Smart Grid and Renewable Energy

Journal Information
ISSN / EISSN : 2151-481X / 2151-4844
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Former Publisher: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 344
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Sameer Khader, Abdel-Karim Daud
Smart Grid and Renewable Energy, Volume 12, pp 31-52; doi:10.4236/sgre.2021.123003

Abstract:
This paper investigates the behaviors of Boost DC Chopper used in Photovoltaic energy systems where the solar irradiation changes during the day time causing current and voltage changes. Varying the solar irradiation causes output chopper voltage changes in order to keep working at maximum extracted solar power. The chopper voltage changes leading to variable duty cycle operation of chopper switch and causes a significant change in switch losses in terms of the dissipated power. In addition to that the chopper behaviors are studied when the chopper voltage is boosting up to a predetermined reference value leading to a significant change in chopper current, voltage, duty cycle and occurred losses. A mathematical model for chopper performances and switch losses is derived, and a simulation model using Matlab/ Simulink platforms is conducted to follow the chopper behaviors. Simulation results for concreteSUNPOWER panel type SPR-315E-WHT-D with 315 Watts peak indicates that during the daylight time transistors are exposed to complicated changes in their current, voltage and dissipated power. Furthermore changing the output voltage according to load requirements causes heavy stress on the transistor in terms of current, oscillations and losses as well. Simulation results show that there are optimized values of irradiation, chopper voltage and duty cycle where the transistor losses are minimized. In addition to that, projecting the transistor losses over the daylight time at a given irradiation rate shows how these losses vary among the year, and the amount of energy dissipated across the main chopper switch which is around 2970 Whr/yr for the present case. Furthermore, the conducted simulation also shows the occurred in the transistor behaviors when solar irradiation changes, and can be serving for further studies.
Chenyuhu Yang
Smart Grid and Renewable Energy, Volume 12, pp 1-15; doi:10.4236/sgre.2021.121001

Abstract:
Faced with the exhaustion of traditional energy sources, the development of new energy devices is the current priority. Supercapacitor is a new type of energy storage device with high power density and long cycle life. Carbon material, metal oxide and conductive polymer are three common electrode materials of supercapacitors. Based on China’s energy situation, this paper puts forward new ideas from coal to graphene to supercapacitors. In addition, the research progress of graphene supercapacitors is summarized, including the principle of supercapacitors, preparation methods from coal to graphene, graphene electrode materials and different modification, and some possible scientific problems in the research process of different modified graphene electrodes are also reviewed and prospected.
Husain Alsamamra, Iyad Isaila, Jawad Shoqeir
Smart Grid and Renewable Energy, Volume 12, pp 17-29; doi:10.4236/sgre.2021.122002

Abstract:
Energy demand overall the world increases rapidly in various sectors, one of the highest energy consumption sector is the building sector. Installation of PV systems is one of the solutions to cover this demand and will serve in promoting energy efficiency in the Palestinian municipalities in decreasing the electricity bill, and using the saved money in constructing new projects and improving the level of services provided to citizens. In this work, Al-Dahriya municipality has been taken as a case study. The municipality installed 20 KW of photovoltaic panels on the roof of the main building in 2015. The cumulative values for one year after installation the PV system represent a total consumed electricity by the main building was 71,506 kw, while the total generated power by the PV system that transferred to building was 32,664 kw, and 5323 kw exported to the grid with total generated power by PV system was 37,987 kw. The participation of energy that produced by the photovoltaic system is 53.12% of the total power demand of the building. The value of generated power varies between the summer months and winter months through the difference of the solar radiation intensity and the number of shinning hours, the largest reading of solar radiation intensity is in the summer months. The study ensures the importance of applying selected thermal insulation materials in order to decrease the heat transfer through the boundary wall of the building. Furthermore, this study covers the other buildings and utilities of municipality and recommended with certain issues in order to promote energy efficiency.
Dieudonné Kaoga Kidmo, Bachirou Bogno, Kodji Deli, Deli Goron
Smart Grid and Renewable Energy, Volume 11, pp 127-164; doi:10.4236/sgre.2020.119009

Abstract:
This study aimed at investigating the characteristics of the wind power resource in the Far North Region of Cameroon (FNR), based on modelling of daily long-term satellite-derived data (2005-2020) and in-situ wind measurements data (1987-2020). Five different reliable statistical indicators assessed the accuracy level for the goodness-of-fit tests of satellite-derived data. The two-parameter Weibull distribution function using the energy factor method described the statistical distribution of wind speed and investigated the characteristics of the wind power resource. Six 10-kW pitch-controlled wind turbines (WT) evaluated the power output, energy and water produced. A 50 m pumping head was considered to estimate seasonal variations of volumetric flow rates and costs of water produced. The results revealed that the wind resource in FNR is suitable only for wind pumping applications. Based on the hydraulic requirements for wind pumps, mechanical wind pumping system can be the most cost-effective option of wind pumping technologies in FNR. However, based on the estimated capacity factors of selected WT, wind electric pumping system can be acceptable for only four out of twenty-one sites in FNR.
Dialo Diop, Mamadou Simina Drame, Moussa Diallo, David Malec, Dominique Mary, Philippe Guillot
Smart Grid and Renewable Energy, Volume 11, pp 89-102; doi:10.4236/sgre.2020.117007

