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The dynamic performance and effect of hybrid renewable power system with diesel/wind/PV/battery
Abstract
Diesel generators often supply electric power to isolated islands and off-grid remote loads. In remote locations, the cost of fuel can be very high due to the limited accessible transportation. Inclusion of renewable energy into diesel-based grids results in a hybrid renewable energy system (HRES) and can reduce fuel consumption and environmental pollution. However, the output variability of renewable energy sources injected into diesel-based systems may impact the power quality and stability of the power system. The operation of HRES requires a good understanding of the dynamic behavior of each energy source connected to the system. This work focuses on the dynamic performance and effects of renewable energy sources on power quality and stability of the power system. A simulation program called the RPM-Sim (renewable-energy power-system modular simulation) is used to investigate the case studies. Dynamic and transient events (wind variation, fault events, etc.) are studied and improvement of power quality and stability for the cases identified below are presented in this paper.
... A great deal of work has been previously reported to enhance the efficiency and to improve the quality of HPS comprising different renewable energy sources . A lot of research works are going on across the world to look for a new HPS technology for the last two decades [15][16][17][18]. A number of studies have given importance to the physical structure of the renewable power plant and its mathematical modeling [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. ...
... Components of HPS [3][4][5]14,[16][17][18][20][21][22][25][26][27][28][29][30][31]39,44,45,47, RES [14,[80][81][82][83][84] SMES [20,21,45,47,52,53,57,62,63,70,73,75,76,79,83,[85][86][87][88] ESCs [5,[17][18][19][20][21]25 ...
... Components of HPS [3][4][5]14,[16][17][18][20][21][22][25][26][27][28][29][30][31]39,44,45,47, RES [14,[80][81][82][83][84] SMES [20,21,45,47,52,53,57,62,63,70,73,75,76,79,83,[85][86][87][88] ESCs [5,[17][18][19][20][21]25 ...
Concerned with the increasing greenhouse gases in the atmosphere due to fossil fuels, the entire world is focusing on electricity generation through renewable energy resources. The most advantageous aspect of the distributed renewable sources is to provide the electricity to remote, scattered and the deprived rural areas by developing the hybrid power system at the smaller scale where power transmission through grid extension is not viable due to some economical, technical or environmental constraints for building new transmission lines. An accurate and adequate control strategy becomes inevitable to uphold the smooth operation by restraining the frequency and voltage deviation within its limit ensuring the highest degree of reliability of hybrid power system to provide an adequate power quality. In this paper, a comprehensive review of different control strategies adopted in isolated and interconnected multi-area hybrid power systems is presented.
... [12]. It is reported in [13] that in some of 5 these countries, fossil fuel equals to a substantial portion of their total imports. Being a small island nation, the Maldives represent only a tiny fraction of the global greenhouse emission and yet, it is extremely vulnerable to the effects of climate change and the associated sea level raise [14&15]. ...
... Consequently the decision was made to choose the capital cost of supply from the Maldivian company. This was deemed necessary to avoid any error in the capital cost calculation based on the quotes from the international 13 suppliers who had no or little knowledge about the commercial environment of the country. ...
... However, this does not in the project. As a result, the cash flow stream and the NPC given by each of the sensitivity cases do not represent the reality in the simulation in this project, because the additional investments of each year along with all other costs and revenues requires to be taken into account, for it to represent the real NPV 12 of the project 13 . Therefore, a model (a working XL spreadsheet) which performs similar calculations to HOMER, but took into account the correct depreciation of the additional investments that occur later in the project was developed by replicating the cash flow model of HOMER. ...
