ALBERT

Description: A novel hybrid of pearl millet and napier grass ( Pennisetum glaucum [L.] R. Br. x Pennisetum purpureum Schumach), PMN10TX15, was characterized and investigated as an alternative energy source. Pyrolysis reactions of the PMN10TX15 were carried out in a batch reactor operated at 400-600 °C and atmospheric pressure, aiming to investigate its feasibility for energy conversion and products generation. Initially, the biomass was expected to generate great quantities of bio-oil owing to its high volatile matter (86.94%) and energy content (16.44 MJ/kg). However, not only bio-oil was obtained, but also interesting yields and composition of syngas and biochar. Bio-oil, biochar, and syngas products obtained at 600 °C achieved the highest heating values of 19.9, 28.7, and 4.1 MJ/kg, respectively. Phenols detected in the liquid byproducts could establish an alternative route for its petroleum primarily source, offering potential application to the plastic industry. Furthermore, the pyrolysis at 500 °C yielded the highest mass balance of 94.4% and energy recovery of 82.8%.

Description: T he barrier created in the intrinsic multiple quantum well (MQW) region of a quantum well solar cell (QWSC) appears to be trapezoidal in nature. In this paper, a trapezoidal barrier has been considered and the expression for the tunneling current of the QWSC has been obtained. The variation of the tunneling current with temperature has been shown graphically. In addition to this, the expressions for temperature and wavelength dependent refractive indices of different regions of the QWSC have been taken into account while performing the calculations of reflection coefficient. Solar cells having different well width and barrier width have been chosen and the variation of the tunneling current densities with wavelength of incident light and temperature of the device has been studied for each cell. It has been observed that the tunneling current density falls with increase in the temperature of the cell.  

Description: Depletion of fossil fuel reserves, unpredictable fluctuation of diesel prices, and global warming issue have motivated numerous countries to produce new policies for energy that engorge the utilizing of alternative energy sources. Renewable energy resources like solar, hydro, and wind are clean and have potency to be more widely used. Integration of these sources together with back-up units can produce a better clean, economic, and reliable power for all loads conditions as compared to single source systems. The feasibility study of using integrated energy system to supply electric energy for remote rustic school in the southern part of Iraq is investigated in this research paper. In order to carry out the feasibility study of the hybrid system, HOMER software has been employed as a tool for the technical, economic, and environmental assessments. The analyses of the optimal energy systems are explained in details to find the most feasible off-grid system and compared with the options of extension to the grid and diesel generator system.

Description: Damages in gears may result from excessive operating load (overload), inadequate operating conditions, operation near the resonant frequency of a gear structure, or simple fatigue during power transmission. In mechanical design, the engineers must always ensure that the mechanical resonance frequencies of the components are not allowed to match the drive oscillation frequencies of oscillating parts. Various experimental and theoretical techniques have been developed to analyze such vibrational problems. In this paper, the planetary gear was modeled in Pro/ENGINEER Wildfire 4.0 while the Mesh and the structural, modal and response harmonic analysis for different boundary conditions were performed in ANSYS Workbench 15.0. A modal analysis was then performed for these different cases to calculate a few initial natural frequencies and to analyze its movements using the harmonic response. Furthermore, it is observed that the value of the maximum occurred stress obtained by the harmonic response analysis for the three different cases is less than the maximum materials stress.

Description: The rising energy demand and climate change issues have warranted the inclusion of renewable energy resources with existing conventional fuel based generation system. The intermittent renewable generation require adequate battery support in order to minimize load deficit issues in electrical grid. Hence, an attempt has been made in this paper to formulate a short term deterministic Unit Commitment problem in renewable integrated environment with battery storage. Ten thermal generators are scheduled with a 500 MW wind energy generation system supported by 200 MWh battery with backup of four hours. A three stage solution methodology is evolved involving hybrid Particle Swarm Optimization (PSO) technique to provide techno-economic solution to this complex optimization problem. The charge/ discharge scheduling of battery energy storage integrated to wind generation system is taken up as a co-optimization problem. The generation of battery energy storage integrated wind energy system is so scheduled that it relieves the costlier thermal generating units in the most economic manner.

Description: Jordan is considered one of the sun-belt countries, which possesses high solar radiation on its horizontal surface. This work presents the energy output of photovoltaic (PV) module for three sites in Jordan; these three sites are Irbid (32° N and 35° E) in the northern Jordan, Amman (32° N and 36° E) in the central Jordan, and Aqaba (29° N and 35° E) in southern Jordan. The paper analyses the solar radiation data and ambient temperature to compare the PV energy output at these sites. The analysis showed that the Aqaba is the optimum location in term of PV energy production compared to the selected study locations. It is found that the annual energy production for a module with 340 W capacities is 502 kWh.

Description: The integration of distributed generation (DG) resources is growing day by day in electricity grids. There are many reasons which persuade the operators to utilize DGs such as restrictions on the construction and development of transmission lines and distribution network, transition of traditional power systems to restructured electricity markets, the competitive conditions in wholesale and retail markets, the implication of economic and environmental issues in the production of electrical energy, increasing the system reliability and customer satisfactory level. The reliability improvement capability of power systems by utilization of these units has attracted the attention of many electrical engineering experts and power system planners and operators. Reliability plays a prominent role in the satisfaction of all power industry participants, especially the consumers of the electricity. In this paper, the effect of distributed generation units on the power system reliability has been investigated.  Therefore, the virus colony search (VCS) algorithm is employed to determine the optimal placement and size of distributed generators subject to improve the reliability indices. The simulation is carried out on a 34-bus IEEE test network. The optimization results are also compared with the results of both genetic algorithm (GA), particle swarm optimization (PSO) algorithm, differential evolution (DE) algorithm, multi-objective particle swarm optimization (MOPSO) algorithm, modified shuffled frog leaping algorithm (MSFLA), gravitational search algorithm (GSA), biogeography-based optimization (BBO) algorithm, hybrid big bang-big crunch (HBB-BC) algorithm and glowworm swarm optimization (GSO) algorithm.

Description: The use of renewable power sources, like wind power, has been increased recently due to climatic changes caused by fossil fuels and fast depletion of fossil fuels. This has lead to the tremendous increase in the interconnection of wind turbines to power system grid. This interconnection on a large number in to grid causes problems such as power quality, maintaining system voltage, reactive power compensation, control of grid frequency and aspects of power system grid stability. In this proposed scheme, a fuzzy logic controller (FLC) is employed for a STATCOM to improve the power quality. The proposed control scheme supplies the required reactive power to the system and thus relieves the source, leading to unity power factor (UPF) at the source and also it injects currents to reduce total harmonic distortion (THD) to satisfy IEC standard. The proposed control scheme of the STATCOM for the grid connected wind turbine system is modeled and simulated using MATLAB/SIMULINK. For extracting the reference currents, a modified synchronous reference frame theory (MSRFT) based control algorithm , is employed. The current harmonics injected in to the grid shall also affect the voltage quality at the point of common coupling. The synchronous reference frame theory (SRFT) based control algorithm extracts reference currents for grid synchronisation by employing a 3-Φ phase locked loop (PLL). The voltages fed to the 3-Φ PLL shall define the speed of the reference frame and it is going to vary as the PCC voltages are influenced by harmonics injected. This shall have a great influence on the grid synchronisation and the required results shall not be obtained. To eliminate the above said problems, the MSRFT shall be employed here, where the PLL is not utilised for grid synchronisation. To emphasize the advantages of the MSRFT method, a comparative analysis is also performed with SRFT based control algorithm and the simulation results have been presented. To determine the effectiveness of the proposed FLC, a comparative analysis is also performed with a PI controller and the simulation results have been presented. 

Description: This study assessed the impact of lime (Ca(OH) 2 ) soaking pretreatment on biomass digestibility and potential of biogas production compare to untreated corn cob. Corn cob was soaked for different time of incubation, 7, 15, and 30 days. Scanning electron micrograph perceived destruction in the morphology of treated corn cob. The highest cumulative biogas of 360.5, 305.4, 218.6 NmL/gVS was obtained from 30, 15, 7 days pretreated corn cob respectively, which was 2-times higher than the cumulative biogas produced from the untreated corn cob 115.1 NmL/gVS. The best result for the methane yield (136.8 NmL/gVS) was obtained for 30 days soaking. The present study suggested that soaking with Ca(OH) 2 for longer time is effective for increasing digestibility of agriculture waste biomass and improving biogas production.   

Description: Desalination plays critical role in filling the gap between fresh water demand and availability in water scarce Sultanate of Oman since 1976. Installed desalination capacity in the country has almost increased by 60 times that in 1976 with increasing fresh water demand. Even though desalination share in meeting the fresh water demand is increasing, 80-85% of fresh water demand today is still satisfied with ground water. This is leading to increased soil salinity in recent years affecting the crop production. All the planned and installed desalination plants in the country use conventional fuels for their operation. None of the plant is based on any form of renewable energy source. Consumption of fossil fuels for the operation of plants is increasing at an average rate of 3-5% affecting the net export for the country. Sultanate of Oman is considered to be one of the most suitable destinations for solar energy applications and can play a vital and sustainable role in meeting the gap between the demand and supply of fresh water using solar thermal desalination. This paper emphasizes on addressing this aspect for the country. An overview of present desalination status and fresh water demand, fuel requirements, solar energy availability, thermal desalination technologies and solar thermal technologies has been presented in the paper. Conventional thermal desalination and solar thermal technologies for same capacity have been compared for their suitability on the scale of 1 to 5 for various factors based on their suitability for Sultanate of Oman. This paper also discusses few of the challenges and barriers in implementation of solar thermal desalination in the country. Fixed focus type Scheffler dish reflectors (SDR) are suggested as one of the best option to be coupled with multi effect desalination technology for small to medium capacity decentralized type plants. Parabolic trough collectors (PTC) coupled with CCGT or OCGT plants would be a feasible solution for higher capacity desalination plants.

Description: There are various sources of uncertainty in power systems. Solar and wind forecasting inaccuracies, price forecasting errors, load and demand response forecasting volatilities are some types of uncertainty. In addition, the possibility of outage of power system components such as lines, generating units, and loads can deteriorate the operation condition and compromise the security of power system. Hence, in order to reach a more secure operation, the uncertainties must be included in the scheduling to enhance the robustness and resiliency of power system against possible imbalances and contingencies. The inclusion of probabilistic concepts into the security-constrained unit commitment (SCUC) makes the solution of this problem more complex. However, incorporation of them into the SCUC ensures the secure operation of the power system and inhibits drastic detriments. Furthermore, the compressed air energy storage (CAES) technology is utilized to mitigate the intermittencies and uncertainties. The uncertainties are modeled by using scenario generation techniques. The simulation of a large number of stochastic scenarios considering a variety of uncertainties inclines the results to the most probable condition of realization. The results show that even though the stochastic approaches have higher operational cost but it maintains the security of the system for withstanding against plausible uncertainties and contingencies, which may occur due to whether inaccurate forecasting and consequently inappropriate scheduling or maintaining inadequate generation reserve or transmission capacity. In addition, the integration of CAES units has diminished the total cost of operation and has improved the penetration of renewable resources regard to the congestion of the system, especially at peak hours.

