Abstract
This manuscript proposes an efficient hybrid strategy to obtain the optimal solution of operational cost reduction, size reduction of hybrid renewable energy sources and optimal power flow control for off-grid system. Here, off-grid is incorporated with photovoltaic array, wind turbine, Diesel generator, and battery energy storage system. The hybrid method is joint execution of Giza Pyramids Construction (GPC) and Billiards-inspired optimization algorithm (BOA) hence it is named GPC-BOA technique. The major purpose of proposed method is minimizing the operational cost as well as size of hybrid renewable energy sources and improves the power flow of system. In this energy management system of off-grid provides cost reduction which includes the generation, replacement, operating and maintenance, cost of fuel consumption, cost of exchanged power with grid, and the penalty for emissions. Here, the GPC method is employed for forecasting the load requirement of system. The BOA technique optimizes the off-grid system through the deliberation of forecasted load requirement. At last, the proposed approach is performed on MATLAB platform and the performance is assessed using existing techniques.
Keywords
Nomenclature and abbreviations
Module de-rating factor
Solar radiation under Standard test conditions
Cell temperature
Ambient temperature
Nominal operating photovoltaic cell temperature
Solar radiation at which NOCT condition
Rated power output of wind turbine
Rated power of single WT
Usage of power
Output and input power
Total inductive load
Energy demand
Discharging efficiency
Self-discharging factor
Depth of discharge
Cost of PV, WT, DG battery and converter
Power of PV, WT, DG, load and battery
annual served cost
Real Interest rate
Gravity of earth
Kinetic friction coefficient
angle
generated power from PV, WT, and DG
number of workers
motion of stone block
current position
generated solution
velocity of balls 1 and 2 after impact
minimum and maximum
permitable value
selection pressure
number of pockets
precision rate
Error Rate
hybrid renewable energy sources
Billiards-inspired optimization algorithm
battery energy storage system
normal operating cell temperature
Total Net Present Cost
Cost of energy
particle swarm optimization
solar radiation
temperature coefficient
solar panel cell temperature standard test condition
ambient temperature at which normal operating cell temperature (NOCT) condition
solar radiation on PV
efficiency of photovoltaic array at MPP
power output of wind turbine
wind speed at wind unit hub height, wind speed rated, cut in and cut out wind speed
rated power
rating of inverter
total non-inductive load
generated energy
charging efficiency
efficiency of converter
rated power of PV, WT, DG converter with battery
consumption of fuel
total annualized cost
processing time of the system
mass of stone
angle
gravity of earth
velocity of stone
number of stone blocks
power and voltages of the system
motion of workers
primary solution
velocity of balls 1 and 2 before impact
mass of the balls N and M number of balls and position
objective function
new positions as well as old position values of balls
random values
recent iteration and maximum iteration
Giza Pyramids Construction
photovoltaic
Multi Agent Systems
Demand supply Management
Loss of power supply probability
Genetic algorithm
Wing fly suit algorithm
Introduction
In recent days, the number of distributed generation (DG) systems depending on Renewable Energy Sources (RES) like solar, wind, battery, etc. is utilized in multiple applications. But the coupling of RES with basic distribution networks is the difficult task due to these RES are intermittent, and provides lower quality of power [1]. To overcome this drawback, the smart micro-grids are introduced in many applications that coupled the renewable power generation, energy storage, and energy usage nearly via optimal communication and control techniques [2–4]. For this operation, power electronic converters with the ability of bidirectional power transmission a well as four-quadrant function is needed [5]. The different types of control techniques are utilized in the power converter controller as well as micro-grid control stations for the reliable power delivery and keep the voltage level as well as frequency level to be constant [6]. Residential users as the main part of power users are varying passive energy users with active small-scale power distributors [7].
The maximum number of constructions in India is grid-connected [8–12], where contains more amount of small as well as rural groups. Because of the large distance from cities, that places are not able to obtain the power from national power grid. The coupling of which places with the national power grid is complex task, so the Diesel Generator (DG) is one of the possible solution for providing the power to rural places [13–15]. But the continuous increment of Diesel Fuel cost, more amounts of transmission cost, and worry about the power leakage problems will affect the proper power delivery through the Diesel generator [16]. The number of PV system placed in the residential as well as commercial areas is higher at past decades but currently which is slowly reduced even if, the size of PV systems is reaches the maximum of 5.5 kW from 1 kW [13, 14]. Natheless their benefits, the intermittency characteristics of RES denotes challenge that may be overcome through hybridization [17, 18]. The battery is required to store these renewable energy which helps to achieve the power demand at the time of unavailability of sources [19, 20]. The storage device may employed to smooth the transmission as one source to another source as well as maintain the power transmission utilizing sources through small dynamic response like fuel cells [21, 22].
The cost-effective hybrid renewable energy system (HRES) likes (PV) [23] and Biogas Generator (BG) with battery becomes a hopeful off-grid energy system on environment. The coupling of multiple renewable sources rejects large sizing problems as well as increasing the performance of the system and lower cost of power delivery [24, 26]. Also, HRES has the ability to reduce the sending and receiving losses on long distance areas. In recent days, HRES is accepted in most applications due to its technical as well as environmental advantages. Also, the better management systems will promising that HRES operations are done in better quality and lower cost way.
Various literary works are listed here. Elsisi et al. [27] have clarified a new IoT architecture for online gas-insulated switchgear (GIS) condition monitoring based on traditional observation systems. The presented IoT architecture was resultant from the Cyber-Physical System (CPS) concept on Industry 4.0. Though, cyber-attacks and classification of GIS isolation flaws signify the key challenges on execution of IoT topology for online monitoring and tracking of GIS status. Partial discharge pulse sequence features were taken out for every flaw to signify the inputs for the IoT architecture. Elsisi [28] have illustrated a novel robust control process for wind energy conversion system. The presented system may buffer deviations on generator speed due to wind speed penetration and load demand fluctuations on power grid. The novel system was built on the basis of novel simple frequency domain conditions as well as Whale Optimization Algorithm (WOA). This process was employed to design a robust proportional-integral-derivative (PID) controller depends on the WOA to improve the damping characteristics of wind energy conversion system. Elsisi [29] have provided a novel variable structure gain scheduling (VSGS) for frequency regulation. The VSGS may take benefit of the BFOA-fed PI controller that was reduction of settling time. Elsisi et al. [30] have studied an adaptive neuro-fuzzy inference system (ANFIS) from efficient control system for WECS. Though, ANFIS needs an appropriate data set for training and testing to tune their membership functions. In this sense, the study also proposes an efficient approach to make an enough data set. Exactly, an algorithm called mayfly optimization algorithm (MOA) was established to get optimal proportional integral derivative (PID) controller parameters. To prove the benefits of the proposed system, it was related with three dissimilar algorithms on literature. Many test scenarios were accomplished to authorize the efficacy and robustness of the proposed ANFIS-based system.