The islands of the republic of Maldives, with 80% of the land mass less than 1m above the sea level and 44% of its’ people living within 100 m of the coastline is one of the most threatened nations from sea level raise by global warming and climate change. The average sea level raise in the Maldives, recorded by the Meteorological Department of Male' International Airport is 1.7mm/year, with a maximum hourly sea level raise of approximately 7mm/year. This rate is far higher than the observed global trends in mean sea level raise. In consequence, the Maldives is well known for raising global warming and climate change to the attention of the international community, since, if the scientific warning is true, the entire country could be eradicated from the surface of earth. Considering this serious threat, the government has expressed its interest in exploring the possibility of switching from diesel to renewable sources to generate electricity. Beginning with experimental hybrid projects implemented in small islands, the government has recently started installing Photovoltaic (PV) on the rooftops of government buildings in the capital city of Male’. It has little contribution to cater the fast growing demand of electricity in Male’. Its contribution to serve the governments’ initiative to deploy Renewable Energy Technology (RETs) at large scale too, is very much limited due to the limited space available. The capital city Male’ consumes 71% of the total electricity generated by STELCO nationwide. This reflects the alarmingly high population density in the city which has a land area of just 5.8 km2; the home for ~ 42% of the population. Thus, the research, contained in this thesis, is based on modelling a gird connected Distributed Generation Photovoltaic (DGPV) system that is technically sound and financially viable, and can effectively take over partial load on the State Electric Company (STELCO)s’ national grid in Male’, which is planned to be extended to the newly build city of Hulhumale’; an island man-made to provide shelter for the homeless families in the highly populated Male’. This has not been done in any of the previous research. The hypothesis presented, justify the limitation of deploying RETs at a large scale in the Maldives from a techno-economic perspective. Despite the RET potential benefits, the study has focused on the severe constraints and challenges that would limit this change in generation technology. Based on accurate and reliable long term prediction of the future growth of electricity demand on the national grid of STELCO, the research demonstrates modelling of the proposed system using one of the most popular software, Hybrid Optimization of Multiple Energy Resources (HOMER) and the application of universally accepted design guidelines. Its economic feasibility has been done using an XL model developed by replicating the economic modeling of HOMER. The prediction of future growth on the grid for the next twenty years (2011-2030) has been made using multiple regression, one of the most widely used forecasting techniques. The predictions were validated by comparison with the results obtained from an industrial standard tool, the GMDH Shell. The modelling of the proposed supply system has been done using these predictions to identify the optimal system configuration that could meet the load requirement under the constraints specified in the simulation. HOMERs powerful sensitivity analysis feature has been used in this study to explore the energy yield that could be delivered to the grid under the constraints applied. The system being technically sound and financially viable, it represents a realistic and practical alternative solution for the energy requirement of Male’. Its implementation could be the turning point in transforming the energy sector of the country.
... Consequently, despite the distinct features of each energy source, they can work together to meet the energy demand based on the load requirement (Dehghani et al., 2023). Studies indicate that these combined systems have unique interactions with the grid compared to individual systems (Kemp et al., 2023;Pan et al., 2009). For instance, a study conducted in South Africa materialized by measurements on a hybrid PVdiesel generator microgrid, found dynamic changes in the supply voltage (Maritz et al., 2024). ...
... While numerous papers present the simulation results of hybrid systems' steadystate and dynamic operation regarding power quality and system stability (Pan et al., 2009), few discuss conclusions drawn from field measurement analysis demonstrating the operations of such installations. ...
The scientific objective of this study is to demonstrate how a hybrid photovoltaic-grid-generator microsystem responds under transient regime to varying loads and grid disconnection/reconnection. The object of the research was realized by acquiring the electrical magnitudes from the three PV systems (25 kW, 40 kW, and 60 kW) connected to the grid and the consumer (on-grid), during the technological process where the load fluctuated uncontrollably. Similar recordings were also made for the transient regime caused by the grid disconnection, diesel generator activation (450 kVA), its synchronization with PV systems, power supply to receivers, and grid voltage restoration after diesel generator shutdown. Analysis of the data focused on power supply continuity, voltage stability, and frequency variations. Findings indicated that on-grid photovoltaic systems had a 7.9% maximum voltage deviation from the standard value (230 V) and a frequency variation within ±1%. In the transient period caused by the grid disconnection and reconnection, a brief period with supply interruption was noted. This study contributes to the understanding of hybrid system behavior during transient regimes.
... The impact of wind power generation on transmission system is presented in [2] where the impacts on power flow, short circuit current and power quality is analyzed after the integration of 68 MW wind farm into a 69 kV transmission system. Dynamic and transient events like wind variation, fault events, etc. are studied and improvement of power quality and stability of a hybrid renewable power system are proposed in [3]. A case study on the transient performance of a typical subtransmission network in Namibia in relation to grid integration of wind energy is presented in [4]. ...