Description: Nanostructured nickel oxide (NiO) films were deposited on preheated glass substrate using spray pyrolysis technique. This study examined the influence of deposition temperature on properties of aged nickel oxide thin films. A preferred orientation along the (1 1 1) plane was observed with a polycrystalline cubic structure. Films were formed with a stoichiometric ratio at higher deposition temperatures. It was revealed that the surface morphology and elemental composition of NiO films can be optimized by deposition temperature. The optical band gap grew as deposition temperature increased. Refractive index decreased with increasing deposition temperature. Optical band gap varied from 3.31 eV to 3.69 eV as deposition temperature increased. The deposition temperature has an influence on properties of aged NiO films. These results may be of interest in the development of affordable and efficient solar cell fabrication especially in developing countries. 

Description: This paper deals with the design, the analysis and the implementation of an integral terminal sliding mode controller. Such controller is developed to track the peak power of a photovoltaic system. The selected nonlinear sliding surface is based on the derivative of the photovoltaic power with respect to the photovoltaic voltage. In addition, the development of the control law does not require the knowledge of the photovoltaic voltage or current reference which makes it simple to implement. Experimental tests are carried out to demonstrate the efficiency of the proposed scheme. The obtained results show that the designed sliding mode controller is robust to environment changes.

Description: The aim of this work lies in investigating the grid frequency in the application of demand-side primary frequency control (PFC) with battery energy storage systems (BESS). In such an application, batteries participate in the PFC serving as energy buffer between their associated loads and the grid, and they are charged and discharged following the grid frequency conditions. The investigation focuses on the effect of PFC on the utilization of the battery in terms of its number of cycles. This includes studying the effects of the frequency dead-band on the battery charge/ discharge durations and the effects of droop settings on the charge/ discharge current rates. A case study of a 0.468 kWh battery pack is used to study the battery utilization under the reliability standards of PFC in the four interconnections of the North American grid. One-year line frequency data of the power system practically measured at Little Rock-AR is used in the analysis.

Description: The world’s energy demand is growing and conventional sources are diminishing. Sustainable/renewable energy sources are gaining possibilities to come up with solutions to the long standing energy problems, environmental crisis, economic development and quality of life. By adopting renewable technologies in developing countries like India, effective steps are being taken towards clean mechanism and fortifying more sustainable future. From the past three decades there has been a strenuous pursuit to development, demonstration, application, production and research of renewable/sustainable technologies for use in distinct sectors. In this paper, availability, current status in market, policies, and different constraints of renewable technologies in India has been summarized.

Description: This paper proposes a studied system made up of interconnected microgrids (MGs) in which each one includes a hybrid renewable energy system (HRES). The proposed power dispatch strategy ensures load satisfaction in each MG by maintaining the equilibrium between production and consumer demand powers via interactions among MGs and the utility grid. The purpose of this paper is to provide an adequate supply to the different MGs by adapting production to consumption according to the available hybrid power production. This is done  with the consideration of the dispatch of the power exchanged among MGs and the main grid. The cooperation between the multiples MGs ensures higher resilience and flexibility of the whole distribution system. The case study results are provided to show the feasibility of this proposed power dispatch strategy in the smart grid environment.

Description: Providing stable voltage at nominal level according to universally accepted standards is a primary concern of any public electricity network.  In a renewable energy fed power electronic based DC microgrid system, renewable sources can have fluctuating power characteristics due to various environmental factors. In such an environment, chances of voltage instability are highly probable due to varying power nature of renewable sources and loads connected. In this paper, a bidirectional converter connected with battery storage is controlled based on the voltage of the micro grid in order to tackle the aforementioned problem. A selector based control algorithm in conjunction with proportional integral controller is used to trigger the bidirectional converter. Proposed control technique is simulated and implemented in a 60V DC microgrid and results are analysed.

Description: Energy management optimization is still a big challenge for Microgrid, which includes Renewable Energy and Hydrogen Fuel Cell. In this paper, an online Adaptive Model Predictive Control (AMPC) based Energy Management Strategy (EMS) is proposed to increase the energy sources lifetime of the microgrid while minimizing hydrogen consumption. The EMS problem is simplified according to the control structure of microgrid system and the cost function of system is built and transferred to standard format of the Quadratic Programing problem to solve. Moreover, adaptive algorithm is used to automatically adjust the weights of different targets according to the states of system. It is shown by simulation results for different cases from MATLAB-Simulink TM that proposed EMS has significant effects on controlling State-of-Charge (SoC) of battery and a noticeable improvement on extension of Hydrogen Fuel Cell lifetime and battery charge-sustainability

Description: This paper proposes a power management procedure for a grid tied PV storage system in electric vehicle charging station (EVCS) . The procedure is designed to be implemented in the power control system of the CS. The control proceeds depending on the integration of renewable energy sources by adopting an optimization algorithm, in order to minimize stress on existing power and to reduce the cost of consumed energy based on the electrical grid in standalone mode. This work explains in detail the approach via simulation results of a 15kW PV-Grid system connected with 40kWh lithium-ion battery and a load flow of five EVs. A digital technology aimed to assign a reliable data communication between the CS and the plugged EV is described in this research through a power predictive model. Otherwise, various parameters are involved in this approach to set the optimal operation mode of a charging process for instance, the instantaneous power of the PV array, the available energy in the battery storage buffer and the limited power the grid can offer. MPPT algorithm followed by error regulation to control the boost converter switch, the voltage source converters (VSC) for the inverter and also the current control loop for charging storage buffer are all pillars to build an efficient power forecasting model. To test the validation of the model, simulation results of several charging scenarios express the effectiveness of the proposed CS effectively.

Description: For the efficient utilization of solar energy, its concentration is required. Central Receiver systems have higher concentration ratio as compared to other concentrated solar power techniques. The solar flux density distribution and the temperature on the receiver plate are important parameters in assessing the net thermal energy, in predicting the performance of solar concentrator and in the design of solar receiver. Here the flux distribution on the flat receiver of the ganged type model heliostat system consisting of nine heliostats has been evaluated by using the thermocouple method which is the indirect method of flux measurement. The variation of the solar flux density distribution on the receiver plate have been estimated for the different numbers of heliostat by using the energy balance equation. For this model heliostat system the peak flux and average flux values are estimated to be 3950.57 (± 3%) W/m 2 and 1798.77 (± 3%) W/m 2 respectively. This analysis will be useful for sizing of the receiver. For the average flux value on the receiver plate the receiver size for the nine heliostats system will be 0.3m x 0.3m with the intercept factor of 64%.The average optical concentration ratio was 5.6 with the optical efficiency of the system 0.50 ± 3 % during the test period.

Description: Wind speed prediction has several applications and various atmospheric parameters like temperature, humidity, pressure, wind direction can be used to predict it. A number of methods using mathematical and biological moels have been proposed by various researchers to predict the wind speed. This paper explores the use of one-against-all (OVA) and one-against-one (OVO) multiclass Support Vector Machine (SVM) algorithms for wind speed prediction. The algorithms are tested on wind speed data having hundreds of samples of training and test data sets. The results of employing the two algorithms are compared for predicting the wind speed and results indicate that one-against-one algorithm produces better results than the one-against-all algorithm.

Description: This paper presents the design and development of a novel highly efficient synchronous buck converter operating both  as a battery charge controller with five stage charging method and also as  improved Maximum Power Point Tracker (MPPT) for operation in Solar Photovoltaic (PV) Systems. The algorithm regulates the duty cycle of the switching devices of the converter following a variable step size perturb and observe (P&O) MPPT technique. At the same time it provides precise control on the battery charging voltage and current according to five charging stages which is desirable for protection of battery health and maximizing charging rate. Thus the algorithm developed provides a combined solution for maximizing the transfer of solar electricity generated by the PV module(s) and also ensuring a long battery lifetime. Both these aspects, which are generally investigated separately earlier, are treated in an integrated fashion in this work. The work analyses in detail about the converter power loss as well as describes the development of MPPT technique and battery charging method used in the controller. A prototype of 1500W MPPT Charge Controller based on this algorithm has been designed, fabricated and tested. It shows satisfactory performance of the MPPT charge controller in terms of performance parameters i.e. converter efficiency, MPP tracking efficiency, MPP tracking time, fluctuation of PV operating point around MPP, input operating voltage range of the controller, independency of battery type as well as provision of temperature compensation.

Description: Diesel is in vogue as a fuel in transportation sector from a long time. Diesel being a fossil fuel is depleting very quickly and soon will be scarce enough to be used as a fuel economically. Biodiesels, possessing the properties almost equivalent to diesel are found to be the one of the prospective alternative choice to substitute the petroleum based fuel. One such biodiesel is prepared from neem oil. Neem oil, being non-edible oil has very few uses and can be easily found in India and other south-east Asian countries. Neem oil methyl ester (NOME) is a biodiesel, prepared by the esterification of neem oil. Diethyl ether (DEE) was also used to blend with diesel and biodiesel separately. Various proportions of diesel, biodiesel and DEE were investigated in the four-cylinder DI diesel engine. The higher latent heat of evaporation of DEE gives the cooling effect in the engine cylinder. It contains high oxygen in its chemical composition along with the very low cetane number. Due to this, the smoke, carbon monoxide (CO) and Nitrogen oxide (NO X ) were decreased on its addition. However, unburned hydrocarbon (HC) emissions were increased. Graphs have been plotted for various engine parameters and emission levels of diesel and its blends. It has been found that diesel along with DEE has an adverse effect on performance characteristics due to the large difference in their flash point and improper combustion however biodiesels along with DEE are a good prospective fuel as it gives very good performance and emission characteristics.

Description: Delhi, the capital of India is receiving 89 per cent of its power from thermal power plants. Due to rapid depletion of fossil fuels and environment pollution, government introduced Delhi Solar Energy Policy. The objective of the policy is to shift from thermal to solar power generation through installation of 2GW of solar rooftop systems by FY25. Accordingly, there is potential of producing 49 per cent of solar power through Solar Residential Rooftop Systems (SRRS). For achieving this, there is need of synergy between two major stakeholders i.e. government and potential consumers (owners of residential units). The major provision of the policy is to provide financial subsidies, technical support and generation based incentives to encourage residential roof owners for the installations of SRRS. Still the installations of SRRS are dismally low. Apart from the formulation of policy; the awareness factor plays pivotal role enabling roof owners to take informed quality decision. The main contribution of this research paper is to explore the awareness levels of potential consumers for the SRRS as well as about government subsidies towards SRRS installations. The average awareness score on a scale of 1 to 5 about SRRS has been found significantly low i.e. 1.99. This study revealed that there was no relationship between awareness level and demographic profile of respondents. The awareness of people towards government subsidy has also been found quite low. In view of the research outcomes, there is need to disseminate information (through strategic advocacy) about government incentives and SRRS, among residential owners for achieving the targets of the policy.

