exposure, there was a 10% drop in power production [82]. Due abundant, and cost-eﬀective as technology progresses. It is to its stochastic and random character, renewable energy sys- also resistant to supply and price swings while it remains tems pose substantial issues to traditional grids, such as fre- equally qualiﬁed for funding from mutual and multinational quency variation, voltage ﬂuctuation, and harmonics. organizations aiming to increase the renewable energy out- The low eﬃciency and unreliability of PV systems [83] puts in these countries. This is accomplished by inexhaust- are the most serious challenges. This article’s technoeco- ible energy sources available as well as the introduction of nomic model simulates minigrid, microgrid performance microgrids/standalone systems as ideal solutions to rural utilizing meteorological data, demand proﬁles, technology electriﬁcation problems in developing nations. In particular, capabilities, and pricing data to identify the ideal component microgrids, standalone remote-grid systems are suitable for sizing of hybrid minigrids for rural electriﬁcation. The ﬁnd- oﬀ-grid lighting because they minimize device costs by com- ings show how system sizing is inﬂuenced by location, bining streetlight storage and using pole-mounted solar PV International Journal of Photoenergy 19 Table 6: Challenges of oﬀ-grid electriﬁcation in a nutshell. Licensing Policies Tariﬀ Financial Technical Social setting Minor projects There are no When dimensioning, there No energy access plan Minigrids economic Licenses are are ignored by community-based is no consideration for identiﬁes oﬀ-grid areas feasibility is under doubt expensive ﬁnancing educational future need programs initiatives Licensing is a There are not There is no long-term Tariﬀs are too high for time-consuming Programs for Technical standards are enough examples electriﬁcation plan in rural populations to and short-term inadequate of productive use place sustain complicated funding scenarios process Regulations that are only There is no Fiscal Components that are in eﬀect for a short period There is no suitable diﬀerentiation incentives are mismatched with the of time and are subject to payment method made between not available environment change project sizes The rate of External stakeholders are Tariﬀ criteria are strict, There is no monitoring There was no return on not involved in the and there is no mechanism in place, and community input investment is collaboration because it is distinction between there are no responsible, throughout the predicted to done in isolation comprehensive ﬁnancial certiﬁed employees planning stage below In minigrid initiatives, There are not enough There is not Initial there is no clear restrictions in place to enough technical investment description of stakeholder assure dependable expertise to hire costs are high duties operation and maintenance local workers for both charging batteries and distributed generation. These USD 428.08 per year, respectively. This is also evidenced by technologies ensure a critical position in meeting the global our results in Table 5. energy demands, and they are more than capable of provid- Consistent with the aforementioned, not only could ing power in a more eﬀective, safe, secure, and updated standalone PV power systems be the ideal solution to the manner. electriﬁcation of rural areas in Rwanda but also these sys- The use of standalone solar PV systems can provide sig- tems could help the government and environmental agen- niﬁcant energy and environmental beneﬁts over grid- cies in the eﬀorts to minimize weather-related problems connected solar PV systems. In communities with tradi- and stir up the development of green energy systems as the tional energy and the greatest solar capacity, standalone country strives to provide reliable and sustainable energy solar PV systems present the strongest air pollution control to all its citizens. It is also believed that the proposed standa- beneﬁts. In fact, the solar rooftop provides environmental lone solar PV system would equally contribute to the devel- beneﬁts by replacing traditional (conventional) grid electric- opment of future renewable energy generation systems in ity. The standalone and microgrid systems simulated in this other countries with similar environmental, climate, paper have provided best results; however, due to ﬁnancial weather, and meteorological conditions around the world. instability of most of the Sub-Saharan countries, a standa- In particular, neighboring countries such as Burundi, Dem- lone PV system proves to be more viable to those scattered ocratic Republic of Congo (DRC), Tanzania, and Uganda, households. and all other countries in the region are estimated to be good candidates for such a system. 6. Conclusion Data Availability Limited access to energy slows down the development and makes it harder for governments and people to establish The data used to support the ﬁndings of this study are avail- growth targets. In this study, we designed and simulated able from the corresponding author upon request. oﬀ-grid PV power systems to provide electricity to a Rwan- dan remote county using HOMER software. Simulation Conflicts of Interest results revealed that an islanded PV system for a dwelling home is the ideal oﬀ-grid power generation system for use The authors declare that they have no conﬂicts of interest. in rural areas. The system is particularly cost-eﬀective com- pared with a microgrid PV system that supplies electricity to References a rural community in Rwanda. Results indicate that the total NPC, LCOE, and operating costs of a standalone energy sys- [1] N. U. Blum, R. Sryantoro Wakeling, and T. S. Schmidt, “Rural tem are estimated to USD 9284.40, USD 1.23 per kWh, and electriﬁcation through village grids–Assessing the cost 20 International Journal of Photoenergy [17] T. I. J. de Dieu Uwisengeyimana and A. Teke, “Current over- competitiveness of isolated renewable energy technologies in Indonesia,” Renewable and Sustainable Energy Reviews, view of renewable energy resources in Rwanda,” The Journal vol. 22, pp. 482–496, 2013. of Energy and Natural Resources, vol. 5, no. 6, pp. 92–97, 2016. [2] S. Szabó, K. Bódis, T. Huld, and M. Moner-Girona, “Energy [18] J. Dong, M. M. Olama, T. Kuruganti et al., “Novel stochastic methods to predict short-term solar radiation and photovol- solutions in rural Africa: mapping electriﬁcation costs of dis- tributed solar and diesel generation versus grid extension,” taic power,” Renewable Energy, vol. 145, pp. 333–346, 2020. Environmental Research Letters, vol. 6, no. 3, p. 034002, 2011. [19] J. D. Dieu Niyonteze, F. Zou, G. N. Osarumwense Asemota, [3] J. P. Murenzi and T. S. Ustun, “The case for microgrids in elec- and S. Bimenyimana, “Solar-powered mini-grids and smart metering systems , the solution to Rwanda energy crisis,” trifying Sub-Saharan Africa,” in IREC2015 The Sixth Interna- tional Renewable Energy Congress, Sousse, Tunisia, March 2015. vol. 1311, p. 012002, 2019. [20] A. R. Gautam, K. Gourav, J. M. Guerrero, and D. M. Fulwani, [4] P. Buchana and T. S. Ustun, “The role of microgrids & renew- able energy in addressing Sub-Saharan Africa’s current and “Ripple mitigation with improved line-load transients response in a two-stage DC-DC-AC converter: adaptive SMC future energy needs,” in IREC2015 The Sixth International Renewable Energy Congress, Sousse, Tunisia, March 2015. approach,” IEEE Transactions on Industrial Electronics, vol. 65, no. 4, pp. 3125–3135, 2018. [5] U. Deichmann, C. Meisner, S. Murray, and D. Wheeler, “The economics of renewable energy expansion in rural Sub- [21] D. Kumar Lal, B. Bhusan Dash, and A. K. AkellaOptimization of PV/wind/micro-hydro/diesel hybrid power system in Saharan Africa,” Energy Policy, vol. 39, no. 1, pp. 215–227, 2011. HOMER for the study area,” International Journal on Electrical [6] S. Bimenyimana, G. N. O. Asemota, J. D. D. Niyonteze, Engineering and Informatics,vol. 3,no.3, pp. 307–325, 2011. C. Nsengimana, P. J. Ihirwe, and L. Li, “Photovoltaic solar technologies: solution to aﬀordable, sustainable, and reliable [22] N. Hagumimana, J. Zheng, G. N. O. Asemota et al., “Concen- trated solar power and photovoltaic systems: a new approach energy access for all in Rwanda,” International Journal of Photoenergy, vol. 2019, Article ID 5984206, 29 pages, 2019. to boost sustainable energy for all (Se4all) in Rwanda,” Inter- national Journal of Photoenergy, vol. 2021, Article ID [7] S. Rehman and L. M. al-Hadhrami, “Study of a solar PV- 5515513, 32 pages, 2021. diesel-battery hybrid power system for a remotely located pop- [23] M. K. Deshmukh and A. B. Singh, “Modeling of Energy Perfor- ulation near Rafha, Saudi Arabia,” Energy, vol. 35, no. 12, pp. 4986–4995, 2010. mance of Stand-Alone SPV System Using HOMER Pro,” Energy Procedia, vol. 156, pp. 90–94, 2019. [8] A. O. Adewuyi and O. B. Awodumi, “Renewable and non- renewable energy-growth-emissions linkages: review of [24] O. A. Controller-in-loop, A hybrid PV-battery system for on- grid and oﬀ-grid applications—controller-in-loop simulation emerging trends with policy implications,” Renewable and Sus- validation. tainable Energy Reviews, vol. 69, pp. 275–291, 2017. [25] C. Marino, A. Nucara, M. F. Panzera, M. Pietrafesa, and [9] U. Sureshkumar, P. S. Manoharan, and A. P. S. Ramalakshmi, A. Pudano, “Economic comparison between a stand-alone “Economic cost analysis of hybrid renewable energy system and a grid connected PV system vs. grid distance,” Energies, using HOMER,” in IEEE-International Conf. Adv. Eng. Sci. vol. 13, no. 15, p. 3846, 2020. Manag. ICAESM-2012, vol. 8, pp. 94–99, 2012. [26] M. Hafeez, M. Hariri, M. Khairunaz, M. Desa, and S. Masri, [10] S. Bahramara, “Optimal planning of hybrid renewable energy Grid-connected PV generation, vol. 2040, 2020. systems using HOMER: a review,” Renewable and Sustainable Energy Reviews, vol. 62, pp. 609–620, 2016. [27] F. A. Alturki and E. M. Awwad, “Sizing and cost minimization of standalone hybrid WT/PV/biomass/pump-hydro storage- [11] D. Toke, “Renewable ﬁnancial support systems and cost-eﬀec- based energy systems,” Energies, vol. 14, no. 2, p. 489, 2021. tiveness,” Journal of Cleaner Production, vol. 15, no. 3, pp. 280–287, 2007. [28] T. Wu, H. Zhang, and L. Shang, “Optimal sizing of a grid- connected hybrid renewable energy systems considering [12] L. Olatomiwa, R. Blanchard, S. Mekhilef, and D. Akinyele, hydroelectric storage,” Energy Sources, Part A: Recovery, Utili- “Hybrid renewable energy supply for rural healthcare facilities: zation, and Environmental Eﬀects, pp. 1–17, 2020. an approach to quality healthcare delivery,” Sustainable Energy Technologies and Assessments, vol. 30, pp. 121–138, 2018. [29] B. E. Türkay and A. Y. Telli, “Economic analysis of standalone and grid connected hybrid energy systems,” Renewable Energy, [13] M. Hossain, S. Mekhilef, and L. Olatomiwa, “Performance vol. 36, no. 7, pp. 1931–1943, 2011. evaluation of a stand-alone PV-wind-diesel-battery hybrid system feasible for a large resort center in South China Sea, [30] D. Mazzeo, N. Matera, P. de Luca, C. Baglivo, P. Maria Con- Malaysia,” Sustainable Cities and Society, vol. 28, pp. 358– gedo, and G. Oliveti, “Worldwide geographical mapping and 366, 2017. optimization of stand-alone and grid- connected hybrid renew- able system techno-economic performance across Koppen- Gei- [14] L. M. Halabi, S. Mekhilef, L. Olatomiwa, and J. Hazelton, “Per- ger climates,” Applied Energy, vol. 276, p. 115507, 2020. formance analysis of hybrid PV/diesel/battery system using HOMER: a case study Sabah, Malaysia,” Energy Conversion [31] A. Chakir, M. Tabaa, F. Moutaouakkil et al., “Optimal energy and Management, vol. 144, pp. 322–339, 2017. management for a grid connected PV-battery system,” Energy Reports, vol. 6, pp. 218–231, 2020. [15] L. Olatomiwa, S. Mekhilef, and O. S. Ohunakin, “Hybrid renewable power supply for rural health clinics (RHC) in six [32] R. Srivastava, A. N. Tiwari, and V. K. Giri, “An overview on geo- political zones of Nigeria,” Sustainable Energy Technolo- performance of PV plants commissioned at diﬀerent places gies and Assessments, vol. 13, pp. 1–12, 2016. in the world,” Energy for Sustainable Development, vol. 54, pp. 51–59, 2020. [16] O. Ekren, C. Hakan Canbaz, and Ç. B. Güvel, “Sizing of a solar- wind hybrid electric vehicle charging station by using HOMER [33] A. C. Duman and Ö. Güler, “Economic analysis of grid- software,” Journal of Cleaner Production, vol. 279, p. 123615, connected residential rooftop PV systems in Turkey,” Renew- 2021. able Energy, vol. 148, pp. 697–711, 2020. International Journal of Photoenergy 21 [49] K. N. B. Akshai and R. Senthil, “Economic evaluation of