Energy crisis is one of the most acute problems in the present world. Scarcity of fossil fuel based energy sources has made the problem more severe. In this situation, one of the viable alternative solutions is to use renewable energy sources in integration with conventional power system. It is a great challenge for power system engineers to make proper integration between existing power system and renewable energy sources. This paper depicts the transient stability and the voltage stability of a power system network when renewable energy is integrated in distribution level. A simple power system has been simulated in CYME PSAF release 3.00 with and without renewable sources. It is observed that due to inclusion of renewable energy sources at distribution level, system stability increases.
... Experimentos com fontes de energia renováveis e GMG sem nenhum tipo de controle já foram realizados e foi possível observar as flutuações de potência, desvios de frequência e motorização do GMG [11]. ...
O uso de microrredes tem sido estuada como uma possibilidade de aliviar as redes de distribuição, pois em caso de picos de demanda ou contingencias, a microrrede pode operar de forma isolada, aliviando o sistema de distribuição e fornecendo uma energia de qualidade e mais eficiente, pois sua geração se encontra mais próxima das cargas. A microrrede também pode ser usada de forma totalmente isolada e essa configuração é muito usada em locais remotos onde não há acesso a rede de distribuição. Nestes locais grande parte das microrredes são formadas por geradores a diesel, que demandam um alto consumo de combustível na sua operação. Fontes renováveis como eólica e solar seriam a melhor opção nestes casos, contudo, essas fontes são intermitentes e sua operação é sempre associada a fontes de geração constante. Neste cenário surge as microrredes hibridas, que possibilitam o uso de fontes renováveis para gerar energia limpa e ainda reduzem o consumo de combustível dos geradores a diesel. No entanto, a grande variação de potência das fontes renováveis, ocasionada pela sua intermitência, pode gerar graves problemas na qualidade da energia elétrica e instabilidades no sistema híbrido e assim comprometer a operação da microrrede. Desta forma, este artigo realiza uma análise aprofundada das metodologias mais relevantes propostas na literatura especializada, apontando as principais vantagens e desvantagens de cada uma. Buscando assim, apresentar as pesquisas com o desenvolvimento mais promissor na solução das instabilidades ocasionadas por uma microrrede hibrida, formada por sistemas fotovoltaicos e geradores a diesel.
... 3) LSVSC Control Technique: LSVSC stands for the load side voltage source converter. This converter improves power quality of the islanded Microgrid [12]. The LSVSC is controlled in IM (islanded mode) to produce the PCC voltage (V L ) while maintaining the load demand. ...
... 219,220 Besides time-shifting with energy storage, some articles have also addressed the reliability and power quality enhancement by a hybrid of different RESs. [221][222][223][224] Though there can be other possibilities too for matching supply and demand. In case of a reinforced power grid, overproduction in a particular region can be compensated by transmitting its energy to less productive areas at that instant. ...
... Regarding the cost, the maintenance cost of the grid connected PV system with battery storage is assumed as zero. The author has fixed the installed sixe of PV on the house is 5kWp system and the tilting angle of the PV panel is ignored [9,10]. ...
This paper present on the analysis of an energy storage sizing for a small grid-connected PV system. This project is to study the proper sizing of energy storage (battery) in a grid-connected PV system for consumers whom purchase and sell electricity from and to the utility grid. The goal is to minimize the total cost of the operation for a consumer with a PV system with a battery storage system. This is to make sure that minimizing the total annual operating cost while maintaining an efficient system. This study uses typical consumer load consumption, and solar irradiance data throughout a year, while varying the type of battery storage (study lead acid and Lithium ion battery) as an energy storage for a similar system. Since lithium ion is not the main options to be integrated with PV system, this study will then reveal the data in terms of cost on why it is not a popular choice.
... 219,220 Besides time-shifting with energy storage, some articles have also addressed the reliability and power quality enhancement by a hybrid of different RESs. [221][222][223][224] Though there can be other possibilities too for matching supply and demand. In case of a reinforced power grid, overproduction in a particular region can be compensated by transmitting its energy to less productive areas at that instant. ...
