Search

Rising electricity consumption and the desire to reduce carbon emissions have increased interest in renewable energy sources such as wind and solar power. This study describes how to successfully implement and simulate a wind power system and a photovoltaic (PV) power system using MATLAB/Simulink. The presented research exhibits the successful implementation of a wind power system and a photovoltaic (PV) power system using MATLAB/Simulink. The wind power system includes a wind turbine, battery bank, inverter, and load, while the PV power system comprises PV panels, battery bank, inverter, and load. By conducting simulations, the study demonstrates the power output of both systems under various operating conditions, providing evidence for the potential of renewable energy sources in power generation. [ABSTRACT FROM AUTHOR]

Due to the intermittent nature of solar irradiation, it is inevitable to integrate the system of energy storage in the PV standalone system. In this paper, Energy Storage System ESS composed of a battery bank and Supercapacitor SC has been employed to maintain power supply to the load. Because of the fast rate of charge/discharge of SC, it would handle the surge transient energy and that would reduce the required capacity of the battery, increase the life span, and lessen the maintenance cost. The control strategies ensure well power flow control between the PV system and ESS and thus meet the load demand, moreover sustain the DC-link voltage regulated. In the implemented control techniques, a protective improvement is proposed which would limit overcharging of the battery. That would minimize battery degradation and enhance the reliability of the system. This is performed by employing the battery uncompensated power to reduce the stress on the battery during the large fluctuations in the power due to load/irradiance variation. The control approach is based on providing optimal reference current for the ESS with fast dynamic response and reduce the computational burden when implementing in real-time, hence stable power could be delivered to the load. Moreover, the generated PV power is controlled based on the battery charging state and the demand power and this would ensure stable control of DC output voltage. The aforementioned points have led to vigorous PV system having a long-life battery and are capable of preserving energy balance between generations and load even at the abrupt load/solar irradiation variations. . A profile of solar irradiance for selected area has obtained and the system is tested under these data, and it has shown well dynamic response and this could be used for consideration of prototype implementation. The proposed control system is simulated by MATLAB/Simulink and the results show good performance under different scenarios of load/solar irradiation variations

Access to electricity remains elusive for over 700 million people worldwide. Although much attention has been given to solving this vexing problem in the context of communities in Sub-Saharan Africa and South Asia, often overlooked is that in even within so-called developed countries access to electricity might not be universal. It is estimated that more than 200,000 people living in North America do not have a connection to the electric grid. Many of these people live on Native American reservations or other Tribal Lands. Recently, there has been a concerted effort in the public, private, and non-profit sectors to electrify these homes with off-grid solar systems. This paper analyzes the electrical energy usage characteristics of 127 homes on the Navajo reservation in the southwestern United States. The homes have identical 3.8 kW solar arrays, 35.1 kWh 48 V gel lead acid battery banks, and 8 kW inverters. High-resolution inverter data was collected from these systems for a two-year period. Several statistical analyses were conducted on the data, including computing the statistical moments, creating empirical distributions of daily consumption, and analyzing consumption variation across different timescales. The results show average consumption of 2.78 kWh per day, but with a wide range of variation among homes. The implications of the analyses on pre-implementation system design, post-implementation interventions, and comparisons to incipient electricity consumption characteristics elsewhere in the world are discussed. The use of the average daily consumption in data-driven load estimation is evaluated and found to offer promising improvements over survey-based methods. • Analysis of 2-years of load data from off-grid residential solar systems on the Navajo Nation. • The study finds average daily consumption to be 2.78 kWh/day but with wide variation among the homes. • Statistical characteristics including statistical moments and quantiles are provided. • Analyses show how different component sizes could meet load and reliability targets. [ABSTRACT FROM AUTHOR]

The electrification of transport, has placed a great deal of attention into electrical energy storage. Several battery technologies exist, but all of them are based on banks of modules that connected together add up the voltage of the current needed for each application. The chemical processes that occur within the modules may condition the life of the battery. This points to the direction of management systems that can control how the batteries are used. In this work we suggest an IoT platform that can manage the control of multi-modular battery banks and that can be accessible for the many (MIT license). The platform has been proven to be sound, and it gives multiple possibilities to users and developers. A use case has been shown on this paper in which the platform allows the management of a real battery bank providing real data and applying an intelligent algorithm that forecasts the charging process and controls that the variables are within acceptable ranges.

To simultaneously satisfy the electricity and freshwater requirements, a superstructure of a solar-wind-diesel hybrid energy system (HES) with multiple types of storage devices driving a reverse osmosis desalination (ROD) process is established in this paper. The corresponding mathematical model of the HES, potentially including photovoltaic cells, a wind turbine, a diesel generator, a ROD unit, different battery storage technologies, or a water tank is developed and features mixed integer linear programming. The optimum design and operation schemes of the HES can be obtained by taking the minimum total annual cost as the optimization objective. To verify the effectiveness of the proposed method, an example of a solar-wind-diesel system for supplying a ROD process in Saudi Arabia is adopted. The results show that a photovoltaic panel, wind turbine, diesel generator, lead-acid battery, Li-ion battery and water tank are selected in the HES with the minimum total annual cost (i.e., 1.16 × 105 USD·y−1), by satisfying the requirement of the renewable energy penetration rate (i.e., 0.8). Then, a quantified method is proposed to determine the optimal design and operation schemes of the HES, including both economic and environmental aspects. Finally, the HES with various generators and multiple types of storage devices shows a better performance in terms of economy and renewable energy utilization. [ABSTRACT FROM AUTHOR]

This paper proposes an accurate and efficient Universal Adaptive Stabilizer (UAS) based online parameters estimation technique for a 400 V Li-ion battery bank. The battery open circuit voltage, parameters modeling the transient response, and series resistance are all estimated in a single real-time test. In contrast to earlier UAS based work on individual battery packs, this work does not require prior offline experimentation or any post-processing. Real time fast convergence of parameters' estimates with minimal experimental effort enables update of battery parameters during run-time. The proposed strategy is mathematically validated and its performance is demonstrated on a 400 V, 6.6 Ah Li-ion battery bank powering an induction motor driven prototype electric vehicle (EV) traction system.