grid [34] H. M. Ridha, C. Gomes, H. Hizam, M. Ahmadipour, A. A. Hei- dari, and H. Chen, “Multi-objective optimization and multi- connected and standalone photovoltaic systems using criteria decision-making methods for optimal design of stan- PVSyst,” IOP Conference Series: Materials Science and Engi- dalone photovoltaic system: a comprehensive review,” Renew- neering, vol. 912, no. 4, 2020. able and Sustainable Energy Reviews, vol. 135, p. 110202, 2021. [50] S. Odeh and I. Ibrik, “Performance assessment of standalone [35] M. J. Mayer and G. Gróf, “Techno-economic optimization of PV systems for rural communities,” Australian Journal of grid-connected, ground-mounted photovoltaic power plants Mechanical Engineering, pp. 1–10, 2019. by genetic algorithm based on a comprehensive mathematical [51] J. Kumar, N. R. Parhyar, M. K. Panjwani, and D. Khan, model,” Solar Energy, vol. 202, pp. 210–226, 2020. “Design and performance analysis of PV grid-tied system with [36] H. A. Kazem, M. T. Chaichan, A. H. A. al-Waeli, and energy storage system,” International Journal of Electrical and K. Sopian, “A novel model and experimental validation of dust Computer Engineering, vol. 11, no. 2, pp. 1077–1085, 2021. impact on grid-connected photovoltaic system performance in [52] B. K. K. Prasad, K. P. Reddy, K. Rajesh, and P. V. Reddy, Northern Oman,” Solar Energy, vol. 206, pp. 564–578, 2020. “Design and simulation analysis of 12.4 kWp grid connected photovoltaic system by using PVSYST software,” The Interna- [37] E. Aykut and Ü. K. Terzi, “Techno-economic and environ- mental analysis of grid connected hybrid wind/photovoltaic/- tional Journal of Recent Technology and Engineering, vol. 8, no. 5, pp. 2859–2864, 2020. biomass system for Marmara University Goztepe campus,” International Journal of Green Energy, vol. 17, no. 15, [53] Z. B. Duranay and H. Guldemir, “Modelling and simulation of pp. 1036–1043, 2020. a single phase standalone PV system,” in 2019 11th Interna- [38] R. Khezri, A. Mahmoudi, and M. H. Haque, “Optimal capacity tional Conference on Electronics, Computers and Artiﬁcial Intelligence (ECAI), Pitesti, Romania, June 2019. of solar PV and battery storage for Australian grid-connected households,” IEEE Transactions on Industry Applications, [54] Y. Cui, J. Zhu, F. Meng, S. Zoras, J. McKechnie, and J. Chu, vol. 56, no. 5, pp. 5319–5329, 2020. “Energy assessment and economic sensitivity analysis of a grid-connected photovoltaic system,” Renewable Energy, [39] B. K. Das, “Optimal sizing of stand-alone and grid-connected vol. 150, pp. 101–115, 2020. solar PV systems in Bangladesh,” International Journal of Energy for a Clean Environment,vol.21,no.2,pp.107–124, 2020. [55] N. Gupta, R. Garg, and P. Kumar, “Sensitivity and reliability models of a PV system connected to grid,” Renewable and Sus- [40] M. Al-Maghalseh, “Generation unit sizing, economic analysis tainable Energy Reviews, vol. 69, pp. 188–196, 2017. of grid connected and standalone PV power plant,” Int. J. Energy Appl. Technol., vol. 6, no. 1, pp. 1–7, 2019. [56] M. P. Bonkile and V. Ramadesigan, “Power management con- trol strategy using physics-based battery models in standalone [41] H. A. Attia and F. D. A. Gonzalo, “Stand-alone PV system with PV-battery hybrid systems,” J. Energy Storage, vol. 23, pp. 258– MPPT function based on fuzzy logic control for remote build- 268, 2019. ing applications,” International Journal of Power Electronics and Drive Systems, vol. 10, no. 2, p. 842, 2018. [57] S. S. Dheeban, N. B. Muthu Selvan, and C. Senthil Kumar, “Design of standalone PV system,” International Journal of [42] A. Iqbal and M. T. Iqbal, “Design and analysis of a stand-alone Scientiﬁc and Technology Research, vol. 8, no. 11, pp. 684– PV system for a rural house in Pakistan,” International Journal 688, 2019. of Photoenergy, vol. 2019, Article ID 4967148, 8 pages, 2019. [58] E. Roumpakias and A. Stamatelos, “Performance analysis of a [43] Y. Chaibi, M. Salhi, and A. el-jouni, “Sliding mode controllers grid-connected photovoltaic park after 6 years of operation,” for standalone PV systems: modeling and approach of con- Renewable Energy, vol. 141, pp. 368–378, 2019. trol,” International Journal of Photoenergy, vol. 2019, Article ID 5092078, 12 pages, 2019. [59] V. S. Bibin Raj and G. G. Devadhas, “Design and development of new control technique for standalone PV system,” Micro- [44] M. A. Omar and M. M. Mahmoud, “Design and Simulation of processors and Microsystems, vol. 72, p. 102888, 2020. a PV System Operating in Grid-Connected and Stand- Alone Modes for Areas of Daily Grid Blackouts,” International Jour- [60] N. Manoj Kumar, K. Sudhakar, and M. Samykano, “Techno- nal of Photoenergy, vol. 2019, Article ID 5216583, 9 pages, economic analysis of 1 MWp grid connected solar PV plant in Malaysia,” International Journal of Ambient Energy, vol. 40, no. 4, pp. 434–443, 2019. [45] P. K. Bonthagorla and S. Mikkili, “Performance investigation of hybrid and conventional PV array conﬁgurations for grid- [61] N. Kumar, V. Saxena, B. Singh, and B. K. Panigrahi, “Intuitive connected/standalone PV systems,” CSEE Journal of Power control technique for grid connected partially shaded solar and Energy Systems, pp. 1–16, 2020. PV-based distributed generating system,” IET Renewable Power Generation, vol. 14, no. 4, pp. 600–607, 2020. [46] M. Salimi, F. Radmand, and M. Hosseini Firouz, “Dynamic modeling and closed-loop control of hybrid grid-connected [62] Y. Z. Alharthi, M. K. Siddiki, and G. M. Chaudhry, “Techno- renewable energy system with multi-input multi-output con- economic analysis of hybrid PV/wind system connected to troller,” Journal of Modern Power Systems and Clean Energy, utility grid,” in 2019 IEEE Texas Power and Energy Conference vol. 9, no. 1, pp. 94–103, 2021. (TPEC), pp. 1–6, College Station, TX, USA, February 2019. [47] M. Dali, J. Belhadj, and X. Roboam, “Hybrid solar-wind sys- [63] E. Kurt and G. Soykan, “Performance analysis of DC grid con- tem with battery storage operating in grid-connected and stan- nected PV system under irradiation and temperature varia- dalone mode: control and energy management - experimental tions,” in 2019 8th International Conference on Renewable investigation,” Energy, vol. 35, no. 6, pp. 2587–2595, 2010. Energy Research and Applications (ICRERA), pp. 702–707, Brasov, Romania, November 2019. [48] M. I. Hlal, V. K. Ramachandaramurthy, A. Sarhan, A. Pouryekta, and U. Subramaniam, “Optimum battery depth [64] H. Rezk, M. A. Abdelkareem, and C. Ghenai, “Performance of discharge for oﬀ-grid solar PV/battery system,” J. Energy evaluation and optimal design of stand-alone solar PV- Storage, vol. 26, p. 100999, 2019. battery system for irrigation in isolated regions: a case study 22 International Journal of Photoenergy renewable energy microgrids,” Elektr. J. Electr. Eng., vol. 17, in Al Minya (Egypt),” Sustainable Energy Technologies and Assessments, vol. 36, p. 100556, 2019. no. 3, pp. 23–35, 2018. [65] HOMER Energy LLC, “HOMER Pro version 3.7 user manual,” [81] T. R. Shah and H. M. Ali, “Applications of hybrid nanoﬂuids in HOMER Energy, p. 416, 2016, http://www.homerenergy.com/ solar energy, practical limitations and challenges: A critical pdf/HOMERHelpManual.pdf. review,” Solar Energy, vol. 183, pp. 173–203, 2019. [66] T. Lambert, P. Gilman, and P. Lilienthal, “Micropower system [82] B. M. A. Mohandes, L. el-Chaar, and L. A. Lamont, “Applica- modeling with HOMER,” Integration of Alternative Sources of tion study of 500 W photovoltaic (PV) system in the UAE,” Energy: Farret/Integration of Alternative Sources of Energy, pp. Applied Solar Energy, vol. 45, no. 4, pp. 242–247, 2009. 379–418, 2006. [83] M. A. Green, Y. Hishikawa, E. D. Dunlop et al., “Solar cell eﬃ- [67] J. D. D. Niyonteze, F. Zou, G. Norense Osarumwense Ase- ciency tables (version 53),” Progress in Photovoltaics: Research mota, S. Bimenyimana, and G. Shyirambere, “Key technology and Applications, vol. 27, no. 1, pp. 3–12, 2019. development needs and applicability analysis of renewable [84] A. Niraula, “Scaling up of oﬀ-grid solar micro grids: moving energy hybrid technologies in oﬀ-grid areas for the Rwanda towards a ‘utility in a box’ model for rapid deployment,” power sector,” Heliyon, vol. 6, no. 1, article e03300, 2020. 2015, https://static1.squarespace.com/static/ [68] S. Firth, K. Lomas, A. Wright, and R. Wall, “Identifying trends 536b92d8e4b0750dﬀ7e241c/t/55ed3aebe4b049db23e2c0c7/ in the use of domestic appliances from household electricity 1441610475311/Dissertation_Msc_Anjal.pdf. consumption measurements,” Energy and Buildings, vol. 40, [85] M. H. Alaaeddin, S. M. Sapuan, M. Y. M. Zuhri, E. S. Zainudin, no. 5, pp. 926–936, 2008. and F. M. al- Oqla, “Photovoltaic applications: status and [69] W. M. Amutha and V. Rajini, “Cost beneﬁt and technical anal- manufacturing prospects,” Renewable and Sustainable Energy ysis of rural electriﬁcation alternatives in southern India using Reviews, vol. 102, pp. 318–332, 2019. HOMER,” Renewable and Sustainable Energy Reviews, vol. 62, [86] J. Amankwah-amoah, “Solar energy in Sub-Saharan Africa : pp. 236–246, 2016. the challenges and opportunities of technological leapfrog- [70] A. Jamalaiah, C. P. Raju, and R. Srinivasarao, “Optimization ging,” Thunderbird International Business Review, vol. 57, and operation of a renewable energy based pv-fc-micro grid no. 1, pp. 15–31, 2015. using HOMER,” in 2017 International Conference on Inventive [87] T. Reber, S. Booth, D. Cutler, X. Li, and J. Salasovich, Tariﬀ Communication and Computational Technologies (ICICCT), considerations for micro-grids in Sub-Saharan Africa, US Aid, pp. 450–455, Coimbatore, India, March 2017. 2018, https://www.nrel.gov/docs/fy18osti/69044.pdf. [71] M. Khemariya, A. Mittal, P. Baredar, and A. Singh, “Cost and [88] USAID, “Challenges and needs in ﬁnancing mini-grids Mini- size optimization of solar photovoltaic and fuel cell based inte- Grids Support Toolkit,” Energy U.S. Agency for International grated energy system for un-electriﬁed village,” The Journal of Development, 2018, June 2021, https://www.usaid.gov/ Energy Storage, vol. 14, pp. 62–70, 2017. energy/mini-grids/ﬁnancing. [72] H. Louie, E. O'Grady, V. van Acker, S. Szablya, N. P. Kumar, [89] A. A. Eras-Almeida, M. Fernández, J. Eisman, J. G. Martín, and R. Podmore, “Rural oﬀ-grid electricity service in Sub- E. Caamaño, and M. A. Egido-Aguilera, “Lessons learned from Saharan Africa [technology leaders],” IEEE Electriﬁcation rural electriﬁcation experiences with third generation solar Magazine, vol. 3, no. 1, pp. 7–15, 2015. home systems in latin America: case studies in Peru, Mexico, [73] G. Prinsloo, A. Mammoli, and R. Dobson, “Customer domain and Bolivia,” Sustainability, vol. 11, no. 24, p. 7139, 2019. supply and load coordination: a case for smart villages and [90] E. I. Come Zebra, H. J. van der Windt, G. Nhumaio, and A. P. transactive control in rural oﬀ-grid microgrids,” Energy, C. Faaij, “A review of hybrid renewable energy systems in vol. 135, pp. 430–441, 2017. mini-grids for oﬀ-grid electriﬁcation in developing countries,” [74] M. E. Khodayar, “Rural electriﬁcation and expansion planning Renewable and Sustainable Energy Reviews, vol. 144, of oﬀ-grid microgrids,” The Electricity Journal, vol. 30, no. 4, p. 111036, 2021. pp. 68–74, 2017. [91] M. F. N. Peterschmidt, M. Rohrer, and B. Kondev, “RECP [75] D. E. Olivares, A. Mehrizi-Sani, A. H. Etemadi et al., “Trends minigrid policy toolkit doublepage,” 2014, http://www in microgrid control,” IEEE Transactions on Smart Grid, .minigridpolicytoolkit.euei-pdf.org/policy-toolkit. vol. 5, no. 4, pp. 1905–1919, 2014. [76] M. Hoel, “Depletion of fossil fuels and the impacts of global warming,” Fuel and Energy Abstracts, vol. 37, no. 6, p. 460, [77] T. S. Ustun, C. Ozansoy, and A. Zayegh, “Recent developments in microgrids and example cases around the world–A review,” Renewable and Sustainable Energy Reviews, vol. 15, no. 8, pp. 4030–4041, 2011. [78] IRENA, Future of solar photovoltaic: deployment, investment, technology, grid integration and socio-economic aspects (A Global Energy Transformation: paper), 2019. [79] R. K. Akikur, R. Saidur, H. W. Ping, and K. R. Ullah, “Compar- ative study of stand-alone and hybrid solar energy systems suitable for oﬀ-grid rural electriﬁcation: a review,” Renewable and Sustainable Energy Reviews, vol. 27, pp. 738–752, 2013. [80] A. Abdulkarim, N. Faruk, A. O. 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Publisher: Hindawi Publishing Corporation
Copyright: Copyright © 2021 Kuo-Chi Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ISSN: 1110-662X
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DOI: 10.1155/2021/1211953
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Abstract