Description: This paper presents a simulation tool that optimizes the generation output from different renewable energy resources of a virtual power plant (VPP). A real case study of a VPP planned to be installed in Kayathar in India is adopted in this research. The VPP is combined of a 4.4 MW wind farm, a planned solar photovolatic plant, a biogas plant, a biomass plant, and storage. The VPP is connected to the grid, and the optimum scenarios obtained were those that imported zero energy from the grid and utilized the storage system effectively.

Description: This paper presents a comparative study between three controllers for the Doubly Fed Induction Generator (DFIG) integrated into a wind turbine system. The active and reactive powers between the stator of DFIG and the grid are controlled independently by using three control strategies, the first called the active disturbance rejection control (ADRC), the second is the classical Proportional-Integral (PI) and the third called polynomial RST controller. First, a modeling of wind turbine and DFIG is presented. Also, in order to maximize the power of wind energy conversion, the use of MPPT control is indispensable. Then, these three control strategies are designed, simulated and their performances were tested and compared in terms of instruction tracking and robustness.  The simulations were realized by Matlab/Simulink software.

Description: The present research investigated the activity of catalysts from biomass waste derived from Palm Empty Fruit Bunch (PEFB). An important factor for assessing the feasibility of biodiesel production is related to its economic evaluation. The sludge of Palm Oil (SPO) is generated from palm oil processing industry. SPO was potentially as biodiesel feedstocks due to its low price. The investigation of free fatty acid esterification reactions on SPO with methanol was conducted in this research. Recently, a new strategy of preparing a heterogeneous solid catalyst from biomass wastes has been developed. The parametric investigation was carried out by varying the molar ratio of methanol to SPO catalyst to oil (8:1 - 14:1), the amounts of catalyst (0.5 - 5 wt. % SPO), and the reaction temperatures (40 - 60 °C). It is concluded that the optimum conditions of esterification reactions were acquired at molar ratio of methanol to SPO catalyst to oil 12:1, the amounts of catalyst 5 wt. % of SPO, and the reaction temperature of 60 °C.

Description: The presence of wind generator in interconnected power systems is an important aspect to be considered while studying transient faults. A deeper understanding of transient stability study is essential for the qualitative assessment of the system which includes wind generator. This understanding can be achieved by calculating transient stability index using singular perturbation method. For the calculation of this transient stability index, the state variables are modelled in a realistic approach of slow and fast time frames. In this study, the transient stability assessment results obtained using the method of singular perturbation are compared with the corresponding results calculated using catastrophe theory and linearized singular perturbation methods. In order to understand the implications of presence of a wind generator in the system during transient faults, the study also focuses on the effect of circuit breaker clearing time and generator transient reactance. 

Description: Present work simulates and analyzes the rooftop photovoltaic (PV) system on buildings roofs of the University of Surabaya, Indonesia for electricity power generation. The work also to calculate greenhouse gas (GHG) emission reduction that can be obtained by PV system mounted on the building roofs. The surface area of the roofs was determined using Polygon feature of Google Earth TM . The energy output of the system was simulated with SolarGIS pvPlanner software program. The grid-connected PV system type was chosen in the simulation. Greenhouse gas (GHG) emission reduction analysis was carried out using RETScreen program simulation. It was found that about 10,353 m 2 of the rooftop of the university buildings could be used for panel installation. The total capacity of the panels is found about 2,070 kWp with total electricity production is about 3,180 MWh per year and could supply up to 80% of the campus energy demand. The system would serve as a means of reducing 3,367.6; 2,477.2, or 1,195.7 tons of CO 2 to the atmosphere in comparison to the same amount of electricity produced by burning coal, oil, or natural gas respectively. The unit cost of PV electricity was found ranging from 0.10 – 0.20 USD/kWh. From economic aspects, the rooftops PV system has the potential to provide power at a competitive cost in comparison to other alternative options of power generation.

Description: Multilevel transformerless inverters are widely employed in PV grid-tied applications because of their significant benefits in reducing switching losses and enhancing system efficiency. Wide bandgap (WBG) semiconductor devices such as SiC MOSFETs can increase the system performance and reduce the total losses due to their superior features over Si switching devices. This paper investigates a three level transformerless inverter based on H6 topology. The proposed topology is implemented with SiC MOSFETs and a modulation approach is adopted to reduce the number of conducting switches. Also, a detailed comparison of the use of SiC and Si switching devices in terms of switching and conduction losses, high switching frequency operation, filter size reduction, and thermal analysis and heat sink volume is presented. Simulation results show that total conduction and switching losses are reduced by about 50%, which allow a significant increase in either the switching frequency or the inverter power rating level for the same switching device losses. Additionally, operating at higher switching frequencies using SiC MOSFET leads to a significant reduction in volume and weight of the inductor filter. Furthermore, a thermal analysis is performed using COMSOL software to investigate the heat sink requirement.

Description: Prediction and assessment of solar radiation are necessary pre-requisites in developing solar technology. Here, an artificial neural network (ANN) model has been developed to predict solar energy potential in the Southern part of India: Andhra Pradesh (AP) and Telangana State (TS), lie between 12°41' and 22°N latitude and 77° and 84°40'E longitude. Generalized feed-forward with back-propagation neural networks were considered using MATLAB. Three layered neural network with different architectures are designed and evaluated. For training and testing the network, geographical and meteorological data of 28 sites over a period of recent 22 years from the NASA geo-satellite database were taken. Geographical parameters (latitude, longitude and altitude), meteorological data (temperature, sunshine duration, relative humidity and precipitation) were used as input data, whereas the mean solar radiation was used as the output of the network. All the parameters taken here are in the form of monthly mean. The ANN model has been evaluated for test locations by calculating mean absolute percentage error (MAPE). The correlation coefficients (R-value) between the output of model and the measured value of solar radiation is calculated.  The R-value were more than 0.95, which show high reliability of the model for prediction of solar radiation anywhere within AP and TS. Solar radiation of major cities was predicted using developed model. Predicted solar radiation is analyzed and used to create monthly mean maps using GIS technology. These maps can be useful to estimate solar energy potential at any locations within AP and TS.

Description: Turkey is an energy importing country  and  relies on  coal, oil, natural gas and hydraulic for its energy. Therefore, the Turkish government has prepared strategic plans considering all alternatives including wind, solar, geothermal, biomass and other sources. One of  these, the last 2015-2019 Strategic Plan, was put into force by the Ministry of Energy and Natural Resources in  order to ensure and also to encourage sufficient investment to meet the growing demand for energy in Turkey. High energy demand is, is closely linked to industrialization,  population and economic growth. Thus,  recent projects also include energy efficiency measures to help reduce waste  of  energy  consumption. The energy sector development policies of countries is a strategic area of vital importance. Although Turkey is  potentially a very rich country in terms of renewable energy sources and diversity of the country, the foreign energy  dependence is about 75%. It is clear that the need to increase the share of new and renewable energy      sources in energy production for sustainable development is necessary.   In this study a typical application to choose an appropriate renewable energy resource  in Turkey  using the analytic hierarchy process  is carried out.  The software of Expert Choice which supports  AHP has provided data to be analyzed statistically. It is indicated  that wind energy is in the first place and  biomass takes  the last place. Keywords- AHP Method ;   renewable resources ; strategic plan;  sustainable development ; Turkey.

Description: Paris Agreement stands as the flagship of ongoing international climate change agreements. The Paris Agreement’s central aim is to strengthen the global response to the threat of climate change by keeping a global temperature rise this century well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius. The agreement’s aim is generic and therefore meeting its targets is not a deterministic problem. This paper aims at correlating Paris Agreement with Representative Concentration Pathways (RCPs) over the end of the century, using as starting point the RCP2.6 scenario and consequently proposing and examining pathways that involve substantial decrease of emissions compared to RCP2.6, namely RCP 2.0 and RCP1.0. The results, through the elaboration of an integrated assessment tool (GCAM), provide useful insights on extended pathways for meeting Paris Agreement targets. Our findings include the requirement of major negative emissions. Industrialized and developing countries have substantial contribution, mostly based on their population rather than their economic situation.

Description: This study presents a practical open source implementation that uses double-multiple streamtube model for the aerodynamic performance prediction of straight-bladed vertical axis wind turbines, particularly, the power coefficient ( C p ) and tip speed ratio ( λ ) relationship. To improve the analytical capability of the proposed implementation, important aspects of performance such as dynamics stall and, fixed/variable pitch blade were added. In addition, a fast convergence method for finding the axial induction factor was adopted, giving simplicity to the implementation. Simulated C p ( λ ) curves were compared with the experimental data (wind tunnel and field) reported in the literature. The mean absolute error of the simulated C p ( λ ) curves, in terms of efficiency, was 0.06, with a mean maximum of 0.078 and a mean minimum of 0.047. The good agreement in combination with the low computing time, suggests that the proposed implementation provides a useful tool for predicting aerodynamic properties of the straight-bladed vertical axis wind turbines and, therefore, for its design. The implementation can be carried out successfully by using GNU-Octave.

Description: One of the main challenges in the operation of wind farms is the time varying nature of output power. So far, many studies have been done for modeling the variations of wind farm output power. However the extremely fast variations of wind generation have not been considered in previous studies. The variations of active/reactive powers in the wind turbine and wind farms with sampling time equal to 0.01 s are studied and modeled in the present paper. For this purpose, a massive amount of actual records of voltage and current waveform data are collected from the Manjil wind farm in the north of Iran. Analyses of results show that the rate of change of active/reactive powers of the wind turbine and wind farm is very high. A stochastic model based on the auto-regressive moving-average (ARMA) process is proposed to model the fast variations of active/reactive powers of the wind turbine and wind farm. The presented model as a basic and simple model can be utilized in many applications such as SVC control system to compensate the reactive power and flicker suppression of wind plants.

Description: A new converter of single switch mode with high step up ratio is proposed in this manuscript. The proposed converter design is a combination of Voltage Tripler (VT) and sepic boost converter. This design uses MOSFET switch with reduced switching and conduction loss.  Converter achieves high step up voltage gain with appropriate duty cycle and less voltage strain on the switch. The energy stored in the inductor can be recycled towards the output capacitor. The working condition of the converter under Continuous Conduction Mode (CCM) is given in detail. The input of 30V of PV source is boosted to 400V by this proposed converter. The main advantage of the proposed converter is single switch, reduced component stress and size, the ripple current and voltage is less. The efficiency attained is 93%. The simulation of this converter is done using MATLAB Simulink.