In current scenario, people tend to move towards outskirts and like to settle in places that are close to nature. But, due to urban lifestyle and to fulfill the basic needs, demand of electricity remains the same as in urban areas. This demand of electricity can be only fulfilled by using hybrid renewable energy resources, which is easily available in outskirts. Renewable energy resources are unreliable and more expensive. Researchers are working to make, it more reliable and economic in terms of utilization. This article proposes a metaheuristic grasshopper optimization algorithm (GOA) for the optimal sizing of hybrid PV/wind/battery energy system located in remote areas. The proposed algorithm finds the optimal sizing and configuration of remote village load demand that includes house electricity and agriculture. The optimization problem is solved by minimization of total system cost at a desirable level of loss of power supply's reliability index (LPSRI). The results of GOA are compared with particle swarm optimization (PSO), genetic algorithm (GA) and hybrid optimization of multiple energy resources (HOMER) software. In addition, results are also validated by modeling and simulation of the hybrid energy system and its configurations at different weather conditions-based results. Hybrid PV/wind/battery is found as an optimal system at remote areas and sizing are N pv = 60 , N wind = 10 , N bat = 40 , N inv = 20.25 and N con = 24.13 with cost of energy (COE) (0.3473$/kWh) and loss of power supplies reliability index (LPSRI) (0%). It is clear from the results that GOA based methods are more efficient for selection of optimal energy system configuration as compared to others algorithms. [ABSTRACT FROM AUTHOR]

The current publication is directed to achieve a high-performance stand-alone PV system having the capability of tracking maximum output power, providing fixed output DC voltage, and attaining efficient system utilization, under different irradiation levels. A new maximum power point tracking (MPPT) approach integrating the incremental conductance algorithm and fuzzy logic control, and enhanced with PI-controller, was proposed to track maximum power. To provide fixed output DC voltage and approaching full system utilization, the PV system is equipped with a battery bank, electrolyzer; as a dump load, and buck-boost converter, with two controllers. The results of the proposed MPPT technique; modified incremental conductance (MINC), are compared with the corresponding results of three prevalently implemented MPPT algorithms: perturbed and observed (P&O), modified variable step-size P&O (VSZ-PO) and the ordinarily incremental conductance (INC). The highest output power, best tracking efficiency and best output power response are achieved by utilizing the proposed MPPT method. The results of the output voltage response and electrolizer on/off states confirm the ability of the PV scheme to provide fixed DC voltage and attain efficient system utilization, under varying irradiances.

The increasing power demand in the world's energy basket and the focus on reducing carbon emission, in tandem with upgrade constraints on conventional grids, has elicited the employment of renewable energies. Specifically, answering the power and cooling/heating demands of remote areas where the grid cannot or can merely supports using locally available and utilizable renewable energies is a focal topic. Herein, a cogeneration system driven by solar energy through parabolic trough collector (PTC) utilization integrated with organic Rankine cycle (ORC), and diffusion absorption refrigeration (DAR) cooling system is proposed. The system is backed up by phase-change material (PCM) and battery bank for solving the intermittence nature of solar energy, and targeted at being employed in a residential building in Shahr Asb, a village in Yazd province, Iran, with a population of less than 600. The system is appraised through exergy evaluation to gauge the efficiency and performance of the system, and life cycle assessment analyses (exergoenvironmental evaluation), to present beneficial data on the mutual impact of the system's performance and environmental conditions. The HYSYS, MATLAB, TRNSYS, and HOMER software and programming environments were utilized to model the cogeneration system. The exergy analysis indicated that the PTC field contributed to the highest exergy destruction (31.80 kW) of the system (67.89 kW) with PTC and system exergy efficiency of 55.23% and 67.89%, respectively. Consistent with the exergoenvironmental analysis, the highest values of cumulative environmental impacts were pertinent to EX-101 expander, (204.02 Pts/h - 29.49%) and E-102 heat exchanger (154.44 Pts/h - 22.33%), individually. Consequently, to mitigate the system's undesirable environmental impacts, the operating conditions of these devices must be amended. The parametric analysis showed that the rise in mole fraction of hydrogen as the inert gas of the DAR system positively affects the evaporator duty and temperature. The required power ( 10.76 kW) and cooling (44.55 kW) are provisioned by utilizing 80.76 kW and 364.30 kW of heat duty in the DAR and ORC system, respectively, which is met by the battery bank and PCM when solar energy is absent during the night. [ABSTRACT FROM AUTHOR]

