PV Power Source Research Articles

Optimal solution of multiobjective stable environmental economic power dispatch problem considering probabilistic wind and solar PV generation

The Environmental Economic Power Dispatch (EEPD) problem, a widely studied bi-objective nonlinear optimization challenge in power systems, traditionally focuses on the economic dispatch of thermal generators without considering network security constraints. However, environmental sustainability necessitates reducing emissions and increasing the penetration of renewable energy sources (RES) into the electrical grid. The integration of high levels of RES, such as wind and solar PV, introduces stability issues due to their uncertain and intermittent nature. This paper addresses these concerns by formulating and solving the Stable Environmental Economic Power Dispatch (SEEPD) problem, which includes fixed zonal reserve capacity from conventional thermal generators and uncertain reserves from RES. Uncertainties in RES and load demand are modeled using random variable generation techniques, applying Gaussian, Weibull, and log-normal probability density functions (PDFs) for load demand, wind velocity, and solar irradiance, respectively. The stochastic SEEPD problem extends to multiple periods by replicating the single-period problem for each interval in the planning horizon, linking periods through intertemporal ramping costs, physical ramp rate, and fixed zonal reserve constraints on dispatch variables. Multi-Objective Evolutionary Algorithms (MOEAs) have gained importance for solving complex nonlinear problems involving multi-objective functions. This paper applies the latest MOEAs to tackle the proposed SEEPD problem, incorporating stochastic wind and solar PV power sources. Network security constraints, such as transmission line capacities and bus voltage limits, are considered along with constraints on generator capabilities and intertemporal spinning reserves, ramp-up and ramp-down constraints for thermal generators. A bidirectional coevolutionary-based multi-objective evolutionary algorithm is employed, integrating an advanced constraint-handling technique to ensure compliance with system constraints. The simulation results show that the proposed formulation achieves a better trade-off between various conflicting objective functions compared to other state-of-the-art MOEAs.

Multi‐objective multiperiod stable environmental economic power dispatch considering probabilistic wind and solar PV generation

AbstractThe economic‐environmental power dispatch (EEPD) problem, a widely studied bi‐objective non‐linear optimization challenge in power systems, traditionally focuses on the economic dispatch of thermal generators without considering network security constraints. However, environmental sustainability necessitates reducing emissions and increasing the penetration of renewable energy sources (RES) into the electrical grid. The integration of high levels of RES, such as wind and solar PV, introduces stability issues due to their uncertain and intermittent nature. This article addresses these concerns by formulating and solving the economic environmental and stable power dispatch (EESPD) problem, which includes fixed zonal reserve capacity from conventional thermal generators and uncertain reserves from RES. Uncertainties in RES and load demand are modelled using random variable generation techniques, applying Gaussian, Weibull, and log‐normal probability density functions (PDFs) for load demand, wind velocity, and solar irradiance, respectively. The stochastic EESPD problem extends to multiple periods by replicating the single‐period problem for each interval in the planning horizon, linking periods through intertemporal ramping costs, physical ramp rate, and fixed zonal reserve constraints on dispatch variables. Multi‐objective evolutionary algorithms (MOEAs) have gained prominence for solving complex non‐linear problems involving multi‐objective functions. This article applies the latest MOEAs to tackle the proposed EESPD problem, incorporating stochastic wind and solar PV power sources. Network security constraints, such as transmission line capacities and bus voltage limits, are considered along with constraints on generator capabilities and intertemporal spinning reserves, ramp‐up and ramp‐down constraints for thermal generators. A bidirectional coevolutionary‐based multi‐objective evolutionary algorithm is employed, integrating an advanced constraint‐handling technique to ensure compliance with system constraints. The simulation results show that the proposed formulation achieves a better trade‐off between various conflicting objective functions compared to other state‐of‐the‐art MOEAs.