Increased energy demands due to rapid industrialization, environmental concerns with fossil fuel–based generation, diminishing fossil energy resources, transmission network congestion, and technical performance deterioration are the motivations behind the integration of small renewable distributed generation (DG) units and turning the existing power systems into a restructured one. Optimizing the technical benefits offered by DG placement is a well‐known challenge for distribution network operators (DNOs) for both fossil and renewable energy resource–based DGs, but renewable DG systems have several power quality (PQ) challenges associated additionally. Power quality is a very significant characteristic of renewable DG systems because today's loads are more sensitive to PQ disturbances and penetration of renewable energy as well as nonlinear loads is proliferating in distribution power networks. So the need for innovative power quality improvement (PQI) techniques becomes inevitable due to ongoing reformation in traditional distribution networks by the integration of renewable energy. This article presents a comprehensive analysis of power quality challenges with grid integration of renewable DG systems and current research status of associated mitigation techniques. Firstly, this paper puts emphasis on theoretically illustrating all the crucial power quality challenges associated with grid integration of renewable energy, and secondly, a thorough survey, of all PQI techniques introduced till date, is elaborated along with highlighting the opportunities for future research. Furthermore, all the crucial power quality issues, the impact of high penetration of renewable energy and mitigation techniques on power quality, are demonstrated also by simulating a grid integrated PV‐based DG system in MATLAB/Simulink. This article is believed to be very beneficial for academics as well as industry professionals to understand existing PQ challenges, PQI techniques, and future research directions for renewable energy technologies.
... Wai et al ont proposé une nouvelle méthode de gestion de l'énergie pour un système électrique hybride qui comporte une pile à combustible et une batterie [Wai13]. Les performances dynamiques et les effets des sources d'énergies renouvelables sur la qualité de l'énergie et la stabilité d'un système électrique hybride (avec un générateur diesel, un système éolien, une source solaire PV et une batterie) ont été étudiés par Pan et al dans [Pan09]. Le contrôle de qualité de l'énergie d'un micro-réseau comportant une micro turbine, une source solaire PV, une éolienne et une pile à combustible a été étudié par [Li07]. ...
Les Systèmes électriques à Puissance Distribuée (SPD) sont utilisés dans de nombreux secteurs industriels. La sûreté de fonctionnement (SDF) et la continuité de service de ces SPDs sont aujourd'hui des préoccupations majeures. Une stratégie de gestion globale de l'énergie adaptée ainsi que leur stabilité sont des exigences fondamentales pour que ces systèmes puissent fonctionner correctement. La présence de charges déséquilibrées ainsi que les interactions entre convertisseurs dans ces systèmes peuvent conduire à l'instabilité du bus DC commun. Un des cas les plus connus en terme de cause d'instabilité est celui d'une charge "à puissance constante" (CPL). Par ailleurs, toute défaillance au niveau de l'interrupteur commandable du convertisseur peut provoquer de graves dysfonctionnements du système. Tout défaut non détecté et non compensé en temps réel peut rapidement mettre en danger l'ensemble du système de puissance. Par conséquent, la mise en oeuvre de méthodes efficaces et rapides de détection et de compensation de défaut est impérative. Afin d'assurer la continuité de service de ces systèmes. Dans ce mémoire, nous étudions la gestion de l'énergie, la stabilité et la continuité de service d'un DC-SPD. Après l'étude de la gestion de l'énergie et la stabilité du système, une méthode de stabilisation active décentralisée est proposée afin d'augmenter le domaine de stabilité du SPD et afin deéviter l'instabilité en présence de charges déséquilibrées. Par ailleurs, des méthodes de détection de défaut au niveau d'un interrupteur commandable, efficaces et très rapides, sont également proposées. Nous présentons également une topologie de convertisseur DC-DC à tolérance de pannes, intégrant un interrupteur redondant ; dans tous les cas de défaut (court-circuit ou circuit-ouvert), cette topologie doit permettre deassurer la continuité de service du système de puissance en mode normal. Les études théoriques ont été validées par la simulation et par des tests expérimentaux
... The presence of energy storage system may allow a better management of the electric system allowing the full exploitation of renewable energy sources. Distribution companies start to recognize that storage has the unique ability to act as a buffer between the grid and generation that is either intermittent or not controlled by the utility2345. ...