Description: In this work, the laminar flame speed and flame structure of biogas/H2 fuel mixtures were studied numerically from pure biogas to biogas with an addition of 15% H2 in volume by using the CHEMKIN software with the GRIMECH 2.11 kinetic mechanism. The effect of hydrogen addition to biogas on laminar flame speed and flame structure has been studied as well as the variation of the aeration rate from stoichiometric conditions to lean conditions. The trends in laminar flame speed results obtained are explained by means of numerical results on temperature profile and heat release rate. CO, CO2 and NO profiles are also observed for the different mixtures studied.  Hydrogen addition in biogas flames shows an important effect, especially in zones near stoichiometric flames, decreasing its effects in lean mixtures combustion.

Description: The total energy demand has been escalating day to day globally as well as the quest for sustainable and affordable energy enforcing the paradigm shifts of predominant fossil fuels. The prospective bioavailability of biomass residues in India could induct the gasification and co-gasification technologies through the interaction of various sources either by adopting biochemical or thermochemical methods. Both gasification and co-gasification studies experimented with deoiled jatropha seed cake (JC) residues and wood chips (WC) along with their blends at the mass ratio of 75:25, 50:50 and 25:75 in the lab scale down draft type biomass gasifier. Thermogravimetric analysis at the heating rate of 30 o C per min in the nitrogen atmosphere was carried out to investigate the thermal decomposition behavior along with pyrolytic kinetics. The produced syngas was analyzed for its chemical composition (CO, H 2 , CH 4 , CO 2 , and O 2 ) by a portable gas analyzer. The co-gasification of 75JC:25WC exhibited the higher calorific value than the gasification of JC and WC individually at the respective pyrolytic regimes. It acts as evidence for substantial synergetic effects and thermal interaction for blending JC with WC during co-gasification for syngas production. The JC residues with low activation energy could be cogasified with WC to overcome the demand for fuel sources with higher activation energies. 

Description: One of the fundamental aspects of any economy is the availability and provision of sustainable energy. This is because it forms the central part of social, environmental and economic challenges in any country. Most governments worldwide, are now considering locally accessible, available, and renewable substitute energy options to address the concerns of emissions of greenhouse gases, climate change impacts and the necessity for the provision of cleaner energy. Reliance on fossil fuels for energy provisions is well documented. South Africa thus depends largely on coal as the core energy source contributing about 77%, with 92% production of the total coal consumed on the continent. Biogas, as an alternative is a renewable and sustainable energy source that can offer green energy. Biogas has proven to be a promising, realistic and feasible technology in providing clean and reliable energy. This paper, therefore, aims at presenting the potentials and status of biogas utilization, the technological associated benefits, future prospects and lingering challenges in South Africa.

Description: The aim of this research is to develop and evaluate the solar powered catamaran for a response to low carbon destination and sustainable tourism for Ko Mak Island, Thailand. The development process includes ship design, PV system design and shipbuilding. Thus, it has designed that are the length with 7.5 Meters and the width with 3.5 meters. Similarly, it has installed 1.8 kWp photovoltaic generation system and 2 units of 3-hp induction motors. The performance evaluations have been accomplished in the open water in the designated route. The result showed that the uppermost speed of the catamaran was 9.18 km/h at 4,500 W. At normal cruise speed of 2,000 W, the catamaran speed was 7.77 km/h and maximum travel distance without charging at depth of discharge equally to 0.6 is 41.96 km. Therefore, the catamaran cruise distance would cover any common travel route of Ko Mak Island. Furthermore, the 19-km extended travel route has been guided for the boat cruise and monitoring. The cruise has been performed in calm weather condition, which insolation of the cruise was 27.18 kWh. The PV system could generate electricity equally to 4.1 kWh or with efficiency of 15.08 percent. However the total consumption was 5.7 kWh. The average cruise speed was 6.26 km/h and the average motors consumption was 1,889.37 W. Finally it turned out that the boat has good maneuver response and good throttle response, passengers can walk to several parts for doing activities conveniently.

Description: The main sources of electricity generation are hydroelectric and thermo-fossil type in Ecuador. Gross hydroelectric production have sometimes exceeded 50% of national production. However, this type of hydroelectric is often threatened by droughts and their effect on the water reservoirs which our country has experienced on some occasions, such as in 2009. On the other hand, the National Plan for Good Living 2013-2017, in conjunction with the National Master Plan for Electrification 2013-2022, has planned new hydroelectric generation projects, which are expected to exceed 90% of the national balance. The objective of this article is to model the monthly production of hydroelectric energy for prediction purposes, by implementing five stochastic process models on a historical series of monthly hydroelectric energy production in Ecuador, during the period 2000-2015. The results show that the model that best fit the data of this time series is the ARIMA model (1, 1, 1)x(0, 0, 1) 12 with seasonality. This model shows that the energy monthly production can be forecasted to one and twelve months. The range used was from 2000 to 2014 and it was validated with data from January to December of 2015.  With this model, the forecast is made for the year 2020, proving an increase of monthly production.  The real values are in the confidence interval of the predicted values of the ARIMA model with annual seasonality. This model will help to describe and predict hydroelectric energy generation of Ecuador. In other words, it could be used in future planning studies of the electric sector.

Description: Electricity generation, electric power transmission and final distribution to an electricity meter are some of the processes performed in the industry of electric power. Power quality is an important factor to show the wellness of electric power. Due to the changing behavior of power generation in wind systems, more power quality issues may occur. This paper presents the simulation and analysis of Distribution Static Synchronous Compensator for voltage sag mitigation, harmonic distortion and power factor improvement using the control strategy named hybrid PSO-Firefly algorithm. The hybrid control strategy effectively enhances the performances of Distribution Static Synchronous Compensator in order to provide the faster and dynamic response. By utilizing the novel control strategy the compensation in the proposed work was completely admirable when compared with the existing techniques like proportional integral and derivative controller and proportional integral and derivative-particle swarm optimization control. The reduction of harmonics achieved to a lower percentage as 1.216 in the proposed work. The operation of simulated control method for Distribution Static Synchronous Compensator is performed in MATLAB SIMULINK.

Description: In this study, an economic model is proposed to simulate the optimal operation of a grid-connected microgrid regard to the uncertainties of microgrids’ components. In this study, the wind farms are considered as renewable resources and an innovative technology of advanced rail energy storage (ARES) is deployed as a storage unit. In the optimization model, the stochastic nature of wind energy and the intermittency of loads are contemplated in the model by employing scenario-based Monte Carlo approach to simulate the implication of uncertainties. The objective function of the optimization problem is defined subject to maximize the profit of microgrid’s components, and the problem is solved by employing crow search algorithm (CSA). Ultimately, the results of the numerical study are presented and discussed which confirm the effectiveness of the model and appropriate performance of the selected storage technology.

Description: This paper is focused on the improvement of the current quality at the Point of Common Coupling (PCC) of a three-phase grid connected photovoltaic system supplying unbalanced and nonlinear loads. The photovoltaic (PV) system is composed of a PV generator interfaced to the grid via a DC–DC power stage connected to a grid-tied inverter. Therefore, to improve the grid current quality at the PCC, the PV inverter is performed as a shunt active power filter in addition to its main task which is the injection of the PV generated power. Thus, this paper proposes a novel and efficient algorithm aimed to extract the correct disturbing current introduced by the nonlinear and unbalanced loads. This disturbing current including the reactive power, harmonic and unbalanced currents, is considered as the reference current in the effective control strategy of the PV inverter. Therefore, the good obtained simulated results point out the effectiveness and the reliability of the proposed algorithm to improve the quality of the grid current and compensate the disturbing current by eliminating the reactive and unbalanced currents and reducing the total harmonic distortion with a fast dynamic response.

Description: In the variable speed wind energy conversion system, one of the operational problems is to handle the speed uncertainty and discontinuity of wind, that influence the power generation from a wind energy conversion systems (WECS). In order achieve a stable power output from a WECS despite variations in the wind speed, a number of control algorithms were devised in the literature over the past few years. Pitch angle control is widely used for regulation of output power fluctuations in a WECS. The control objective is to maintain stable power generation against wind speed variation, which can be achieved by regulating the pitch angle and/or generator torque. In view of handling the uncertainties owing to wind speed variations, this paper pursued a comparative assessment of three controllers, namely Proportional-Integral control, Fuzzy logic control (FLC) and Model predictive control (MPC) schemes. To evaluate their performance a simulation setup for implementing these three controllers applied to a WECS is prepared in MATLAB/Simulink. From the obtained results, it is envisaged that the proposed MPC exhibits excellent response and robustness of the WECS in face of uncertainties owing to intermittency and discontinuity of the wind speed.

Description: Artificial neural network (ANN) needs to be applied to the complex, multivariate, and highly variable biomass and pyrolysis data to define optimum input variables and develop effective models.  In this study, two different ANN methods, the feed-forward network (FFN) and the cascade-forward network (CFN), were applied to model pyrolysis product yields (biochar-BC, bio-oil-BO, and gas mixture-G) from 11 biomass and pyrolysis variables through hierarchical modeling approach.  Both methods were supplied with two subsets of data, with two-thirds being used for training and one-third for testing the performances of the methods, after normalizing all data (72 samples).  The performances of both ANN methods were evaluated by using three statistical parameters.  In general, FFN and CFN methods had very similar performances in training and testing.  Both methods had mean R 2 of 0.91, 0.96, and 0.95 for training BC, BO, and G, respectively.  For testing of all FFN and CFN models, the R 2 values of BC and G were less than 0.50, but the R 2 values of BO were over 0.50 (up to 0.81) for only the last 5 models of FFN and CFN.  Both types of ANNs are promising tools in predicting pyrolysis product yields.

Description: Household distributed power systems that the renewable energy such as the PV and the wind power are introduced as energy sources are expected to spread in the future as efforts for global decarbonization. EV has already been recognized the role as a battery for the energy management of the household distributed power system. The Micro EV which is a kind of EV requires frequent charging from a household AC outlet due to its small capacity, so it is necessary to suppress the harmonics of the AC power source and charge the battery at an appropriate power factor. For this reason, the charger of micro EV generally has two stages of a converter which performs input control with a PFC (power factor correction) function and a converter which performs charge control. However, the reduction in size and the weight is an important factor for the traveling performance of EVs, and the miniaturization and the weight reduction are also required for the onboard charger. Therefore, in this paper, a method to control the input current and charge control to the battery with a single converter is proposed. By using the proposed single-stage converter, it is possible to dramatically improve the energy density and the power conversion efficiency. Moreover, it is confirmed that the proposed circuit can cope with dc input from the dc bus, and is also an effective application in the dc bus based household distributed power system which is expected to spread in the future.

