Prospects of Hybrid Renewable Energy-Based Power System: A Case Study, Post Analysis of Chipendeke Micro-Hydro, Zimbabwe
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Received April 25, 2021, accepted May 3, 2021, date of publication May 10, 2021, date of current version May 24, 2021.
Digital Object Identifier 10.1109/ACCESS.2021.3078713
Prospects of Hybrid Renewable Energy-Based
Power System: A Case Study, Post Analysis
of Chipendeke Micro-Hydro, Zimbabwe
GM SHAFIULLAH 1 , (Senior Member, IEEE), TJEDZA MASOLA2 ,
REMEMBER SAMU 1 , (Graduate Student Member, IEEE),
RAJVIKRAM MADURAI ELAVARASAN 3,4 , SHARMINA BEGUM5 ,
UMASHANKAR SUBRAMANIAM 6 , (Senior Member, IEEE),
MOHD FAKHIZAN ROMLIE 7 , (Senior Member, IEEE),
MOHAMMAD CHOWDHURY8 , AND M. T. ARIF 9 , (Member, IEEE)
1 Discipline of Engineering and Energy, Murdoch University, Perth, WA 6150, Australia
2 AlintaEnergy, Perth, VIC 8007, Australia
3 Electricaland Automotive Parts Manufacturing Unit, AA Industries, Chennai 600123, India
4 Clean and Resilient Energy Systems (CARES) Laboratory, Texas A&M University, Galveston, TX 77553, USA
5 College of Engineering and Aviation, Central Queensland University (CQUniversity), Rockhampton, QLD 4701, Australia
6 Department of Communications and Networks, College of Engineering, Prince Sultan University, Riyadh 12435, Saudi Arabia
7 Department of Electrical and Electronics Engineering, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Malaysia
8 School of Design and the Built Environment, Curtin University, Perth, WA 6102, Australia
9 School of Engineering, Deakin University, Geelong, VIC 3216, Australia
Corresponding authors: GM Shafiullah (gm.shafiullah@murdoch.edu.au) and Rajvikram Madurai
Elavarasan (rajvikram787@gmail.com)
ABSTRACT Fossil fuel-based energy sources are the major contributors to greenhouse gas (GHG) emission
and thus the use of renewable energy (RE) is becoming the best alternative to cater for the increasing
energy demand in both developing and developed nations. Chipendeke is a rural community in Zimbabwe,
in which electricity demand is partially served by the only micro-hydro plant and hence, load shedding is a
regular practice to keep essential services running. This study explored a suitable opportunity to identify a
feasible system with different energy sources that can fulfill the current and projected future load demand
of the community. A techno-economic feasibility study for a hybrid RE based power system (REPS) is
examined considering various energy sources and cost functions. Six different system configurations have
been designed with different sizing combinations to identify the most optimum solution for the locality
considering techno-economic and environmental viability. The performance metrics considered to evaluate
the best suitable model are; Net Present Cost (NPC), Cost of Energy (COE), Renewable Fraction (RF),
excess energy and seasonal load variations. In-depth, sensitivity analyses have been performed to investigate
the variations of the studied models with a little variation of input variables. Of the studied configurations,
an off-grid hybrid Hydro/PV/DG/Battery system was found to be the most economically feasible compared
to other configurations. This system had the lowest NPC and COE of $307,657 and $0.165/kWh respectively
and the highest RF of 87.5%. The proposed hybrid system could apply to any other remote areas in the region
and anywhere worldwide.
INDEX TERMS Chipendeke, Zimbabwe, hybrid renewable energy power systems, hydro, solar photo-
voltaic, battery, diesel generator.
I. INTRODUCTION electricity increases the potential to improve living stan-
Energy particularly electrical energy is an essential part dards, increase opportunity, improve health, productivity and
of modern days living, business and innovation. Access to reduces poverty [1]–[3]. It is now considered a basic human
right for modern-day living, however, it is not equally experi-
The associate editor coordinating the review of this manuscript and enced by all. More than half a billion people in Sub-Saharan
approving it for publication was Khursheed Aurangzeb. Africa still do not have access to basic electrical energy
This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/
VOLUME 9, 2021 73433
GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System services [4]. One example of such a nation is Zimbabwe, still make investments unattractive. Additionally, the policy in which only 42% of its total population has access to elec- still does not mention any development of stand-alone micro- tricity, with a rural electrification rate of only 13% [5], [6]. grids to electrify remote areas in which rural electrification Fuelwood is still being commonly used in both urban and rate is only 13% [6]. The NREP also reports that the Zim- rural areas. In rural areas, they meet more than 80% of their babwean government will introduce mechanisms for funding energy requirements from fuelwood, whilst 15-30% of urban RE systems as well as implement a RE technologies program also rely on wood for cooking. Due to unsustainable wood that encourages independent power producers (IPPs) to invest harvesting and clearing of lands for agriculture, the coun- in RE projects in Zimbabwe. Additionally, a fund is to be try now faces fuelwood shortages and increased siltation of established by the Ministry of Energy to promote solar energy rivers thus affecting electricity generation from run-of-the- to address the electricity crisis. In line with the Government river hydro project, such as the case of Chipendeke, South of initiatives, this study aims to develop a hybrid renewable Mutare in Zimbabwe [7]. energy-based power systems (REPS) model to identify the Zimbabwe’s electricity power system relies heavily on coal techno-economic and environmental aspects of such imple- (65%) and hydro (35%), which leaves the reliable power mentations. supply in danger during the recurring droughts. A total of Recently, integration of RE sources in both grid-connected 12 billion metric tons of good quality coal reserves are and off-grid systems was found to be the most efficient and available in Zimbabwe, with calorific values of around attractive solution considering technical, economic and envi- 32 MJ/kg [8]. Zimbabwe has an installed electricity capacity ronmental perspectives, though there are potential limitations of 1900 MW though on average only 492 MW is opera- as generations from RE sources are variable and weather tional against a peak demand of 2200 MW [9]. Zimbabwe dependent. This issue becomes critical in rural areas in the has suffered a rapid increase in energy demand mainly due absence of a central grid connection or the case of an off- to economic and population growth. Around 50% of Zim- grid system. Hence, hybrid power systems combining energy babwe’s population do not have access to basic electrical storage or diesel generator with RE sources in the form of energy services, and 35% of the electricity currently being microgrids (MGs) can make the systems more stable, reliable used are imported [10], [11]. Against this backdrop, there is and efficient. It is evident from research that hybrid power an urgent need to explore all the possible generation tech- systems with RE sources can be reliable, cost- economic, nologies to increase the electrification rate. Inaccessibility effective and more sustainable compared to either grid- to energy directly affects economic growth, food production, connected or stand-alone generators utilising a single fossil education, health, clean water, well-being, and social security. fuel-based power source [15], [16]. Many countries around Energy is considered as an enabler in achieving Sustainable the world such as Australia [16], Bangladesh [17], India [18], Development Goals (SDGs) and it should be ‘‘affordable, Maldives [19], Saudi Arabia [20] and Zimbabwe [21] are reliable, sustainable and modern’’. One of the main goals of currently doing in-depth research to deploy microgrid- the SDGs is SDG7 to ensure energy access to all [12], [13]. based energy-efficient and reliable power systems for rural In addition to lacking energy access in many countries, still, communities. the major share of the national energy mix in most countries In literature, various methods of analysis, different RES is by the use of fossil fuels which contribute to greenhouse combinations and different types of hybrid systems have gas (GHG) emissions. Moreover, the source of fossil fuel is been reported. Linear programming [23], excel-based [21], limited and highly depending on this source may make the HOMER [24], [25], RETScreen [26], LINGO [27] and arti- power system unreliable. Therefore, many countries strive ficial intelligence [28], are frequently employed tools used deliberately to minimize the use of fossil fuels to attain