During the last decades, the use of sustainable energies instead of conventional fuel has been increased due to the global anxiety on environmental and economic problems like climate changes, the limitation of traditional resources, and the increase of electricity consumption. In the present work, design, modeling, and simulation of a Hybrid Power System (HPS), which is united a Wind Turbine System (WTS) with a battery bank, is presented. However, the power operation of the HPS is controlled by a power supervisory in order to reduce energy loss. The supervisory has been implemented in STM32F4 by using the 'PIL simulation' technology and tested under different scenarios of climatic conditions. The results indicate that, during a windy climatic condition, the proposed HPS is broadly enough to generate 100% of the required power with 0.005% of LPSP and 99.84% of RF. Whereas, through a moderate wind speed, the HPS reaches 0.675% of LPSP and 66.94% of RF. But, with a low wind speed, the HPS achieves 0.919% of LPSP and 26.10% of RF. Besides, the proposed WTS was broadly sufficient for supplying the needed power, with an empty battery, especially, when the available wind velocity is around 14.3 m/s at least. Furthermore, it illustrates the efficiency of the supervisory control. [ABSTRACT FROM AUTHOR]

This paper explains a full design and implementation process of a feasible solar car as an effective alternative to the gasoline powered car. A solar car is independent of fossil fuels, and would entirely eliminate emissions. Comparing to the previous manufactured solar cars which were characterized by expensive, one seat driver and unfeasible, the presented solution in this study develops a commercially feasible version of a solar car. The structure’s mass and passengers’ mass are considered to calculate the required electrical power for the car to be able to reach the target speed at 100 km/h. A three photovoltaic panels of 320 W are parallel connected as a photovoltaic array to charge a lithium ion battery bank of 48 V and 200 Ah during the day hours. The testing of the implemented car guarantees the successful and flexible design and promises an effective commercial prototype of solar car. The presented work is done in the American University of Ras Al Khaimah.

This paper presents an application of fractional control scheme named Tilt Integral Derivative (TID) to control a stand-alone hybrid energy system composed of a solar photovoltaic (PV) system and a battery bank (BB). A three-level NPC inverter is inserted in order to increase the efficiency of the energy injected into the AC load. Variation in solar radiation or AC load may cause power imbalance, which leads to variation in DC link voltage. As a solution, a buck-boost converter is connected between the DC link and the battery bank to ensures the transfer of energy in both directions. The parameters of TID controller were tuned using a powerful optimization technique known a Genetic Algorithm (GA) by minimizing the Mean Square Error (MSE) used as a performance index. The effectiveness of the proposed TID controller is demonstrated through a comparison with a conventional Proportional-Integral-Derivative (PID) controller, whose parameters are computed by the pidtool function of the Matlab/Simulink tool where the DC link voltage behavior is previously modeled by a capacitor transfer function. The obtained results show that the proposed TID controller provides a stable DC bus with low chattering, regardless of the rapid irradiation and load changes, when compared to a conventional PID controller. [ABSTRACT FROM AUTHOR]

The current publication is directed to achieve a high-performance stand-alone PV system having the capability of tracking maximum output power, providing fixed output DC voltage, and attaining efficient system utilization, under different irradiation levels. A new maximum power point tracking (MPPT) approach integrating the incremental conductance algorithm and fuzzy logic control, and enhanced with PI-controller, was proposed to track maximum power. To provide fixed output DC voltage and approaching full system utilization, the PV system is equipped with a battery bank, electrolyzer; as a dump load, and buck-boost converter, with two controllers. The results of the proposed MPPT technique; modified incremental conductance (MINC), are compared with the corresponding results of three prevalently implemented MPPT algorithms: perturbed and observed (P&O), modified variable step-size P&O (VSZ-PO) and the ordinarily incremental conductance (INC). The highest output power, best tracking efficiency and best output power response are achieved by utilizing the proposed MPPT method. The results of the output voltage response and electrolizer on/off states confirm the ability of the PV scheme to provide fixed DC voltage and attain efficient system utilization, under varying irradiances. [ABSTRACT FROM AUTHOR]

In this paper a new wind pumping system is developed. This system is hybrid between mechanical and electrical wind pumping systems. It combines the advantages of these two systems. The developed wind pumping system consists of wind turbine, special gearbox, DC machine, battery bank, and water pump. Three wind pumping systems have been modeled and then simulated by using MATLAB/SIMULINK. The simulation results show that the developed wind pumping system has the best performance. Thus, the extracted water volume of the developed system is 984.1 m3, where mechanical and electrical systems extract 737.2 and 642.9 m3 respectively. [ABSTRACT FROM AUTHOR]

In this paper, a wind/photovoltaic/battery/diesel hybrid system with hourly analysis during a year is modeled and optimized for different cities of Iran with various ranges of wind, solar and ambient temperature. A number of solar panels, wind turbines, batteries as well as nominal capacity of diesel engine are considered as design parameters. Fuel ratio and total annual cost (TAC) are selected as two simultaneous objective functions, and particle swarm optimization algorithm is used to find the optimum value of design parameter. The optimum results reveal that Zahedan has the significant lower TAC compared with other studied cases. Optimum cost increases 4.63%, 5.85%, 8.24%, 15.45% and 17.60%, respectively, in the Bushehr, Kerman, Tabriz, Tehran and Mashhad as compared with Zahedan. Optimum results reveal that annual cost extremely increases for the system with the absence of diesel engine (highest fuel ratio). For example, TAC increases at least 100% for the improvement of fuel ratio from 0.8 to 1 for all studied cities. The results also reveal a regular fluctuation in the battery charging and discharging is observed in the high available radiation cities such as Zahedan and Kerman. Furthermore, TAC increases in a linear manner, while fuel ratio increases in an exponentially manner with the increase in the number of PV panels in the optimum situation for all studied cases. [ABSTRACT FROM AUTHOR]