Description: - This paper presents a solar array simulator (SAS) to emulate the actual characteristics of solar arrays under different environmental conditions and load variations. SASs are essential in the evaluation of maximum power point tracking (MPPT) algorithms and their power converters. The proposed SAS adopts a modular structure where multiple voltage-controlled buck DC-DC converters are adopted. An active current distribution control is proposed to achieve a balanced current in the parallel connected converters.  The effect of the proposed controller on the circulating current impedance is analysed, and the controller’s parameters are designed to obtain excellent current distribution and fast dynamic response. The SAS’s performance is explored through a Simulink model with a variable resistor load and at different irradiance levels. The results confirm the validity of the proposal, in which excellent performance was obtained in terms of tracking the desired V-I characteristics and the current distribution between the converters.

Description: This paper proposes coordinated active and reactive power control strategy of wind-biogas based hybrid system for rural electrification (HSRE) in order to provide continuous and reliable source of electricity to a cluster of villages. In the control strategy used for HSRE, a predefined part of load is being supplied by the grid and the remaining part, under steady state as well as small signal disturbances, is taken care by a hybrid system of controllable and intermittent sources of energy. Induction generator (IG) based wind energy conversion system (WECS) has been considered as a source for HSRE. Since reactive power is needed by both IG and load, an additional source of reactive power, static synchronous compensator (STATCOM) is used to fulfill the reactive power requirement. The synchronous generator has been used for power generation from biogas-genset which is fitted with electronic speed governor and automatic voltage regulator (AVR). The concept of defined grid operation is achieved by considering dynamics of system voltage angle as well which cannot be achieved by the usual control techniques for frequency and voltage magnitude. The developed hybrid system is given a small signal disturbance in load as well as input wind power. The robustness of proposed control strategy has been showed from the dynamic performance results by maintaining power balance between system components while regulating the system voltage and frequency.

Description: This work presents a technical-economic analysis of several biomass gasification-based power plants for decentralized generation. The major aim is to make a preliminary evaluation of their feasibility in the Colombian context by means of the cost of electricity (COE). The analysis was conducted using information provided directly by power plant manufacturers from several continents. A silvicultural analysis of the major commercial forest plantations in Colombia allowed to determine suitable forest crops for energy projects, with energy potentials ranging from 500 kWe to 2000 kWe. Results from the study show that COE varies from 10.2 cUSD/kWe-h to 40.8 cUSD/kWe-h depending on the technology used. For lower cost plants, the share of investment cost in COE is of 45-50%, whereas for more expensive technologies it is of 63-67%. The methodology used provides technical, economic, and energy support to make informed decisions regarding the best technology for small-medium power applications using biomass.

Description: In this paper, we examine the relationship between justice dimensions (procedural, distributive, and interactional justice) and conflict (task and relationship) in buyer–supplier relationships. We develop a nuanced understanding of how justice dimensions reduce task and relationship conflict in buyer–supplier relationships. In addition, we hypothesize that task conflict mediates the relationship between justice dimensions and relationship conflict. We also hypothesize that the effect of justice dimensions on conflict is contingent on the buyer–supplier cultural distance and the degree of autonomy provided to the supplier. Based on primary data on buyer–supplier relationships, our results show that procedural and interactional justice dimensions are more important than distributive fairness. Furthermore, managers can reduce the relationship conflict by mitigating task conflict, which has not been asserted in the buyer–supplier relationship literature. Our results suggest that supplier autonomy and cultural distance, as contextual variables, influence the relationship between interactional justice and conflict dimensions, but they do not influence the relationship between procedural or distributive justice and conflict dimensions. We discuss the relative importance and role of the three justice dimensions in mitigating relational conflicts in buyer–supplier relationships, and implications of our results to theory as well as practice.

Description: Integrating insights from organizational information processing theory and social categorization theory, we examine how top management team (TMT) tenure diversity affects team performance. We propose a theoretical framework that examines how these two conflicting processes occur simultaneously within diverse TMTs by arguing that TMT tenure variety influences information processing while TMT tenure separation influences the social categorization process. We argue for the presence of nonlinear relationships between tenure variety, tenure separation, and team performance. Furthermore, we propose that these relationships are moderated by the level of TMT behavioral integration. Based on a sample of 357 senior managers from 126 firms in China, we find that both TMT tenure variety and TMT tenure separation have opposing and nonlinear relationships with TMT performance, and the relationship between TMT tenure separation and TMT performance is moderated by the level of TMT behavioral integration. Our results help clarify the conflicting conclusions of previous TMT tenure diversity research. Our findings suggest that the effect of diversity depends on the type of diversity as they affect different processes. Our findings also explain how the opposing effects of both information processing and social categorization can occur simultaneously in the TMT. Furthermore, the effects of both processes are not linear while the level of diversity variety and diversity separation can affect the marginal effects. Finally, TMT behavioral integration processes affect how tenure diversity plays its role in team performance.

Description: The issue of scheduling interrelated activities is important and of particular concern to design managers. One tool that helps us to solve this issue is the design structure matrix (DSM) which can explicitly represent the information dependencies among interrelated activities. Based on the DSM method, this study presents effective approaches for sequencing interrelated activities with the goal of minimizing total feedback length, which is a good approximation for reducing project completion time. First, we prove two new properties of the problem, and develop an insertion-based heuristic. Second, the proposed heuristic is further improved by combing it with simulated annealing and genetic algorithm. Computer experiments show that our approaches outperform existing heuristics, in that with similar settings, our approaches often produces better solutions.

Description: This paper's novelty is the modeling of competition in production quantity and product-launch timing, which has been silent regarding the impact of these interdependent decisions on firm survival. We rigorously address the competitive interplay between a startup and an established rival by developing a game-theoretic model that captures the startup's vulnerability to failure through maximizing its survival likelihood. We allow the established rival to behave strategically by anticipating the startup's timing and production decisions prior to making its own production decision. We propose that unless the market-entry investment is low, a survival-maximizing startup should wait to launch its product, and do so with a larger production output than the established rival, when delaying the product launch enables the startup to charge a high price. Insights on the established firm involve the benefit from behaving strategically, which is when competing with either a survival-maximizing or profit-maximizing startup. If the market-entry investment is large, comparing a survival-maximizing startup with a profit-maximizing startup suggests that the former produces at a larger scale than the latter when either startup competes with an established rival, which in turn is forced to reduce its production level.

Description: Product lifecycle management (PLM) is a strategic and holistic approach for the management of information, processes, and resources supporting the entire product lifecycle from concept to disposal. Several systems are available to manage data and information during the lifecycle. A PLM system does not have to be considered as a unique solution, but as a set of software supporting different perspectives and activities related to the lifecycle management. A full comprehensive implementation of PLM systems is rare. Since PLM reflects the peculiarities of processes and data structures, implementation differences are evidently observable among companies. The design of methods and tools supporting an assessment of PLM implementation inside a company can enable a correct definition of PLM strategies and goals. Based on these premises, the paper aims to specify a methodology for carrying out a gap analysis of PLM with the scope of discovering existing technological and methodological gaps, and planning actions for improvement. The proposed methodology implements a visual and lean reference model, and an assessment questionnaire for data collection. Lesson learned and feedback from three industrial applications are also described and discussed.

Description: The proposed research article presents an optimum Fuzzy-PID controller with a derivative filter to stabilize the frequency in a unified power system which includes renewable sources of energy like solar thermal power generating units. The scrutinized system consist of two area unified power system where each area is consisting of a thermal unit with reheat turbine and a solar thermal unit. The automatic generation control is exercised in each area with the help of two distinct Fuzzy-PIDF controllers. A novel optimization method named the Grey Wolf Optimizer is applied for optimizing the   coefficients of the proposed fuzzy-PIDF controller. A time dependent objective function (Integral Time Absolute Error) has been employed in this case as fitness function. Different controllers such as PID, Fuzzy-PID and Fuzzy-PIDF are used to stabilize the frequency oscillation as well as tie-line power variation in the multi-area system subject to a disturbance of 0.01 p.u. in the system. The efficacy of the recommended Fuzzy-PIDF controller is also  established in view of various time domain specifications like minimum undershoots, settling time and maximum overshoots. To check the robustness and sensitiveness of the controller, the system is subjected to random loading and parameter variations.

Description: This study presents a comparative investigation of the performance characteristics of both manual and proposed control of a standard frequency converter. A simple and accurate control stage is added to the system, based on sensing Photovoltaic voltage output. System performances are analysed from the energy intake. Advantages and drawbacks of the proposed control are enumerated. Experimental results are shown using a laboratory test bed composed of a 2.5-kWp, 2.5-HP centrifugal pump and a tank of 0.5-m3 capacity. It presents a good agreement with the numerical simulation and theoretical explanation.

Description: This paper presents the design and development of a scenario where the residential user is involved, with three fundamental elements such as home energy management systems (HEMS), photovoltaic (PV) systems and efficient behavior by means of changes in consumption habits. The objective is to analyze its impact on the household electricity conservation through programs focused on active demand side management (ADSM). The proposed scenario starts from incentives arisen from changes in consumption habits of all the load by 30%, the control of automatic loads and energy self-generation in two different locations in Colombia: Bogota and Cajica. As a result, a monthly reduction of 35.49% is observed in relation to the habitual consumption when the user modifies his habits of using energy in his residence.

Description: In this study, an experimental study has been evaluated on a variable compression ratio diesel engine to investigate the compression ratio effects on engine performance, combustion, emission, vibration, and noise characteristics. The result of engine characteristics were studied at 12:1, 14:1, and 16:1 compression ratios under partial load condition. Experimental engine was operated with diesel, biodiesel and diesel-biodiesel blends throughout the experiments. Experimental study indicated that compression ratio considerably affects the engine characteristics that measured in this study. It is observed that in the experiments, higher compression ratio results in higher brake thermal efficiency and thus lower specific fuel consumption. Higher compression ratios resulted with higher cylinder pressure and thus improved combustion. Increasing compression ratio improved carbon monoxide emission, however, increased carbon dioxide emission and nitrogen oxides formation. Also, noise and vibration of the engine reduced with the increment of compression ratio.

Description: Power generation through the renewable energy sources has become more viable and economical than the fossil fuel based power plants. By integrating small scale distributed energy resources, microgrids are being introduced as an alternative approach in generating electrical power at distribution voltage level. The power electronic interface provides the necessary flexibility, security and reliability of operation between micro-sources and the distribution system. The presence of non-linear and the unbalanced loads in the distribution system causes power quality issues in the Microgrid system. This paper explores and reviews different control strategies developed in the literature for the power quality enhancement in microgrids. Also comparisons of different control methods are presented with suggestions for future research.