An efficient hybrid strategy to obtain optimal solution of operational cost reduction, size reduction of HRES and optimal power flow control for off-grid system with hybrid technique. The main innovation of the proposed work is the hybrid algorithm to get the general optimal solution is gathered as search space of these operators. The proposed study is valuable to solve by two optimization issue. The hybrid approach is joint performance of GPC and BOA hence it is named GPC-BOA technique. The major purpose of proposed method is minimizing the operational cost as well as size of the HRES and improves the power flow of system. Here, the GPC method is employed for forecasting the load requirement of system. The BOA technique optimizes the off-grid system through the deliberation of forecasted load requirement. The performance of the proposed system is performed on matrix laboratory/Simulink working platform.
The below explained sections are below: Section 2 clarifies the brief review of current investigation work. Section 3 describes that configuration of energy management optimal design of off-grid HRES. The proposed approach of Giza Pyramids Construction and Billiards-Inspired Optimization algorithm (GPC-BOA) described on section 4. Section 5 describes that result and discussions. Section 6 accomplishes the paper.
Recent research work: A brief review
In literature, numerous investigation tasks are obtainable depending on energy management for optimal design of off-grid HRES for residential electrification using various techniques. Some of the reviews are:
Kumar et al. [31] clarified the optimal control approach of Hybrid Renewable Energy System (HRES) that has parallel implementation of Lightning Search algorithm using Artificial Neural Network and Recurrent Neural Network (PLSANN). The implemented work was considered Photovoltaic (PV), Wind Turbine (WT), Fuel Cell (FC) and Battery. The DC link was utilized to interconnect the considered renewable sources. The PQ issues were assumed in the origin of wind / photovoltaic energy in a power grid. Through PLSANN/RNN approach, the converter was analyzed and the flow of energy was controlled. For the management of active power, LSA was utilized. For managing the reactive power RNN was utilized. A hybrid MDABSA approach was introduced by the Sureshkumar and Ponnusamy [32] for PFM under SG system. The hybrid MDABSA strategy was the hybrid wrapper of MDA and BSA. According to transmission power amid source as well as load side. The BSA was locating that online control signal. The major contribution of the introduced method was the control of flow of power. Aktaş and Kırçiçek [33] have suggested a strategy for PFM in hybrid system. The hybrid system was incorporated via offshore wind, marine current, battery, ultra capacitor and HRES. The introduced approach was determined the generated power amount as well as load demand by real time. The introduced strategy was assumed the nine different dynamic operations. In the HRES power generation, battery and ultra-capacitor were supported.
Collota et al. [34] have implemented fuzzy logic strategy with particle swarm optimization for effectual energy management. An industrial wireless sensor networks permits for utilizing energy storage devices for lossless power transmission, easy implementations and achieve better performance. The implementation of network elements was difficult work due to examine the needs. The energy usage of industrial wireless sensor networks has been reduced by using optimization methods. Based on storage device condition and ratio between maximum processing time and workload, the fuzzy controller techniques have been implemented with this approach. This approach has been used to find the resting period of sensors. The required output and criterions have been obtained by using particle swarm optimization algorithm. Nge et al. [35] have suggested the Lagrange multipliers for managing the energy of PV system. The contribution of the introduced approach was increase the return over a period when the battery stores the energy barrier. Based on the demand, the price signals were controlled by the introduced strategy. The SSA-CS approach was developed by Lingamuthu and Mariappan [36] for the control of power flow under HRES system. The sources of the MG system were taken as PV, WT, MT and battery using PHS. The objective of cost function was optimized by the introduced hybrid approach. Et-Taoussi el al. [37] has suggested a strategy for the management of power flow in the low voltage urban micro-grid. The control of power flow was analyzed under the day-ahead power flow, residential load consumption, power of PV, electricity tariffs. The stability and reliability of system were guaranteed by DES power references. The major purpose of the introduced method was cost reduction and CO2 emission.
Chang et al. [38] have illustrated a new secure management system for renewable microgrids taking into account the necessary policies to diagnose cyber-attacks that occur on communication networks, generally used at secondary control layer of microgrids (MG). The ability to extract high-level features based on the use of fast Fourier transform (FFT) and deep learning (DL) was considered a strong system against small mutations or novel attacks. Li et al. [39] have provided a new secure transactive power management structure for household AC/DC microgrids taking uncertainty concerns into account. The presented model was built with the advanced method of directed acyclic graphs to promise the privacy and security of the nodes. Hossain et al. [40] have explained energy management schemes in uncertain environments and scheduling system to diminish the working cost of grid-connected microgrid. Optimization issues were formulated as real-time programming methodswere solved by developing modified particle swarm optimization (MPSO) algorithms. He et al. [41] have exhibited a new distributed framework to solve the multi-objective issue that is composed of numerous conflicting objective functions. To overwhelmed the impact of inconsistent measurement units for every objective function. It will divide a multi-objective optimization issue into three sub-problems: the maximization, minimization, normalization. Mansouri et al. [42] have studied a three-goal optimization framework for microgrid energy management under the presence of smart homes and demand response (DR) program. The model was executed on distribution system of 83 buses through 11 microgrids. Uncertainties of power output and load demand of renewable energy resources (RES) were taken into account, and the objective function was modeled under the form of bio-objective and tri-objective models with the fuzzy max-min process.
Mokhtara et al. [43] have illustrated a methodology for optimal design of diesel/PV/wind/battery hybrid renewable energy system (HRES) for the electrification of residential buildings in rural areas Barik and Das [44] have introduced to assess the optimal allocation of suitable integrated resources planning for eco friendly sustainable energy-based hybrid microgrids with distributed generation.
Background of research work
The literature review indicates that various optimization approaches have been utilized for efficient energy management under smart grid system. In recent days, research involving smart grids is maximum utilized in whole world as well as will turn into beautiful field of investigation, due to the entire advantages, which may be aimed for end-users with energy distributors. The smart grids may develop the grid energy efficiency to the advantage of end-users via scheduling and coordinating the small priority home devices; hence, its consumption of the power obtain benefit of the most suitable energy prices and/or energy sources in provided time. The effectiveness, reliability, and safety development of power distribution networks are consummate via the computing and communication technologies. However, to attempt the rising electricity demand, and proficient energy consumption, a novel approaches are required. Because, the existing approaches is not suitable for numerous homes to have the similar appliances with the power ratings (kW) and identical length of operation time (LOT). Moreover, the various analytic algorithms are accessible that may course enormous volume of data. These mentioned problems are motivated to do these research works.
Configuration of energy management for optimal design of off-grid HRES
The Fig. 1 portrays that general architecture of proposed system. The proposed off-grid system is connected with photovoltaic (PV), wind turbine (WT), Diesel Generator (DG), battery storage system (BSS), and power converter. The proposed method is the combination of GPC and BOA hence it is named GPC-BOA method.