Abstract:
This study aims to evaluate the optical losses of photovoltaic modules due to Saharan dust deposition in Dakar, Senegal, West Africa. For this purpose, an air-dust-glass system is modeled to simulate optical losses in transmittance and reflectance. To do this, we have collected dust samples from Photo-Voltaic (PV) surface in Dakar area (14°42'N latitude, 17°28'W longitude), Senegal. X-ray fluorescence reveals that silicon (Si), iron (Fe), calcium (Ca) and potassium (K) mainly composed these dust samples. Then, dust refractive indices obtained from an ellipsometer were used as an input to be used in the model. Simulations show that for radiation (at normal incidence) arriving on a dust layer of 30 μm-thick (corresponding to a dust deposit of 1.63 g/m2), 79% of the visible spectrum is transmitted; 19% is reflected and 2% is absorbed. Overall, the transmittance decreases by more than 50% as of dust layer of 70 μm-thick corresponding to a dust deposit of 3.3 g/m2.
D. Soro, M. Sidibé, Y. Doumbia, S. Touré, B. Marí
Smart Grid and Renewable Energy, Volume 11, pp 51-60; doi:10.4236/sgre.2020.114004

Atushi Umemura, Rion Takahashi, Junji Tamura
Smart Grid and Renewable Energy, Volume 11, pp 1-20; doi:10.4236/sgre.2020.111001

Abstract:
In recent years, power generation using renewable energy sources has been increasing as a solution to the global warning problem. Wind power generation can generate electricity day and night, and it is relatively more efficient among the renewable energy sources. The penetration level of variable-speed wind turbines continues to increase. The interconnected wind turbines, however, have no inertia and no synchronous power. Such devices can have a serious impact on the transient stability of the power grid system. One solution to stabilize such grid with renewable energy sources is to provide emulated inertia and synchronizing power. We have proposed an optimal design method of current control for virtual synchronous generators. This paper proposes an optimal control method that can follow the virtual generator model under constrains. As a result, it is shown that the proposed system can suppress the peak of the output of semiconductor device under instantaneous output voltage drop.
Ibrahim M. Kadad, Kandil M. Kandil, Talal H. Alzanki
Smart Grid and Renewable Energy, Volume 11, pp 103-125; doi:10.4236/sgre.2020.118008

Abstract:
This study examines the correlation between solar UVB and different weather parameters in Kuwait climate. To achieve that purpose, an experimental outdoor facility is designed and set up at the College of Technological Studies, Kuwait for regular monitoring of solar global radiation, UVB radiation and ambient temperature in Kuwait from beginning of January 1st 2014 until the end of December 2019. Outcomes reveal that the change of solar UVB as well as global radiation through the whole day inaugurate the same behavior for the recorded data in clear day times. Statistical analysis is carried out to obtain a correlation linking UVB radiation and both ambient temperature and global solar radiation. Regression analysis of the current work shows that there is a solid correlation among UVB radiation and both ambient temperature and global solar radiation, especially for intermediate to small global solar radiation ranges. In addition, UV index is evaluated for various months at all day times. It is important to record that UV index with the maximum values is attained in May-August months through midday period. Also, UV index values do not surpass the accepted extreme value which is higher than 9 during any time of the study period.
Koilraj Gnanadason M., Senthil Kumar P., H. Wilson Vincent, M. Koilraj Gnanadason, P. Senthil Kumar, Vincent H. Wilson
Smart Grid and Renewable Energy, Volume 11, pp 73-87; doi:10.4236/sgre.2020.116006

Abstract:
The demand of fresh water is becoming an increasingly important issue across the world. To alleviate this problem, a single slope single basin solar still was designed and tested. Top glass cover 9° slope ensures a very good transmission of solar radiation inside the still. In this paper a review of factors that improve the performance of the still is presented. Energy balances are made for each element of the still; solar time, direction of beam of radiation, clear sky radiation, optical properties of the cover, convection outside the still, convection and evaporation inside are accounted. Theoretical analysis of the heat and mass transfer mechanisms inside the solar still has been developed to find out heat transfer coefficients such as internal and external heat transfer modes and thermo physical properties such as dynamic viscosity, density, thermal conductivity, latent heat of evaporation and saturated vapor pressure for passive solar distillation system. Heat transfer coefficients were estimated for the present system since the still efficiency depends on heat transfer modes. It is also suggested that the water temperature plays a vital role in the distillate output since it increases significantly with the rise of basin water temperature. It is also found that the rise in water temperature increases the evaporative heat transfer coefficient value significantly.
Laura Giménez De Urtasun, David M. Rivas-Ascaso, Noemi Galán Hernández, Giorgos Papadoupoulos, Kostas Tsatsakis
Smart Grid and Renewable Energy, Volume 11, pp 29-49; doi:10.4236/sgre.2020.113003

Abstract:
Most of the isolated electrical systems throughout the world suffer from similar problems of fragility and high dependence on external resources to generate energy. Smart Grid solutions and integration of renewable energies in order to solve their problems have increased, although it is necessary to know their specific characteristics to select the optimal solutions for each case. Therefore, as the overall objective of INSULAE Project, the development of an Investment Planning Tool, IPT, is on the way. This paper provides a view on a characterization methodology developed for the set of Reference Islands and how it will help to exploit the IPT developed. For that, characterization vectors have been defined based on a selection of Key Performance Indicators (KPIs). And Reference Islands have been obtained from the analysis of KPIs data gathered from EU islands considering the vectors formed. The linkage of new islands to reference islands helps provide the new islands with an assessment on the possibility space of their investment plans with the aim of being a decarbonization plan considering the demonstrations already evaluated.
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