Description: In this paper, a simultaneous optimization method using GA of configuration and operation of emergency generator s in medical facilities with power source of renewable energy is proposed. The simultaneous optimization of configuration and operation needs search of enormous combinations, which is generally considered to be a difficult problem. Here, PV is assumed as renewable energy, but since its output depends on the weather, fluctuation of the generated power is not small. From the viewpoint of an emergency generator, this is a factor of short-term variations in load, so there is concern that the efficiency will decline. In the proposed method, genes are divided into configuration chromosomes and operation chromosomes, and the operation chromosomes are multiplexed so that they can be switched by the time zones and the loads so as to be robust for short-term variability. The effectiveness of the proposed method is examined by a case study using amount of insolation and actual data in a hospital.

Description: The continuous growth of electricity demand has presented a new challenge for power system utilities in preserving the system efficiency. Thus, Distributed Generation (DG) has attracted a lot of interest since it provides clean, reliable and cost-effective power supply. However, DG type, location and size should be properly chosen. To this end, this paper presents a DG placement and sizing method regarding system losses reduction, voltage magnitude and stability enhancement. The system weakest buses were selected for DG allocation in the basis of sensitivity methods and optimal DG size of a single DG unit has been determined by means of the quadratic curve-fitting technique.  Multiple DG units’ placement has been performed using loss improvement and loss reduction indices. Proposed approach has been applied to the 33- bus distribution system. Power system modeling and simulations have been performed using MATLAB\PSAT toolbox. Simulation results have shown accurate and satisfactory results in enhancing the steady-state voltage profile and decreasing total power losses.

Description: The organic Rankine cycle (ORC) has been using to covert renewable energy, such as waste heat, solar energy, geothermal energy, biomass, ocean energy and so on, to mechanical energy or electrical energy. In general, these kinds of renewable energies cannot be constantly supplied, and so the ORC should operate at various working conditions. For example, waste energy at a factory is usually varied depending on the type of production process, and solar energy also widely varies depending on weather and time. Hence, the ORC must be operated at off-design points due to the fluctuation of the available thermal energy. Its performance at off-design points can be worse than expected, since the components used in the ORC system are matched to the design point. When the ORC system is operated at a far off-design point, its output does not reflect its actual performance. This study investigated the performance of an ORC operating at far off-design points with components that were appropriately matched to its operating condition. In order to investigate the effect of the components used in the ORC system, the experimental results were compared with the performance of the ORC that was designed with components matched to the design point. The compared results showed that the efficiency of the ORC system at far off-design points could be greatly improved when the components used in the ORC system were matched appropriately to the actual ORC operating condition.

Description: This survey investigates a dynamic modeling, simulation and control of Photovoltaic (PV)-wind hybrid system connected to electrical grid, considering changes of environmental conditions. In addition, the daily variations of critical load power are considered. The studied hybrid system consists of two Photovoltaic (PV) stations placed at different locations and one wind farm are integrated into main AC bus to enhance the system effectiveness. The PV/wind hybrid system feeds large plant with critical variable loads and electrical utility grid. The technique of extracting maximum power point is applied for both photovoltaic stations and wind farm to capture maximum power under varying climatic conditions. Modeling and simulation of the studied hybrid system is performed using matlab-Simulink software. The reliability of the studied hybrid system is analyzed under various operating conditions such as changes of solar irradiation and wind speed.  Control strategy for power flow is proposed to supply critical load demand of plant. The simulation results show that when the injected power from hybrid system is larger than critical load power, the excess power will be injected to electrical grid.  Otherwise, when injected power is lower than critical power demand, electrical utility grid in cooperated with hybrid power system will supply the critical load power. In addition, when the injected power from hybrid system is unavailable, load demand is entirely fed by electrical utility.

Description: The multi-carrier microgrid (MCMG) is a restricted district comprising convertors and energy storage systems (ESSs) that are used to fulfill various energy demands. The structure and optimal operation of these MCMGs with regard to fulfilling multi-carrier demands are presented in relation to their rapid spread. In this paper, a two-stage optimum planning and design method for an MCMG is presented in the planning horizon. The investment and operation (fuel and maintenance) costs are considered concurrently to find the optimal type and size of components over the planning horizon. At the first stage, the genetic algorithm (GA) is applied to determine the optimal type and size of components, such as combined heat and power (CHP), boiler, transformer, and solar panels. At the second stage, the mixed-integer nonlinear programming (MINLP) technique is used and simulated by the GAMS software to solve the operational problem with regard to the forecasted energy demands. This method is examined on a typical MCMG and the effectiveness of the proposed method is proven.

Description: This paper applies demand side management (DSM) method as a new control strategy for frequency control in a microgrid powered by the diesel driven generator (DDG), wind and solar photovoltaic (PV) power sources. In order to level the frequency fluctuation due to intermittent power generation, the power consumption of the non-critical loads (i.e., heat pump, freezer) and power charging-discharging of plug-in hybrid vehicles (PHEV) are controlled through the controllers (PI/PID). The parameters of the controllers are optimized using Particle Swarm Optimization (PSO) and Firefly Algorithm (FA). Different disturbance conditions such as step perturbation and random variations of load, solar PV and wind output power has been considered to investigate the performance of the microgrid. Simulation studies confirmed that the performance of the FA optimized PID controller is better than the PSO optimized PI/PID controllers and FA optimized PI controller in terms of frequency deviation and setting time.

Description: In the last decade, renewable energy resources and energy storage systems (ESSs) played a pivotal role in the enhancement of the security of power systems. They exhibit great potential in power system operations: maintaining the load balance and improving power system security. This paper investigates the impact of linear and nonlinear energy resources on security-constrained economic dispatch (SCED) solution with different contingencies as a time-varying optimization problem. Linear ESSs are prominent in the literature on SCED. However, most of the previous studies do not take into account the impact of ESSs' nonlinear characteristic as highlighted in this paper. Therefore, the SCED problem should be discussed as a time-varying optimization problem. A new procedure is presented to handle time-varying optimization problems by finding the switching points and generator response equations. Not only this paper highlights the limitations of linear ESS characteristic and the effectiveness of using nonlinear characteristic of ESS in SCED solutions; illustrated on modified IEEE 6-bus and 14-bus systems, but also different optimization methods are used to validate the proposed procedure.

Description: Offshore wind power generation, transmission and integration around the world are becoming higher, and it provides technical and economic challenges for future practitioners and industries to make an alternative transmission system to an existing system in reduction of cost. In most of countries, e.g. The German government planned to install 25000MW of offshore wind farms by 2030. The greater part of offshore wind farms are integrated with High Voltage AC (HVAC) transmission to the onshore grid. Offshore wind farms are integrated with High Voltage DC (HVDC) transmission for long distances (〉50km) to the grid because of capacitive cable current in HVAC. The major challenge in HVDC transmission is the installation, operation and maintenance (O&M) of the Voltage Sourced Converter (VSC) HVDC substation in the offshore climate. Currently, in case offshore wind farm the research have been fastened to reduce the complexity with increasing reliability and minimizing cost. This paper gives a comprehensive review of integration of offshore wind farm via Low Frequency AC or Fractional Frequency AC (LFAC or FFAC) transmission. LFAC transmission is adopted from HVAC and it is operated at one third of nominal frequency (16.67 Hz). As compared to HVDC the main advantage of LFAC is an absence of the offshore converter station, hence system complexity and cost reduced. In design considerations, especially the offshore transformer is one of the challenges. This paper presents a comprehensive review on components and its design considerations of  offshore novel LFAC transmission. The offshore wind turbine considerations, collector network and different types of onshore frequency converters explained in detail.

Description: The control of CO2 emission is a global urgent issue, and the decarbonizing is being promoted in various fields. Also at residences, the electricity consumption is increasing instead of fossil fuels because of the electrification of heat source, shifting from gasoline car to EV and so on, therefore the reduction of the increasing burden of commercial power generation caused by the increase of electricity consumption at residence is extremely important task. Distributed power systems for households that can supply necessary electricity by renewable energy to each house is considered to be an effective solution. In order that the distributed power system which is desirable to be able to use various renewable energy become widely used for households, independent and autonomous operation of each power source is an important factor. This paper presents the behaviour of the power control in parallel operation of dc-dc converters directly connected to the dc bus with battery and the power behaviour of whole system. As a result, it was found that when multiple conditioners are connected to the dc bus in a renewable energy system for household, it is possible to realize autonomous charging with good balance even without the current balance control. It is important to expand use of the combination of dc bus and autonomous converters to utilize various renewable energy sources in the EV society coming in the near future.

Description: Bird droppings on the module surface of photovoltaic (PV) systems significantly reduce their electrical power production owing to their shading effects. However, the removal of bird droppings from the surface is difficult when the PV systems are installed in remote or offshore areas. Toward this aim, this study compared the different methods for connecting PV modules to reduce the degradation of electrical power production of PV systems due to bird droppings. For indoor experiments, 22 module configurations to connect nine modules (3 × 3) in the PV system and six different shading patterns of bird droppings were considered in this study. The results showed that the degradation effects of the PV array with the parallels connected in series were less than the other arrays. Therefore, we could suggest a module configuration method to minimize the degradation of PV systems due to bird droppings.

Description: The solar energy is an ever-growing power source among all the renewable ones. Several issues shall be faced by power engineers as far as the design of photovoltaic (PV) plants is concerned. One of these consists in the “partial shading”, that is the non-uniform irradiation on different cells of the same PV module or different modules of the same PV plant. The partial shading leads to undesired effects, such as the electrical mismatch, with possible generation of hot spots, and generally to a decreased production of electric energy. To mitigate the partial shading effects, different methods are feasible. Among them, the dynamic reconfiguration of the electrical connections between modules represents an effective solution. In this paper, an algorithm of reconfiguration for a small-scale PV plant is proposed and the experimental results showing the related benefits in terms of energy recovery are reported.

Description: The biggest challenge of solar energy is the intermittency of energy produced, since it depends on the availability of sun and real-time weather conditions. This intermittency is a concern for large-scale grid connected photovoltaic (PV) system to provide stable and reliable energy production. Battery energy storage system (BESS) can support to solve this intermittency by producing stable energy and provide smooth generation. Integrating the BESS with PV system in large-scale grid will control the energy flow from PV system to make sure to produce stable energy and balance between the demand and generation. This paper investigates an energy management mechanism for large-scale grid connected photovoltaic (PV) systems with batteries. The proposed system consists of a 1 MW PV system and 1 MW lithium-ion batteries connected to the grid by DC-DC converters and DC-AC inverters. MATLAB-SIMULINK is used to simulate the PV-batteries system under different circumstances of various irradiance and temperature levels. The proposed energy management strategy is verified by the results of simulation.