The use of hybrid storage systems has become a global solution in recent years to supply electronic devices with reliable, continuous and clean energy. Several benefits of energy storage systems can be properly combined through the use of these technologies and an adequate energy supply for specific uses can be achieved. In today's world, there is a constant global requirement for more energy, which has to be cleaner at the same time than energy produced by traditional generating technologies. This has encouraged the penetration of distributed generation technologies and, in particular, renewable energy sources. This paper also discusses various kinds of energy storage devices and studies their demerits and merits of these devices. The observations made from different types of renewable energy sources and their functions in hybrid systems are then analyzed. Certain energy storage systems have been simulated and modelled. In hybrid storage devices, the necessary electronic power circuits have been introduced. Finally, some realistic examples of a hybrid power system such as a battery supercapacitor are modeled, simulated and presented. [ABSTRACT FROM AUTHOR]

This work deals with the optimization of an hybrid energy system used to supply an isolated site. The proposed system combines a wind turbine, a photovoltaic panel, a diesel generator and a battery bank to electrify atypical home. An energy cost-effectiveness approach is adopted in accordance with meteorological data, time profile of energy consumption, and the cost of different alternative systems. A variety of performances is obtained through simulations within the Homer Pro environment. The selection of an optimal combination is based on the maximum integration of renewable energy in the suggested system with a minimum of gas emission. According to the obtained results, the overall cost of the selected installation is about 72,900 €, with 0.415€ the unit cost of a kWh electric energy provided with a contribution of renewable energy of around 86%. Simulations show a technical and financial benefits of the different configurations obtained to supply the target site. To control the proposed hybrid energy system, a supervision algorithm is developed and implemented on TMS320F28027 DSP platform. The proposed energy system aims to take advantages of renewable energy sources and shift to conventional sources only when necessary in order to ensure source autonomy and service continuity.

This paper explains a full design and implementation process of a feasible solar car as an effective alternative to the gasoline powered car. A solar car is independent of fossil fuels, and would entirely eliminate emissions. Comparing to the previous manufactured solar cars which were characterized by expensive, one seat driver and unfeasible, the presented solution in this study develops a commercially feasible version of a solar car. The structure's mass and passengers' mass are considered to calculate the required electrical power for the car to be able to reach the target speed at 100 km/h. A three photovoltaic panels of 320 W are parallel connected as a photovoltaic array to charge a lithium ion battery bank of 48 V and 200 Ah during the day hours. The testing of the implemented car guarantees the successful and flexible design and promises an effective commercial prototype of solar car. The presented work is done in the American University of Ras Al Khaimah. [ABSTRACT FROM AUTHOR]

The fluctuating nature of solar energy necessitates suitable energy storage systems. Compared to typical battery banks, supercapacitors offer longer cycle life eliminating the need to replace them regularly. However, compared to a typical maximum power point tracking controller, where the battery bank and resistive load fed by a switch‐mode DC–DC converter allows impedance matching for maximum power transfer, a supercapacitor bank's significantly large capacitive load does not permit the typical impedance matching for maximum power transfer. This study compares the theoretical difference between battery versus supercapacitor energy storage, and highlights of the supercapacitor‐assisted LED converter technique in achieving high‐efficiency renewable energy‐based DC‐microgrid systems. [ABSTRACT FROM AUTHOR]

Telecom sites get the power normally from the grid. At the occurrence of power outages power need to be supplied for telecom sites. The battery bank is a good option for telecom sites to fulfil power demand. This paper discusses a smooth battery bank charging and discharging system with solar power as the input supply source. The system requires a large capital investment, but it provides uninterrupted emergency power when needed. Maintaining battery banks is essential for getting optimum performance. This paper also discusses the power requirements for telecom sites backup and various parameter impacts on battery life. Methods are derived to optimize charging management of batteries in order to get maximum lifespan in addition to better battery performance throughout its useful life. [ABSTRACT FROM AUTHOR]

Hybrid systems have emerged as a reliable solution to meet the increasing demand loads in various fields and address the electricity shortage in remote areas. Consequently, research efforts have been directed towards determining the optimal sizing of hybrid system components to cater to different areas' demand loads. Effective energy management of hybrid micro-grid components is essential to ensure the delivery of high-quality and cost-effective power supply globally. Various optimization techniques have been employed to achieve this objective and determine optimal solutions. This paper proposes an improved version of the Flow Direction Algorithm (FDA), named mFDA, to determine the optimal sizing of a standalone system comprising solar panels, a diesel generator (DG), and a battery bank to meet the demand load in Luxor, Egypt. The primary objective of this research is to reduce the cost of energy (COE) of the system, the net present cost (NPC) of the proposed hybrid power system, the probability of a power supply loss (LPSP), and the size of a microgrid's components. The proposed methodology aims to provide an effective solution to optimize the hybrid system's performance and energy management, which can be applied in other regions as well. To achieve economic energy with high quality and effective sizing with the lowest annual cost in the shortest amount of time, Results from the proposed mFDA are evaluated with those from the original (FDA), Grey Wolf Optimizer (GWO), Gorilla Troops Optimizer (GTO), a new Optimization technique based on COOT Bird Natural Life Model (COOT), and Smell Agent Optimization (SAO) algorithm. The MATLAB program's simulation results indicate that the proposed modified mFDA algorithm performs better than other algorithms when it comes to designing hybrid microgrid component sizing. After 44 iterations, the mFDA approach demonstrates stable convergence characteristics and achieves a minimum Cost of Energy (COE) of approximately 0.2658555/kWh, a Low Probability of Sustainable Power (LPSP) of 0.06555, and a Net Present Cost (NPC) of 7,767,179. The original FDA method closely follows, attaining a COE of about 0.2658555/kWh, LPSP of 0.06555, and NPC of 7,767,179. • Effective energy management of hybrid micro-grid components. • Improved approach using modified Flow Direction Algorithm (mFDA). • Primary objective: reduce cost of energy, net present cost, LPSP, and size. • mFDA achieves best design of hybrid microgrid components in shorter time. • Proposed approach helps achieve economic energy with low annual cost. [ABSTRACT FROM AUTHOR]