Overall architecture of GPC-BOA system.
The major purpose of GPC-BOA method is diminishing the cost of energy as well as size of HRES and control of power flow system. The PV system is associated through DC to DC converter that minimizes the ripple of the system and given the power to DC bus. The wind turbine is linked with AC to DC converter due to the energy generated from the WT is an AC. The direct ac supply is not secure for the energy management system so which is converted into DC form and then it’s given to the systems for doing the objective operations [37]. Also, Battery is connected with dc to dc converter. Battery is utilized for storing excess power of GPC-BOA system. The mathematical modelling of each component of GPC-BOA system is explained under beneath section.
The PV, WT, DG, powers are given to the load which is controlled by the proposed approach. In the proposed approach, the Multi Agent Systems (MAS) are considered for the smooth operations. The MAS is important for increasing demands in distributed energy systems which is a self-standing system and utilize the data to communicate with others as well as getting knowledge about the environment. Here, the MAS system includes load agent (home, colleges, etc.), generation agent (PV, WT, and DG), and storage agent (Battery), deign agent (GPC-BOA), and control agent.
The main work of load agent is computing and controlling the loads at each hour’s as well assending the needed data’s to other agents. In this research work, the home is considered as the load.
Generation agent (GA)
The hybrid renewable energy resource comes under the generation agent. In this research work, PV, WT, and DG are considered as the generation agent. The main work of this agent is calculating the power generation conditions of the sources and sends the data about the availability of power to the control agent [37]. Based on the suggestions from the control agent, which joining, rejecting, and coupling or de-coupling the energy generating systems. The mathematical modelling of this agent is shown below,
Modelling of PV
The PV is employed for converting solar energy into corresponding electric energy. Based on weather condition, air temperature and the radiation of solar, the energy of PV is generated.
The PV array outcome may be expressed,