sus- in hybrid system analyses. Salisu et al. [29], highlighted the tainability in the energy sector [14]. Renewable energy (RE) importance of a solar PV-wind-diesel-battery storage hybrid sources, such as wind, solar PV and hydro on the other hand, system in Nigeria and identified Giri village as the best loca- are climate-friendly as they are free from GHG emissions and tion for their study. They used HOMER optimization tool to are abundant in nature. This has been proven by the increase determine the Net Present Cost (NPC), Cost of Energy (COE) in RE penetration into the energy mixes of many countries. and Renewable Fraction (RF) of the proposed hybrid sys- To address the energy crisis and SDGs goal, the tem [29]. Elkadeem et al., modelled a system to determine Zimbabwe National Renewable Energy Policy (NREP) was the NPC, COE and reduction in carbon dioxide emissions for published in March 2019 [6]. The goals and objectives of the Sudan [30]. NREP included the installation of 1100 MW of renewables A modified crow search algorithm was employed in [31] by 2025 and 2100 MW of renewables by 2030. Renew- for the optimisation of a hybrid solar photovoltaic (PV)- ables in this context referred to grid-connected solar PV, diesel-PHS (Pump Hydro Storage) system based on mini- grid-connected wind, small hydro and bagasse. The policy mum operation costs. An excel-based model with various reported the provision of tax and sale of power to third party hybrid system configurations in the Turkish Republic of incentives by the government and also reduce license fees for Northern Cyprus was investigated in [11]. In this study, renewable energy projects. However, the policy does not out- a PV/Wind hybrid system incorporated with a Hydrogen Fuel line any possible feed-in tariffs for RE resources which might Cell (HFC) and PHS was found to be cost-effective, efficient 73434 VOLUME 9, 2021
GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
and viable. A detailed review on prospects of wind and micro-hydro project became the income-generating source
solar power systems with PHS was performed and concluded for many community members. However, due to change in
that, for long term storage, PHS could be promising in the climatic condition rainfall dropped and drought started as
future [32]. gradually the river lost its normal flow and, the micro-hydro
Ganesanet al. [33] developed a model using Wind/PV/ project alone became incapable to meet the energy demand
Diesel system and found that the operational cost of DG will and the demand growth. Hence, implementation of a hybrid
be reduced with the use of RE resources. Fiedler et al. [34], REPS could provide opportunities to extend the health ser-
studied 11 locations in Sweden and compared the energy vices, education, business as well as to improve the social
cost of a hybrid PV-wind system to that of PV system alone. living standards.
They also determined the effect of the size of the load on
the proposed system. Table 1 summarises various hybrid A. IMPACT OF THE PROJECT
REPS including system type, model or methodology The project focused on the two main aspects of Chipendeke
employed and the outcome of those studies. community’s life, which are the domestic and social aspects.
Research on energy harvesting from RE sources in The clinic or health was the top priority, followed by the
Zimbabwe is still limited even though it lies in a sunny belt primary school, residential households and finally the busi-
with daily average solar radiation of about 5.5 kWh/m2 and nesses. Table 2 [55] summarises the benefits or the impacts
a total of around 4000 hours per year of solar radiation [21]. that this project had on these four sectors.
Furthermore, the Chipendeke region, which is a case study
location of this analysis, has average daily radiation of B. OPERATION OF THE SYSTEM
about 6 kWh/m2 [22]. With this great potential of solar There are two people in charge of operating the system. One
energy, a hybrid REPS with diesel backup may partially or person comes in the morning, and another is on standby in
fully support the deficit energy demand of Zimbabwe and the evening for any faults or circuit tripping. Total eight peo-
particularly the need of Chipendeke. ple trained in the basic operation of the micro-hydro power
plant, but for serious faults, ZESA is called in. The system
II. CASE STUDY: CHIPENDEKE MICRO-HYDRO POWER is checked periodically, as well as every 3 hours. Data is
SCHEME collected in a counter book, recording the energy produced
This study considers a stand-alone power system that is since 2010.
already in operation in a rural settlement named Chipendeke
in Zimbabwe to analyse and show that such systems have C. LOAD SHEDDING
a significant influence on communities. Improvements for Load shedding usually occurs a lot more between July to
this system are then proposed based on energy demand with November as this is the driest time of the year and genera-
climate-friendly RE sources. tion from micro-hydro power plant drops during this period.
The Chipendeke with a catchment area of 9 villages, Households and businesses are the first to be switched off,
located 65 kilometres from the city of Mutare. The European with priority being given to the clinic. When the power gen-
Union donated $65000 towards Chipendeke micro-hydro eration drops to very low, the whole system shuts down and
project through the African Caribbean Pacific Energy Facil- turned back on at night to provide electricity for lighting.
ity. The implementation of this project was led by Practical
Action [54], which is an international organisation that uses D. CONNECTION FEES AND TARIFFS
smart technologies to eradicate poverty. The potential site for To keep the micro-hydro power system operational and to
the micro-hydro power plant was identified along Chitoro meet maintenance and operational cost the community mem-
River, which runs through Chipendeke. The plant can pro- bers are required to pay energy tariffs as well as connection
duce 25 kW of electricity and have a lifespan of 20 years. fees as set out in Table 3 [56]. The school and clinic pay
Initially, community members were against the idea of having the lowest tariffs as these locations provide a service to the
a micro-hydro plant as they did not believe that they could community. Businesses pay the highest tariffs as they are a
operate and generate electricity. form of income-generating operation and this is also used to
The Chipendeke micro-hydro scheme is one of the pioneer- encourage business owners to use electricity more efficiently.
ing micro-hydro schemes in Zimbabwe. The improvements
that the community has made since its inception proved that E. ISSUES AND FUTURE UPGRADES
it is a community that flourishes when it has the resources Women in Chipendeke community greatly appreciate the
and would be a prime candidate for government funding addition of lighting facilities but have also expressed a desire
as part of the country’s rural electrification scheme. After for more amount of power generation for cooking [55]. Cur-
the micro-hydro project, a rapid increase in energy demand rently, they still rely on wood fuel for their cooking needs.
was observed and a forecast of future demand growth was Secondly, there is no backup power system available dur-
estimated in the Chipendeke community. Chipendeke has ing times of the year when water levels are low. Moreover,
proven that it thrives with the use of electricity, with improve- the data recording system of the micro-hydro plant is very
ments at the health centre, education and businesses. This primitive and old, which is the critical information for the
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GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System TABLE 1. Summary of hybrid REPS in literature. 73436 VOLUME 9, 2021
GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System TABLE 1. (Continued.) Summary of hybrid REPS in literature. TABLE 2. Impacts of the micro-hydro project in the Chipendeke community [55]. regular maintenance, upgradation, lifespan estimation of the the start of the micro-hydro, therefore power demand has plant and for future planning activities. increased [55]. There are plans to include a small cottage The secretary-general of Chipendeke micro-hydropower industry as well as carpentry, welding and peanut butter mak- scheme strongly believes that the micro-hydro plant needs ing machines within the community. Chipendeke committee to upgrade. The Chipendeke community has grown since also wants to supply electricity to surrounding villages and VOLUME 9, 2021 73437
GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
TABLE 3. Chipendeke micro-hydro Scheme tariffs and connection fees • REPS under Zimbabwe climatic condition were not cov-
[56].
ered in detail by the existing researches.