Hindawi International Journal of Photoenergy Volume 2021, Article ID 1211953, 22 pages https://doi.org/10.1155/2021/1211953 Research Article Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study 1,2,3 4 4 Kuo-Chi Chang , Noel Hagumimana , Jishi Zheng, 5 6 Godwin Norense Osarumwense Asemota , Jean De Dieu Niyonteze , 7 5 8,9 Walter Nsengiyumva , Aphrodis Nduwamungu , and Samuel Bimenyimana Department of Applied Intelligent Mechanical and Electrical Engineering, Yu Da University of Science and Technology, Miaoli County, Taiwan Department of Business Administration, North Borneo University College, Sabah, Malaysia School of Electronic, Electrical and Physics, Fujian University of Technology, Fuzhou, China Fujian Province Key Laboratory of Automotive Electronics and Electric Drive, Fujian University of Technology, Fuzhou 350118, China University of Rwanda, African Centre of Excellence in Energy for Sustainable Development, Kigali 4285, Rwanda Carnegie Mellon University Africa, Kigali, Rwanda Laboratory of Optics, Terahertz and Non-destructive Testing, School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China Huaqiao University, Intelligence and Automation in Construction Provincial Higher-Educational Engineering Research Centre, 361021 Xiamen, China Hello Renewables Ltd., Kigali, Rwanda Correspondence should be addressed to Kuo-Chi Chang; albertchangxuite@gmail.com and Noel Hagumimana; hagumanoel@gmail.com Received 3 May 2021; Revised 26 July 2021; Accepted 6 September 2021; Published 5 October 2021 Academic Editor: James Connolly Copyright © 2021 Kuo-Chi Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In recent years, several factors such as environmental pollution, declining fossil fuel supplies, and product price volatility have led to most countries investing in renewable energy sources. In particular, the development of photovoltaic (PV) microgrids, which can be standalone, oﬀ-grid connected or grid-connected, is seen as one of the most viable solutions that could help developing countries such as Rwanda to minimize problems related to energy shortage. The country’s current electriﬁcation rate is estimated to be 59.7%, and hydropower remains Rwanda’s primary source of energy (with over 43.8% of its total energy supplies) despite advances in solar technology. In order to provide aﬀordable electricity to low-income households, the government of Rwanda has pledged to achieve 48% of its overal electriﬁcation goals from oﬀ-grid solar systems by 2024. In this paper, we develop a cost-eﬀective power generation model for a solar PV system to power households in rural areas in Rwanda at a reduced cost. A performance comparison between a single household and a microgrid PV system is conducted by developing eﬃcient and low-cost oﬀ-grid PV systems. The battery model for these two systems is 1.6 kWh daily load with 0.30 kW peak load for a single household and 193.05 kWh/day with 20.64 kW peak load for an oﬀ-grid PV microgrid. The hybrid optimization model for electric renewable (HOMER) software is used to determine the system size and its life cycle cost including the levelized cost of energy (LCOE) and net present cost (NPC) for each of these power generation models. The analysis shows that the optimal system’s NPC, LCOE, electricity production, and operating cost are estimated to 1,166,898.0 USD, 1.28 (USD/kWh), 221, and 715.0 (kWh per year, 37,965.91 (USD per year), respectively, for microgrid and 9284.4(USD), 1.23 (USD/kWh), and 2426.0 (kWh per year, 428.08 (USD per year), respectively, for a single household (standalone). The LCOE of a standalone PV system of an independent household was found to be cost-eﬀective compared with a microgrid PV system that supplies electricity to a rural community in Rwanda. 2 International Journal of Photoenergy renewable energy is much less costly [7]. Given that many of 1. Introduction Africa’s rural areas are plagued by an unsustainable energy Small electricity systems that can run independently, known system, building standalone, minigrid can solve energy prob- as oﬀ-grid microgrids, could play a pivotal role in the devel- lems for scattered people [8]. In developing nations like opment of electricity systems based on decentralized renew- Rwanda, where power outages are common, implementing able energy (RE) technologies. These networks are more supportable energy development and clean energy needs cost-eﬀective than stretching transmission lines to rural extensive preparation, particularly given the ﬁnancial impacts. places [1, 2], thereby providing the possibility to produce As a result, the HOMER (hybrid optimization model of elec- suﬃcient electricity in countries where the national demand tric renewable) Pro software can design, prepare, and simulate surpasses the regular production. In East Africa, for exam- the model in a variety of environments, including restrained ple, the energy deﬁciency is a signiﬁcant impediment to and unrestrained systems, standalone, grid systems, and/or social and economic growth. The capital expenses of wide storage. The microgrid system design has advantages that lead grids can be incredibly expensive for developing countries to eﬃcient source loading for microgrids and facilitate power leading to a shortage of roads and utilities [3–5]. To this systems operators. HOMER’s beneﬁts lie in the features used end, community-based microgrids are considered the best in the design, planning, and simulation of the microgrid option that would help rural areas in developing countries model discussed in [9, 10]. In contrast to African countries, to reap the beneﬁts of geospeciﬁc renewable energy sources. developed countries like the United States, China, and Japan The people who are not connected to nor served by the have increased their investment in renewable energy by bil- public or private power grid are referred to as “oﬀ-grid lions of dollars. Researchers are attempting to produce more users.” According to the authors’ deﬁnition in Ref. [6], the electricity from cost-eﬀective resources that are not detrimen- term “oﬀ-grid” refers to a system and way of life that allows tally impacting the environment [11]. people to function without the assistance of remote infra- HOMER was used to examining selected rural places in structure, including an electrical grid. It is a method of gain- Nigeria based on the availability of wind and solar energies ing access to electricity that is used in countries and areas so that healthcare centers or clinics in isolated regions can where there is limited access to electricity due to a dispersed provide quick delivery of medical services to the people or remote population. It corresponds to living without rely- who need them. It uses the best technical and economic ing on one or more public services, commonly referred to as design and sizing of hybrid electric power system compo- electrical grids. Oﬀ-grid users are people who live oﬀ the nents like wind, PV, battery, and inverter systems, where grid, and those systems can be categorized as standalone PV/wind/diesel/battery hybrid setup is best for rural health power systems, minigrids, and microgrids, which should centers, while PV/diesel/battery hybrid systems are best for typically provide energy to a smaller community. In this Port Harcourt considering the quality of renewable energy research, the HOMER software (HOMER Pro, version potential [12]. 3.13.1) had been used to model, simulate, and optimize Tourist destinations in the South China Sea, Malaysia potential renewable energy sources, as well as solutions to were at risk due to the widespread use of diesel generators ensure universal access to energy Rwandan for oﬀ-grid users. and pollutants from diesel-based power plants. HOMER HOMER has a built-in optimizer through the proprietary software was used for economic and technical analysis of derivative-free method that was adopted in Section 2. The the system. The best optimized standalone hybrid energy simulation models took place in Rwanda’s Western province system consists of PV, wind, diesel generator, converter, ° ° ′ ′ (Rutsiro, Rwanda, 1 56.3 S, 29 19.5 E). To optimize standa- and battery. The output has proved the diesel-only system lone solar systems, several site visits were conducted in the has a higher net present cost, cost of energy, and CO emis- Rutsiro district of Rwanda’s Western province, precisely to sion compared to the optimized hybrid renewable energy the location of the typical sample residential house used in system [13]. this section. The owner of the residential house listed his The study on decentralized power stations in Sabah, electric household items, along with their rated power and Malaysia [14], with a diverse combination of photovoltaic daily usage hours. For this study, a sample size of 121 resi- (PV), diesel generators, system converters, and storage batte- dential houses was chosen. ries. The impact of PV integration using HOMER was prop- erly quantiﬁed by analyzing the practical behaviors of diﬀerent PV penetration levels. The analysis based on tech- 2. Literature Review: A Comparative Analysis of nical, economic, and environmental constraints has resulted in satisfying the load demand with the minimum total net Standalone and Minigrid-Connected Solar present cost (NPC) and the levelized cost of energy (LCOE). Energy in a Rural Area The sensitivity analysis and the impact of diﬀerent PV pen- With the mounting consequences of global warming, pollu- etration levels on the system performance and the genera- tion, scarcity of fuel, and energy use, renewable energy sources tion of harmful emissions has been carried out. The (RES) is constantly getting more attention around the world. ﬁndings reveal an increase in the use of renewable energy (RE) sources in energy generation, as well as a decrease in Therefore, the need for renewable energy to plan and build a grid-connected or standalone, microgrid, the minigrid system the reliance on standalone diesel generators. has risen and will continue to increase. When the price of con- The ability to supply power for rural health clinics ventional energy is compared to the price of renewable energy, (RHC) in six geopolitical regions of Nigeria has also been International Journal of Photoenergy 3 Table 1: Summary of comparative analysis based on standalone, microgrid, on-grid, and oﬀ-grid results. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type M.K The objective is to Deshmukh, quantitatively estimate Street 1. Athokpam 2018 — Standalone Electrical HOMER energy losses due to the lighting Bharatbushan standalone operation Singh [23] mode The current method can work in various operating modes, and during U Villages, transient and steady-state On-grid and Hybrid PV battery with 2. Subramaniam 2020 — islands, and Electrical situations. With both oﬀ- oﬀ-grid controller et al. [24] hilly areas grid and on-grid situations, the suggested power management controls were approved. The study looked at the Comparative analysis economics of an islanded of the costs of a C Marino Standalone Residential PV project with two 3. 2020 Italy Electrical standalone and a grid- et al. [25] photovoltaic user conﬁgurations that networked PV system measure diminishing self- vs. grid distance suﬃciency. This review highlights the recent development of systems for generating MH grid-connected PV (GPV) Grid synchronization Mohamed Grid- Villages, involving many sub- 4. 2020 — Electrical and islanding detection Hariri et al. connected islands components, like DC-DC methods [26] converters, PV modules, maximum power point tracking (MPPT), and inverter technologies The aim was sizing and Hybrid photovoltaic FA Alturki, price reduction of islanded Saudi Remote (PV)/wind turbine 5. EM Awwad 2020 Standalone Electrical hybrid WT/PV/biomass/ Arabia community (WT)/biomass/pump [27] pump-hydro storage- hydro/storage energy systems This study provides a new approach to maximizing the scale of grid-connected renewable energy sources integrated with the salp swarm algorithm (SSA) T Wu et al. Grid- Salp swarm algorithm pumped storage system. 6. 2020 — Load serving Electrical [28] connected (SSA). This method enables diﬀerent energy sources to be explored and their combination to contact the base in the optimum conﬁguration of the hybrid system The research explores the viability of using wind and BE Türkay, Standalone solar energy. Using AYTelli 7. 2011 Turkey and grid- Pilot area Electrical HOMER hydrogen as storage in renewable connected combination with energy [29] traditional grid-based electricity to fulﬁll the 4 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type electricity needs of the pilot area The goal of this work is to bridge the absence of direct comparisons between the technoeconomic output of islanded and grid- Standalone Oﬃce D Mazzeo Hybrid renewable networked investigations 8. 2020 Koppen and grid- building Electrical et al. [30] system in the same operating connected district. environment, providing global technoeconomic mapping, and optimizing islanded and grid- networked PV-wind systems The research focused on the grid-connected development system’s A Chakir et al. Grid- 9. 2019 — Load serving Electrical MATLAB/Simulink management, connection [31] connected with the grid, and storage hybrid renewable energy system’s management The various cases were examined based on their location, design and year of development, as well as the power, the technology used, and performance Standalone that can help design a PV R Srivastava 10. 2020 — and grid- Load serving Electrical Review plant considering the et al. [32] connected achievements of the previously commissioned plant. The material of the PV module and panel tilt angle was found to be crucial for the design of a PV plant The study focused on a cost-beneﬁt analysis of grid-aﬃliated rooftop PV systems for private use. There was the suggestion AC Duman, Ö Grid- 11. 2020 Turkey Load serving Electrical HOMER to increase the number of Güler [33] connected private PV incentives and cultivate a regional support system, considering solar diﬀerences among regions The purpose of the research was to provide a thorough analysis of the recent progress in the HM Ridha Standalone Remote 12. 2020 — Electrical Review design of standalone PV et al. [34] photovoltaic areas systems. Multiobjective optimization (MOO) and multicriteria decision- making (MCDM) International Journal of Photoenergy 5 Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type methodologies, including the mathematical models used to measure the PV module power output and storage battery Grid-connected, ground- mounted technoeconomic optimization of genetic algorithm-based photovoltaic power plants MJ Mayer Hungarian Grid- 13. 2019 Load serving Electrical use Mathematical model on a comprehensive et al. [35] region connected mathematical model. The target function is the internal rate of return and a genetic algorithm performs the optimization Dust is one major parameter aﬀecting photovoltaic eﬃciency, yield, and proﬁtability X-ray diﬀraction HA Kazem Grid- Load linked to the grid. The 14. 2020 Oman Electrical (XRD) and X-ray et al. [36] connected management proposed model in the ﬂuorescence (XRF) paper took account of the dust on the grid-aﬃliated photovoltaic output power innovatively The research focused on technology, cost-beneﬁt, and environmental analyses of grid-aﬃliated hybrid wind/PV/biomass systems, Marmara Marmara Grid- E Aykut, ÜK University, Goztepe 15. 2020 University, connected Load serving Electrical HOMER Terzi [37] campus. The performance Turkey hybrid of the hybrid electricity system was assessed using both the net present cost (NPC) and cost of energy (COE) and found to be cheaper This research speciﬁes the optimum solar capacity for grid-aﬃliated households, R Khezri et al. Grid- Households photovoltaic (PV), and 16. 2020 Australia Electrical [38] connected serving battery energy storage (BES) to minimize the net present cost of electric power networks The study sized an islanded and grid-aﬃliated solar PV electricity Standalone provision to a small 17. BK Das [39] 2020 Bangladesh and grid- Load serving Electrical HOMER neighborhood. The result connected reﬂects major cost savings through the incorporation of the PV module into the grid 6 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type This study provided a layout for a grid-aﬃliated PV system and an islanded PV system. Factors inﬂuencing device design Grid- Open distribution and size were also ALM Maher connected Industrial 18. 