Description: In the recent years, system miniaturization and energy efficient are the two major area of focus of the researchers and scientist in solar collectors. The engineered colloidal fluids called nanofluids have replaced the conventional heat transfer fluids in solar systems due to its excellent thermal properties, optical properties, heat transfer rate, efficiency, and transmission and extinction coefficients. However, most of the research studies purchased the nanomaterials from the suppliers and this involves higher cost. Also, this also increases cost of the solar collectors. Hence, low cost graphite powder is converted into reduced graphene oxide (rGO) and detailed characterizations have been done in this work. Aqua based rGO nanofluids with 0.0005, 0.001, and 0.002 wt. % are prepared by two step method. The nanofluids are found to be stable up to 10 days because of oxygenated groups on the edge of rGO flakes. The rGO nanofluids show an enhancement in thermal conductivity and surface tension in comparison with the base fluid. Newtonian behavior in viscosity is observed for all the tested concentrations.

Description: Several studies of distribution network enhancement focused only on the optimization of either the integration of distributed generations (DG) or network reconfiguration. However, very few researches have been done for distribution network reconfiguration simultaneously with the DG location and sizing. This paper proposes a multi-objective operations management based on network reconfiguration in parallel with DGs allocation and sizing for minimizing active power loss, annual operation costs (installation, maintenance, and active power loss costs) and improving the power system voltage profile. An original Pareto-based evolutionary algorithm is proposed to equally optimize multiple objective functions providing Pareto optimal solutions, where the network manager can select an option. Simulations are successfully carried out on IEEE 33 bus test system for a single and multiple DGs optimal integration. The obtained results show the beneficial effects of applying these multi-objective operations management for multiple DGs integration in the distribution network.

Description: The importance of the module’s temperature has been severally discussed in previous reviews. What is of concern to us is the percentage of the power loss with each increase in unit temperature. The experiment illustrated in this research has allowed the monitoring of the variants in the power produced during the two months of August and December. The parameters of module temperature and solar irradiation have been monitored, and the maximum output voltage and the power produced were recorded. The drop in power was usually a result of increase in temperature but on a different scale, which draws attention to other parameters that may affect the percentage of drop in power. The system was simulated using the tool of MATLAB using the module data sheet, and the difference in power produced was noted. The objective of this research is to improve the simulation tools in order to be more accurate in increasing the number of parameters that may contribute to the power produced from the cells. 

Description: Hybrid power generation systems are an effective solution for the variable generated power of renewable energy sources. In this paper, a grid-connected hybrid power generation system including wind turbines, solar panels, wave generators and power storage batteries for a village in the Chabahar Bay in southeastern of Iran is optimally designed. The purpose of selecting this region is to investigate the economic feasibility of using wave generators in hybrid power generation systems. In the design, during various operating scenarios simulated with Homer software, adding power generation resources to the village will provide part of the required power locally, which will reduce the cost of purchasing electricity from the power grid, and even profitability is also achieved with the sale of electricity to the power grid. On the other hand, the reliability of power grid is improved in terms of the Loss of Power Supply Probability (LPSP) index.

Description: In pyrolysis, tar is undesired byproduct because it causes operational problems such as the contamination in the inner wall of a reactor, blockages in pipes, corrosion and formation of tar aerosols and carcinogenic. Therefore, it is necessary to take steps for removing or decomposing tar into fuel gas (bio-syngas) and other compounds that are more useful. In this experiment, catalytic process was selected to decompose tar derived from wood waste pyrolysis. The study focused on the effect of temperature on catalytic tar decomposition using a fixed bed reactor which was equipped with preheater to convert tar into gas product. The variables studied were temperatures between 500 – 700 0 C and length of catalyst bed between 0.67 – 1.34 cm. Yields of gas, bio-oil, char and aqueous and also compositions of gas and liquid product were evaluated. The liquid product are represented in terms of acid compounds, hydrocarbon compounds, ketone compounds, oxygenate compounds, aromatic hydrocarbon - one cyclic (AH-1), poly aromatic hydrocarbon - two cyclic (PAH-2) and poly aromatic hydrocarbon - three cyclic (PAH-3). The results showed that the yields of gas and char increased by increasing temperature from 500 to 700 0 C, while bio-oil decreased. In addition, increasing temperature resulted new compounds of AH-1, PAH-2 and PAH-3. The yields of PAH-2 and PAH-3 on liquid product and H 2 and methane on gas product also increased, while yields of acid, ketone, AH-1 decreased. 

Description: Many energy saving concepts are deployed to achieve the environmental and economic targets. But for many years, terminology and definition of energy saving concepts was a source of confusion and debate. In this paper, we analyze some representative literature examples about these concepts and their meanings. Then we develop a methodology to classify energy saving concepts in a new way with clear borders that can help energy analysts to detect all energy saving measures without interference between concepts. We first link each concept with physical parameters such as energy and output losses. These parameters are extracted from an extended energy flow model. Each parameter is related to output variation (i.e. output increased, decreased, or fixed). After that, each concept is matched with its corresponding parameter. Combining the 2 ways, the classification of energy saving concepts is finally done in relation with output variation. According to our logic, four energy use concepts are defined to compose energy saving:  “Energy Recovery”, “Energy Sufficiency”, “Energy Efficiency”, and “Useful output reduction”.

Description: Cultivation mode selection is considered to be an important aspect as this corresponded to the amount of lipid produced by microalgae and to be used for biodiesel production. In this study, phototrophic, mixotrophic and heterotrophic mode were used to cultivate Ankistrodesmus sp. in mon-culture for 17 days. It was found that, mixotrophic Ankistrodesmus sp. shown the highest cells number (9.77 ± 0.59 x 10 6 cell mL -1 ), cell productivity (1.23 ± 0.08 x 10 6 cell mL -1 day -1 ), specific growth rate (0.43 ± 0.04 day -1 ), biomass yield (1.61 ± 0.05 g L -1 ), total lipid content (10.55 ± 0.15 % wt), methyl palmitate yield (0.142 ± 0.005 µg mL -1 ) and the shortest doubling time (1.63 ± 0.15 day). This was due to effect of glucose as an external carbon source in mixotrophic culture. However, without light Ankistrodesmus sp. grew poorly under heterotrophic mode affected by the lower pH of culture. It was also observed that the mix-cultures of Ankistrodesmus sp. and Chlorella sp. cultivated under mixotrophic mode shown better cell growth of Ankistrodesmus sp. than Chlorella sp. cells. This indicates that, Ankistrodesmus sp. has a higher tolerance towards the culture condition and has better chances of survival in the presence of other microalga species.  Hence, the study shows that cultivating Ankistrodesmus sp. under mixotrophic mode will provide a better cell growth profile, enhance the lipid content and strong endurance.

Description: The renewable energy sources (RES) are globally recognized as a suitable option for sustainable development in many off-grid applications. Recently, the integrated systems with two or more RES are being paid great attention for electrification of isolated areas and found to be an acceptable solution rather than uneconomical grid extension. In the present study, the integrated renewable energy system (IRES) model is developed using solar, wind, biomass and biogas energy sources to meet the electricity demand of the isolated rural community of Khatisitara village of Gujarat state in India. The operational strategy of IRES model is developed considering the distribution network losses as a system design parameter. The developed IRES model is optimized for minimum net present cost of the system using particle swarm optimization (PSO) algorithm in MATLAB environment. The well-established genetic algorithm (GA) was used to validate the optimization results obtained from PSO. Further, the effects of distribution losses (DL) on the system sizing, reliability and economy have been evaluated. The sensitivity analysis was performed to assess the effect of economically influencing parameters on the developed model. Finally, the break-even analysis was performed for the grid extension distance to examine the economic feasibility of IRES against grid extension. The simulation result shows that the impacts of DL on IRES reliability and economy are significant. Further analysis shows that the IRES using locally available renewable energy sources is a feasible option for rural electrification in considered study area rather than grid extension.

Description: Oscillating wing is an innovative approach for power extraction from wind. The parameters which define the oscillatory motion of an airfoil are optimized using the Response Surface Methodology (RSM). The objective of the optimization is to maximize the power extraction from wind.  The flows around the oscillating airfoil are computed unsteady and laminar using a Navier-Stokes solver. The computations are conducted parallel in a PC cluster. The oscillatory motion is defined as a combination of plunging and pitching. The optimization variables are the oscillation frequency, the plunge and pitch amplitudes and the phase shift between plunging and pitching. The calculated highest power coefficient is about 0.40, which is comparable to the power coefficient values of conventional rotating wind turbines. The optimum motion is obtained when the reduced frequency is almost unity. Moreover, the maximum power coefficient increases as the plunge amplitude increases. 

Description: The space-based solar power system for the baseload power supply on the ground is more than science fiction now, and it will be practical in the coming future. Due to its high estimated space launching cost, it was suspended in earlier attempts. With Technological advancements and research going on worldwide, its practical implementation could be possible by 2030. This work is motivated in a direction to reduce total system cost. The economic model of the system has interrelated parameters which can be optimized for the high efficiency and cost-effective performance. In this work, a cost minimization method is derived, and results are investigated for economically efficient space-based solar power prototype design. The Derived generalized mathematical Expressions are appropriate to evaluate the cost-effectiveness and performance of the microwave-based wireless power transfer system. The effect of transmitting antenna size is investigated for the desired power density on the receiving ground antenna. The Levelized cost of energy (LCOE) is also calculated for the space-based solar system; it can be easily yielded from the generalized cost expression .

Description: An attempt has been made to find the energetic feasibility of solar photovoltaic home lighting systems (SPVHLS) for some locations in India. In this perspective modules of 37Wp of different technologies have been adopted. The study has been divided in three parts viz. (1) a general discussion on replacing PV-systems with frequently used conventional fuel devices. (2) Comparison of PV-systems with diesel generator and (3) Evaluation of GHG-emission mitigation for some conventionally fuel devices. The process analysis method has been adopted to evaluate total embodied energy. Output energy/energy saved was calculated by the comparison of these systems with conventionally used devices and with diesel generator. For feasibility analysis of these systems, energy yield ratio (EYR) and energy payback period (EPBP) have been evaluated. The EYR value of 2 years and EPBP value of 11 years have been found approximately in case of wick lamp. However, with diesel generator, EPBP value has been found approximately 4 years. GHG-emission mitigation (tCO 2 ) of 934 was found in case of kerosene lantern and 41551, 76350 for diesel oil and Kerosene oil operated Generator respectively.  