Power quality assessment and compliance of grid-connected PV systems in low voltage networks using microinverters

AbstractSolar PV has experienced unprecedented growth in the last decade, with the most significant additions being utility-scale solar PV. The role of grid inverters is very critical in feeding power from distributed sources into the grid. With the increasing growth of grid-tied solar PV systems (both rooftop and large-scale), the awareness of power quality issues has risen with new regulations and standards to ensure the stability of the power grid. The power quality of microinverters has been investigated under steady solar irradiation and PV power source and also under real outdoor conditions in compliance with the accepted solar PV integration requirements. The current total harmonic distortion (THD) measured for the studied microinverter under outdoor conditions far exceeded the current THD for the study under steady indoor conditions and was beyond the accepted standard. However, the voltage THD outputs for the two studied cases were in good agreement with the grid codes. The voltage and current THD for the 400 Wm−2 (60 Wp) and the 1000 Wm−2 (146 Wp) scenarios under the steady solar irradiation (solar PV power) were 2.24%, 13%, and 2.27, 6.93%, respectively. The voltage and current THDs for the outdoor study were 2.03% and 14.28% for Solarex (pc-Si module), 1.94%, and 27.43% for Juta (mc-Si modules), and 1.97% and 33.6% for Dunasolar (a-Si glass module). Results showed a strong correlation between the intermittence of solar radiation and the current THD. 67%, 54%, and 37% of the recorded power factor for Dunasolar, Juta, and Solarex modules, respectively, exceeded the limits prescribed by the standards.

Optimal energy management of grid-connected PV for HVAC cooling with ice thermal storage system

Studies have shown that reducing cooling energy costs and increasing operational efficiency may be achieved by utilizing ice thermal energy storage (ITES) technology while maintaining the thermal requirements in space cooling facilities. Optimal control of the ITES system and integration of renewable energy (RE) sources such as PV and geothermal, depending on the availability of resources and application, can further improve the operation of HVAC's cooling systems and mitigate the increased energy cost required for ice formation and overall cooling energy.This study presented optimal switching control of the ice-build chiller for ITES charging and PV power source. Inputs to the model, simulations, and validations were implemented using the available data, which include the historical exogenous meteorological data, temperatures at the inlet and exit of the plant components, manufacturer's information, and readings from the plant's SCADA chosen for the case study.The main aim of the study was to develop an optimal control model that minimizes the energy consumption and cost in the Ice built chiller and other devices, such as pump fans in the HVAC system, by optimal charge and discharge of the ITES and supplementary utilization of the greener energy source PV source under the time of use (ToU) tariff and desired cooling load demand. The case study for a healthcare building was considered in implementing the model.Simulations were implemented in the MATLAB optimization toolbox with the Solving Constrained Integer Programs (SCIP) solver, which was chosen to address mixed integer programming (MIP) problems. It incorporates algorithms like a branch and cut conflict analysis and pre-solving techniques to handle intricate optimization problems involving continuous and discrete decision variables.The optimal switching control model yields approximately 33 % of energy cost savings during the summer months that involve using the HVAC with ITES compared to the current system control (baseline). Additionally, the ITES temperature remained below 0 °C to maintain thermal requirements as an operation constraint. The inclusion of PV and battery options as a source of power to the pumps accounted for 10–15 % of the overall energy usage of the system. Optimal control of the system to utilize the stored energy during peak pricing and high demand periods eliminated the extreme dependence on grid energy in some instances. Despite the additional capital required for the controller, solar PV, and batteries installation, the study projects a return on investment within two years, with a 20-year lifetime energy cost savings estimate of 35 % if inflation and annual electricity price increases are estimated at 5 % and 10 %, respectively.

Cumulative Emissions of CO2 for Electric and Combustion Cars: A Case Study on Specific Models