• Lack of researches that integrate continuous power gen-
eration from hydro with the variable PV generation.
To address the above research gaps, this study brings the
following contributions as well as outcomes in the research
domain:
• This study investigated the Zimbabwe power system and
climatic conditions with forecasted or load growth for
the hybrid REPS to fill the gap and explore the potential
for Zimbabwe. It covers a rural Chipendeke commu-
nity and data utilized were gathered through operational
reports of Chipendeke micro-hydro scheme and from
interviews with the residents.
are hoping to expand the system to 100 kW by making use of • Coordinated operation of Chipendeke’s micro-hydro
other renewable sources such as solar and biogas. They also together with solar PV, energy storage and diesel gen-
hope to sell excess electricity to ZESA in the future [54]. erator (DG) could not only help to reduce the energy
crisis but also overcome the fluctuation problems that are
F. SOLUTIONS FOR CHIPENDEKE associated with these renewable energy sources (RES).
• This is one typical study to be performed for Zimbabwe,
Chipendeke is a growing community that has embraced the
use of RE sources. As the population grows and the electricity hence it is of paramount importance to policymakers as it
demand increases, there is a need for more generation capac- aligns with Vision 2030, in which the country hopes to
ity. The main issues identified for the system are: increase the electrification rate and reduce greenhouse
gas emissions.
6 kW generation deficit due to the El Nino drought
• The outcome of this research will be a useful tool for
which caused a reduction in the water levels of Chitoro
power utilities and government bodies in planning for
river.
the deployment of hybrid REPS for rural communities.
The current system is not capable of addressing the
• The proposed research method can be used in any
cooking needs of the community. As a result of this,
remote or islanded areas to identify the techno-economic
firewood is the main source of cooking energy, which
aspects for the deployment of hybrid REPS.
plays a significant part in deforestation and air pollution.
The rest of this paper is organised as follows; Section II
There is load shedding between July to November. These
presents the details of the case study. Section III presents the
are the driest months of the year and there is currently
research gaps and contributions whilst Section IV outlines
no backup system to cater for the reduced water levels
the employed methodology. Section V presents the results
during this dry period.
in order to identify the techno-economic and environmen-
Therefore, there is a significant scope of research to investi- tal feasibility of the proposed REPS while the discussions
gate the feasibility of developing a hybrid REPS, for Chipen- and the concluding remarks are presented in Section VI and
deke which can address the current and expected extended Section VII respectively.
demand for electricity and can be an example to other parts
of Zimbabwe and beyond. IV. METHODOLOGY
Hybrid REPS have been developed to support both the current
III. RESEARCH GAPS and CONTRIBUTIONS and future predicted load demand of the Chipendeke commu-
Considering the needs of Chipendeke community as well as nity. Initially, a generic method is developed to estimate the
for Zimbabwe, this research aims to investigate the potentials current and future load demand of the community. A model
of hybrid REPS including existing hydro for Chipendeke is then developed using the Hybrid Optimization Model for
community with an emphasis on techno-economic and envi- Multiple Energy Resources (HOMER) [57] and optimisation
ronmental benefits. Existing literature explored the potential- analyses of the models are performed to select an optimum
ities of hybrid REPS taking into account local perspectives model for Chipendeke. The model performances are evalu-
and other fundamental characteristics as shown in Table 1. ated based on performance metrics such as; NPC, CoE and
Table 1 also demonstrated a comparative analysis of the RF. Finally, sensitivity analyses are performed to study the
proposed research with the existing researches. A few of the effects of the optimum model with little variation of several
major research gaps are: input parameters. Figure 1 shows the step by step methodol-
• From the reviewed literature, it was observed that there ogy while a detailed explanation for each is provided in the
is a little or no research available that investigated following subsections.
the hybrid renewable energy system considering load Different energy sources are considered in simulations to
growth or forecasted load data. get an optimized system configuration. Six case scenarios
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GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
FIGURE 1. Methodology flowchart.
were studied using HOMER simulation software and
compared their performances based on performance metrics.
Scenarios are:
• Case-1: Base Case: Hydro-Only
• Case-2: Hydro, Solar PV and Battery (Hydro/PV/Battery)
• Case-3: Hydro, Solar PV, Diesel Generator (DG)
(Hydro/PV//DG)
• Case-4: Hydro, Solar PV, DG and Battery (Hydro/
PV/DG/Battery)
• Case-5: Hydro, DG and Battery (Hydro/DG/Battery)
• Case-6: Hydro and DG (Hydro/DG)
FIGURE 2. Current load profile of Chipendeke.
A. COMMUNITY LOAD DEMAND
In collaboration with Hivos Project Manager, a load profile
of Chipendeke community was determined. Various assump- eral estimations were made based on information provided
tions were made for the community and hours of working by Mr. Mapfumo, as well as collected information from the
of appliances. For the 200 households at Chipendeke, it is facilities located in the community. Table 4 shows the four
assumed that each house has 4 rooms, with one bulb in each critical locations that require power to be supplied and details
room for lighting. of the appliances listed that have been considered. These
assumptions were made based on the operational hours of
1) LOAD PROFILE various appliances as shown in Table 5.
In collaboration with Hivos project manager, a load profile To develop a load profile, the operating hours of each of
of Chipendeke community was determined. Various assump- these appliances are required. Figure 3 and Figure 4 show
tions were made for the community and hours of working a minimum approximation of the power consumption of
of appliances. For the 200 households at Chipendeke, it is each appliance and its time of operation for an average
assumed that each house has 4 rooms, with one bulb in each weekday and weekend use based on the analytical model
room for lighting. in [58]. The various assumptions made in Table 6 as well as
household cooking stove load also considered as represented
in Figure 3 and Figure 4.
2) CURRENT LOAD PROFILE
Based on the preliminary analysis it was found that Chipen-
deke currently has a peak demand of approximately 15 kW 3) PREDICTED LOAD PROFILE
which occurs at 8 am with higher levels of electricity demand According to Hivos project manager, the community of
during the morning and evening periods as shown in Figure 2. Chipendeke has grown by 7% within the last 8 years. As there
This load profile does not include the use of cooking stoves, is no published statistical record about the population growth
as this is not currently supported by a micro-hydro scheme. in Chipendeke, this growth is estimated based on the word of
To determine a suitable hybrid system for Chipendeke, sev- mouth from the community leaders.