Abstract The foremost issues of 21st century are challenging demand of electrical energy and to control the emission of Green House Gases (GHG) emissions. Renewable energy resources based sustainable microgrid emerges as one of the best feasible solution for future energy demand while considering zero carbon emission, fossil fuel independency, and enhanced reliability. In this paper, optimization and implementation of institutional based sustainable microgrid are discussed based on cost analysis, carbon emission, and availability of energy resources. Various microgrid topologies are considered for addressing the most ideal solution. The metrological data such as irradiance is acquired from solar satellite data of NASA (National Aero Space Agency) while the data for wind speed is taken from synergy enviro engineer’s site. HOMER® simulation tool is used for modelling and optimization purpose.

The conversion from existing electrical networks into an all-renewable and environmentally friendly electrification scenario is insufficient to produce and distribute energy efficiently. Electrochemical devices’ premature degradation as a whole caused by electrical stressors in smart grids is incipient from an energy management strategies (EMS) perspective. Namely, few electrical-stress degradation models for photovoltaic panels, batteries, fuel cells, and super/ultra-capacitors (SCs), and particular stressors can be found in the literature. In this article, the basic operating principles for such devices, existing degradation models, and future research hints, including their incorporation in novel EMS, are condensed. The necessity of extending these studies to other stressors and devices is also emphasized. There are many other degradation models by non-electrical stressors, such as climatic conditions and mechanical wear. Although novel EMS should manage both electrical and non-electrical degradation mechanisms and include non-electrochemical devices, models with pure non-electrical-stressors are not the subject of this review since they already exist. Moreover, studies for the degradation of non-electrochemical devices by electrical stressors are very scarce.

This paper presents a three-port three-phase current-fed dc–dc converter with high-frequency isolation and bidirectional power flow. Port I is fed by a battery bank, port II employs a set of photovoltaic modules, and port III is connected to a dc link. The topology uses three single-phase H-bridge cells in the primary side and a three-phase H-bridge converter in the secondary one. High-frequency isolation is ensured by three single-phase transformers connected in an open delta-wye configuration. The theoretical analysis is performed considering the fundamental component of the voltage across the transformers. Maximum power point tracking, the battery current, and the power flow between the primary and secondary sides are controlled by the use of variable duty cycle technique in the primary side and the use of phase-shift technique between the primary and secondary bridges. In order to validate the study, experimental results of the proposed system considering the dc rated voltages as 48 V/96 V/380 V for Ports I/II/III, respectively, and rated power of 3.5 kW are carried out. [ABSTRACT FROM AUTHOR]

This work deals with the optimization of an hybrid energy system used to supply an isolated site. The proposed system combines a wind turbine, a photovoltaic panel, a diesel generator and a battery bank to electrify atypical home. An energy cost-effectiveness approach is adopted in accordance with meteorological data, time profile of energy consumption, and the cost of different alternative systems. A variety of performances is obtained through simulations within the Homer Pro environment. The selection of an optimal combination is based on the maximum integration of renewable energy in the suggested system with a minimum of gas emission. According to the obtained results, the overall cost of the selected installation is about 72,900 €, with 0.415€ the unit cost of a kWh electric energy provided with a contribution of renewable energy of around 86%. Simulations show a technical and financial benefits of the different configurations obtained to supply the target site. To control the proposed hybrid energy system, a supervision algorithm is developed and implemented on TMS320F28027 DSP platform. The proposed energy system aims to take advantages of renewable energy sources and shift to conventional sources only when necessary in order to ensure source autonomy and service continuity. [ABSTRACT FROM AUTHOR]

This work deals with a renewable energy based microgrid (MG) for standalone operation. The places, where renewable energy sources such as wind, solar, hydro, etc., are in abundance, use them to generate electricity by developing wind–hydro based MG. The main control unit of MG is voltage source inverter (VSI) in which an indirect current control is applied. This VSI is used for power quality improvements through harmonics suppression of nonlinear loads; voltage regulation during contingencies such as load unbalance; and reactive power compensation at point of common coupling according to the system requirement. It is capable of providing power balance under various changes among the generation, storage, and demand units. For appropriate functioning of VSI, a reweighted zero attractor least mean square control algorithm is applied to generate pulsewidth modulation switching pulses for VSI. A model of MG is developed in MATLAB/Simulink environment to simulate its performance in normal and dynamic conditions at linear and nonlinear loads. A prototype of MG is developed in the laboratory of 10 kW to validate the control and simulated performances. [ABSTRACT FROM AUTHOR]