Equivalent circuit of PV system.
According to wind speed, the result of the WT is defined at four operational areas. Because of the low wind speed that means the speed is less than the cut in wind the output power of wind turbine similar with zero. Hence, the turbine does not rotate. When the speed of wind is amid the cut-in and nominal then the outcome is a function of wind speed. The rated output power is found as third region. While the wind speed is greater than cut out speed then it turned off, for the purpose of preventing from damage. The WT output power is used to evaluate the given expression,
Wind system generates the power depending on wind speed (WS). The result of the wind is defined as,
DG utilized under hybrid power system for achieving load requirement at time of lower availability of power from renewable sources as well as storage devices. The availability of utilized fuel with DG based on output power which can be expressed as,
The power converter is utilized to convert alternating current to direct current or direct current to alternating current. The efficiency of PC can be revealed as,
The main work of SA is monitoring the condition of power on storage devices as well as gathering the data from generation agent as well as load agent to make charging and discharging operations. The modeling of battery is explained in below section.
Modeling of battery
Here, the battery is considered as the storage agent. The implementation of battery is very simple process and it stores the amount of energy from the generating sources. It doing the charging operation at the time of power continuously supplied from generating sources. When it reaches the limited energy level, it starts to make the discharging operation. The equivalent circuit of battery portrays on Fig. 3.