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GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
TABLE 4. Chipendeke community load requirements. TABLE 5. Load operating hour assumptions.
To cater for the future load growth of the community,
it is assumed that within the 25-year lifespan of the project,
the community will grow by 15%. Therefore, an updated
load profile is prepared based on the load profile shown
in Figure 3 and Figure 4 and considering 15% load growth
as shown in Figure 5. This is used to determine the hybrid
REPS for the Chipendeke community, considering variations
of weekday and weekend load demand. The main difference
between a weekend and a weekday is the lower electricity
demand from the primary school during weekends. The peak
demand for both a weekday and a weekend is 32 kW which mate/seasonal changes and error rate though the system was
occurs at 6 am, with a weekday average demand of 16.84kW designed to provide 100L/s in both the dry and wet seasons.
and a weekend average demand of 16 kW. Monthly load pro- As information regarding the seasonal changes for this river
file considered for the study of the Chipendeke community was not available, monthly precipitation data of the surround-
is shown in Figure 6. A day to day random variability of 2% ing areas of Rusape [59], Wedza [60], and Old Mutare [61] is
has been considered for load due to the seasonal variations considered. These areas are the closest locations to Chipen-
as well as the changes of usage by the consumers in the deke for which rainfall data was obtainable and used to
community. HOMER changes each day’s load profile by this determine the average monthly rainfall for the area.
amount that the load retains the same shape with a variation This rainfall data was then compared to the historical data
of its magnitude, either scaled up or down. repository managed by NASA [62]. Table 6 was used to
determine the average rainfall for Chipendeke as it considers
B. CLIMATE DATA all three closest areas to it. It is assumed that the speed of the
1) RAINFALL river will have monthly variations that are in proportion to the
The Chipendeke micro-hydro project depends on the water amount of precipitation that occurs. As observed in Table 6,
flow in Chitoro River. A river water speed of 75L/s has the speed of the river remains at 75 L/s from May to Septem-
been used for simulation in this study considering the cli- ber which is the dry season of the year, then higher speeds
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GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
FIGURE 3. Weekday load requirements.
FIGURE 4. Weekend load requirements.
are observed during the rainy season from November to 3) SOLAR RESOURCE
February. Hourly solar radiation data for Chipendeke are collected
from the historical data repository managed by NASA [63].
The daily radiation and the clearness index of Chipendeke are
2) RENEWABLE RESOURCE SELECTION
shown in Figure 7. Chipendeke receives average daily radi-
Chipendeke has a high average solar radiation of
ation of 6 kWh/m2 /day, with the lowest amount of radiation
around 6 kWh/m2 /day which makes it a good candidate
occurring in June.
for the use of solar PV, whilst the average wind speed of
the area is only 4.65 m/s. The minimum speed at which a
wind turbine begins to produce power, or the cut-in speed is C. MODEL EVALUATION USING HOMER
approximately 3 m/s [21], and with Chipendeke average wind The model was developed in HOMER based on the current
speed very close to this, therefore wind is not considered as a micro-hydro scheme already at Chipendeke and included
potential source for the REPS. additional RE sources available in the area. The model is
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GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
TABLE 6. Rainfall in millimetre (mm) and litre (L) for three adjacent areas of Chipendeke [59]–[61].
FIGURE 7. Global horizontal radiation and clearness index [63].
FIGURE 5. Predicted load profile for Chipendeke.
value of all the revenue it earns over its lifetime [57]. To deter-
mine whether or not to continue with a project, the eco-
nomic or financial feasibility is a very important parameter to
consider for this decision. Traditionally when determining the
economic feasibility of energy systems, the levelized cost of
electricity (COE) is one of the most important parameters to
consider as it is the generated electricity cost by the system.
The mismatching effect between the demand and generation
was incorporated in the analyses by utilizing the demand met
by the system, not the energy generated [57]. Additionally,
as the RES is unable to meet 100 per cent of the demand, the
FIGURE 6. Predicted monthly load profile for Chipendeke.
deficit will be acquired from a diesel generator at the local
grid tariff (GT), and this will affect the COE of the system.
optimization based on the considered energy resources and The portion of energy that is from a renewable power source
cost of resources. Furthermore, sensitivity analysis is done that is delivered to the load is referred to as the RF. A high
to evaluate economic feasibility with various technology RF value means that the system is making more use of
options. To estimate the most feasible system configuration renewable energy [59].
the three core capabilities of HOMER, simulation, optimiza- A hybrid REPS, is a combination of RE sources, a storage
tion and sensitivity analysis [57] are executed. battery and DG with a specific dispatch strategy. A set of rules
For this study, the three main performance metrics that to control the operation of the energy sources and to charge
were taken into consideration are the NPC, COE and RF or and discharge the battery under different circumstances are
contribution from renewable resources. Various resources are called dispatch strategies. Several dispatch strategies for
considered in six different cases and hybrid power systems hybrid REPS are discussed in [30], [31]. However, in this
are compared and evaluated based on these metrics. The NPC study, only cycle charging (CC) and load following (LF)
is the present value of all the costs that the entire system dispatch strategies are considered [11]. In the CC strategy,
incurs throughout the project lifetime, minus the present the prime role of the generators is to serve the primary
73442 VOLUME 9, 2021GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System load. Excess generation after meeting the primary load is TABLE 7. Technical data and study assumptions. used to charge the battery bank. Only primary load (and operating reserve) are served by the LF strategy. RE sources are responsible to charge the battery bank. Diesel generators are not required to run just to support grid frequency and voltage hence, a diesel-off operation is enabled in this study. The inverters used in the hybrid REPS are expected to have grid-forming capabilities. D. SENSITIVITY ANALYSIS A sensitivity analysis considers outlines how changes in vari- ables in an extended range can affect system performance. The model has been simulated and the considered sensitivity variables are local load, solar irradiance, cost of PV, cost of the battery, hydro turbine efficiency, diesel price, nominal discount rate and inflation rate. The model has been identified the NPC of the most optimum system with the variations of the sensitivity variables. E. HYBRID SYSTEM COMPONENTS To carry out the economic analysis of the system, several variables were defined in HOMER model. These variables include the capital costs, operation, maintenance and replace- ment costs and project lifetime. This technical information can be found in Table 7. It is important to note that for this project, the lifetime of the existing micro-hydro scheme has been set to 12 years. This is because the average lifetime of this type of hydro system was 20 years and the micro-hydro scheme at Chipendeke has already been in operation for 8 years. A typical snapshot of the studied REPS is shown in Figure 8. FIGURE 8. A typical snapshot of the studied REPS. V. RESULTS AND ANALYSIS A. OPTIMIZATION ANALYSIS 1) CASE-1: BASE CASE SCENARIO–HYDRO ONLY than the communities current energy demand. Figure 9 also From the preliminary analysis, it is evident that the existing shows the power generation options of other case scenarios hydro plant is not enough to meet the current community and it is seen that Hydro/PV/DG/Battery system is the most load demand. The major crisis is in the drought season. The suitable when the average load is more than 310 kWh/day simulation results of the Case-1 or Base Case scenario also which is the current demand of the community. provides similar findings. A hydro-only system can meet Figure 10 shows the power generation from hydropower community load demand of only 164 kWh/day with the hydro throughout the day from which it is observed that there is less efficiency of 75% as shown in Figure 9, which is far lower generation during the middle of the year when there is a low VOLUME 9, 2021 73443
GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
FIGURE 9. Electricity generation from hydro with the variations of turbine FIGURE 11. Cumulative nominal cash flow of the Hydro/PV/DG/Battery
efficiency. and the Hydro/DG system.