This work includes calculations of the cumulative CO2 emissions of two comparable cars—the VW Golf VII—one with a combustion engine and the other with an electric motor. Calculation of CO2 emissions was performed, taking into account the stages of production, utilization and use of the above-mentioned vehicles. For the use phase, it was assumed that the total mileage of the car will be 150,000 km over 10 years. For the electric vehicle, calculations were made assuming five different sources of electricity (from coal only, from natural gas only, from PV and wind turbines, an average mix of European power sources and an average mix of Polish power sources; W1–W5 designations, respectively). For individual sources of electricity, cumulative CO2 emissions were taken into account, that is, resulting both from the production of electricity and the use of the resources (for example, technical service per 1 kWh of electricity produced). The obtained results of the analysis show that for the adopted assumptions regarding operation, for variants W2–W5, the use of an electric car results in lower cumulative CO2 emission than a the use of a combustion car. For a combustion car, the value was 37,000 kg-CO2, and for an electric car, depending on the variant, the value was 43, 31, 16, 23 and 34 thousand kg-CO2 for variants W1 to W5, respectively. Based on the emissions results obtained for individual stages of the use of selected vehicles, a comparative analysis of cumulative CO2 emissions was performed. The purpose of this analysis was to determine whether the replacement of an existing combustion car (that has already been manufactured; therefore, this part of the analysis does not include CO2 emissions in the production stage) with a new electric car, which has to be manufactured, therefore associated with additional CO2 emissions, would reduce cumulative CO2 emissions. Considering three adopted average annual car mileages (3000, 7500 and 15,000 km) and the previously described power options (W1–W5), we sought an answer as to whether the use of a new electric car would be burdened with lower cumulative CO2 emissions. In this case we assumed an analysis time of 15 years. For the worst variant from the point of view of CO2 emissions (W1, electricity from coal power sources only), further use of a combustion car is associated with lower cumulative CO2 emissions than the purchase of a new electric car over the entire analyzed period of 15 years. In turn, for the most advantageous variant (W3, electricity from PV or wind power sources) with an annual mileage of 3000 km, the purchase of a new electric car results in higher cumulative CO2 emissions throughout the analyzed period, whereas for an annual milage of 7500 or 15,000 km, replacing the car with an electric car “pays back” in terms of cumulative CO2 emissions after 8.5 or 4 years, respectively.

A Design and Modelling of PV-Diesel Hybrid Energy System with Fuzzy Logic Controller

— Renewable energy, such as wind and photovoltaic arrays, has become the core energy in micro-grids used for supplying remote areas and areas suffering from electricity outages. Many limitations, such as weather fluctuations and low efficiency, lead to designing and developing a hybrid energy system. The integration of photovoltaic arrays and diesel gensets has become one of the most common approaches to generating electricity for remote communities. Although the integration of photovoltaic arrays and diesel gensets has the potential to reduce the cost of electricity production by harnessing free energy from the sun to reduce the power generated by diesel engines, it tends to complicate the control of the entire system due to the intermittent nature of the renewable energy sources and changing load demand. This paper proposes a fuzzy logic controller of PV-Diesel hybrid energy system, which is used as an effective tool in facilitating optimum power-sharing between the PV power source, charging, and discharging batteries and diesel generator as a backup based on the dynamics of the available PV energy at any time. Optimizing power control in the PV-Diesel hybrid energy system is key to minimizing the cost of power generation and maximizing the overall efficiency of the PV-Diesel hybrid energy system. The MATLAB-Simulink is used to design the fuzzy logic controller of the PV-Diesel hybrid energy system and to validate its performance. Five scenarios during the day have been tested to show the performance of the fuzzy logic controller. The results showed the accurate controlling of the power flow in the PV-Diesel hybrid system and the power saved about 2%.

Multiscale power fluctuation evaluation of a hydro-wind-photovoltaic system

The hybrid energy systems are required to operate stably in different time scales. Previous studies on the stability are carried out under the unrealistic assumption of discontinuous time scales. Therefore, a second time scale model for the hybrid energy systems is presented in this study. To overcome the possible uncertainty caused by the discontinuous time scale assumption, a new method is introduced to analyze power fluctuations for the hybrid power system considering the hydroelectric power station (HPS) and PV-wind complementarity. Compared with traditional statistics, the proposed three indices, discussed in terms of variation frequency, have the ability to show the stability and complementarity characteristics of the hybrid system with the time scale varying from second to hour, The results show that the volatility of wind power and photoelectric increase with the increase of time scale. In (100, 102) seconds, the HPS could not compensate for as they do not meet flexibility demand in that particular frequency domain, and hydro-electric power is able to compensate wind and PV power sources well when the time scale is over 102 s. The obtained stability evolution law has important reference significance for the subsequent studies on the stability of hybrid energy systems.