The distributed energy resources (DER) contains several technologies, such as diesel engines, small wind turbines, photovoltaic inverters, etc. The control of DER components with storage devices and (controllable) loads, such as batteries, capacitors, dump loads, are central to the concept of the Micro Grids (MGs). A MG can operate interconnected to the main distribution grid or in islanded mode. This paper presents experimental tests for static and dynamic stability analysis carried out in a dedicated laboratory for research in distributed control and micro-grid with a high share of renewable energy production. Moreover to point out, on a laboratory scale, the coupling between DR and storage and to effectively compensate wind fluctuations a number of tests have been done. In order to find out the parameters of various types of DER components for dynamic simulation models a number of tests are required under different operation modes and loads. The testing reporting here includes three modes of operation: stand alone, parallel/hybrid and grid connection.
... The presence of energy storage system may allow a better management of the electric system allowing the full exploitation of renewable energy sources. Distribution companies start to recognize that storage has the unique ability to act as a buffer between the grid and generation that is either intermittent or not controlled by the utility2345. The distributed generation is taking importance pointing out that the future utility line will be formed by distributed energy resources and micro-grids. ...
The distributed energy resources (DER) contains several technologies, such as diesel engines, small wind turbines, photovoltaic inverters, etc. The control of DER components with storage devices and (controllable) loads, such as batteries, capacitors, dump loads, are central to the concept of the Smart Grids (SGs). A SG can operate interconnected to the main distribution grid or in islanded mode. This paper presents experimental tests for static and dynamic stability analysis carried out in a dedicated laboratory for research in distributed control and smart grid with a high share of renewable energy production. Moreover to point out, on a laboratory scale, the coupling between DR and storage and to effectively compensate wind fluctuations a number of tests have been done. In order to find out the parameters of various types of DER components for dynamic simulation models a number of tests are required under different operation modes and loads. The testing reporting here includes three modes of operation: stand alone, parallel/hybrid and grid connection.
This paper presents the simulation of an off grid Photovoltaic (PV) system with battery and generator backup for a house located in the remote areas of Edo State ,Nigeria. The case study is for a house with a peak load of 1.26kW and 3.4kWh daily energy consumption. The design was carried out using Homer Pro and simulation was performed in the Matlab Simulink software, the system is made up of 1.23kW PV comprised of 4 modules (325W, 2 in series, 2 in parallel), MPPT (maximum power point tracking), a DC-DC buck converter for stepping down the voltage, 4 batteries each of 12V, 350Ahr (48V, series connection), and a backup generator of 4.8kW. The system also incorporates a 1.6kW inverter which converts the output DC voltage from 48V to an equivalent AC. A step-up transformer connected directly to the inverter boosts the voltage from 48V AC to an output voltage of 220V AC for supply to the load. The dynamic simulation results and response to changing inputs are presented in this paper.
In the remote part of Nigeria, most households suffer from lack of electricity due to inaccessibility to the utility grid. This paper presents the simulation of a Photovoltaic (PV) hybrid system with battery and generator backup of an off-grid Stand-alone PV system for a house located in remote Benin City, Edo State in Nigeria. House peak load is 1.26kW and daily energy consumption is 3.4kWh, with no access to the electricity grid for fulfilment of load requirement to meet the basic electrical needs. The system is designed in Homer Pro and simulated using the Matlab Simulink software, it comprises of a 1.23kW PV made up of 4 modules (325W each with 2 in series and 2 in parallel), A MPPT (maximum power point tracking), a DC-DC buck converter, 4 backup battery of 12V, 350Ahr connected in series and a 4.8kW emergency generator system with a 1.6kW inverter which converts the output DC voltage of 48V from the converter to an alternating AC. The inverter is connected directly to a step-up transformer which boosts the voltage from to 220V AC for supply to the load. The system dynamic simulation results and response to changing inputs are presented in this paper.
When two systems are hybridized with the addition of a storage device, the system's reliability increases dramatically. Even in this instance, enough battery bank capacity is necessary to supply electricity to the load on lengthy cloudy and non- days. As a result, in particular geographical places where the environment is acceptable, the appropriate sizing of system components is an important feature of hybrid power system hybrid models of renewable power generation. The planned research will determine whether such non-use is justifiable or whether using hybrid models in particular regions with acceptable conditions would be useful.