FIGURE 10. Power output from hydro throughout the year.
amount of rainfall. The hydro system produces its peak power
at the end and beginning of the year, due to the increased FIGURE 12. Electricity generation from different sources for the studied
systems.
water flow in the river.
2) CASE STUDY ANALYSIS
Figure 12 shows the electricity generation from different
As the only existing hydro plant is not enough to meet
energy sources for the studied five cases (Case 2-6). The
the current and future load demand of Chipendeke com-
optimised case is Case-4 that includes Hydro/PV/DG/Battery
munity, this study explores possible generation options to
system, where hydro generates a maximum of 75% of the
meet communities current and future load demand. Five more
total generated electricity while PV generates 14% as shown
case scenarios were investigated by integrating suitable RE
in Figure 12. The remaining 11% is generated by the diesel
generation technologies to identify the most suitable option
generator. In Case-2, PV generates the maximum electricity
based on techno-economic and environmental perspectives.
of 52.5% in the Hydro/PV/Battery system with the sacrifice
Optimal system performance and sensitivity analyses have
of the highest NPC due to the increased use of batteries to
been carried out using HOMER to evaluate the performances
store energy from PV during daytime and use this stored
of Hydro/PV/Battery, Hydro/PV/DG, Hydro/PV/DG/Battery,
energy at night.
Hydro/DG/Battery and Hydro/DG systems.
It is found that the Hydro/PV/DG/Battery system (Case-4)
is the most optimum based on the considered performance
metrics compared to the other studied systems cases. The
best-optimised model comprised a 25-kW hydro, 14.0 kW
PV, 10 kW Genset, 36 batteries at 12V and 14.1 kW inverter
to support the load of 144,450 kWh/yr.
In Case-4 a Hydro/PV/DG/Battery system, NPC, COE
and RF are $307,658, $0.165/kWh and 87.5% respectively,
while in Case-6 a Hydro/DG system, NPC, COE and RF
are $451, 652, $0.242/kWh and 70.4% respectively. The
cumulative nominal cash flow of the Hydro/PV/DG/Battery,
the lowest cost system and the Hydro/DG, the highest
cost system is shown in Figure 11. The simple payback
and discounted payback period of the optimized Case-4 or
Hydro/PV/DG/Battery system are 2.33 year and 2.44 year FIGURE 13. Renewable fraction, access electricity and capacity shortage
respectively. of the studied systems.
73444 VOLUME 9, 2021GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
FIGURE 14. Component- and Type-wise costs for the five studied systems.
From Figure 13 it is seen that Case-2 or Hydro/PV/Battery in the capital costs as it is a system that is already in place.
system is the only system that generates 100% electricity However, the micro-hydro has been in operation for 8 years,
from RE sources while it has the maximum of 41.6% excess with a life span of 20 years, therefore, it needs replacement
electricity, as there is surplus electricity from PV due to high cost after another 12 years into the operation and the hydro
generation. Hence, it is evident that 100% of RE-based gener- turbine replacement cost is fixed for all the studied cases.
ation is possible for the Chipendeke community with the sac- At the same time, in cost type, it is seen that the replacement
rifice of costs. On the other hand, the renewable fraction and cost is the highest for most of the studied cases throughout
the excess electricity for the optimised system, i.e., Case-4 the project lifetime as there is a need to replace hydro turbine
are 87.5% and 10.1% respectively. From Figure 13, it is also and batteries. Another significant cost is the fuel cost as fuel is
seen that the capacity shortage and unmet electric load are needed to run Genset. Fuel cost is the lowest in the optimised
negligible for all the studied cases, hence, it can be stated Hydro/PV/DG/Battery system while it is the highest in the
that all the studied cases can meet the load demand of the Hydro/DG system as DG contributed 25.8% of the total
community. electricity in this case.
Figure 14 shows the NPC of the studied cases from where One of the goals of the study is to increase RE penetra-
it is observed that the majority of the costs are for the DG and tion to reduce greenhouse gas emissions for a sustainable
the Battery. The micro-hydro scheme has not been included and climate-friendly power system for the future. Table 8
VOLUME 9, 2021 73445GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
TABLE 8. Comparison of emission parameters for the five studied cases.
shows that the Hydro/PV/Battery system has no emissions
as it is a 100% RE-based system although it is the costli-
est system. From Table 8, it is evident that the optimised
Hydro/PV/DG/Battery system has less emissions compared
to the Hybrid/DG/Battery, Hydro/PV/DG and Hydro/DG
systems.
3) OPTIMUM SYSTEM FOR CHIPENDEKE
From the case study analyses, it is observed that Case-4 or
Hydro/PV/DG/Battery system has been selected as the most
FIGURE 16. Cost summary of the optimised system.
optimum system considering techno-economic and environ-
mental perspectives. Figure 15 describes the power out-
put of the optimised system from different energy sources
throughout the year. The middle of the year is when there supplied to the load via the inverter, as well as from the micro-
is the lowest amount of rainfall and clear skies, allowing the hydro. During the summer period as shown in Figure 18, there
PV system and the DG to deliver the remaining power. The is a slightly higher amount of output power from the hydro
rainy season occurs at the end and beginning of the year and system due to increased rainfall. The generator is in operation
this is when hydro has a higher generation while DG requires during early morning and night time.
its least. DG contributed more from April to August when the
generation from hydro and PV is comparatively less. B. SENSITIVITY ANALYSIS
From the sensitivity analysis, the models were analysed to
explore the characteristics of the studied cases with little
variations of the input parameters. From Figure 19 it can be
stated that with the increase of solar irradiation the COE of the
optimised system is decreasing which indicates that energy
generation from PV is comparatively cheaper compared to
FIGURE 15. Monthly electricity production from different sources for the
optimised system. other considered sources. Figure 19 also shows that renew-
able fraction has increased with the increase in solar irradia-
Figure 16 represents the capital, operating, replacement, tion. From Figure 20, it is seen that with the increase of load
resource and salvage costs for 25 years lifespan of the project demand the total NPC increases as the optimised system need
for individual components as well as the total NPC of the opti- to generate more electricity to meet the consumer demand.
mised system. The total NPC of the entire system was found Annual electricity production also needs to increase to meet
to be $307,657, with the capital, replacement and resource the increased load demand.
costs of $44,039 and $152,545 and $94,795 respectively, Finally, the model identifies the variability of its perfor-
where the replacement cost is the highest. A significant cost mance due to the changes of key variables as uncertainties
is also required for fuel to run the Genset which is shown as make difficulties for the designer or utilities in implement-
resource costs. ing hybrid REPS system in the future. For example, due to
The time series analysis takes a closer look at the gener- technological growth, there will be significant changes in PV
ation sources at certain periods throughout the year. During price with time which should be considered in making a good
the winter period as shown in Figure 17, the load is mainly design decision. Again, inflation or nominal rate may change
supported by the hydro system, complemented using solar with time. Moreover, the equipment costs may vary with
PV. However, in the early morning during peak demand with time, places, manufacturer and country of origin, which also
less PV generation hydro and DG fulfill the load demand. need to be considered in designing a hybrid REPS system.