Energy efficiency of a novel low voltage direct current supply for the future building

This paper presents the energy efficiency performances of a proposed Low Voltage Direct Current supply concept and other conventional on-grid photovoltaic chains architectures. A photovoltaic power source was considered in the studied nano-grids. The proposed chain architecture allows the photovoltaic generated energy to take a shorter path heading toward the load. The notion of relative saved energy was introduced to compare the studied PV systems energy performances. The obtained results revealed that the use of the low voltage direct current supply concept is very interesting and the use of direct current loads instead of alternative current loads, when a photovoltaic power is generated locally, is more efficient. The installed PV power source in the building should be well sized regarding to the consumed power in order to register a high system RSE. The efficiency of the new low voltage direct current architecture is 10% higher than the conventional one.

Energy Efficiency Performances of LVDC Nanogrids Powered Buildings

The Low Voltage Direct Current (LVDC) system concept has been growing in the recent times due to its characteristics and advantages like renewable energy source compatibility, more straightforward integration with storage utilities through power electronic converters, and distributed loads. This paper presents the energy efficiency performances of a proposed LVDC supply concept and other classical PV chains architectures. A PV source was considered in the studied nanogrids. The notion of relative saved energy (RSE) was introduced to compare the studied PV systems energy performances. The obtained results revealed that the use of the proposed LVDC chain supply concept increases the nanogrid efficiency. The installed PV power source in the building should be well sized regarding the consumed power in order to register a high system RSE. The efficiency of the new LVDC architecture is 10% higher than the conventional LVDC one.

Energy Efficiency of LVDC Supplies Including PV Sources

The Low Voltage Direct Current (LVDC) system concept has been growing in the recent times due to its characteristics and advantages like renewable energy source compatibility, more straightforward integration with storage utilities through power electronic converters and distributed loads. This paper presents the energy efficiency performances of a proposed LVDC supply concept and others classical PV chains architectures. A PV source was considered in the studied nanogrids. The notion of Relative Saved Energy (RSE) was introduced to compare the studied PV systems energy performances. The obtained results revealed that the employment of the LVDC chain supply concept is very interesting and the use of DC loads as an alternative to AC loads, when a PV power is generated locally, is more efficient. The installed PV power source in the building should be well sized regarding to the consumed power in order to register a high system RSE.

Adaptive frequency regulation strategy in multi-area microgrids including renewable energy and electric vehicles supported by virtual inertia

With the increased level of penetration of distributed generators (DGs), renewable energy sources (RESs) in microgrids (μGs), the impact of damping, and low inertia effect on the grid stability increase in the situation of uncertainties. This leads to some important issues that happened in the power systems such as power fluctuaCVtions due to the variable nature of RESs, frequency regulation degradation, voltage rise, and excessive supply due to full DGs generation in the grid electricity. A solution to improve the stability is to provide inertia virtually by virtual synchronous generators (VSGs) that can be created using an appropriate control mechanism. Therefore, to overcome the aforementioned challenges, a robust control strategy should be applied. In this study, a new adaptive control technique for on-line tuning the integral controllers’ gains for power charging/discharging of plug-in electric vehicles (EVs) has been proposed using Harris hawks optimization (HHO) based Balloon Effect (BE) supported by a virtual inertia controller considering high-level penetration of RESs in islanded and interconnected μGs. The main target is to regulate the suggested μG frequency powered by a PV power source and a diesel generator in the presence of random load variations and flexible loads for enhancing system robustness and validity in face of parametric uncertainties and disturbances. The time delay caused by the communication process between the area and the control center is considered for the interconnected μGs dynamic model. The discussion and analysis of the results show that the suggested control strategy has a better performance on frequency regulation, and maintaining the stability of the μG system as compared to another powerful controller called coefficient diagram method (CDM) in presence/absence of the virtual inertia control loop.

An Integrated Comparative Assessment of Coal-Based Carbon Capture and Storage (CCS) Vis-à-Vis Renewable Energies in India’s Low Carbon Electricity Transition Scenarios