2019 Palestine Electrical source simulator described and analyzed. [40] and zone (OpenDSS) The results showed a good standalone improvement in the overall energy losses and voltage proﬁle concerning load and capacity production It provided a precise Buck- Boost DC-DC converter design powered by the fuzzy logic controller HA Attia, F United Remote (FLC). The research 19. delAma 2018 Arab Standalone Electrical Fuzzy logic control building concentrated on Gonzalo [41] Emirates suggesting a suitable solar PV panel model conﬁguration and attachment Thermal modeling of a typical Pakistani rural house was performed using BEopt throughout this research to assess the A Iqbal, MT Standalone 20. 2019 Pakistan Rural area Electrical HOMER Pro hourly load proﬁle. System Iqbal [42] PV studies indicated that such a system can primarily reinforce the lighting and loading of appliances in a rural household The study tracked how the maximum power point (MPP) transferred the Y Chaibi et al. Standalone Sliding mode MPPT/ 21. 2019 — Load serving Electrical maximum available power [43] PV MATLAB Simulink to the load. The control fed the AC load by a sinusoidal output current The study proposed a viable solution to the problem of energy output in the private dwellings MA Omar, Grid- Unconventional PV sector using unpredictable MM connected Residential 22. 2018 Palestine Electrical system/MATLAB PV systems operating in Mahmoud and sector software islanded and grid-aﬃliated [44] standalone modes. The battery storage framework enables private dwellings to secure stable energy operations This paper brieﬂy PK Grid- discusses the modeling, 23. Bonthagorla, S 2020 — connected/ Load serving Electrical MATLAB/Simulink simulation, and Mikkili [45] standalone performance evaluation of hybrid and conventional International Journal of Photoenergy 7 Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type array conﬁgurations during diﬀerent PSCs in MATLAB/Simulink environment A fresh concept to active modeling and locked-loop Hybrid control of hybrid grid- M Salimi et al. 24. 2021 — grid- Load serving Electrical MATLAB/Simulink aﬃliated multi-input [46] connected multioutput (MIMO) renewable energy systems was addressed A hybrid system associated Grid- with the grid was connected described in the study. The M Dali et al. 25. 2010 — and Load serving Electrical Standalone inverter experimental ﬁndings [47] standalone show that the system can modes operate parallel to or independent of the grid A multiobjective optimization design Non-dominated accounted for lossy load MI Hlal et al. Oﬀ-grid or Load separating genetic likelihood (LLP), energy 26. 2019 Malaysia Electrical [48] standalone management algorithm (NSGA-II) cost (COE), price of method battery life loss, and cost of service, substitution, and repair. The study is based on the evaluation of economic KNB Akshai, Household Simulation software 27. 2020 — Standalone Electrical expenses of grid-aﬃliated R Senthil [49] electricity PVsyst and islanded photovoltaic systems using PVsyst This research proposes a hybrid system consisting of an array of photovoltaic S Odeh et al. (PV) and rechargeable 28. 2019 Palestinian Standalone Load serving Electrical PVsyst software [50] batteries integrated into the distribution grid to share loads with the grid system The research resolved the power grid stability and control problems. The PV J Kumar et al. Residential System advisor model grid system consists of an 29. 2020 — PV grid-tied Electrical [51] load serving (SAM) software 8.0 kW PV array and battery energy storage unit connected to the power grid over AC or DC links This study mainly explores the design features of a solar photovoltaic device based on a grid Grid- 30. J Kumar [52] 2020 — Island Electrical PVsyst software connection. The analysis connected sheds light on various subjects like creating Sankey energy loss diagrams, eﬃciency 8 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type proportion, and total photovoltaic plant capacity A water-pumping double- deck converter and inverter for a single-phase islanded PV system were ZB Duranay, Load Water investigated. The single- 31. H Guldemir 2019 — Standalone MATLAB/Simulink management pumping phase islanded PV system [53] was modeled using insolation and temperature values as simulation data The study was a technoeconomic evaluation of grid- aﬃliated residential construction applications photovoltaic (PV) systems. Y Cui et al. Grid- Domestic 32. 2020 — Electricity @risk software The system met the [54] connected building residential electricity demand from April to October and the 1530.23 kWh excess electricity was supplied to the grid The research developed grid-connected PV system sensitivity and reliability models. For PV cell and DC-DC converters, Pareto analysis and N Gupta et al. Grid- analytical relationships of 33. 2017 — Load serving Electrical logic gate [55] connected ﬁrst-order sensitivity are representations formed and the developed models can be implemented to any PV system for better performance For an islanded PV- battery energy storage (BES) hybrid device, a power management control strategy is suggested in the research. MP Bonkile, V The evaluation shows that Load Physics-based Single-particle model 34. Ramadesigan 2019 — Standalone the power management management battery (SPM) [56] design was successful and met many islanded PV- BES hybrid systems goals, without overcharging, no output excess power generation, and no power transfer to the dump load The research concept of this paper includes the SS Dheeban Load mathematical simulation 35. 2019 — Standalone Electrical MATLAB Simulink et al. [57] management of the solar panels and a battery backup study of the standalone unit International Journal of Photoenergy 9 Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type The emphasis of the research was on the eﬃciency of a grid- Performance ratio aﬃliated PV system in E (PR), yield factor (YF), Central Greece that was Roumpakias, Grid- reference yield (YR), 36. 2019 Greece Load serving Electrical operational for six years. A Stamatelos connected capacity factor (CF), The study indicates a [58] and an array to capture slight eﬃciency reduction losses (LC) over the years, which declined between 1 and 4 percent This research recommends Sub-maximum power a single-phase linear PV BR VS, GG 37. 2019 — Standalone Load serving Electrical point tracking (S- default scheduler system. Devadhas [59] MPPT) It initializes any device to zero in the shortest period The primary target of the research was to build a sun-based PV plant at two diverse campuses. The specialized feasibility used Photovoltaic the open rack or free stand N Manoj geographical mounting position Grid 38. Kumar et al. 2017 Malaysia Load serving Electrical information systems crystalline innovation- connected [60] (PVGIS) and Watts PV based PV plant utilizing software the PVGIS and PV Watts software. The specialized presentation acquired through PVGIS is very similar to the PV Watts results In the study, an instinctive control procedure dependent on ‘ﬁfth-order general integrator (FOGI)’ N Kumar et al. Grid- Fifth-order general 39. 2019 — Load serving Electrical was proposed for [61] connected integrator (FOGI) framework-associated sun-powered photovoltaic (PV) energy conversion system (SECS) The study assessed a hybrid renewable energy system linked to the power grid with 15000.0 kW daily load demand and YZ Alharthi Grid- 40. 2019 — Load serving Electrical HOMER 2395.3 kW peak load. The et al. [62] connected net present cost (NPC), levelized energy cost (LCOE), and system environmental eﬀects were examined The eﬃciency of a DC grid-aﬃliated PV device E Kurt et al. Grid- under insolation and 41. 2019 — Load serving Electrical PSCAD [63] connected temperature variations was investigated in the study. The DC-DC boost 10 International Journal of Photoenergy Table 1: Continued. S. Authors & Adopted Consumption Year Location Load type Method Objectives no. references technologies type converter was constructed to increase the system’s performance An optimal islanded irrigation solar PV battery system (BS) for Al Minya, Egypt, was used in the study paper. The energy H Rezk et al. 42. 2019 Egypt Standalone Irrigation Electrical HOMER costs obtained were lower [64] than those previously reported due to the correct selection of PV size and shape, as well as the correct selection of the site achieved by hybrid optimization model for electric renew- demand and supply [19]. Sustainable power sources to replace able (HOMER). At the selected sites, the technoeconomic fossil fuels have been prioritized throughout the world for feasibility of using hybrid photovoltaic/wind/diesel with bat- both economic and environmental reasons. The authors in tery storage systems to match the load of a typical rural [20, 21], conﬁrmed the feasibility of a stable standalone elec- healthcare center was evaluated. The system is based on tricity generation system for oﬀ-grid users using HOMER to long-term daily meteorological data ranging between 18 model, evaluate, and optimize sustainable power sources that and 39 years in this study. The ﬁndings of HOMER simula- replace traditional energy sources. Table 1 below summarizes tions show that the hybrid system is the best solution for all the successfully implemented researches made on a standa- of the study’s locations. Since the diesel-only system pro- lone, microgrid, and grid-connected solar systems in diﬀerent vides the highest COE and emits CO2, the hybrid systems parts of the world and their results prove to be viable. involving PV/diesel/battery are considered ideal for RHC This study gives a complete comparison of the state-of- at remote locations within Iseyin and Port-Harcourt, due the-art deterministic methodology to build a minigrid, to the quality of renewable energy potential [15]. including the inﬂuence of operating strategies to provide Fossil fuels like oil and gas are still playing a role in energy recommendations on conceptual models and operating generation though people are now considering an alternative strategies to researchers, developers, and professionals in that provides energy demand by reducing it via energy eﬃ- the ﬁeld. The standalone like, home lighting system (HLS) ciency and environment-friendly use of that energy resources. requires no major maintenance, and consumers could use Since transport consumes a lot of conventional energy and it without being subjected to any inﬂuences, whereas mini- generates greenhouse gases, therefore, the proposed measure grids are administered by cooperative societies founded by to alter this issue is to use electric transportation. The HOMER local governments and beneﬁciaries. In order to provide program was used in this study [16] to develop and optimize a minigrid services in underdeveloped countries, it is neces- wind-solar hybrid energy charging station that will be beneﬁ- sary to establish an appropriate business strategy. The com- cial for supplying power from renewable resources eﬀectively parison as explained in literature, and Table 1 below was and sustainably, managing grid load, and establishing addi- mainly based on consumer characteristics, net present cost, tional charging stations. and the cost of energy, where it will depend on the quantity PV systems have used distributed microgrids as eﬃcient of the consumer as well as the diﬀerent components avail- local electricity sources in regulated environments for energy able to be used in each household. Therefore, the result of consumers and inexhaustible energy generation. The global the method adopted in our research compared to the elec- deployment of PV microgrids has expanded while taking tricity tariﬀ in Rwanda is much more viable. the beneﬁt of daily unrestricted solar insolation. In Rwanda, HOMER is particularly well suited to assessing prospective the average daily solar irradiation is between 4.0 and electricity possibilities in rural areas, as well as investigating 5.0 kWh/m the technical and economical eﬀectiveness of hybrids provided /day [17]. The highest solar radiation for the selected site is seen in July where the value is a village load and energy resource availability. Therefore, this 5.87 kWh/m /day. Energy storage has been proposed, with means diﬀerent areas with diﬀerent solar resources will pro- the backup used during peak demand, power shortages, vide diﬀerent output solar powers where a minigrid supply blackouts, or some other power loss in grid-connected sys- system is being proposed for rural electriﬁcation programs. tems. Global studies show that the world’s total implemented When the obtained energy costs were compared to the exist- photovoltaic capacity has been steadily increasing [18]. ing, current costs of electricity in Rwanda, it was discovered Rwanda is educating private investors on how to implement that this was the most cost-eﬀective option. Previously, the solar energy projects and narrow the gap between electricity solar home system was a simple choice, which included the International Journal of Photoenergy 11 Site visit and data collection Cost parameter of PV Location of RE activity Solar data (initial capital, replacement, O&M) Cost parameter of batteries Load profile Power plant components (initial capital, replacement, O&M) Cost parameter of inverter Transmission and Available resources (initial capital, replacement, distribution system O&M) Selecting renewable System lifetime Concept of system constraint energy technology Simulation results and evaluation Electrical energy evaluation Economic evaluation Generation Consumption Net present cost Cost of energy Figure 1: Illustration of the framework for analysis of the study. Abbreviations: RE: renewable energy; O&M: operation and maintenance. System profile System analysis Results Optimal sizing Load components Sensitivity analysis Net present cost Battery storage • Cost of Optimization energy • Capital Converter module cost Simulation • Capacity shortage System module • Renewable Energy balance energy fraction System control, constraints Fuel consumption Figure 2: A detailed schematic representation of HOMER software. implementation of PV panels, batteries, charge controllers, causing market distortions, and necessitating research pro- and inverter units for every residence and business structure jects for new electric power plants. in the village that used roof areas [22]. The methodology of this study is depicted in Figure 1 below. All of the study requirements were conducted based on our team’s site visits and data collection. The data collected 3. Methodology include electricity load demand proﬁle, available resources, power plant production capacity, solar power plant compo- HOMER software analyzed the data gathered from govern- nents, and constraints. HOMER software performed the tech- noeconomic analyses in this research. The purpose of these mental energy organizations considering diﬀerent photovol- taic systems uses in Rwanda’s rural settlements [65]. technical and economic analyses was to develop a practicable oﬀ-grid photovoltaic system that would suit Rwanda’spower HOMER software created a variety of models that demon- sector at lower tariﬀs and maximum availability. strate how diﬀerent natural sustainable energy sources com- bine to produce green power in this study. In addition, we started working with power plant owners and operators 3.1. HOMER Pro Software. The HOMER Pro microgrid soft- throughout the research to ensure the study’s reliability. ware is the world’s standard software for optimizing micro- According to these experts, relevant guidelines for the rural grids, from community power and islet utility services to electriﬁcation planning process are lacking, posing risks, grid-aﬃliated sites, and army assets [65]. Figure 2 presents 12 International Journal of Photoenergy W E RWANDA AFRICA W E 0 30 60 Kilometers W E MUKUNGU Figure 3: Location map of the selected study area (Mukungu village). 6 0.7 a schematic representation of the HOMER software. Imita- tion, optimization, and sensitivity analysis are the three pri- 0.6 mary functions of HOMER. It can strengthen power balance 0.5 measurements, load proﬁling, location-speciﬁc tools, and 0.4 system components are all factors taken into consideration 0.3 by HOMER. 