Equivalent circuit of Battery.
The charging and discharging functions of battery can be denoted,
here f1 (T) is the energy demand as well as f G (T) is the generated Energy, μ bd is the discharging efficiency and μ bc represents the charging efficiency, α is the self-discharging factor, here α is fixed at 0. The efficiency of converter is denoted as μ cNV . The minimal and maximal storage ability of battery may be calculated with below equation,
here
DA is utilized to optimize the hybrid renewable energy sources which choose the optimal size of HRES and change the size of HRES based on that value to provide an optimal result of energy management. In this paper, GPC-BOA is considered as the design agent; it helps to reduce the size of HRES and also helps to reduce the cost of energy (COE).
Control agent (CA)
CA performs the supervisory function which checks the data from the various agents with respect to their objective values. The main work of CA is monitoring all the equipment of HRES which uses the energy management condition to achieve the stability among demand and supply side for achieving the optimal result such that higher reliability, lower cost and minimum size [37]. In this research work, Demand supply Management (DSM) is introduced which is coupled with GPC-BOA technique for the objective functions. DSM was introduced to minimize the power utilization of loads and also minimize the maximum size of HRES. Here, two loads are considered for HRES optimization size. The processing stage of HRES size optimization is as follows,
•Initially, the PV and WT generate the energy and which is utilized for the charging purpose of battery.
•In second stage, the energy not utilized by the first load (if the battery is filly charged) is transmitted to the second load.
•If the PV and WT cannot gives the required amount of power to achieve the first load, the control agent needs for utilizing second load. Still it cannot give the needed load, the stored energy from the battery is utilized.
•If the power given by the HRES is not enough to achieve the needed load as well as the battery is filtered, DG is utilized to transmit the required amount of power. If the whole system cannot achieve the demand, the loss of power transmission is calculated.
Problem formulation
The Total Net Present Cost (TNPC) should be minimum for optimal energy transmission operations. To achieve this, the sizing of HRES is most important which can be derived as [37],
TNPC is mostly utilized on HRES implementation process which may be calculated by using the following equation.
The cost of PV, WT, DG, battery and converter can be denoted as c pv , c wt , c dg , c bS , c cNV . The consumption of fuel can be denoted as FUEL CONS .
LPSP is mainly utilized for calculating system reliability. Basically, the total power shortage proportion in excess of total power requirements is called as LPSP. LPSP means that the rate of disappointment of load which is expressed as,
RF is utilized for fixing lower energy value at whole load supplied using HRES. The following equation helps to calculate the RF value,
The annualized cost of system is separated by served cost is known as the COE of system which can be expressed as,
In long distance areas, fuel usage is lower due to higher transmission cost. According to the fuel usage, the CO2 emission is calculated which is as follows,
To reduce the cost of energy as well as size of HRES, GPC-BOA is implemented in this approach. In this research work, GPC-BOA is considered as the design agent. The integration of Giza Pyramids construction and Billiards-inspired Optimization algorithm helps to achieve the optimal result of energy management operations.
Processing steps of Giza Pyramids Construction
In GPC, initially the stone blocks are dispersed on all sides of the pyramid construction point. So, the workers want to move the stone blocks into the construction point. The starting positions of every block are analyzed first. Ramp is utilized to pass the stone blocks into the construction point [45]. The transmission time of stone from dispersed place to construction place is depends on the strength and availability of workers. At first all the workers try to identify the best position to moving the stone and start to push the stone after finding the correct position. If one worker cannot move the stone block, new worker is placed on that place instead of previous worker. This process is continuing until the stone reaches the destination point. The force utilized by the workers for the movement of stone can be expressed as,
The acceleration of stone block may be computed with below equation,
Initially generate the input power and input voltage of the system, cost function, and maximal iteration of system. Also, initialize the population of stone blocks and workers.
where the generated power from PV, WT, and DG can be denoted as p pv , p wt , p dg . S specifies number of stone blocks and W specifies number of workers.
The input parameters are randomly created after the method of initiation. In this research, the power and voltages are randomly created with below matrix Z:
The equation for fitness function may be denoted,
The motion of stone block and motion of workers can be computed using the following equations,
Based on the motion of stone block as well as motion of workers, the new position can be evaluated which is expressed as,
If one worker cannot push the stone, another one person is substituted on which place instead of that worker. The availability of substituting workers can be evaluated using the following expression,
Update the position of the workers as well as stone blocks in all iteration.
If the process reaches the objective condition, it will be terminated otherwise it continuing from step 3.
BOA is type of meta-heuristic algorithm depends on billiards games. The long stick utilized for playing billiards game is known as cue. The purpose of this stick is to restrict the billiards balls [46]. All the players consist of the number of balls. The position of all the balls assumed as the variables. Initially, all the balls are randomly distributed on the billiards table, from which the best ball is choose as pockets. Then all balls are splitted into two groups namely cue and normal balls. After that, all the cue balls beat their aiming balls and goes near the pocket. The kinematic as well as collision law is generated during the time of cue ball beating the normal balls. The GPC-BOA algorithm shows a Fig. 4(a). Figure 4(b) shows the Flow process of the proposed work.