Roadmaps for India’s energy future foresee that coal power will continue to play a considerable role until the middle of the 21st century. Among other options, carbon capture and storage (CCS) is being considered as a potential technology for decarbonising the power sector. Consequently, it is important to quantify the relative benefits and trade-offs of coal-CCS in comparison to its competing renewable power sources from multiple sustainability perspectives. In this paper, we assess coal-CCS pathways in India up to 2050 and compare coal-CCS with conventional coal, solar PV and wind power sources through an integrated assessment approach coupled with a nexus perspective (energy-cost-climate-water nexus). Our levelized costs assessment reveals that coal-CCS is expensive and significant cost reductions would be needed for CCS to compete in the Indian power market. In addition, although carbon pricing could make coal-CCS competitive in relation to conventional coal power plants, it cannot influence the lack of competitiveness of coal-CCS with respect to renewables. From a climate perspective, CCS can significantly reduce the life cycle GHG emissions of conventional coal power plants, but renewables are better positioned than coal-CCS if the goal is ambitious climate change mitigation. Our water footprint assessment reveals that coal-CCS consumes an enormous volume of water resources in comparison to conventional coal and, in particular, to renewables. To conclude, our findings highlight that coal-CCS not only suffers from typical new technology development related challenges—such as a lack of technical potential assessments and necessary support infrastructure, and high costs—but also from severe resource constraints (especially water) in an era of global warming and the competition from outperforming renewable power sources. Our study, therefore, adds a considerable level of techno-economic and environmental nexus specificity to the current debate about coal-based large-scale CCS and the low carbon energy transition in emerging and developing economies in the Global South.

Improvement of transient stability in microgrids using RSFCL with series active power filter

Now a day’s non-conventional energy sources like PV power and Wind power sources are well developed because conventional energy sources are reduced day by day and at the same time the population has been increased. These drawbacks can be overcome by developing the microgrids. In current trends, microgrid protection is a very challenging task. Due to the interconnection of several distributed generators, fault currents are produced. Resistive type superconducting fault current limiter is used for the protection of microgrids because its operating time is very less, it stops the abnormal currents with in the first cycle and continuity of supply is possible. But R-SFCL had some disadvantages, it is not compensated for the reactive power. Then voltage levels are not compensated, for that reason series active power filters are used along with R-SFCL. Here series active power filters are compensating the voltage magnitudes and reduce the harmonics and then transient stability is improved in the microgrids. This work is done using MATLAB/Simulink.

Modelling and performance analysis of directly coupled vapor compression solar refrigeration system

This paper proposes a method for the analysis and simulation of solar energy driven vapor compression refrigeration system with variable speed compressor under the real weather condition using the data sheets (of the PV panel and compressor) available from the manufacturers. The solar refrigeration system considered in this research study includes a non-tracking PV power source directly-coupled with a variable speed DC compressor. The operating point of the compressor of the considered solar refrigeration system is determined on the current versus voltage (I-V) plane, by intersecting the I-V curve of the PV panel with the I-V curve of the compressor. The operating speed of the compressor is determined to model the hourly variation of the performance of the refrigeration system. The analysis and simulation result show that the COP of the refrigeration cycle for the selected days is around 2.25 when the compressor runs at low speed, and the COP drops to its lowest value of 1.85 when the compressor operates at the highest speed. Furthermore, the simulation results indicated that an estimated radiation intensity 315 W/m2 is required to be received on the tilted panel to run the considered compressor at its minimum rotational speed of 1800 rpm. To drive the compressor at its maximum rotational speed (4200 rpm), an estimated radiation intensity of 700 W/m2 is required to fall on the PV panel. Finally, the proposed method can be used to estimate the performance of a directly coupled solar PV refrigeration system with variable speed compressor under specific weather condition.

Forecasting Analysis Based on Multi-scale and Multi-time with Uncertainty

Abstract The dissemination of distributed resources presents a new paradigm for the power industry. Especially solar power is creating a new chapter for trading electricity as a new source. Solar power sources and load resources are each uncertain by their size and time factors. This paper discusses the uncertainties due to the accuracy of the forecast by forecasting PV power source and by forecasting load resource based multi-scale and multi-time. To do this, artificial neural networks are used to forecast these resources at a different time interval and the amounts by aggregation. Uncertainty from the forecasting results is discussed.