0.2 HOMER simulates feasible systems with device conﬁgu- 0.1 rations in the simulation model. After each simulation, there 0 0 is an optimization step. To achieve the best possible match, 123456789 10 11 12 all imitated systems are categorized and reﬁned according Month to speciﬁed parameters. Sensitivity analysis, on the other Daily radiation (kwh/m /day) hand, is an optional function that allows HOMER users to Clearness index model resource variables that are outside their control, like fuel prices and wind speeds. As a result, researchers can Figure 4: Solar energy proﬁle at the preferred site. see how the ideal system changes because of these modiﬁca- tions [66]. The optimization ellipsoid encircles the simula- tion ellipsoid, showing that an imitation consists of several simulations. The sensitivity analysis ellipsoid, encircles the consumption of people living in Rwanda’soﬀ-grid areas optimization ellipsoid, as in Figure 2. was calculated, as well as the energy needs of each house. As a result, this investigation is aimed at approximating 3.2. Data Collection. In this survey, data were collected consumer requests, which is a prerequisite for designing from 121 households in four Rwandan provinces, exclud- a power plant. ing Kigali city, using a specially designed questionnaire. Oﬀ-grid solar power deployment necessitates a year’s Residents in the area were asked a series of questions as worth of solar irradiation. The National Aeronautics and part of this study. The data were then summarized and Space Administration provided the input data for solar analyzed using the Statistical Package for the Social Sci- resources over a year in this case (NASA). Other data from ences (SPSS version 23.0). Consequently, the total energy the Rwanda Meteorology Agency was obtained and Daily radiation (kwh/m /day) Clearness index International Journal of Photoenergy 13 Table 2: The projected everyday electricity demand for 121 houses in the village. Equipment in 121 No. in Power consumption Total power consumption Hours of use/day (Hrs/ Watt-hours/ No. households use (W) (W) day) day 1 Lamps 891 10.0 8910.0 5.0 44550.0 2 Mobile phone 335 10.0 3350.0 8.0 26800.0 3 Ceiling fan 0 75.0 0.0 0.0 0.0 4 Radio 113 20.0 2260.0 5.0 11300.0 5 Television 49 120.0 5880.0 5.0 29400.0 6 Computer 4 100.0 400.0 5.0 2000.0 7 Refrigerator 5 500.0 2500.0 24.0 60000.0 8 Iron 19 1000.0 19000.0 1.0 19000.0 193,050.0 Watt-hours/day = Daily total energy consumption in 121 households 193.05kWh/day Abbreviations: W: Watt; kWh: kilowatt-hour; Hrs: hours. The temperature power coeﬃcient is zero if the temper- compared to NASA’s data to ensure that the solar resource data obtained was correct. All these data were accurate, ature eﬀects on the PV array are not modeled by HOMER and they satisfy the requirement to be used in our study. software. Equation (1) becomes [65] Finally, the obtained data helped us to evaluate and verify the integration of solar power systems into Rwanda’s power P = Y f : ð2Þ PV PV PV system. T,STC 3.3. Selected Site. Rwanda’s government had approved a rural electriﬁcation strategy in the termination of 2016, On the other hand, HOMER can deﬁne the monthly average clearness index K using the following [65]: in which the government, private industry, and relevant stakeholders collaborated to signiﬁcantly boost rural elec- triﬁcation and establish lofty potential targets. Thus, in H ave K = , ð3Þ Rwanda’s rural areas, pico/minihydropower, and minigrids o,ave from solar energy have been successfully implemented [67]. Mukungu village located in the Karongi District of where Y is the PV array rated capacity (kW), f is the PV PV PV Rwanda’s Western province was chosen for this study, discounting factor (%), G is the PV array incident solar ° ° ′ ′ with GPS coordinates of S 02 13.9310 and E 29 24.590 . 2 irradiation (kW/m ), G is the emitted radiation under T,STC In addition, the details of the chosen village location are normal assessment conditions (1 kW/m ), α is the temper- shown in Figure 3. This village has a picohydropower ature power coeﬃcient (%/ C), T is the PV cell temperature plant that provides energy to up to 400 households in ( C), T is the PV cell temperature standard test condi- c,STC the oﬀ-grid region, promoting economic development. tions (at 25 C); H is the normal monthly irradiation from ave Solar energy, fortunately, can also be used as an alternative the earth (kWh/m /day); and H is the extraterrestrial o,ave energy source in this situation. horizontal insolation (kWh/m /day). 3.4. Solar Resource Availability Evaluation. HOMER utilizes 3.5. Load Details of the Selected Site. All types of electrical four renewable energy sources: biomass, hydro, solar, and appliances at home, as well as the time that the appliances wind, as well as other fuels that the system’s equipment are used by the residents, determine energy consumption requires [65, 66]. Rwanda has abundant renewable energy [68]. The estimated load was determined in this study based resources, and it is attempting to electrify Rwanda’soﬀ- on a survey directed at various communities across the grid villages. The Mukungu village solar resources were country. Experienced judges tested a series of the developed extracted from the surface meteorology and solar website questionnaires for validity and used them to gather energy of NASA. The solar energy proﬁle at the preferred study site consumption data from respondents. Representatives from is depicted in Figure 4. 121 households completed the questionnaires about their Generally, the PV array’s power output is determined by household electrical devices and monthly power consump- the angle of incidence of the solar radiation on the earth. tion pattern in the research. Table 1 shows the summary of HOMER calculates the PV array output in Equation (1) results obtained through analysis of other studies and their below [65]: input data. The daily energy demand of 121 homes, as well as their respective power ratings, are shown in Table 2. The electricity demand in remote areas is lower than in P = Y f ½ 1+ αðÞ T − T : ð1Þ PV PV P c c,STC PV T,STC cities, according to a comprehensive energy consumption 14 International Journal of Photoenergy Daily profile Seasonal profile 0 3 6 9 12 15 18 21 Yearly profile 24 14 kW 11 kW 8.4 kW 5.6 kW 2.8 kW 0 kW 90 180 1 270 365 Day of year (a) Daily profile Seasonal profile 15 20 0 36 912 15 18 21 Yearly profile 20 kW 16 kW 12 kW 8.0 kW 4.0 kW 0 0 kW 90 180 1 270 365 Day of year (b) Figure 5: The daily, seasonal, and yearly load proﬁles: (a) electric load for the distinct oﬀ-grid household and (b) electric load for microgrids for a rural community in an oﬀ-grid area. survey conducted in Rwanda. Household appliances that use (iii) The project’s lifespan was decided based on the electricity include radios, light bulbs, mobile phones, ceiling component warranty, which was estimated to be fans, electric irons, refrigerators, and laptops. Within each around 25 years. The load proﬁle used in this survey hour of the year, we must measure the sum of primary load during imitation is shown in Figure 5 in kilowatts using HOMER, either by importing hourly data from a ﬁle or by permitting HOMER to create hourly data 3.6. System Design Components. We used various compo- from typical everyday load proﬁles. Consequently, HOMER nents in this research depending on the photovoltaic systems generates typical load results depending on the consumer’s we needed to simulate. Photovoltaic solar was the resource features of everyday load [65]. The photovoltaic systems in the HOMER analysis. In addition, electricity is stored were designed, and their performance was evaluated in this and converted using batteries and a converter. The eﬃciency study, taking into account the following suppositions: and cost of each of the system’s components have a signiﬁ- cant impact on the design outcomes. Data from Rwandan (i) 193.05 kWh per day is the primary load, and generating companies and private sector companies’ mini- 20.64 kW peak load was assumed for an outside- grid remote grids, as well as existing literature, were used grid PV microgrid for the rural society (121 to develop the study’s technical and cost parameters. households) Tables 2 and 3 show the performance and cost of each com- (ii) The prime load of 1.6 kWh per day and 0.30 kW ponent for an islanded PV system for a single home and an peak load were assumed for a remote grid solar outside-grid PV microgrid for a remote neighborhood, PV microgrid system in the rural community respectively. Hour of day kW Hour of day kW kW kW Jan Feb Jan Mar Feb Mar Apr Apr May May Jun Jun Jul Jul Aug Aug Sep Sep Oct Oct Nov Nov Dec Dec International Journal of Photoenergy 15 Table 3: System elements and their costs for an islanded PV of an individual home. Rated Capital cost Replacement cost O&M cost/year Lifetime No. Component capacity (USD) (USD) (USD) (years) 1 Converter (system converter) 1.0 kW 3000.00 2500.00 800.00 15 Batteries (generic 1.0 kWh lead 2 1.0 kWh each 300.00 2,00.00 40.00 10 acid) 3 PV (generic ﬂat plate) 1.0 kW 1500.00 1100.00 40.00 25 3.7. Design and Modeling of Selected PV Systems in Rwanda. imitate, and process available inexhaustible power genera- Rwanda has a large number of untapped renewable energy tion technologies to ensure everyone in Rwanda has access source sites. Electricity is generated using hydro, solar, meth- to sustainable energy. Importantly, several site visits to a del- ane, peat, geothermal, wind, and waste energy. According to egate of selected residential houses in Rutsiro district, West- Rwanda’s Environmental Management Agency (REMA) ern province, Rwanda, were made to design standalone solar Outlook report from 2007, there are approximately photovoltaic systems, eﬃciently. Moreover, the electrical 1200 MW of untapped power generation resources in devices, power rating, and hours of use variables were used Rwanda [67]. Unfortunately, so many of these resources during the studies. remain unexplored. Rwanda’s gross electricity generation The sketch of the islanded remote grid photovoltaic sys- was just 224.6 MW in 2019 [67]. tem for an individual household is shown in Figure 6(a). The HOMER is a sophisticated numerical modeling frame- distinct islanded solar home system, comprises the PV panel, work that oﬀers much more details than traditional statistical batteries storage, converter, DC, and AC buses, and electric modelers. It can perform imitation and responsiveness analy- load. As shown in Figure 6, the total load proﬁle was sis with modest data [69]. Better designs are produced for 1.6 kWh/day and 0.30 kW daily peak load. The estimated daily energy consumption for 121 residential houses in the likely inputs using net present cost (NPC), which is cost- eﬀective. In addition, it generates power balance equations village was 193.05 kWh/day, as demonstrated in Table 2 for every one of the 8760 hours annually, to simulate network above. So, the daily energy load average for one residential operations. Consequently, it helps to determine viable conﬁg- house in an oﬀ-grid area can be easily estimated to be urations and approximate the installation cost and implemen- 1.6 kWh/day per residential house. tation of the power system over the project’s life [69–71]. Previous researchers and experts in renewable energy HOMER computes the average annualized cost for every and minigrids or microgrids have provided insights on what item utilizing diversiﬁed costs and penalties for device pollut- hybrid systems are, why we need them, their uses, and appli- ants. This value is also used to calculate the overall net present cations for sustainable energy development. According to cost and the levelized energy cost (LCOE or COE) [65]. In the previous surveys and the outcome of this study, standa- HOMER software, the NPC can be evaluated using [65, 66] lone systems for one single household and a community are the ﬁrst-choice decision to be made while they may not be cost-eﬀective. iðÞ 1+ i CRF i, N = , ð4Þ ðÞ ðÞ 1+ i − 1 3.7.2. Oﬀ-Grid PV Microgrid System for Rural Community. The microgrid is important to intelligent power systems where i is the yearly actual interest rate and N is the dura- for increasing the distribution system’s energy supply reli- tion (years). Also, Equation (5) assesses the levelized energy ability and resilience. A microgrid is an interconnected col- cost [65, 66]: lection of distributed energy and demand entities that function in either grid-connected or island mode within ann,tot the network. Microgrids comprise small cell phone towers COE = ð5Þ E + E + E prim def grid,sales (as well as nanogrids), large commercial, industrial, and mil- itary facilities with generation capacities ranging from kilo- where C is the overall annualized cost, E and E watts to megawatts [72–75]. ann,tot prim def During our study, Figure 6(b) is the representation of the are the yearly overall basic and postponed load, respectively, oﬀ-grid solar photovoltaic microgrid system for rural areas. and E is the yearly power grid sales. grid,sales The average daily load for that rural area was 193.05 kWh 3.7.1. Standalone Solar Photovoltaic for a Single Residential per day and a daily 20.64 kW peak (for 121 households). In addition, the photovoltaic system provides DC, while the House. First and foremost, those who are unable to connect to and be assisted by the publicly or privately owned utility converter transforms DC to AC and vice versa, which is sup- plied to the battery storage facility. Undeniably, research on grids are known as “oﬀ-grid users” [6]. As a result, standalone PV, minigrids, and microgrids various conﬁgurations or architectures of microgrid systems can be used to provide electricity to such users. As previ- is gaining more attention to achieve the goals of carbon emission reduction. ously stated, this part used HOMER Pro software to design, 16 International Journal of Photoenergy AC DC AC DC Electrical load PV Electrical load PV 193.05 kW h/d 1.60 kWh/d 20.64 kW peak 0.30 kW peak Converter 1 kWh LA Converter 1 kWh LA (a) (b) Figure 6: Various types of photovoltaic solar systems: (a) the standalone photovoltaic for a single residential household and (b) the PV microgrid system for the rural community in the oﬀ-grid area. Table 4: Comparative simulation analysis for the proposed PV systems (we did not consider the sensitivity variables). Cost summaries Electricity production (kWh per year) Resource System architectures Total NPC LCOE (USD/ Operating cost (USD per (portion) (USD) kWh) year) Standalone (1 Solar 2426.0 9284.4 1.23 428.08 household) Microgrid Solar 221,715.0 1,166,898.0 1.28 37,965.91 (community) 4. Simulation and Optimization Results Using comprises 1.64 kW PV, 3 strings of batteries, and 0.262 kW of a system converter. The total operating cost and NPC Homer Pro Software for such photovoltaic systems are USD 428.08 and USD 9284.41 per year, respectively. HOMER’s micropower optimization model was used to pro- In contrast, the oﬀ-grid PV microgrid system for rural cess the modeling and simulation results. For each respon- communities has shown a high LCOE compared to the stan- siveness case it solves, HOMER imitates each system in the dalone PV for an individual household. It generates search space and rates all practicable systems in order of 221,715.0 kWh total yearly production and comprises decreasing net present cost. HOMER optimizes small power 150.0 kW PV, 443 strings of batteries, and 20.8 kW of system systems by simulating a variety of device options under dif- converter. For this photovoltaic system, the total NPC, ferent restrictions and stimuli. These systems are compared LCOE, and operating costs were also USD 1,166,898.00, using optimization tables. The optimization table contains USD 1.28 per kWh, and USD 37,965.91 per year, respec- information about each system’s architecture, such as the tively. In addition, PV output power and batteries’ charge number of batteries, converter size, and PV capacity. It also state (SOC) of the simulated photovoltaic systems are graph- includes information on costs like the levelized energy cost ically illustrated in Figure 7 below, where (a) is an islanded (LCOE), net present cost (NPC), running costs, preliminary solar PV system for a dwelling house and (b) is a PV micro- capital, and clean energy proportion. Also, two solar energy grid system for a remote neighborhood in the oﬀ-grid area. systems were designed in this research using a large number Because access to electricity is a key driver of