This study presents an advanced control structure aimed at the optimal economic energy management of a renewable energy‐based microgrid. This control scheme is applied to energy optimisation in a microgrid with non‐dispatchable renewable sources, such as photovoltaic and wind power generation, as well as dispatchable sources, as distributed generators, hybrid storage systems compound by battery bank, supercapacitors, hydrogen storage unit, and one electric vehicle charging station. The proposed controller consists of a Lyapunov‐based hybrid model predictive control based on mixed logical dynamical (MLD) framework. The main contribution of the proposed technique is the assurance of the closed‐loop stability and recursive feasibility, by a novel approach focused on MLD models, using ellipsoidal terminal constraints and the Lyapunov decreasing condition. Finally, simulation tests under different operational conditions are performed and the attained results have shown the safe and reliable operation of the proposed control algorithm compared to existing and well‐known energy management techniques. [ABSTRACT FROM AUTHOR]

This paper deals with analysis of power generating units installed within the technological centre. To be able to analyse behaviour of such a complex system with accumulation, the dynamic model of the technology was created using the EMTP-ATP software. The current configuration of the dynamic model is based on the block diagram containing all the unconventional sources of electric power. The values produced by ATPDraw are shown in graphs for reference. The dynamic model will serve the purpose of research and observation of the entire technological centre with respect to transients at individual sources of power.

Highlights • A charge/discharge schedule for a battery was optimized. • 20 charge/discharge rates were simulated. • Increasing the number of rates improved performance. • At 12 charge/discharge rates the improvement plateaued. • An input sensitivity analysis was conducted. Abstract This paper proposes strategies to optimize the daily charge and discharge schedule of a battery bank, in order to minimize the operating cost of a building that uses renewable energy sources. The schedule was optimized using a range of battery charge and discharge rates over a 24 h period. These rates were controlled using a genetic algorithm (GA) and a particle swarm optimization algorithm (PSO), which utilized day-ahead prediction data for electricity consumption and electricity price, as well as electricity output from a photovoltaic system and a wind turbine. The results showed that the building operating costs decreased as the number of available charge and discharge rates was increased. The average daily operating cost was reduced by up to 31% using the GA and by up to 28% using the PSO, compared to the scenario where no battery was used. Furthermore, the reduction in average daily operating costs began to plateau as the number of charge and discharge rates reached 12. It was also shown that the scaling of irradiance, wind speed and electricity price inputs impacted the optimized daily operating cost of the building. A sensitivity analysis was conducted to investigate how this scaling of inputs affected the overall performance of the GA. It was found that the optimized daily operating costs were almost unchanged after numerous scaling percentages were applied to the electricity price, with additional cost reductions of up to 3% compared to the scenario where no scaling percentages were applied. In contrast, scaling percentages applied to weather data were found to have a more significant impact on the optimized operating costs, with additional cost reductions of up to 17% compared to the scenario where no scaling percentages were applied. Moreover, a non-linear relationship was observed between the weather data scaling percentage and optimized daily cost. [ABSTRACT FROM AUTHOR]

This paper presents an approach to the energy management and control of the effective cost of energy in real-time electricity pricing environment. The strategy aims to optimise the overall energy flow in the electrical system that minimises the cost of power consumption from the grid. To substantiate these claims different cases of time-of-use (TOU) and renewable energy electricity tariff, i.e. in summer and winter seasons, and the robustness of system is analysed. A given energy demand for commercial usage in the city of Tshwane (South Africa) is used to investigate the behaviour of the designed method during low and high demand periods. As grid integrated renewable energy resources, photovoltaic (PV) is an important consideration in assuring excellent power supply and environmental issues in the commercial building. An adaptive optimal approach in the framework of model predictive control (MPC) is designed to coordinate the energy flow on the electrical system. The results show that the proposed adaptive MPC strategy can promote the new approach of an optimal electrical system design, which reduces the energy cost to pay the utility grid by about 46% or more depending on the set target. [ABSTRACT FROM AUTHOR]

With the aim of increasing the self-consumption rate of grid-connected Photovoltaic (PV) home systems, two main options can be implemented: the inclusion of an energy storage system, in particular a battery bank, and the adoption of a Demand Side Management (DSM) strategy. However, both the reshaping of the load consumption curve with the displacement of deferrable loads and the optimal management of the battery bank require estimation of the daily PV generation profile. The assessment of the on-site energy production can be carried out based on weather forecast data. However, the latter are characterized by uncertainty, which may affect the achievable self-consumption rate. This work investigates the influence of weather forecast errors on the performance of home PV systems equipped with a battery bank and characterized by a certain share of deferrable loads. Two different weather forecast services are considered, referring to the annual meteorological conditions occurring in Rome, and energy consumption data for 150 different households are analysed. The self-consumption rate is maximized by solving a suitable optimization problem, while different combinations of relative battery capacity, PV-to-load ratio and share of deferrable loads are considered. Two different approaches—deterministic and stochastic—are adopted and compared with an ideal approach where the PV generation profile is perfectly forecasted. The results show that the adoption of the deterministic approach leads to a reduction in the achievable self-consumption rate in the range of 0.5–4.5% compared to the ideal approach. The adoption of a stochastic approach further reduces the deviations from the ideal case, especially in the case of consumption profiles with a high share of deferrable loads. Finally, a preliminary economic analysis proves that the use of a battery bank is not yet a cost-effective solution and a price reduction of the current battery prices is therefore required. [ABSTRACT FROM AUTHOR]