Flowchart of GPC-BOA algorithm.

Flow process of the proposed work.
The kinetic energy as well as speed of the balls can be expressed as,
Initially generate the input power and input voltage of the system, cost function, equivalent generation limits and maximal iteration of system. Also initialize the number of balls and position of balls using the following expression,
N = 1, 2, … 2n, M = 1, 2, … m
here,
The input parameters are randomly generate on range of [0, 1] which can be expressed as,
The calculation of fitness function determined from objective function that may be denoted as,
Calculate the number of pockets and position of each pocket. The pockets collect the balls when the players move the balls into the pockets. The pocket helps to find the winner of the game with less evaluation cost.
Then finding the pockets, the balls ordered in one by one and after that are splitted into two similar groups’ namely normal balls and cue balls. The grouping of normal balls can be expressed as,
The grouping of cue balls can be expressed as,
The pockets are choose for each ball using the following expression,
After the collision, the new position of balls are updated using below expression,
When the winner of game is selected, the process reaches the termination point otherwise the process is continuing from step3.
In this segment the simulation result of proposed approach is defined. For diminishing energy cost as well as size of HRES, GPC-BOA is implemented in this work. The proposed approach is executed through MATLAB Simulink platform. The efficiency of the proposed approach is examined with comparison of existing methods as genetic algorithm (GA), particle swarm optimization (PSO), and wing fly suit algorithm (WFSA) [47]. In the below section described the analysis of case studies. Figure 5 portrays that analysis of predicted electricity demand of proposed system. Here, the predicted electricity demand is 0 at starting stage then it increased to 2GJ/h at 7 h. It reaches maximal value of 12GJ/h at 18 h and then starts to decrease. Figure 6 portrays that cost performance of proposed technique with existing methods (a) GA (b) PSO (c) WFSA. In Fig. 6 (a), the cost of GA is 50$MWh at starting stage but the cost of proposed method is 30$MWh at starting stage. The cost of GA arrives maximal value of 300$MWh at 5 hour. In Fig. 6(b), the cost of PSO is 50$MWh at starting stage but the cost of proposed method is 30$MWh at starting stage. The cost of PSO reaches maximal value of 300$MWh at 5hour. In Fig. 6(c), the cost of WFSA is 40$MWh at starting stage but the cost of proposed method is 30$MWh at starting stage. The cost of WFSA arrives maximal value of 290$MWh at 5hour but the cost of proposed method arrives maximal value of 270$MWh at 5hour. The cost of proposed method is lower than existing GA, PSO and WFSA systems.