The renewable energy sources (RESs) are a viable alternative to fulfill the ever-rising energy demand. The present power distribution system contains nonlinear loads that bring up power quality issues like harmonics in source current, voltage sag and swell etc. This paper provides exhaustive review of control techniques of shunt active power filter (SAPF), maximum power point tracking (MPPT) and RES integrated with SAPF. Artificial neural network (ANN) based control system is designed to improve SAPF performance in terms of total harmonic distortion. The training data generated from conventional PI and perturb & observe (P&O) technique is used to train ANN based controller for SAPF and MPPT respectively. The photovoltaic (PV) integrated SAPF is simulated in MATLAB and then validated in real-time with microsecond time step on field-programmable gate array (FPGA) based computational engine of OPAL-RT 4510.
In this paper, we propose a framework for modeling the production of smart hybrid renewable energy minigrids as a production possibility curve. Modeling the individual and joint production possibilities of hybrid renewable minigrids demonstrates the absolute and comparative advantages in terms of energy production that each minigrid has depending upon weather conditions and technology employed. Comparative advantage in a particular technology leads to specialization in production that guarantees mutually beneficial trading possibilities for the minigrids to mitigate the effects of weather variations on energy production. The optimum point of production or the production equilibrium that forms the basis for mutually beneficial trading is arrived at by maximizing the joint production possibility function subject to certain constraints. These constraints are given by consumer theory that prescribes various utility functions for optimizing the total energy production and modeling weather/climate variations. We graphically illustrate the computation of production equilibrium under various constraints such as output maximization during sunny or windy weather conditions. Once the total amount of energy production as stipulated by the production equilibrium has been decided, minigrids can trade towards an optimal level for their consumption. The terms of mutually beneficial trade are dictated by the marginal opportunity costs of energy production for each minigrid. Finally, we formulate the energy trading price ratio which provides the minigrids with an incentive to cooperatively exchange energy.
Hybrid renewable energy systems (HRES) are becoming popular for remote area power generation applications due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. Economic aspects of these technologies are sufficiently promising to include them in developing power generation capacity for developing countries. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue for, improving their performance, establishing techniques for accurately predicting their output and reliably integrating them with other conventional generating sources. The paper describes methodologies to model HRES components, HRES designs and their evaluation. The trends in HRES design show that the hybrid PV/wind energy systems are becoming gaining popular. The issues related to penetration of these energy systems in the present distribution network are highlighted.
We analyzed a power system network that consisted of two types of
power generation: wind turbine generation and diesel generation. The
power quality and the interaction of diesel generation, the wind
turbine, and the local load were the subjects of investigation. From an
energy-production standpoint, producing as much wind energy as possible
is advantageous in terms of decreasing the fuel consumption of the
diesel engines and reducing the level of pollution. From the customer
point of view, good power quality at the receiving end is important. The
purpose of this paper is to show the impact of the wind power plant on
the entire system. In addition, we discuss how the startup of the wind
turbine and the transient condition during load changes affect the
system's voltage and frequency
The aim of the present paper is to develop and apply a software tool for designing hybrid renewable energy systems. The hybrid system consists of a wind generator and photovoltaic modules which are the renewable technologies for energy production. The programme has been applied for simulating a hybrid system with the above mentioned technologies in order cover the electricity and water needs of the Merssini village on Donoussa island in the Aegean Sea of Greece. The Merssini village is occupied by 20 year-round residents while the population is doubled during the summer period. The village is non-electrified and faces a problematic scarcity of fresh water. In the analysis that follows, the considered technical data as well as the results of programme runs for winter and summer seasons are presented. The electricity consumption consists of both the household and desalination plant consumption. The system is supplemented with batteries and a micro hydraulic plant for energy storage. The simulation programme was used to optimise the design of the system as well as to manage the energy supply and energy storage. The results prove that this simulation programme constitutes a valuable tool for the determination not only of the optimum combination of technologies, but also the optimum energy management of complex hybrid systems.
This version of the RPM-SIM User's Guide supersedes the October 1999 edition. Using the VisSimTM visual environment, researchers developed a modular simulation system to facilitate an application-specific, low-cost study of the system dynamics for wind-diesel hybrid power systems. This manual presents the principal modules of the simulator and, using case studies of a hybrid system, demonstrates some of the benefits that can be gained from understanding the effects of the designer's modifications to these complex dynamic systems.