Electric forklifts, dominantly powered by lead acid batteries, are widely used for material handling in factories, warehouses, and docks. The long charging time and short working time characteristics of the lead acid battery module results in the necessity of several battery modules to support one forklift. Compared with the cost and time consuming lead acid battery charging system, a fuel cell/battery hybrid power module could be more convenient for a forklift with fast hydrogen refueling and long working time. In this paper, based on the characteristics of a fuel cell and a battery, a prototype hybrid forklift with a fuel cell/battery hybrid power system is constructed, and its hardware and software are designed in detail. According to the power demand of driver cycles and the state of charge (SOC) of battery, an energy management strategy based on load current following for the hybrid forklift is proposed to improve system energy efficiency and dynamic response performance. The proposed energy management strategy will fulfill the power requirements under typical driving cycles, achieve reasonable power distribution between the fuel cell and battery and, thus, prolong its continuous working time. The proposed energy management strategy is implemented in the hybrid forklift prototype and its effectiveness is tested under different operating conditions. The results show that the forklift with the proposed hybrid powered strategy has good performance with different loads, both lifting and moving, in a smooth and steady way, and the output of the fuel cell meets the requirements of its output characteristics, its SOC of battery remaining at a reasonable level.

In this paper, cost-efficient operation problem of photovoltaic/battery/fuel cell hybrid energy system has been evaluated in the presence of demand response program. Each load curve has off-peak, mid and peak time periods in which the energy prices are different. Demand response program transfers some amount of load from peak periods to other periods to flatten the load curve and minimize total cost. So, the main goal is to meet the energy demand and propose a cost-efficient approach to minimize system’s total cost including system’s electrical cost and thermal cost and the revenue from exporting power to the upstream grid. A battery has been utilized as an electrical energy storage system and a heat storage tank is used as a thermal energy storage system to save energy in off-peak and mid-peak hours and then supply load in peak hours which leads to reduction of cost. The proposed cost-efficient operation problem of photovoltaic/battery/fuel cell hybrid energy system is modeled by a mixed-integer linear program and solved by General algebraic modeling system optimization software under CPLEX solver. Two case studies are investigated to show the effects of demand response program on reduction of total cost. [ABSTRACT FROM AUTHOR]

It is a great challenge for DC microgrids with stochastic renewable sources and volatility loads to achieve better operation performance. This study proposes an energy management strategy based on multiple operating states for a DC microgrid, which is comprised of a photovoltaic (PV) array, a proton exchange membrane fuel cell (PEMFC) system, and a battery bank. This proposed strategy can share the power properly and keep the bus voltage steady under different operating states (the state of charge (SOC) of the battery bank, loading conditions, and PV array output power). In addition, a microgrids test platform is established. In order to verify the effectiveness of the proposed energy management strategy, the strategy is implemented in a hardware system and experimentally tested under different operating states. The experimental results illustrate the good performance of the proposed control strategy for the DC microgrid under different scenarios of power generation and load demand. [ABSTRACT FROM AUTHOR]

This paper presents a real-time coordinated control of the hybrid ac/dc microgrids involving energy storage and pulsed loads. Grid-isolated hybrid microgrid applications require special considerations due to the intermittent generation, online energy storage control, and pulsed loads. In this study, we introduce a comprehensive frequency and voltage control scheme for a hybrid ac/dc microgrid consisting of a synchronous generator, solar generation emulator, and bidirectional (ac/dc and dc/dc) converters. A bidirectional controlled ac/dc converter with an active and reactive power decoupling technique is used to link the ac bus with the dc bus, while regulating the system voltage and frequency. A dc/dc boost converter with a maximum power point tracking function is implemented to maximize the intermittent energy generation from solar generators. Current-controlled bidirectional dc/dc converters are applied to connect each lithium-ion battery bank to the dc bus. Lithium-ion battery banks act as energy storage devices that serve to increase the system resiliency by absorbing or injecting power. Experimental results are presented for verification of the introduced hybrid ac/dc power flow control scheme. [ABSTRACT FROM AUTHOR]

In this paper, a study of Hybrid power system to supply energy to an electric vehicle is presented. The hybrid system is used to produce energy without interruption and it consists of a proton exchange membrane fuel cell (PEMFC) and a battery bank. PEMFC systems work in parallel via DC/DC converter and the battery bank is used to store the excess of energy. The mathematical model topology, the identification of each subsystem and the control supervision of the global system are the contribution of this paper. Obtained results under Matlab/Simulink and some experimental ones are presented and discussed. [ABSTRACT FROM AUTHOR]

This paper deals with analysis of power generating units installed within the technological centre. To be able to analyse behaviour of such a complex system with accumulation, the dynamic model of the technology was created using the EMTP-ATP software. The current configuration of the dynamic model is based on the block diagram containing all the unconventional sources of electric power. The values produced by ATPDraw are shown in graphs for reference. The dynamic model will serve the purpose of research and observation of the entire technological centre with respect to transients at individual sources of power. [ABSTRACT FROM AUTHOR]

There are high numbers of remote villages that still need electrification in some countries. Extension of the central electrical power network to these villages is not viable owing to the high costs and power losses involved. Isolated power systems such as rural microgrids based on renewables could be a potential solution. Photovoltaics (PV) technology is particularly suited for countries like India due to factors such as the available solar resource, the modularity of the technology and low technology costs. It was identified that unlike larger isolated power systems, rural microgrids have a low energy demand as the loads are mainly residential and street lighting. Hence, these microgrids could be of a single-phase configuration. At present, the typical procedure followed by planners of rural networks does not consider the importance of PV source siting and optimisation of network structure. An improved design procedure is introduced in this work based on the use of centres of moments for central PV system sizing, simulated annealing for network structure optimisation and load flow based parametric analysis for confirming the PV microgrid structure before detailed software-based PV design. Case studies of two remote villages are used to inform and illustrate the design procedure.