Analysis of predicted electricity demand of GPC-BOA system.

Cost performance of proposed technique with existing methods (a) GA (b) PSO (c) WFSA.
Figure 7 portrays that cost comparison of GPC-BOA with existing systems. The maximum cost of existing techniques as GA, PSO, and WFSA is 320$MWh, 290$MWh, and 300$MWh at 5hour. But the maximum cost of proposed system is 270$MWh at the time of 5hour. The cost of GPC-BOA is lower than existing methods. The performance of GPC-BOA system is analyzed depending on weather condition under the four cases like spring, summer, autumn and winter which is explained below.

Cost comparison of GPC-BOA with existing systems.
This section explains the performance of electrical energy of proposed system on spring season. Figure 8 shows the power consumption of proposed method. The maximum consumption of power through compression chiller (CoC), light, non-schedulable residential electrical appliances (nsch), dish washer (dw), washing machine (wm), vacuum cleaner (vc), and car is 0.3GJ/h, 1GJ/h, 2GJ/h, 2GJ/h, 2.5GJ/h, 3GJ/h and 12GJ/h. Figure 9 portrays power performance of proposed method (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 9(a), the solid oxide fuel cell-gas turbine power (SOFC-GT), charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 4GJ/h at 17 h, 12.2GJ/h at 20 h, and 4.8GJ/h at 16 h. In Fig. 9(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 25GJ at 7hour and 34GJ at the time of 8 h.

Power consumption of proposed method for case 1.

Power analysis of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES for case 1.
Figure 10 shows power analysis of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 10(a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 3.5GJ/h at 21 h, 5.5GJ/h at 21 h, and 3.5GJ/h at 3 h. In Fig. 10(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 12GJ at 4hour and 22GJ at the time of 7 h.

Electricity power and energy for case 1.
This section explains the analysis of electrical energy of GPC-BOA system on summer season. Figure 11 shows power consumption of proposed system. The maximum consumption of power through compression chiller (CoC), light, non-schedulable residential electrical appliances (nsch), dish washer (dw), washing machine (wm), vacuum cleaner (vc), and car is 0.3GJ/h, 1.6GJ/h, 2GJ/h, 1.8GJ/h, 3GJ/h, 3.6GJ/h and 12.2GJ/h. Figure 12 portrays power analysis of proposed method (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 12(a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 3.5GJ/h at 7 h, 4.9GJ/h at 7 h, and 3.5GJ/h at 5 h. In Fig. 12(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 10GJ at 8hour and 20GJ at the time of 6 h.

Power consumption of proposed method for case 2.

Power performance of proposed method (a) SOFC-GT, dch,e, ch,e (b) De,t, eES for case 2.
Figure 13 shows the power performance of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 13(a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 4.4GJ/h at 18 h, 12.4GJ/h at 18 h, and 4.6GJ/h at 2 h. In Fig. 13(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 25GJ at 6hour and 35GJ at the time of 8 h.