The combined utilization of renewables such as solar and wind energy is becoming increasingly attractive and is being widely used for substitution of oil-produced energy, and eventually to reduce air pollution. In the present investigation, hourly wind-speed and solar radiation measurements made at the solar radiation and meteorological monitoring station, Dhahran (26°32′N, 50°13′E), Saudi Arabia, have been analyzed to study the impact of key parameters such as photovoltaic (PV) array area, number of wind machines, and battery storage capacity on the operation of hybrid (wind + solar + diesel) energy conversion systems, while satisfying a specific annual load of 41,500 kWh. The monthly average wind speeds for Dhahran range from 4.1 to 6.4 m/s. The monthly average daily values of solar radiation for Dhahran range from 3.6 to 7.96 kWh/m2. Parametric analysis indicates that with two 10 kW wind machines together with three days of battery storage and photovoltaic deployment of 30 m2, the diesel back-up system has to provide about 23% of the load demand. However, with elimination of battery storage, about 48% of the load needs to be provided by diesel system.
Depleting oil and gas reserves, combined with growing concerns of atmospheric pollution/degradation, have made the search for energy from renewable sources of energy, such as solar and wind, inevitable. Literature indicates that commercial/residential buildings in Saudi Arabia consume an estimated 10–40% of the total electric energy generated. In the present study, hourly mean wind-speed and solar radiation data for the period 1986–1997 recorded at the solar radiation and meteorological monitoring station, Dhahran (26°32′ N, 50°13′ E), Saudi Arabia, have been analyzed to investigate the potential of utilizing hybrid (wind+solar) energy conversion systems to meet the load requirements of a typical commercial building (with annual electrical energy demand of 620 000 kWh). The monthly average wind speeds for Dhahran range from 4.1 to 6.4 m/s. The monthly average daily values of solar radiation for Dhahran range from 3.6 kWh/m2 to 7.96 kWh/m2. The hybrid systems considered in the present analysis consist of different combinations of commercial 10 kW wind energy conversion systems (WECS), photovoltaic (PV) panels supplemented with battery storage unit and diesel back-up. The study shows that with 30 10-kW WECS together with 150 m2 PV, and 3 days of battery storage, the diesel back-up system has to provide 17% of the load demand. However, in the absence of battery storage, about 38% of the load needs to be provided by the diesel system.
A substantial increase of photovoltaic (PV) power generators installations has taken place in recent years, due to the increasing efficiency of solar cells as well as the improvements of manufacturing technology of solar panels. These generators are both grid-connected and stand-alone applications. We present an overview of the essential research results. The paper concentrates on the operation and modeling of stand-alone power systems with PV power generators. Systems with PV array-inverter assemblies, operating in the slave-and-master modes, are discussed, and the simulation results obtained using a renewable energy power system modular simulator are presented. These results demonstrate that simulation is an essential step in the system development process and that PV power generators constitute a valuable energy source. They have the ability to balance the energy and supply good power quality. It is demonstrated that when PV array- inverters are operating in the master mode in stand-alone applications, they well perform the task of controlling the voltage and frequency of the power system. The mechanism of switching the master function between the diesel generator and the PV array-inverter assembly in a stand-alone power system is also proposed and analyzed. Finally, some experimental results on a practical system are compared to the simulation results and confirm the usefulness of the proposed approach to the development of renewable energy systems with PV power generators.
Renewable-energy systems that are under development need a simulation-based analysis to ensure system stability, power quality, and reliability. Such an analysis may reveal design modifications that need to be made before the system is implemented in the field. The modular simulator RPM-SIM, available on the National Renewable Energy Laboratory Web site (http://wind.nrel.gov/designcodes/simulators/rpmsim/), facilitates a low-cost application-specific study of the dynamics of the wind-solar-diesel hybrid power systems. This paper discusses the principal modules of the simulator and provides several examples of a simulation-based analysis of the renewable-energy systems. These examples illustrate the importance of a simulation-based study of the grid-connected and stand-alone or autonomous systems. The RPM-SIM is open-ended and can be easily expanded
Johnson of the Colorado School of Mines and Prof
- The
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The authors gratefully acknowledge Prof. Kathryn E. Johnson of the Colorado School of Mines and Prof. Jan T. Bialasiewicz of the University of Colorado, Denver, for their support on this work. VI. REFERENCES