develop- of hourly parameters in the HOMER software simulation. ment and welfare, Rwanda’s government has set a goal of The simulations and analyses took into account a variety providing electricity to 100 percent of all the population by of solar radiation values. Without taking into account the 2024. Rwanda has future prosperity of renewable resources, sensitivity variables, Table 4 illustrates the imitation and including wind, solar, geothermal, hydro, and methane gas, processing of two dissimilar remote grid solar PV for the all of which should be explored before making any decisions. selected survey site. This will undoubtedly encourage development projects, The simulation in this study considered diﬀerent photo- bringing the total capacity of electricity generation to voltaic systems. As illustrated in Table 5 above, the mini- 556.0 MW by 2024. Unquestionably, the ﬁndings of this mum levelized cost of energy (LCOE) found from the study show that for oﬀ-grid users, small solar standalone simulation results was USD 1.23 per kWh for a standalone systems for individual households are preferable because photovoltaic for an individual household. This standalone they can start providing energy more rapidly at a low price. system generates 2426 kWh total yearly production and International Journal of Photoenergy 17 Table 5: Structure items and their expense for oﬀ-grid PV microgrid systems for the rural community. Rated Capital cost Replacement cost O&M cost/year Lifetime No. Component capacity (USD) (USD) (USD) (years) 1 Converter (system converter) 10.0 kW 21,164.00 16,000.00 8000.00 15 Batteries (generic 1 kWh lead 2 1.0 kWh each 1702.00 1000.00 60.00 10 acid) 3 PV (generic ﬂat plate) 10.0 kW 18,500.00 15,000.00 20.00 25 PV power output 1.6 kW 1.3 kW 0.96 kW 0.64 kW 0.32 kW 0 kW 90 180 270 365 Day of year State of charge (SoC) 24 100% 88% 76% 64% 52% 40% 90 180 270 365 Day of year (a) PV power output 24 160 kW 128 kW 96 kW 64 kW 32 kW 0 kW 90 180 270 365 Day of year State of charge (SoC) 100% 88% 76% 64% 52% 40% 90 180 1 270 365 Day of year (b) Figure 7: PV power output and SOC of the simulated solar photovoltaic systems: (a) the standalone photovoltaic for a single residential house and (b) the oﬀ-grid solar photovoltaic microgrid system for the rural community. Hour of day Hour of day Hour of day Hour of day 18 International Journal of Photoenergy renewable resource availability, technological cost, and per- 5. Discussion formance which cause output power unstable. HOMER The electricity prices is constantly increasing due to the assesses diﬀerent designs using the levelized cost of electric- ity (LCOE), but it cannot assess diﬀerent ﬁnancial world’s fast growing population that needs access to sustain- able electricity to sustain modern life expectancy. In Sub- models [84]. Saharan Africa (SSA), for example, people living without Rural areas’ big issue is lacking consumer demand den- access energy remain a determining factor that contributes sity and generally consists of low-income groups; therefore, to persistent poverty [5]. In this area, urban communities project rate of return on investment is diﬃcult to achieve as planned. High costs, low energy eﬃciency, and a lack of are still served by ineﬃcient and unstable networks, while rural areas still lack access to electricity, except for power suitable rules and information are among issues that PV sys- given to fairly wealthy households by small/private genera- tems confront [85]. Unlike consumers in developed coun- tors. Using fossil fuels to produce energy has long been tries who can aﬀord the high upfront costs of installing regarded as unappealing due to the release of hothouse gases solar panels on their roofs to produce electricity, the number of Africans in stricken need of solar power cannot accom- into the environment that raises the overall carbon trail. The latter encompasses disastrous consequences including modate such an investment, despite the fact that solar power increased global warming as well as its related consequences has a positive economic and environmental case. The global [76, 77]. solar market is controlled by industrialized countries such as In the current era of accelerated development and glob- China, Europe, and the United States, making it diﬃcult for industry knowledge and skills to spread to local businesses. alization, countries all over the world are looking at the low-cost PV systems to replace their existing power genera- The state’s taxes and regulations have made solar-powered tion mix to ensure the reliability, aﬀordability, and sustain- town electriﬁcation prohibitively expensive [86]. Because ability of potential power systems [78]. In fact, most system functioning necessitates real-time measurements of governments have made renewable energy production a solar irradiation and ambient temperature data, the data col- lected is limited due to ﬂaws in the measuring equipment top priority, not only to minimize their overall carbon emis- sions and achieve international climate targets but also to [14]. Because minigrid payback times can easily exceed sev- gain wider socioeconomic beneﬁts. And as per the Interna- eral years, providing a regulatory environment that includes tional Energy Agency, 1.3 billion people everywhere in the valid agreements or subsidies is necessary to limit risks for world cannot have access to reliable electricity, particularly investors [87]. Long-term ﬁnancing for minigrid projects is frequently diﬃcult to come through due to inﬂation is either in the countryside of the developing world where the expan- sion of the utility grid is exceptionally diﬃcult [79]. With high or uncertain [88]. distributed and independent control solutions, the microgrid Challenges regarding policies are as follows: The neces- sity of policy support for oﬀ-grid electricity is critical where model has conﬁrmed to be one of the most realistic solutions that could be used to distribute inexhaustible energy sources mostly there is no long-term electriﬁcation strategy [89]. (DRES) and can mitigate the perceived complications of Licensing challenges are as follows: Retail or generation deployment with increased stability with natural catastro- licensing procedures that are complicated, costly, and time- phes, physical/cyberattacks, and cascading power black- consuming deter investors and businesses from starting outs [80]. minigrid initiatives [90]. Tariﬀ setting challenges are as fol- To date, conventional energy resources cannot provide lows: Tariﬀ design conﬂict is exacerbated by the fact that, enough energy to meet the demand and are generally not envi- in comparison to cheaper grid-based electricity, oﬀ-grid sys- ronmentally friendly. Solving this problem of the energy gap, tem developers must charge signiﬁcantly higher tariﬀsto solar energy can yield an adequate solution [81]. However, meet investment and operating costs [91]. The challenges due to every site requirement, they provide unpredictable are shown in Table 6. power generation. Renewable energy presents a challenge of The construction of a distributed power generation plant power quality, reliability, power system stability, and reactive with a transmission and distribution systems for the gener- power compensation. The intermittent nature of renewable ated power is typically the most cost-eﬀective solution in iso- energy like the solar, wind is less predictable and time- lated areas where grid expansion are considered expensive. variant. The inﬂuence of dust on PV panels in the UAE was Solar energy is an especially appealing renewable choice for researched, and it was discovered that after 5 weeks of outside most of the African countries because it is decentralized, exposure, there was a 10% drop in power production [82]. Due abundant, and cost-eﬀective as technology progresses. It is to its stochastic and random character, renewable energy sys- also resistant to supply and price swings while it remains tems pose substantial issues to traditional grids, such as fre- equally qualiﬁed for funding from mutual and multinational quency variation, voltage ﬂuctuation, and harmonics. organizations aiming to increase the renewable energy out- The low eﬃciency and unreliability of PV systems [83] puts in these countries. This is accomplished by inexhaust- are the most serious challenges. This article’s technoeco- ible energy sources available as well as the introduction of nomic model simulates minigrid, microgrid performance microgrids/standalone systems as ideal solutions to rural utilizing meteorological data, demand proﬁles, technology electriﬁcation problems in developing nations. In particular, capabilities, and pricing data to identify the ideal component microgrids, standalone remote-grid systems are suitable for sizing of hybrid minigrids for rural electriﬁcation. The ﬁnd- oﬀ-grid lighting because they minimize device costs by com- ings show how system sizing is inﬂuenced by location, bining streetlight storage and using pole-mounted solar PV International Journal of Photoenergy 19 Table 6: Challenges of oﬀ-grid electriﬁcation in a nutshell. Licensing Policies Tariﬀ Financial Technical Social setting Minor projects There are no When dimensioning, there No energy access plan Minigrids economic Licenses are are ignored by community-based is no consideration for identiﬁes oﬀ-grid areas feasibility is under doubt expensive ﬁnancing educational future need programs initiatives Licensing is a There are not There is no long-term Tariﬀs are too high for time-consuming Programs for Technical standards are enough examples electriﬁcation plan in rural populations to and short-term inadequate of productive use place sustain complicated funding scenarios process Regulations that are only There is no Fiscal Components that are in eﬀect for a short period There is no suitable diﬀerentiation incentives are mismatched with the of time and are subject to payment method made between not available environment change project sizes The rate of External stakeholders are Tariﬀ criteria are strict, There is no monitoring There was no return on not involved in the and there is no mechanism in place, and community input investment is collaboration because it is distinction between there are no responsible, throughout the predicted to done in isolation comprehensive ﬁnancial certiﬁed employees planning stage below In minigrid initiatives, There are not enough There is not Initial there is no clear restrictions in place to enough technical investment description of stakeholder assure dependable expertise to hire costs are high duties operation and maintenance local workers for both charging batteries and distributed generation. These USD 428.08 per year, respectively. This is also evidenced by technologies ensure a critical position in meeting the global our results in Table 5. energy demands, and they are more than capable of provid- Consistent with the aforementioned, not only could ing power in a more eﬀective, safe, secure, and updated standalone PV power systems be the ideal solution to the manner. electriﬁcation of rural areas in Rwanda but also these sys- The use of standalone solar PV systems can provide sig- tems could help the government and environmental agen- niﬁcant energy and environmental beneﬁts over grid- cies in the eﬀorts to minimize weather-related problems connected solar PV systems. In communities with tradi- and stir up the development of green energy systems as the tional energy and the greatest solar capacity, standalone country strives to provide reliable and sustainable energy solar PV systems present the strongest air pollution control to all its citizens. It is also believed that the proposed standa- beneﬁts. In fact, the solar rooftop provides environmental lone solar PV system would equally contribute to the devel- beneﬁts by replacing traditional (conventional) grid electric- opment of future renewable energy generation systems in ity. The standalone and microgrid systems simulated in this other countries with similar environmental, climate, paper have provided best results; however, due to ﬁnancial weather, and meteorological conditions around the world. instability of most of the Sub-Saharan countries, a standa- In particular, neighboring countries such as Burundi, Dem- lone PV system proves to be more viable to those scattered ocratic Republic of Congo (DRC), Tanzania, and Uganda, households. and all other countries in the region are estimated to be good candidates for such a system. 6. Conclusion Data Availability Limited access to energy slows down the development and makes it harder for governments and people to establish The data used to support the ﬁndings of this study are avail- growth targets. In this study, we designed and simulated able from the corresponding author upon request. oﬀ-grid PV power systems to provide electricity to a Rwan- dan remote county using HOMER software. Simulation Conflicts of Interest results revealed that an islanded PV system for a dwelling home is the ideal oﬀ-grid power generation system for use The authors declare that they have no conﬂicts of interest. in rural areas. The system is particularly cost-eﬀective com- pared with a microgrid PV system that supplies electricity to References a rural community in Rwanda. Results indicate that the total NPC, LCOE, and operating costs of a standalone energy sys- [1] N. U. Blum, R. Sryantoro Wakeling, and T. S. Schmidt, “Rural tem are estimated to USD 9284.40, USD 1.23 per kWh, and electriﬁcation through village grids–Assessing the cost 20 International Journal of Photoenergy [17] T. I. J. de Dieu Uwisengeyimana and A. Teke, “Current over- competitiveness of isolated renewable energy technologies in Indonesia,” Renewable and Sustainable Energy Reviews, view of renewable energy resources in Rwanda,” The Journal vol. 22, pp. 482–496, 2013. of Energy and Natural Resources, vol. 5, no. 6, pp. 92–97, 2016. [2] S. Szabó, K. Bódis, T. Huld, and M. Moner-Girona, “Energy [18] J. Dong, M. M. Olama, T. Kuruganti et al., “Novel stochastic methods to predict short-term solar radiation and photovol- solutions in rural Africa: mapping electriﬁcation costs of dis- tributed solar and diesel generation versus grid extension,” taic power,” Renewable Energy, vol. 145, pp. 333–346, 2020. Environmental Research Letters, vol. 6, no. 3, p. 034002, 2011. [19] J. D. Dieu Niyonteze, F. Zou, G. N. Osarumwense Asemota, [3] J. P. Murenzi and T. S. Ustun, “The case for microgrids in elec- and S. Bimenyimana, “Solar-powered mini-grids and smart metering systems , the solution to Rwanda energy crisis,” trifying Sub-Saharan Africa,” in IREC2015 The Sixth Interna- tional Renewable Energy Congress, Sousse, Tunisia, March 2015. vol. 1311, p. 012002, 2019. [20] A. R. Gautam, K. Gourav, J. M. Guerrero, and D. M. Fulwani, [4] P. Buchana and T. S. Ustun, “The role of microgrids & renew- able energy in addressing Sub-Saharan Africa’s current and “Ripple mitigation with improved line-load transients response in a two-stage DC-DC-AC converter: adaptive SMC future energy needs,” in IREC2015 The Sixth International Renewable Energy Congress, Sousse, Tunisia, March 2015. approach,” IEEE Transactions on Industrial Electronics, vol. 65, no. 4, pp. 3125–3135, 2018. [5] U. Deichmann, C. Meisner, S. Murray, and D. Wheeler, “The economics of renewable energy expansion in rural Sub- [21] D. Kumar Lal, B. Bhusan Dash, and A. K. AkellaOptimization of PV/wind/micro-hydro/diesel hybrid power system in Saharan Africa,” Energy Policy, vol. 39, no. 1, pp. 215–227, 2011. HOMER for the study area,” International Journal on Electrical [6] S. Bimenyimana, G. N. O. Asemota, J. D. D. Niyonteze, Engineering and Informatics,vol. 3,no.3, pp. 307–325, 2011. C. Nsengimana, P. J. Ihirwe, and L. Li, “Photovoltaic solar technologies: solution to aﬀordable, sustainable, and reliable [22] N. Hagumimana, J. Zheng, G. N. O. Asemota et al., “Concen- trated solar power and photovoltaic systems: a new approach energy access for all in Rwanda,” International Journal of Photoenergy, vol. 2019, Article ID 5984206, 29 pages, 2019. to boost sustainable energy for all (Se4all) in Rwanda,” Inter- national Journal of Photoenergy, vol. 2021, Article ID [7] S. Rehman and L. M. al-Hadhrami, “Study of a solar PV- 5515513, 32 pages, 2021. diesel-battery hybrid power system for a remotely located pop- [23] M. K. Deshmukh and A. B. Singh, “Modeling of Energy Perfor- ulation near Rafha, Saudi Arabia,” Energy, vol. 