The excess electricity during day time is stored in the battery. In this study, eight key variables; electric load, the efficiency
During the night time, power from the stored batteries is of hydro, diesel fuel price, nominal discount rate, inflation
73446 VOLUME 9, 2021GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
FIGURE 17. Energy generation from different sources during a week in the winter season.
FIGURE 18. Energy generation from different sources during a week in the winter season.
rate, solar irradiation, PV capital cost and battery capital cost of the key variables. Figure 21 demonstrated the changes of
had been considered to explore the variability of the pro- NPC as well as the sensitivity with the changes of the key
posed optimised system with the variation of these variables. variables from lower range to upper range. From Figure 21,
This will help the designer or decision-maker to identify the it is seen that the NPC is the most sensitive with the changes
effectiveness of the system with the changes of these input of electric load and it has increased with the increase of
parameters regarding performance, reliability, variability and electric load. The efficiency of the hydro turbine is the sec-
robustness. Five manifold values ranging from 30% below ond variable that also changes the NPC significantly and
to 30% above to the best estimate were considered for each the NPC decreases with the increase of hydropower as the
VOLUME 9, 2021 73447GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
VI. DISCUSSIONS
The Zimbabwean government has recently introduced
mechanisms for funding renewable energy-based system
implementation program that encourages IPPs to invest in
renewable energy applications in Zimbabwe. There will also
be a fund established by the Ministry of Energy that will
promote solar energy to address the electricity crisis. After the
inception of a micro-hydro scheme at Chipendeke, the com-
munity has made significant improvements regarding its
socio-economic development and it proved that this commu-
FIGURE 19. Variations of COE and renewable penetrations with the
variations of solar irradiation. nity can thrive when it has the resources. Therefore, govern-
ment funding is essential to build an electrification scheme
in the country’s rural areas. Additionally, this feasibility
study identified the techno-economic prospects of renewable
energy-based system for Chipendeke community, which will
guide the government, policymakers and utilities to identify
the future initiatives to build the electricity sector to develop
a sustainable future for the country.
A. SOCIO-ECONOMIC DEVELOPMENT
FIGURE 20. Variations of NPC and annual electricity production with the Implementation of the proposed hybrid system not only will
variations of electric load. support the current community demand but also could pro-
vide expansion opportunities for the health centre, allowing
system can reduce dependency on other generating sources. them to provide medical assistance to other villages. This
NPC is also reduced with the increase in PV capital cost. renewable energy-based system also can supply power to
Not a significant change in NPC is observed with the the proposed welding and peanut butter making facilities;
changes in the remaining five variables. Hence, this infor- this could provide services and products, not only to the
mation will guide the designer/utilities to explore more community but also to the surrounding cities and villages.
with the key variables and prioritise technology to reduce In addition to this, the use of local artisans for the assembly,
uncertainty. installation and maintenance of the system would result in
FIGURE 21. Effect of variations in the hybrid REPS with the variations of eight key variables.
73448 VOLUME 9, 2021GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
job opportunities. All these opportunities would increase cash in rural areas could implement the government’s agenda.
flow into the community, which may contribute to payments This study focused on an islanded power system that is
of the system’s operational costs. already in operation in Zimbabwe, which has positive impacts
on the community. Improvements were then suggested for
B. EDUCATION FOR FUTURE GENERATION this system, based on the energy needs of the commu-
This facility will explore the possibility of an expansion in the nity. This study developed a hybrid renewable energy-based
educational sector, with the addition of a possible high school, stand-alone power system for the community of Chipen-
which will increase the education rate of the community. deke to evaluate the techno-economic and environmental
In turn, this will produce an educated workforce for the future, potentialities. Including the existing hydro-only system,
which is the key to a country’s development. six case scenarios with many combinations were studied.
From the analysis, it was seen that an off-grid hybrid
C. ENVIRONMENTAL IMPACT Hydro/PV/DG/Battery system is the most optimum solution
As the community of Chipendeke currently relies on firewood with a payback period of 2.33 year for the community. Of the
for cooking, the implementation of this hybrid system would analysed configurations, this system had the lowest NPC and
result in lower levels of deforestation. In addition to this, there COE of $307,657 and $0.165/kWh respectively and the high-
would be health benefits, as the amount of smoke inhalation est RF of 87.5%. Amongst the considered eight sensitivity
would be significantly reduced. With a renewable energy variables, it is found that electricity load changes the NPC
fraction of 87.5%, this system will be in line with the Zimbab- more rapidly and increased with the increase of electric load.
wean government’s goal to reduce carbon emissions by 33% The proposed system will increase future business expan-
by the year 2030, as well as meeting one of its renewable sion opportunities as well as improve the health care and edu-
energy policy objectives of ensuring that rural areas have cation facilities, thus enhancing living standards and reducing
increased access to modern energy. global warming. The implementation of this system would
be in line with the Zimbabwean government’s objectives
D. ELECTRICITY GENERATION to ensure that rural areas have increased access to modern
For this system, the main source of electricity will come from energy and can increase and diversify their energy options.
the micro-hydro system, followed by the PV, and then the This will not only play a part in reaching the government’s
diesel generator. The diesel generation will provide slightly target of reducing carbon emissions by 33% by 2030 but
more generation capacity than required because its minimum would also be contributing to the global initiative to achieve
load ratio is 25%, to prevent it from operating at too low a the UN SDGs, for a sustainable future for the country.
load. It will also cater for the unexpected load demand or can
be used during times of low PV output, periods of system ACKNOWLEDGMENT
maintenance or during faults. It will also complement the use The software license and the technical support was provided
of the hydro system during the rainy season, as there will be a by Murdoch University, Australia. The authors acknowledge
low clearness index due to cloud cover, resulting in less power the Department of Communications and Networks, College
produced from the PV. of Engineering, Prince Sultan University, Riyadh, Saudi Ara-
bia for providing the APC support of this publication.