To deal with increasing energy consumption in the residential sector, distributed energy resources including photovoltaic (PV), fuel cell, etc. have been paid more and more attention. In this study, an optimization model is developed for the PV/Fuel Cell/Battery based residential energy system. While guaranteeing reliable system operation, the model may determine the optimal running strategies with annual running cost or annual CO 2 emissions as the objective function to be minimized. In addition, besides the energy flows among the equipments within the hybrid energy system, the economic information including electricity tariff and natural gas price, as well as some policy issues (e.g., buy-back price) are also accounted. As the results of the model, besides the optimal electric and thermal balances, the rational utilization forms of PV module, fuel cell and battery can be also deduced. To verify the viability of the proposed approach, a numerical example is implemented and analyzed. The optimal operating strategies are deduced and compared from different perspectives. Furthermore, the results demonstrate that the PV module mainly contributes to the environmental performance of the assumed hybrid energy system, while the battery may be beneficial from the economic viewpoint. [ABSTRACT FROM AUTHOR]

A huge attention is paid to integrating buildings with renewable energy resources (RES) as a key factor to act on increasing demand. Meanwhile, utilizing different power resources can be a viable alternative for communities suffering from frequent and planned power outages. Conventionally, diesel generators are utilized as emergency backups to lessen the impact of power outages, but they consume a massive amount of fuel in case of extended outage periods. In this context, the work proposes an alternative microgrid power supply system incorporates photovoltaic solar array and lead-acid battery bank in addition to the conventionally utilized diesel generator for buildings experiencing frequent power outages. Besides, an energy management scheme is proposed to carry out the proposed supply. The main components of the system are modeled in MATLAB and the simulation is performed over a relatively long period (two weeks) to capture the pertinent dynamics of the system. The work is conducted using the example of Al-Shifa' Hospital in Gaza-Strip to verify the effectiveness of the proposed approach. Moreover, different operation scenarios are tested from different perspectives with respect to the planned outages in Gaza-Strip. Simulation results indicate significant fuel savings in addition to a reduction in the total operation time of the diesel generator set (GenSet). [ABSTRACT FROM AUTHOR]

The Stochastic nature of wind power can cause insufficiency of supply in electrical systems. Applying an energy storage system can alleviate the impact of wind power forecast error on power systems performance and increase system tolerance against deficiency of supply. This paper attempts to investigate a new unit commitment (UC) problem based on the cost–benefit analysis and here-and-now (HN) approach for optimal sizing of battery banks (BBs) imicrogrids (MGs) with wind power systems. To solve this problem, particle swarm optimization is used to minimize the total cost and maximize the total benefit. In this paper, 12 scenarios have been considered in the presence of BBs and without them in 2 operating modes: 1) stand-alone mode and 2) grid-connected mode. Using the HN approach, the uncertainty of wind power is applied as a constraint in these operating modes. The mathematical formulations related to the HN approach in MGs and its combination in a UC problem are presented in detail for optimal sizing of BBs. Simulation results show that the best sizes of BBs and the scheduling of distributed generations would be entirely different when the accessibility of wind power is taken into consideration by applying HN approach to the proposed probabilistic UC problem. [ABSTRACT FROM PUBLISHER]

Energy is one of the most important factors in the socioeconomic development of a country. In a developing country like Malaysia, the development of islands is mostly related to the availability of electric power. As an island surrounded by sea, power generated by wave energy source will become one of the most promising solutions for the electrification of island areas. But, the unpredictable nature of the wave energy source is the main drawback. This paper presents a novel stand-alone wave energy supply system modeling with maximum power tracking and an energy storage-based power management algorithm in MATLAB/Simulink environment. The main contributions of this research work are eliminating the intermittent power generation nature of wave energy and efficiently extract the maximum wave power. In the proposed stand-alone system, a DC–DC bidirectional buck-boost converter controller is used to maintain the constant dc-link voltage. It also accumulates the surplus wave power in the battery bank and supplies this power to the load during the wave power shortage. A three-phase complex vector control scheme voltage source inverter is used to control the load-side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from MATLAB/Simulink, it has been found that the overall system is capable of working under variable weather and load conditions, and it can also able to extract the maximum wave power. [ABSTRACT FROM PUBLISHER]

This study presents a robust and cost‐effective microgrid topology for integrating two commonly available wind and small‐hydro renewable energy sources. The proposed topology has two generators, one of them is self‐excited squirrel cage induction generator driven by a small‐hydro turbine and other one is permanent magnet brushless DC generator driven by a small‐scale wind turbine. The proposed system is integrated using a voltage source converter and a boost converter which are maintaining voltage and frequency, mitigating power quality problems and performing mechanical sensorless maximum power point tracking, respectively. A battery bank is also used to balance the load and supply power mismatch and to ensure the supply for critical loads. The proposed control algorithm is tested and verified on a developed laboratory prototype of the system. Test results verify that voltage and frequency of the system are regulated and the power‐quality‐related issues are also resolved in this microgrid. [ABSTRACT FROM AUTHOR]