35, no. 12, pp. 4986–4995, 2010. mance of Stand-Alone SPV System Using HOMER Pro,” Energy Procedia, vol. 156, pp. 90–94, 2019. [8] A. O. Adewuyi and O. B. Awodumi, “Renewable and non- renewable energy-growth-emissions linkages: review of [24] O. A. Controller-in-loop, A hybrid PV-battery system for on- grid and oﬀ-grid applications—controller-in-loop simulation emerging trends with policy implications,” Renewable and Sus- validation. tainable Energy Reviews, vol. 69, pp. 275–291, 2017. [25] C. Marino, A. Nucara, M. F. Panzera, M. Pietrafesa, and [9] U. Sureshkumar, P. S. Manoharan, and A. P. S. Ramalakshmi, A. Pudano, “Economic comparison between a stand-alone “Economic cost analysis of hybrid renewable energy system and a grid connected PV system vs. grid distance,” Energies, using HOMER,” in IEEE-International Conf. Adv. Eng. Sci. vol. 13, no. 15, p. 3846, 2020. Manag. ICAESM-2012, vol. 8, pp. 94–99, 2012. [26] M. Hafeez, M. Hariri, M. Khairunaz, M. Desa, and S. Masri, [10] S. Bahramara, “Optimal planning of hybrid renewable energy Grid-connected PV generation, vol. 2040, 2020. systems using HOMER: a review,” Renewable and Sustainable Energy Reviews, vol. 62, pp. 609–620, 2016. [27] F. A. Alturki and E. M. Awwad, “Sizing and cost minimization of standalone hybrid WT/PV/biomass/pump-hydro storage- [11] D. Toke, “Renewable ﬁnancial support systems and cost-eﬀec- based energy systems,” Energies, vol. 14, no. 2, p. 489, 2021. tiveness,” Journal of Cleaner Production, vol. 15, no. 3, pp. 280–287, 2007. [28] T. Wu, H. Zhang, and L. Shang, “Optimal sizing of a grid- connected hybrid renewable energy systems considering [12] L. Olatomiwa, R. Blanchard, S. Mekhilef, and D. Akinyele, hydroelectric storage,” Energy Sources, Part A: Recovery, Utili- “Hybrid renewable energy supply for rural healthcare facilities: zation, and Environmental Eﬀects, pp. 1–17, 2020. an approach to quality healthcare delivery,” Sustainable Energy Technologies and Assessments, vol. 30, pp. 121–138, 2018. [29] B. E. Türkay and A. Y. Telli, “Economic analysis of standalone and grid connected hybrid energy systems,” Renewable Energy, [13] M. Hossain, S. Mekhilef, and L. Olatomiwa, “Performance vol. 36, no. 7, pp. 1931–1943, 2011. evaluation of a stand-alone PV-wind-diesel-battery hybrid system feasible for a large resort center in South China Sea, [30] D. Mazzeo, N. Matera, P. de Luca, C. Baglivo, P. Maria Con- Malaysia,” Sustainable Cities and Society, vol. 28, pp. 358– gedo, and G. Oliveti, “Worldwide geographical mapping and 366, 2017. optimization of stand-alone and grid- connected hybrid renew- able system techno-economic performance across Koppen- Gei- [14] L. M. Halabi, S. Mekhilef, L. Olatomiwa, and J. Hazelton, “Per- ger climates,” Applied Energy, vol. 276, p. 115507, 2020. formance analysis of hybrid PV/diesel/battery system using HOMER: a case study Sabah, Malaysia,” Energy Conversion [31] A. Chakir, M. Tabaa, F. Moutaouakkil et al., “Optimal energy and Management, vol. 144, pp. 322–339, 2017. management for a grid connected PV-battery system,” Energy Reports, vol. 6, pp. 218–231, 2020. [15] L. Olatomiwa, S. Mekhilef, and O. S. Ohunakin, “Hybrid renewable power supply for rural health clinics (RHC) in six [32] R. Srivastava, A. N. Tiwari, and V. K. Giri, “An overview on geo- political zones of Nigeria,” Sustainable Energy Technolo- performance of PV plants commissioned at diﬀerent places gies and Assessments, vol. 13, pp. 1–12, 2016. in the world,” Energy for Sustainable Development, vol. 54, pp. 51–59, 2020. [16] O. Ekren, C. Hakan Canbaz, and Ç. B. Güvel, “Sizing of a solar- wind hybrid electric vehicle charging station by using HOMER [33] A. C. Duman and Ö. Güler, “Economic analysis of grid- software,” Journal of Cleaner Production, vol. 279, p. 123615, connected residential rooftop PV systems in Turkey,” Renew- 2021. able Energy, vol. 148, pp. 697–711, 2020. International Journal of Photoenergy 21 [49] K. N. B. Akshai and R. Senthil, “Economic evaluation of grid [34] H. M. Ridha, C. Gomes, H. Hizam, M. Ahmadipour, A. A. Hei- dari, and H. Chen, “Multi-objective optimization and multi- connected and standalone photovoltaic systems using criteria decision-making methods for optimal design of stan- PVSyst,” IOP Conference Series: Materials Science and Engi- dalone photovoltaic system: a comprehensive review,” Renew- neering, vol. 912, no. 4, 2020. able and Sustainable Energy Reviews, vol. 135, p. 110202, 2021. [50] S. Odeh and I. Ibrik, “Performance assessment of standalone [35] M. J. Mayer and G. Gróf, “Techno-economic optimization of PV systems for rural communities,” Australian Journal of grid-connected, ground-mounted photovoltaic power plants Mechanical Engineering, pp. 1–10, 2019. by genetic algorithm based on a comprehensive mathematical [51] J. Kumar, N. R. Parhyar, M. K. Panjwani, and D. Khan, model,” Solar Energy, vol. 202, pp. 210–226, 2020. “Design and performance analysis of PV grid-tied system with [36] H. A. Kazem, M. T. Chaichan, A. H. A. al-Waeli, and energy storage system,” International Journal of Electrical and K. Sopian, “A novel model and experimental validation of dust Computer Engineering, vol. 11, no. 2, pp. 1077–1085, 2021. impact on grid-connected photovoltaic system performance in [52] B. K. K. Prasad, K. P. Reddy, K. Rajesh, and P. V. Reddy, Northern Oman,” Solar Energy, vol. 206, pp. 564–578, 2020. “Design and simulation analysis of 12.4 kWp grid connected photovoltaic system by using PVSYST software,” The Interna- [37] E. Aykut and Ü. K. Terzi, “Techno-economic and environ- mental analysis of grid connected hybrid wind/photovoltaic/- tional Journal of Recent Technology and Engineering, vol. 8, no. 5, pp. 2859–2864, 2020. biomass system for Marmara University Goztepe campus,” International Journal of Green Energy, vol. 17, no. 15, [53] Z. B. Duranay and H. Guldemir, “Modelling and simulation of pp. 1036–1043, 2020. a single phase standalone PV system,” in 2019 11th Interna- [38] R. Khezri, A. Mahmoudi, and M. H. Haque, “Optimal capacity tional Conference on Electronics, Computers and Artiﬁcial Intelligence (ECAI), Pitesti, Romania, June 2019. of solar PV and battery storage for Australian grid-connected households,” IEEE Transactions on Industry Applications, [54] Y. Cui, J. Zhu, F. Meng, S. Zoras, J. McKechnie, and J. Chu, vol. 56, no. 5, pp. 5319–5329, 2020. “Energy assessment and economic sensitivity analysis of a grid-connected photovoltaic system,” Renewable Energy, [39] B. K. Das, “Optimal sizing of stand-alone and grid-connected vol. 150, pp. 101–115, 2020. solar PV systems in Bangladesh,” International Journal of Energy for a Clean Environment,vol.21,no.2,pp.107–124, 2020. [55] N. Gupta, R. Garg, and P. Kumar, “Sensitivity and reliability models of a PV system connected to grid,” Renewable and Sus- [40] M. Al-Maghalseh, “Generation unit sizing, economic analysis tainable Energy Reviews, vol. 69, pp. 188–196, 2017. of grid connected and standalone PV power plant,” Int. J. Energy Appl. Technol., vol. 6, no. 1, pp. 1–7, 2019. [56] M. P. Bonkile and V. Ramadesigan, “Power management con- trol strategy using physics-based battery models in standalone [41] H. A. Attia and F. D. A. Gonzalo, “Stand-alone PV system with PV-battery hybrid systems,” J. Energy Storage, vol. 23, pp. 258– MPPT function based on fuzzy logic control for remote build- 268, 2019. ing applications,” International Journal of Power Electronics and Drive Systems, vol. 10, no. 2, p. 842, 2018. [57] S. S. Dheeban, N. B. Muthu Selvan, and C. Senthil Kumar, “Design of standalone PV system,” International Journal of [42] A. Iqbal and M. T. Iqbal, “Design and analysis of a stand-alone Scientiﬁc and Technology Research, vol. 8, no. 11, pp. 684– PV system for a rural house in Pakistan,” International Journal 688, 2019. of Photoenergy, vol. 2019, Article ID 4967148, 8 pages, 2019. [58] E. Roumpakias and A. Stamatelos, “Performance analysis of a [43] Y. Chaibi, M. Salhi, and A. el-jouni, “Sliding mode controllers grid-connected photovoltaic park after 6 years of operation,” for standalone PV systems: modeling and approach of con- Renewable Energy, vol. 141, pp. 368–378, 2019. trol,” International Journal of Photoenergy, vol. 2019, Article ID 5092078, 12 pages, 2019. [59] V. S. Bibin Raj and G. G. Devadhas, “Design and development of new control technique for standalone PV system,” Micro- [44] M. A. Omar and M. M. Mahmoud, “Design and Simulation of processors and Microsystems, vol. 72, p. 102888, 2020. a PV System Operating in Grid-Connected and Stand- Alone Modes for Areas of Daily Grid Blackouts,” International Jour- [60] N. Manoj Kumar, K. Sudhakar, and M. Samykano, “Techno- nal of Photoenergy, vol. 2019, Article ID 5216583, 9 pages, economic analysis of 1 MWp grid connected solar PV plant in Malaysia,” International Journal of Ambient Energy, vol. 40, no. 4, pp. 434–443, 2019. [45] P. K. Bonthagorla and S. Mikkili, “Performance investigation of hybrid and conventional PV array conﬁgurations for grid- [61] N. Kumar, V. Saxena, B. Singh, and B. K. Panigrahi, “Intuitive connected/standalone PV systems,” CSEE Journal of Power control technique for grid connected partially shaded solar and Energy Systems, pp. 1–16, 2020. PV-based distributed generating system,” IET Renewable Power Generation, vol. 14, no. 4, pp. 600–607, 2020. [46] M. Salimi, F. Radmand, and M. Hosseini Firouz, “Dynamic modeling and closed-loop control of hybrid grid-connected [62] Y. Z. Alharthi, M. K. Siddiki, and G. M. Chaudhry, “Techno- renewable energy system with multi-input multi-output con- economic analysis of hybrid PV/wind system connected to troller,” Journal of Modern Power Systems and Clean Energy, utility grid,” in 2019 IEEE Texas Power and Energy Conference vol. 9, no. 1, pp. 94–103, 2021. (TPEC), pp. 1–6, College Station, TX, USA, February 2019. [47] M. Dali, J. Belhadj, and X. Roboam, “Hybrid solar-wind sys- [63] E. Kurt and G. Soykan, “Performance analysis of DC grid con- tem with battery storage operating in grid-connected and stan- nected PV system under irradiation and temperature varia- dalone mode: control and energy management - experimental tions,” in 2019 8th International Conference on Renewable investigation,” Energy, vol. 35, no. 6, pp. 2587–2595, 2010. Energy Research and Applications (ICRERA), pp. 702–707, Brasov, Romania, November 2019. [48] M. I. Hlal, V. K. Ramachandaramurthy, A. Sarhan, A. Pouryekta, and U. Subramaniam, “Optimum battery depth [64] H. Rezk, M. A. Abdelkareem, and C. Ghenai, “Performance of discharge for oﬀ-grid solar PV/battery system,” J. Energy evaluation and optimal design of stand-alone solar PV- Storage, vol. 26, p. 100999, 2019. battery system for irrigation in isolated regions: a case study 22 International Journal of Photoenergy renewable energy microgrids,” Elektr. J. Electr. Eng., vol. 17, in Al Minya (Egypt),” Sustainable Energy Technologies and Assessments, vol. 36, p. 100556, 2019. no. 3, pp. 23–35, 2018. [65] HOMER Energy LLC, “HOMER Pro version 3.7 user manual,” [81] T. R. Shah and H. M. Ali, “Applications of hybrid nanoﬂuids in HOMER Energy, p. 416, 2016, http://www.homerenergy.com/ solar energy, practical limitations and challenges: A critical pdf/HOMERHelpManual.pdf. review,” Solar Energy, vol. 183, pp. 173–203, 2019. [66] T. Lambert, P. Gilman, and P. Lilienthal, “Micropower system [82] B. M. A. Mohandes, L. el-Chaar, and L. A. Lamont, “Applica- modeling with HOMER,” Integration of Alternative Sources of tion study of 500 W photovoltaic (PV) system in the UAE,” Energy: Farret/Integration of Alternative Sources of Energy, pp. Applied Solar Energy, vol. 45, no. 4, pp. 242–247, 2009. 379–418, 2006. [83] M. A. Green, Y. Hishikawa, E. D. Dunlop et al., “Solar cell eﬃ- [67] J. D. D. Niyonteze, F. Zou, G. Norense Osarumwense Ase- ciency tables (version 53),” Progress in Photovoltaics: Research mota, S. Bimenyimana, and G. Shyirambere, “Key technology and Applications, vol. 27, no. 1, pp. 3–12, 2019. development needs and applicability analysis of renewable [84] A. Niraula, “Scaling up of oﬀ-grid solar micro grids: moving energy hybrid technologies in oﬀ-grid areas for the Rwanda towards a ‘utility in a box’ model for rapid deployment,” power sector,” Heliyon, vol. 6, no. 1, article e03300, 2020. 2015, https://static1.squarespace.com/static/ [68] S. Firth, K. Lomas, A. Wright, and R. Wall, “Identifying trends 536b92d8e4b0750dﬀ7e241c/t/55ed3aebe4b049db23e2c0c7/ in the use of domestic appliances from household electricity 1441610475311/Dissertation_Msc_Anjal.pdf. consumption measurements,” Energy and Buildings, vol. 40, [85] M. H. Alaaeddin, S. M. Sapuan, M. Y. M. Zuhri, E. S. Zainudin, no. 5, pp. 926–936, 2008. and F. M. al- Oqla, “Photovoltaic applications: status and [69] W. M. Amutha and V. Rajini, “Cost beneﬁt and technical anal- manufacturing prospects,” Renewable and Sustainable Energy ysis of rural electriﬁcation alternatives in southern India using Reviews, vol. 102, pp. 318–332, 2019. HOMER,” Renewable and Sustainable Energy Reviews, vol. 62, [86] J. Amankwah-amoah, “Solar energy in Sub-Saharan Africa : pp. 236–246, 2016. the challenges and opportunities of technological leapfrog- [70] A. Jamalaiah, C. P. Raju, and R. Srinivasarao, “Optimization ging,” Thunderbird International Business Review, vol. 57, and operation of a renewable energy based pv-fc-micro grid no. 1, pp. 15–31, 2015. using HOMER,” in 2017 International Conference on Inventive [87] T. Reber, S. Booth, D. Cutler, X. Li, and J. Salasovich, Tariﬀ Communication and Computational Technologies (ICICCT), considerations for micro-grids in Sub-Saharan Africa, US Aid, pp. 450–455, Coimbatore, India, March 2017. 2018, https://www.nrel.gov/docs/fy18osti/69044.pdf. [71] M. Khemariya, A. Mittal, P. Baredar, and A. Singh, “Cost and [88] USAID, “Challenges and needs in ﬁnancing mini-grids Mini- size optimization of solar photovoltaic and fuel cell based inte- Grids Support Toolkit,” Energy U.S. Agency for International grated energy system for un-electriﬁed village,” The Journal of Development, 2018, June 2021, https://www.usaid.gov/ Energy Storage, vol. 14, pp. 62–70, 2017. energy/mini-grids/ﬁnancing. [72] H. Louie, E. O'Grady, V. van Acker, S. Szablya, N. P. Kumar, [89] A. A. Eras-Almeida, M. Fernández, J. Eisman, J. G. Martín, and R. Podmore, “Rural oﬀ-grid electricity service in Sub- E. Caamaño, and M. A. Egido-Aguilera, “Lessons learned from Saharan Africa [technology leaders],” IEEE Electriﬁcation rural electriﬁcation experiences with third generation solar Magazine, vol. 3, no. 1, pp. 7–15, 2015. home systems in latin America: case studies in Peru, Mexico, [73] G. Prinsloo, A. Mammoli, and R. Dobson, “Customer domain and Bolivia,” Sustainability, vol. 11, no. 24, p. 7139, 2019. supply and load coordination: a case for smart villages and [90] E. I. Come Zebra, H. J. van der Windt, G. Nhumaio, and A. P. transactive control in rural oﬀ-grid microgrids,” Energy, C. Faaij, “A review of hybrid renewable energy systems in vol. 135, pp. 430–441, 2017. mini-grids for oﬀ-grid electriﬁcation in developing countries,” [74] M. E. Khodayar, “Rural electriﬁcation and expansion planning Renewable and Sustainable Energy Reviews, vol. 144, of oﬀ-grid microgrids,” The Electricity Journal, vol. 30, no. 4, p. 111036, 2021. pp. 68–74, 2017. [91] M. F. N. Peterschmidt, M. Rohrer, and B. Kondev, “RECP [75] D. E. Olivares, A. Mehrizi-Sani, A. H. Etemadi et al., “Trends minigrid policy toolkit doublepage,” 2014, http://www in microgrid control,” IEEE Transactions on Smart Grid, .minigridpolicytoolkit.euei-pdf.org/policy-toolkit. vol. 5, no. 4, pp. 1905–1919, 2014. [76] M. Hoel, “Depletion of fossil fuels and the impacts of global warming,” Fuel and Energy Abstracts, vol. 37, no. 6, p. 460, [77] T. S. Ustun, C. Ozansoy, and A. Zayegh, “Recent developments in microgrids and example cases around the world–A review,” Renewable and Sustainable Energy Reviews, vol. 15, no. 8, pp. 4030–4041, 2011. [78] IRENA, Future of solar photovoltaic: deployment, investment, technology, grid integration and socio-economic aspects (A Global Energy Transformation: paper), 2019. [79] R. K. Akikur, R. Saidur, H. W. Ping, and K. R. Ullah, “Compar- ative study of stand-alone and hybrid solar energy systems suitable for oﬀ-grid rural electriﬁcation: a review,” Renewable and Sustainable Energy Reviews, vol. 27, pp. 738–752, 2013. [80] A. Abdulkarim, N. Faruk, A. O. Oloyode et al., “State of the art in research on optimum design, reliability and control of