Practical investigation for road lighting using renewable energy sources "Sizing and modelling of solar/wind hybrid system for road lighting application"

This study explains a design of a fully independent -off grid- hybrid solar and wind road lighting system according to geography and weather conditions recorded from the Egyptian National Research Institute of Astronomy and Geophysics. Presenting here the virtual simulation by using Matlab/Simulink & real-time implementation of road lighting system consists of 150 W photovoltaic cell, 420 W wind generator, 100 Ah acid gel battery and LED lighting luminar 30 W -12 VDC . Over three different stages; 1.Operating the system with PV only as power source, 2. Switching to Wind generator only configuration and 3. Running the hybrid design with both PV & Wind power sources ; load characteristics and output real-time data will be recorded, evaluated ,compared and validated against the virtual simulation generated by Matlab/Simulink model. The results of this research will be used to investigate the advantages of using a hybrid system to counteract the limitations of solar and wind as solo renewable energy sources due to adverse weather conditions ,the efficiency of the proposed system as an alternative for the current conventional road lighting poles as well as the accuracy of the virtual model data in order to be used for future adaptation of the model for different geographical locations.

The effect of modeling types characterization for PV power source on maximum power point tracking

This paper deals with the problem of energy transfer maximization between a solar power source side and the load demand side. Owing to the multitude of mathematical models in the literature that claim to represent the behavior of the photovoltaic module, the work here is to throw light on the importance of choosing a proper mathematical model of the photovoltaic module for the above‐mentioned context with the target of enlarging the energy yield from such a generator system irrespective changing environmental conditions. First, a comparison between four mathematical models based on a single‐diode representation for photovoltaic generation source is presented. The objective of this analysis is to compute the errors between these models and the experimental data in predicting the maximum power point. Then an easy‐to‐implement tracking method for working on the maximum power point is assumed. The idea of this maximum power point tracking technique is to blend two conventional algorithms, namely incremental conductance and fractional open‐circuit voltage, in such a way as to improve the starting period of the normal incremental conductance algorithm, so that fast and accurate convergence can be achieved. A comparison between the dynamic control performances of the studied four different kinds of the single‐diode model under the maximum power condition is performed, and the impact of increasing the complexity of the single‐diode model commonly utilized to represent photovoltaic cell/module under the energy transfer maximization constraint for autonomous generation applications is finally explored. The paper extends and complements our recently published results in the literature. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A new load frequency control approach in an isolated small power systems using coefficient diagram method

This paper applies the Coefficient Diagram Method (CDM) as a new robust controller design of heat pump (HP) and plug-in hybrid electric vehicle (EV) for frequency control in an isolated small power system powered by diesel generator and renewable photovoltaic PV power source. In order to reduce frequency fluctuation resulted from the fluctuating power generation from renewable energy sources, the smart control of power consumption of HP and the power discharging of EV in the customer side can be performed.The CDM technique has been designed to enhance the performance and robustness against system uncertainties. Simulation studies confirm the superior robustness and frequency control effect of the proposed HP and EV controllers in comparison to other conventional controllers of HPs and EVs like the conventional PID controllers optimized using practical swarm controllers based a specified-structure mixed H2/H∞ control design.

Methods for the Optimal Design of Grid- Connected PV Inverters

The DC/AC inverters are used in grid-connected PV energy production systems as the power processing interface between the PV energy source and the electric grid. The energy injected into the electric grid by the PV installation depends on the amount of power extracted from the PV power source and the efficient processing of this power by the DC/AC inverter. In this paper two new methods are presented for the optimal design of a PV inverter power section, output filter and MPPT control strategy. The influences of the electric grid regulations and standards as well as the PV array operational characteristics on the design of grid-connected PV inverters have been considered. The proposed methods have been applied for the optimal design of PV inverters installed at various sites in Europe. The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid, thus serving as a tool to gain more energy by the optimized PV installation.

The performance of a new positive displacement pump targeted to improve rural water supplies

A new positive displacement pump operating with a simple linear actuator as the prime mover has been designed, built, and evaluated. The aim is to develop a pump that uses a photovoltaic (pv) power source and is suited to supplying water in rural areas of low-income countries. Previous schemes to raise water from boreholes with a pv power source have used sophisticated technology, which can be a significant step beyond the previous experience of the communities being served. A configuration of linear actuator and pump has been chosen by seeking the simplest mechanism from the point of view of both operation and manufacture. Finite-element analysis of the electromagnetic properties of the actuator is shown to be the best way to proceed in the design process. A very simple design with an actuator operating in a normal force configuration is shown to function effectively.