E. EXCESS ELECTRICITY GENERATION
When the hydro scheme was first implemented, water storage REFERENCES
tanks were added to the system to heat water during times of [1] T. Dinkelman. (2011). American Economic Association The Effects
of Rural Electrification on Employment: New Evidence From South
excess electricity. As there is currently a generation deficit Africa. Accessed: Feb. 18, 2020. [Online]. Available: https://www.jstor.
at the hydro system, these tanks are barely in use and as org/stable/pdf/41408731.pdf?refreqid=excelsior%
the optimum hybrid system will produce 16593 kWh/year 3Ab72b18efcdd9173d2e911876522d426f
[2] R. Elavarasan, G. M. Shafiullah, N. M. Kumar, and S. Padmanaban,
of excess electricity, mainly from the excess power from ‘‘A state-of-the-art review on the drive of renewables in Gujarat, state of
the diesel generator because of its minimum load ratio, it is India: Present situation, barriers and future initiatives,’’ Energies, vol. 13,
suggested that the storage tanks will act as dump loads for this no. 1, p. 40, Dec. 2019.
[3] S.-H. Yoo, ‘‘The causal relationship between electricity consumption and
excess electricity. This heated up water may be used for cook- economic growth in the ASEAN countries,’’ Energy Policy, vol. 34, no. 18,
ing, bathing and other requirements by the community. This pp. 3573–3582, Dec. 2006.
excess electricity can also supply power to the community as [4] World Energy Outlook 2012. Accessed: Dec. 18, 2019. [Online]. Available:
www.worldenergyoutlook.org
it expands. [5] W. Bank. (2017). Zimbabwe Energy Situation—Energypedia.info.
Accessed: Oct. 15, 2020. [Online]. Available: https://energypedia.info/
VII. CONCLUSION wiki/Zimbabwe_Energy_Situation
[6] National Renewable Energy Policy 2019. Ministry of Energy and
The Zimbabwean government has established policies to Power Development, Republic of Zimbabwe. Accessed: Jan. 12, 2020.
tackle the energy deficit as well as to reduce the country’s [Online]. Available: https://t3n9sm.c2.acecdn.net/wp-content/
carbon footprint. By increasing and diversifying energy use uploads/2019/08/Zimbabwe-RE-Policy-2019.pdf
[7] E. Chikwati. (Nov. 3, 2016). Drought Effects Cripple Chipendeke.
options, integrating renewable energy into the energy mix The Herald Zimbabwe. Accessed: Oct. 15, 2020. [Online]. Available:
including increasing investment in islanded energy systems https://www.herald.co.zw/drought-effects-cripple-chipendeke/
VOLUME 9, 2021 73449GM Shafiullah et al.: Prospects of Hybrid Renewable Energy-Based Power System
[8] (2014). The Zimbabwean Power Situation. Collinsenergy. Accessed: [29] S. Salisu, M. W. Mustafa, L. Olatomiwa, and O. O. Mohammed, ‘‘Assess-
Oct. 18, 2020. [Online]. Available: https://collinsenergy.wordpress. ment of technical and economic feasibility for a hybrid PV-wind-diesel-
com/2014/04/08/the-zimbabwean-power-situation/ battery energy system in a remote community of north central Nigeria,’’
[9] (2019). Powering Zimbabwe into the Future. Zimbabwe Power Company Alexandria Eng. J., vol. 58, no. 4, pp. 1103–1118, Dec. 2019.
(ZPC). Accessed: Feb. 16, 2020. [Online]. Available: http://www.zpc. [30] M. R. Elkadeem, S. Wang, S. W. Sharshir, and E. G. Atia, ‘‘Feasibility anal-
co.zw/powerstations ysis and techno-economic design of grid-isolated hybrid renewable energy
[10] L. Al-Ghussain, R. Samu, O. Taylan, and M. Fahrioglu, ‘‘Sizing renewable system for electrification of agriculture and irrigation area: A case study
energy systems with energy storage systems in microgrids for maximum in Dongola, Sudan,’’ Energy Convers. Manage., vol. 196, pp. 1453–1478,
cost-efficient utilization of renewable energy resources,’’ Sustain. Cities Sep. 2019.
Soc., vol. 55, Apr. 2020, Art. no. 102059. [31] S. Makhdoomi and A. Askarzadeh, ‘‘Optimizing operation of a photo-
[11] R. Samu and M. Fahrioglu, ‘‘An analysis on the potential of solar photo- voltaic/diesel generator hybrid energy system with pumped hydro stor-
voltaic power,’’ Energy Sources, B, Econ., Planning, Policy, vol. 12, no. 10, age by a modified crow search algorithm,’’ J. Energy Storage, vol. 27,
pp. 883–889, Oct. 2017, doi: 10.1080/15567249.2017.1319437. Feb. 2020, Art. no. 101040.
[12] W. G. Santika, M. Anisuzzaman, P. A. Bahri, G. M. Shafiullah, G. V. Rupf, [32] M. S. Javed, T. Ma, J. Jurasz, and M. Y. Amin, ‘‘Solar and wind power
and T. Urmee, ‘‘From goals to joules: A quantitative approach of interlink- generation systems with pumped hydro storage: Review and future per-
ages between energy and the sustainable development goals,’’ Energy Res. spectives,’’ Renew. Energy, vol. 148, pp. 176–192, Apr. 2020.
Social Sci., vol. 50, pp. 201–214, Apr. 2019. [33] S. Ganesan, U. Subramaniam, A. A. Ghodke, R. M. Elavarasan, K. Raju,
[13] N. M. Kumar, S. S. Chopra, A. A. Chand, R. M. Elavarasan, and and M. S. Bhaskar, ‘‘Investigation on sizing of voltage source for a battery
G. M. Shafiullah, ‘‘Hybrid renewable energy microgrid for a residential energy storage system in microgrid with renewable energy sources,’’ IEEE
community: A techno-economic and environmental perspective in the Access, vol. 8, pp. 188861–188874, 2020.
context of the SDG7,’’ Sustainability, vol. 12, no. 10, p. 3944, May 2020. [34] F. Fiedler, V. Pazmino, and I. Berruezo, ‘‘PV-wind hybrid systems for
[14] G. M. Shafiullah, M. T. O. Amanullah, A. B. M. S. Ali, D. Jarvis, and Swedish locations,’’ in Proc. 4th Eur. PV-Hybrid Mini-Grid Conf., Glyfada,
P. Wolfs, ‘‘Prospects of renewable energy—A feasibility study in the Aus- Greece, 2008.
tralian context,’’ Renew. Energy, vol. 39, no. 1, pp. 183–197, Mar. 2012. [35] M. Guezgouz, J. Jurasz, B. Bekkouche, T. Ma, M. S. Javed, and A. Kies,
[15] G. M. Shafiullah, M. T. Arif, and A. M. T. Oo, ‘‘Mitigation strategies to ‘‘Optimal hybrid pumped hydro-battery storage scheme for off-grid renew-
minimize potential technical challenges of renewable energy integration,’’ able energy systems,’’ Energy Convers. Manage., vol. 199, Nov. 2019,
Sustain. Energy Technol. Assessments, vol. 25, pp. 24–42, Feb. 2018. Art. no. 112046.
[16] G. M. Shafiullah, ‘‘Hybrid renewable energy integration (HREI) system [36] M. Nurunnabi, N. Roy, E. Hossain, and H. Pota, ‘‘Size optimization and
for subtropical climate in central Queensland, Australia,’’ Renew. Energy, sensitivity analysis of hybrid wind/PV micro-grids—A case study for
vol. 96, pp. 1034–1053, Oct. 2016. Bangladesh,’’ IEEE Access, vol. 7, pp. 150120–150140, 2019.