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Published: Oct 5, 2021

References

Rural electrification through village grids--Assessing the cost competitiveness of isolated renewable energy technologies in Indonesia,

N. U. Blum, R. Sryantoro Wakeling, and T. S. Schmidt
Energy solutions in rural Africa: mapping electrification costs of distributed solar and diesel generation versus grid extension,

S. Szabó, K. Bódis, T. Huld, and M. Moner-Girona
The case for microgrids in electrifying Sub-Saharan Africa,

J. P. Murenzi and T. S. Ustun
The role of microgrids & renewable energy in addressing Sub-Saharan Africa’s current and future energy needs,

P. Buchana and T. S. Ustun
The economics of renewable energy expansion in rural Sub-Saharan Africa,

U. Deichmann, C. Meisner, S. Murray, and D. Wheeler
Photovoltaic solar technologies: solution to affordable, sustainable, and reliable energy access for all in Rwanda,

S. Bimenyimana, G. N. O. Asemota, J. D. D. Niyonteze, C. Nsengimana, P. J. Ihirwe, and L. Li
Study of a solar PV-diesel-battery hybrid power system for a remotely located population near Rafha, Saudi Arabia,

S. Rehman and L. M. al-Hadhrami
Renewable and non-renewable energy-growth-emissions linkages: review of emerging trends with policy implications,

A. O. Adewuyi and O. B. Awodumi
Economic cost analysis of hybrid renewable energy system using HOMER,

U. Sureshkumar, P. S. Manoharan, and A. P. S. Ramalakshmi
Optimal planning of hybrid renewable energy systems using HOMER: a review,

S. Bahramara
Renewable financial support systems and cost-effectiveness,

D. Toke
Hybrid renewable energy supply for rural healthcare facilities: an approach to quality healthcare delivery,

L. Olatomiwa, R. Blanchard, S. Mekhilef, and D. Akinyele
Performance evaluation of a stand-alone PV-wind-diesel-battery hybrid system feasible for a large resort center in South China Sea, Malaysia,

M. Hossain, S. Mekhilef, and L. Olatomiwa
Performance analysis of hybrid PV/diesel/battery system using HOMER: a case study Sabah, Malaysia,

L. M. Halabi, S. Mekhilef, L. Olatomiwa, and J. Hazelton
Hybrid renewable power supply for rural health clinics (RHC) in six geo- political zones of Nigeria,

L. Olatomiwa, S. Mekhilef, and O. S. Ohunakin
Sizing of a solar-wind hybrid electric vehicle charging station by using HOMER software,

O. Ekren, C. Hakan Canbaz, and Ç. B. Güvel
Current overview of renewable energy resources in Rwanda,

T. I. J. de Dieu Uwisengeyimana and A. Teke
Novel stochastic methods to predict short-term solar radiation and photovoltaic power,

J. Dong, M. M. Olama, T. Kuruganti et al.
Solar-powered mini-grids and smart metering systems , the solution to Rwanda energy crisis,

J. D. Dieu Niyonteze, F. Zou, G. N. Osarumwense Asemota, and S. Bimenyimana
Ripple mitigation with improved line-load transients response in a two-stage DC-DC-AC converter: adaptive SMC approach,

A. R. Gautam, K. Gourav, J. M. Guerrero, and D. M. Fulwani
Optimization of PV/wind/micro-hydro/diesel hybrid power system in HOMER for the study area,

D. Kumar Lal, B. Bhusan Dash, and A. K. Akella
Concentrated solar power and photovoltaic systems: a new approach to boost sustainable energy for all (Se4all) in Rwanda,

N. Hagumimana, J. Zheng, G. N. O. Asemota et al.
Modeling of Energy Performance of Stand-Alone SPV System Using HOMER Pro,

M. K. Deshmukh and A. B. Singh
Economic comparison between a stand-alone and a grid connected PV system vs. grid distance,

C. Marino, A. Nucara, M. F. Panzera, M. Pietrafesa, and A. Pudano
Sizing and cost minimization of standalone hybrid WT/PV/biomass/pump-hydro storage-based energy systems,

F. A. Alturki and E. M. Awwad
Optimal sizing of a grid-connected hybrid renewable energy systems considering hydroelectric storage,

T. Wu, H. Zhang, and L. Shang
Economic analysis of standalone and grid connected hybrid energy systems,

B. E. Türkay and A. Y. Telli
Worldwide geographical mapping and optimization of stand-alone and grid- connected hybrid renewable system techno-economic performance across Koppen- Geiger climates,

D. Mazzeo, N. Matera, P. de Luca, C. Baglivo, P. Maria Congedo, and G. Oliveti
Optimal energy management for a grid connected PV-battery system,

A. Chakir, M. Tabaa, F. Moutaouakkil et al.
An overview on performance of PV plants commissioned at different places in the world,

R. Srivastava, A. N. Tiwari, and V. K. Giri
Economic analysis of grid-connected residential rooftop PV systems in Turkey,

A. C. Duman and Ö. Güler
Multi-objective optimization and multi-criteria decision-making methods for optimal design of standalone photovoltaic system: a comprehensive review,

H. M. Ridha, C. Gomes, H. Hizam, M. Ahmadipour, A. A. Heidari, and H. Chen
Techno-economic optimization of grid-connected, ground-mounted photovoltaic power plants by genetic algorithm based on a comprehensive mathematical model,

M. J. Mayer and G. Gróf
A novel model and experimental validation of dust impact on grid-connected photovoltaic system performance in Northern Oman,

H. A. Kazem, M. T. Chaichan, A. H. A. al-Waeli, and K. Sopian
Techno-economic and environmental analysis of grid connected hybrid wind/photovoltaic/biomass system for Marmara University Goztepe campus,

E. Aykut and Ü. K. Terzi
Optimal capacity of solar PV and battery storage for Australian grid-connected households,

R. Khezri, A. Mahmoudi, and M. H. Haque
Optimal sizing of stand-alone and grid-connected solar PV systems in Bangladesh,

B. K. Das
Generation unit sizing, economic analysis of grid connected and standalone PV power plant,

M. Al-Maghalseh
Stand-alone PV system with MPPT function based on fuzzy logic control for remote building applications,

H. A. Attia and F. D. A. Gonzalo
Design and analysis of a stand-alone PV system for a rural house in Pakistan,

A. Iqbal and M. T. Iqbal
Sliding mode controllers for standalone PV systems: modeling and approach of control,

Y. Chaibi, M. Salhi, and A. el-jouni
Design and Simulation of a PV System Operating in Grid-Connected and Stand- Alone Modes for Areas of Daily Grid Blackouts,

M. A. Omar and M. M. Mahmoud
Performance investigation of hybrid and conventional PV array configurations for grid-connected/standalone PV systems,

P. K. Bonthagorla and S. Mikkili
Dynamic modeling and closed-loop control of hybrid grid-connected renewable energy system with multi-input multi-output controller,

M. Salimi, F. Radmand, and M. Hosseini Firouz
Hybrid solar-wind system with battery storage operating in grid-connected and standalone mode: control and energy management - experimental investigation,

M. Dali, J. Belhadj, and X. Roboam
Optimum battery depth of discharge for off-grid solar PV/battery system,

M. I. Hlal, V. K. Ramachandaramurthy, A. Sarhan, A. Pouryekta, and U. Subramaniam
Economic evaluation of grid connected and standalone photovoltaic systems using PVSyst,

K. N. B. Akshai and R. Senthil
Performance assessment of standalone PV systems for rural communities,

S. Odeh and I. Ibrik
Design and performance analysis of PV grid-tied system with energy storage system,

J. Kumar, N. R. Parhyar, M. K. Panjwani, and D. Khan
Design and simulation analysis of 12.4 kWp grid connected photovoltaic system by using PVSYST software,

B. K. K. Prasad, K. P. Reddy, K. Rajesh, and P. V. Reddy
Modelling and simulation of a single phase standalone PV system,

Z. B. Duranay and H. Guldemir
Energy assessment and economic sensitivity analysis of a grid-connected photovoltaic system,

Y. Cui, J. Zhu, F. Meng, S. Zoras, J. McKechnie, and J. Chu
Sensitivity and reliability models of a PV system connected to grid,

N. Gupta, R. Garg, and P. Kumar
Power management control strategy using physics-based battery models in standalone PV-battery hybrid systems,

M. P. Bonkile and V. Ramadesigan
Design of standalone PV system,

S. S. Dheeban, N. B. Muthu Selvan, and C. Senthil Kumar
Performance analysis of a grid-connected photovoltaic park after 6 years of operation,

E. Roumpakias and A. Stamatelos
Design and development of new control technique for standalone PV system,

V. S. Bibin Raj and G. G. Devadhas
Techno-economic analysis of 1 MWp grid connected solar PV plant in Malaysia,

N. Manoj Kumar, K. Sudhakar, and M. Samykano
Intuitive control technique for grid connected partially shaded solar PV-based distributed generating system,

N. Kumar, V. Saxena, B. Singh, and B. K. Panigrahi
Techno-economic analysis of hybrid PV/wind system connected to utility grid,

Y. Z. Alharthi, M. K. Siddiki, and G. M. Chaudhry
Performance analysis of DC grid connected PV system under irradiation and temperature variations,

E. Kurt and G. Soykan
Performance evaluation and optimal design of stand-alone solar PV-battery system for irrigation in isolated regions: a case study in Al Minya (Egypt),

H. Rezk, M. A. Abdelkareem, and C. Ghenai
HOMER Pro version 3.7 user manual,

HOMER Energy LLC
Micropower system modeling with HOMER,

T. Lambert, P. Gilman, and P. Lilienthal
Key technology development needs and applicability analysis of renewable energy hybrid technologies in off-grid areas for the Rwanda power sector,

J. D. D. Niyonteze, F. Zou, G. Norense Osarumwense Asemota, S. Bimenyimana, and G. Shyirambere
Identifying trends in the use of domestic appliances from household electricity consumption measurements,

S. Firth, K. Lomas, A. Wright, and R. Wall
Cost benefit and technical analysis of rural electrification alternatives in southern India using HOMER,

W. M. Amutha and V. Rajini
Optimization and operation of a renewable energy based pv-fc-micro grid using HOMER,

A. Jamalaiah, C. P. Raju, and R. Srinivasarao
Cost and size optimization of solar photovoltaic and fuel cell based integrated energy system for un-electrified village,

M. Khemariya, A. Mittal, P. Baredar, and A. Singh
Rural off-grid electricity service in Sub-Saharan Africa [technology leaders],

H. Louie, E. O'Grady, V. van Acker, S. Szablya, N. P. Kumar, and R. Podmore
Customer domain supply and load coordination: a case for smart villages and transactive control in rural off-grid microgrids,

G. Prinsloo, A. Mammoli, and R. Dobson
Rural electrification and expansion planning of off-grid microgrids,

M. E. Khodayar
Trends in microgrid control,

D. E. Olivares, A. Mehrizi-Sani, A. H. Etemadi et al.
Depletion of fossil fuels and the impacts of global warming,

M. Hoel
Recent developments in microgrids and example cases around the world--A review,

T. S. Ustun, C. Ozansoy, and A. Zayegh
Comparative study of stand-alone and hybrid solar energy systems suitable for off-grid rural electrification: a review,

R. K. Akikur, R. Saidur, H. W. Ping, and K. R. Ullah
State of the art in research on optimum design, reliability and control of renewable energy microgrids,

A. Abdulkarim, N. Faruk, A. O. Oloyode et al.
Applications of hybrid nanofluids in solar energy, practical limitations and challenges: A critical review,

T. R. Shah and H. M. Ali
Application study of 500 W photovoltaic (PV) system in the UAE,

B. M. A. Mohandes, L. el-Chaar, and L. A. Lamont
Solar cell efficiency tables (version 53),

M. A. Green, Y. Hishikawa, E. D. Dunlop et al.
Scaling up of off-grid solar micro grids: moving towards a ‘utility in a box’ model for rapid deployment,

A. Niraula
Photovoltaic applications: status and manufacturing prospects,

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Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

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Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

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