Electrical power and energy for case 2.
This section explains that performance of electrical energy of proposed system on summer season. Figure 14 portrays that power consumption of proposed method. The maximum consumption of power through compression chiller (CoC), light, non-schedulable residential electrical appliances (nsch), dish washer (dw), washing machine (wm), vacuum cleaner (vc), and car is 0.1GJ/h at 5 h, 1GJ/h at 21 h, 2GJ/h at 7 h, 1.4GJ/h 18 h, 3GJ/h, 1.6GJ/h at 18 h and 10.8GJ/h at 18 h. Figure 15 portrays power analysis of proposed method (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 15(a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 2GJ/h at 7 h, 12GJ/h at 18 h, and 4GJ/h at 4 h. In Fig. 15(b) the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 25GJ at 6hour and 35GJ at the time of 8 h.

Power consumption of proposed method for case 3.

Power performance of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES for case 3.
Figure 16 shows the power performance of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 16(a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 2GJ/h at 7 h, 12GJ/h at 18 h, and 4GJ/h at 4 h. In Fig. 16(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 25GJ at 6hour and 35GJ at the time of 8 h.

Electrical power and energy for case 3.
This section explains that performance of electrical energy of GPC-BOA system on winter season. Figure 17 shows the power consumption of proposed method. The maximum consumption of power through lift, non-schedulable residential electrical appliances (nsch), dish washer (dw), washing machine (wm), vacuum cleaner (vc), and car is 0.8GJ/h at 7 h, 1.8GJ/h at 7 h, 1.2GJ/h at 18 h, 2.4GJ/h 18 h, 3GJ/h at 18 h, 12GJ/h at 18 h. Figure 18 shows the power analysis of proposed method (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 18(a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 3.4GJ/h at 17 h, 12.2GJ/h at 18 h, and 3.7GJ/h at 1 h. In Fig. 18(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 24GJ at 6hour and 35GJ at the time of 8 h.

Power consumption of proposed method for case 4.

Power performance of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES for case 4.
Figure 19 shows the power performance of GPC-BOA system (a) SOFC-GT, dch,e, ch,e (b) De,t, eES. In Fig. 19a), the SOFC-GT, charging (ch,e) and discharging (dch,e) power of proposed system reaches the maximum value of 4GJ/h at 20 h, 4.8GJ/h at 18 h, and 3.6GJ/h at 1 h. In Fig. 19(b), the demand power and electricity stored in energy storage system (eES) reaches the maximum value of 10GJ at 6hour and 22.5GJ at the time of 7 h.

Electrical power and energy for case 4.
Table 1 describes that output power of PV, WT, MT, and battery using GPC-BOA strategy. The maximal power of PV is 5KW with the minimal power refers 0. The maximal power of WT implies 5 kW and minimal power implies 2KW. The maximal power of battery implies 1 kW and minimal power implies 0. Table 2 illustrates the cost performance of GPC-BOA and existing process. Here, the cost of proposed method reaches the maximum cost of 45$. But the cost of existing WFSA, PSO, and GA methods are 53$, 55$, and 57$. The cost of proposed method is lower to existing methods.
The output power of PV, WT, DG, and battery using proposed approach
Cost analysis of GPC-BOA and existing techniques
In this manuscript proposed a hybrid approach for off-grid connected system. The proposed approach is efficiently diminish the system cost, size of HRES and improve power flow of the system as well as satisfies the load requirement system. The simulation outcome analyzed under four cases like spring, summer, autumn, and winter season. The proposed approach used for generate the evaluation of the sources, storage and approachable load offers. The cost analysis point of view, proposed system efficiently reduce that cost compared to existing system and provide less solution time. The cost of the proposed system achieves the minimum cost of 45$.Based on this work, control problems for the whole system, to recover the security of the whole system may be further investigated on future.