[17] M. Shoeb and G. Shafiullah, ‘‘Renewable energy integrated islanded [37] E. Muh and F. Tabet, ‘‘Comparative analysis of hybrid renewable energy
microgrid for sustainable irrigation—A Bangladesh perspective,’’ Ener- systems for off-grid applications in Southern Cameroons,’’ Renew. Energy,
gies, vol. 11, no. 5, p. 1283, May 2018. vol. 135, pp. 41–54, May 2019.
[18] R. M. Elavarasan, G. M. Shafiullah, S. Padmanaban, N. M. Kumar, [38] F. Wang, Y. Xie, and J. Xu, ‘‘Reliable-economical equilibrium based
A. Annam, A. M. Vetrichelvan, L. Mihet-Popa, and J. B. Holm-Nielsen, short-term scheduling towards hybrid hydro-photovoltaic generation sys-
‘‘A comprehensive review on renewable energy development, challenges, tems: Case study from China,’’ Appl. Energy, vol. 253, Nov. 2019,
and policies of leading Indian states with an international perspective,’’ Art. no. 113559.
IEEE Access, vol. 8, pp. 74432–74457, 2020. [39] J. Barzola-Monteses and M. Espinoza-Andaluz, ‘‘Performance analysis of
[19] I. Ali, G. Shafiullah, and T. Urmee, ‘‘A preliminary feasibility of roof- hybrid solar/H2 /battery renewable energy system for residential electrifi-
mounted solar PV systems in the maldives,’’ Renew. Sustain. Energy Rev., cation,’’ Energy Procedia, vol. 158, pp. 9–14, Feb. 2019.
vol. 83, pp. 18–32, Mar. 2018. [40] G. Bekele and G. Tadesse, ‘‘Feasibility study of small hydro/PV/wind
[20] S. M. Shaahid and I. El-Amin, ‘‘Techno-economic evaluation of off-grid hybrid system for off-grid rural electrification in ethiopia,’’ Appl. Energy,
hybrid photovoltaic–diesel–battery power systems for rural electrification vol. 97, pp. 5–15, Sep. 2012.
in saudi Arabia—A way forward for sustainable development,’’ Renew. [41] M. S. Adaramola, D. A. Quansah, M. Agelin-Chaab, and S. S. Paul,
Sustain. Energy Rev., vol. 13, no. 3, pp. 625–633, Apr. 2009. ‘‘Multipurpose renewable energy resources based hybrid energy system for
[21] L. Al-Ghussain, R. Samu, O. Taylan, and M. Fahrioglu, ‘‘Techno-economic remote community in northern ghana,’’ Sustain. Energy Technol. Assess-
comparative analysis of renewable energy systems: Case study in zim- ments, vol. 22, pp. 161–170, Aug. 2017.
babwe,’’ Inventions, vol. 5, no. 3, p. 27, Jul. 2020. [42] T. Ma, H. Yang, L. Lu, and J. Peng, ‘‘Technical feasibility study on
[22] (2019). Solar Resource Maps of Zimbabwe. Solargis. Accessed: a standalone hybrid solar-wind system with pumped hydro storage for
Jan. 24, 2020. [Online]. Available: https://solargis.com/maps-and-gis-data/ a remote island in Hong Kong,’’ Renew. Energy, vol. 69, pp. 7–15,
download/zimbabwe Sep. 2014.
[23] J. Razak, K. Sopian, Z. Nopiah, A. Zaharim, and Y. Ali, ‘‘Optimal [43] K. Murugaperumal and P. Ajay D Vimal Raj, ‘‘Feasibility design and
operational strategy for hybrid renewable energy system using genetic techno-economic analysis of hybrid renewable energy system for rural
algorithm,’’ in Proc. 12th WSEAS Int. Conf. Appl. Math., Cairo, Egypt, electrification,’’ Sol. Energy, vol. 188, pp. 1068–1083, Aug. 2019.
Dec. 2007, pp. 235–240. [44] Y. Sawle, S. Jain, S. Babu, A. R. Nair, and B. Khan, ‘‘Prefeasibility
[24] G. Shafiullah, A. Oo, D. Jarvis, A. Ali, and P. Wolfs, ‘‘Prospects of solar economic and sensitivity assessment of hybrid renewable energy system,’’
energy in Australia,’’ in Proc. Int. Conf. Electr. Comput. Eng. (ICECE), IEEE Access, vol. 9, pp. 28260–28271, 2021.
Dhaka, Bangladesh, Dec. 2010, pp. 18–20. [45] M. Mehrpooya, M. Mohammadi, and E. Ahmadi, ‘‘Techno-economic-
[25] H. A. Kazem, A. H. A. Al-Waeli, M. T. Chaichan, A. S. Al-Mamari, environmental study of hybrid power supply system: A case study
and A. H. Al-Kabi, ‘‘Design, measurement and evaluation of photovoltaic in iran,’’ Sustain. Energy Technol. Assessments, vol. 25, pp. 1–10,
pumping system for rural areas in oman,’’ Environ., Develop. Sustainabil- Feb. 2018.
ity, vol. 19, no. 3, pp. 1041–1053, Jun. 2017. [46] N. Izadyar, H. C. Ong, W. T. Chong, J. C. Mojumder, and K. Y.
[26] R. Samu, M. Fahrioglu, and C. Ozansoy, ‘‘The potential and economic Leong, ‘‘Investigation of potential hybrid renewable energy at vari-
viability of wind farms in zimbabwe,’’ Int. J. Green Energy, vol. 16, no. 15, ous rural areas in Malaysia,’’ J. Cleaner Prod., vol. 139, pp. 61–73,
pp. 1539–1546, Dec. 2019. Dec. 2016.
[27] H. U. R. Habib, U. Subramaniam, A. Waqar, B. S. Farhan, K. M. Kotb, [47] L. Olatomiwa, R. Blanchard, S. Mekhilef, and D. Akinyele, ‘‘Hybrid
and S. Wang, ‘‘Energy cost optimization of hybrid renewables based V2G renewable energy supply for rural healthcare facilities: An approach
microgrid considering multi objective function by using artificial bee to quality healthcare delivery,’’ Sustain. Energy Technol. Assessments,
colony optimization,’’ IEEE Access, vol. 8, pp. 62076–62093, Mar. 2020. vol. 30, pp. 121–138, Dec. 2018.
[28] M. A. M. Ramli, H. R. E. H. Bouchekara, and A. S. Alghamdi, ‘‘Optimal [48] J. O. Oladigbolu, M. A. M. Ramli, and Y. A. Al-Turki, ‘‘Feasibility study
sizing of PV/wind/diesel hybrid microgrid system using multi-objective and comparative analysis of hybrid renewable power system for off-grid
self-adaptive differential evolution algorithm,’’ Renew. Energy, vol. 121, rural electrification in a typical remote village located in Nigeria,’’ IEEE
pp. 400–411, Jun. 2018. Access, vol. 8, pp. 171643–171663, 2020.
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