Description: This paper focused on an energy management cooperation concept for a dwelling photovoltaic/battery system. The application of multi-agent system (MAS) was investigated as a key technology to provide distributed flexible micro-network control. Indeed, in a multi-agent technique each function of the system is assigned to a separate agent, providing thereby a higher modularity and greater autonomy compared to a traditional system. The agents are usually tightly linked and communicate typically through messaging. The main task in this work was the design of a dynamic system of smart building loads and energy producing equipment, modeled by simple agents that communicate within a MAS approach. The major aim was is to set up an intelligent habitat system which components are able, through intercommunication, to make decisions and optimize energy consumption, without affecting the inhabitant comfort. To validate the elaborated design, different simulations were performed. The results show that this approach is able to reach optimal configurations.

Description: The proper operation of current controllers in the grid tie inverters strongly depend on the accuracy of grid phase detection algorithm of the phase locked loop system. The main aim of this paper is to design and implement a single phase synchonization technique base on T/4 delay PLL. In this work,  the real time T/4 delay PLL algorithm is realized by using fixed point arithmetic computation technique that embedded in the 16 bit-wide digital signal controller dsPIC30f401. The focus of our research is to investigate the effect of the PLL control bias to the PLL ouput performance mainly in the steady state conditions. Based on the experimental results, the accuracy of the phase detection algorithm practically could be achieved by utilizing a relatively high control bias even with  just using a simple proportional controller. Whereas, for a relatively low control bias, the accurate phase detection could be achieved by utilizing a proportional integral controller.

Description: For thin film solar cells, plasmonics is a novel light trapping technique based on light scattering due to metal nanoparticles through excitation of localized surface plasmons. The excited surface plasmon at the interface of a higher dielectric active semiconducting layer and the metal, by channelling incident radiations will trap light within the device for the higher optical path in physically thin structures resulting in enhanced photocurrent. In this paper, through FDTD based electromagnetic simulations, significance of controlled nanopatterning of silver (Ag) on the front side of p-i-n hydrogenated amorphous silicon for light absorption in the devices is analyzed. The analysis includes better control of nanoparticle parameters like size, shape, distribution and spacing for obtaining full benefits of plasmonic effects. It is demonstrated with an attractive strategy of fine tuning the nanostructures, incident light coupling with semiconductor ensures light confinement within the active layer promoting photon absorption across visible and near infrared regions.

Description: Indonesia is a country having a high geothermal energy potential. The geothermal energy in Java island, as a volcanic row island, has been explored and produced. One of the areas that have not been produced is volcanic area around Arjuno and Welirang volcanoes located in East Java. Geochemical survey has been performed to explore a more detailed objective in exploring the potential resource of geothermal energy of this area. Chemical and isotopic analises show the maturity level of waters taken from water springs in the area. The immature water from the water springs is interpreted coming mostly from meteoric water which flows quite fast forming water springs around the area. The geothermal reservoir thermometer has been predicted to arive 300 to 350 degrees C. Using available data and information, geohydrothermal of the area has been modeled. Further, the energy potential has been calculated to achieve about 200 MWe.

Description: In this article simulation analyses have been performed using computational fluid dynamics techniques to investigate the performance of helical and straight-bladed cross flow hydrokinetic turbines with a horizontal layout and similar dimensions. The length and diameter and the type of the hydrofoil of both turbines are selected to be the same. A symmetrical NACA hydrofoil has been used in blade design for both turbines. The simulation analyses were performed for a 2-D NACA0018 hydrofoil and 3-D four bladed turbines. The skewness coefficient and the orthogonal quality tests have been dependent as statistical tools to examine the quality of the mesh for all models. The obtained results have shown that the helical turbine reaches the stall condition at the tip-speed ratio (TSR) of 3.75, while the straight-bladed turbine stops converting energy at 3.1. The highest power coefficient for the helical turbine was about 0.37, while it was found to be around 0.29 for the straight-bladed turbine. These results demonstrate that a helical turbine of 1.5 m in length and 1 m in diameter is more efficient than the same-sized straight-bladed turbine under the same flow conditions. 

Description: In this paper, an interleaved fly-back converter based module integrated converter (IFBC-MIC) for grid interaction of photovoltaic (PV) system is presented. MIC grid integration technology received wide acceptance in PV applications and may assist in achieving maximum power generation for mismatched or partially shaded PV modules by independent control of individual PV modules according to their insolation levels, giving substantially higher output power.This paper develops a MIC system involving interleaved fly-back converter to minimize the switching ripple of the dc link voltage and a simple zero crossing detectors (ZCD) circuits based gird synchronization circuit to avoid the complex phase locked loop (PLL). The proposed system includes the Perturb and Observe (P&O)Maximum Power Point Tracking(MPPT) to enhance the PV power extraction.A 100W PV system is considered for the MATLAB based simulation study and hardware experimentation. Simulation and hardware results prove that the suggested system is highly suitable for portable PV applications.

Description: This paper aims to evaluate the global solar radiation of some representative localities of Cameroon using the linear Angstrom model and non-linear polynomial relations. The Angstrom correlation coefficients for the linear, quadratic and cubic polynomial models calculated using the least square method, for the different regions, would be used to predict the global solar energy of the chosen regions. The predictions would be evaluated by some chosen statistical methods. These include: the mean bias error (MBE), the mean relative error (MRE), the root mean square error (RMSE) and t-statistic (t-stat) error, which are the most widely used ones. The input data for the analyses are the measured global solar radiation and mean number of monthly sun shine hours. The data for the analyses is obtained partly from the archives of National Aeronautics and Space Administration (NASA) and partly from the archives of the Cameroon Department of Meteorology, Douala. The data used covers a period of 23 years. We demonstrate the validity of the developed models by comparing the evaluated values of global solar radiation with the measured ones. Hence the regression equations can be used to confidently predict the global solar radiation of the representative regions in the absence of experimental data. We equally implement a high-precision sun-tracking algorithm is necessary to follow the sun’s trajectory from dawn until dusk, in order to maintain high output power and stability of a solar power system.

Description: In the most countries around the world, solar photovoltaic power plants have a cost-competitive structure for providing energy access and for increasing electricity production. However, solar photovoltaic power integration requires the handling of power quality and stability problems due to its non-controllable and intermittent characteristics. At this point, the need for reliable solar irradiance and solar power forecasting is emerged for the optimal modeling and scheduling of solar photovoltaic power plants. For this purpose, this study conducts an exhaustive and up-to-date review of solar irradiance and solar power forecasting methods used in the literature. Although there are a plenty of review papers in the literature, differently, we have created the extensive and comparative literature tables considering very-short term, short-term, medium-term and long-term forecasting periods in this study. Furthermore, we have examined each paper in terms of its input data, forecasting interval, forecasting model, forecasting accuracy and forecasting results. As a result of overall assessments, this study provides complete and considerable information about the current status and future prospects in solar irradiance and solar power forecasting.

Description: Some areas of Thailand do not allow the installation of wind turbines or require further investigation of the impacts before installation. These areas can be divided into 3 classes with 21 criteria, including residential communities. This article presents an analysis of Thailand’s wind energy potential and identifies suitable areas for wind turbine installation that minimize the environmental and social impacts on nearby communities during operation, in line with policy targets. In this study, we evaluated the possibility of reducing the environmental and social impacts of wind energy development projects in 4 case studies using geographic information system analysis. We used two different formulas to evaluate the wind power potential and create wind resource map for use as a guideline to select suitable areas for wind turbine installation that reduced the negative impacts of future projects on the community. This model removed the risk from the most sensitive areas and included the moderately sensitive rural resident community area. This area is the most affected by the wind turbine project. The suitable areas provide sites for wind turbine installation located in the northeast, including the appropriate wind speed potential.

Description: Geothermal and solar thermal are renewable, clean energy sources with immense potential for electricity generation. Concentrating Solar Power can achieve very high temperatures and high efficiencies compared to geothermal power plants. However, it is intermittent and must be coupled with thermal storage or another source for continuous power generation. Geothermal resources exist in varying temperatures but are too small for economic power production; however, it is not intermittent. This paper briefly summarizes the location-specific design considerations for geothermal and solar thermal plants. The performance of both these types of power plants is analysed in terms of capacity factor, thermal energy storage hours, solar multiple, area requirement, and levelized cost of energy for a given set of environmental conditions at two separate locations, Las Cruces, US and Aydin, Turkey. Electricity consumption for an example airport at Aydin is provided by DHMI Airport authority administration, which was used as load profile for Aydin. This analysis is performed using the System Advisor Model. Simulation of parabolic trough, power tower, linear Fresnel, dish Stirling, and geothermal energy conversion systems are performed and the results are compared.

Description: The main problem in renewable energy system is the variation in power generation from time to time due to the intermittent nature of the renewable sources. Miss matching between power generation and load power causes a deviation from the desired voltage and frequency in power supply. A power flow control of a standalone photovoltaic-wind-battery Hybrid Renewable Energy System (HRES) for stand-alone application is presented here to balance the power generation and load power. Photovoltaic (PV) and wind are the primary power sources and battery acts as backup source to balance the power generation and load power. In spite of sudden load changes and changes in the power generation from PV power and wind power the power balance between the supply and demand effectively maintained by the proposed fuzzy logic controller (FLC). All the renewable sources and backup source are linked to a DC bus through dc-dc converter and the DC bus is connected to AC load through a voltage source inverter. A control strategy is implemented with fuzzy logic controller for smoothing of the power fluctuation and at the same time to maintain the battery state of charge (SOC) with in allowable limits. The various components are modeled and simulated in MATLAB/Simulink. Simulation results justify the ability of proposed controller to balance the power generation and load power.

Description: In this paper, the high-power PV plant is connected to the weak grid by means of a three-phase power transformer. The selection of transformer winding connection is critical especially when the PV inverter has a reactive power controller. In general, transformer winding connection can be arranged in star-star (with neutral earthed) or star-delta. The reactive power controller supports voltage regulation of the power system particularly under transient faults. Its control strategy is based on utilizing the grid currents to make a three-phase reactive unbalanced current with a small gain. The gain is determined by the system impedance. Simulation results exhibit that the control strategy works very well particularly under disturbance conditions when the transformer winding connection is star-star with both neutrals grounded. The power quality in terms of the voltage quality is improved.

Description: Voltage stability is a major concern in power transmission systems due to mismatch between power generation and demand.  Hence maintenance of voltage profile within the acceptable limit   becomes   a challenging task.  In this paper the weakest buses for implementing the reactive power compensators are identified by eigenvalue decomposition technique on partitioned Y-admittance matrix. The size and cost of the SVC are optimized using dragonfly algorithm. The algorithm is implemented on IEEE 14 and 30 bus systems and the results obtained with and without the placement of Static VAR Compensators are compared with the results of other algorithms to show its effectiveness. The further scope of this work is to extend this to renewable energy by implementing the wind generators at the weakest buses there by reducing the electrical distance between the generators and the farthest load buses and securing the system from voltage collapse.