Solar Energy Research Research Articles

Concentrated solar power plants: A critical review of regional dynamics and operational parameters

Paper presents a regionally segregated overview of the globally distributed operational Concentrated Solar Power (CSP) plants. A holistic approach was followed by dividing the global map into 5 different regions (Americas, Africa, Europe, Asia and Australia) by covering 112 currently operational CSP plants. The objective of the research methodology used is to enable concerned regional developers to study the local trend followed in brief and compare the same with the trend followed in other regions. Region 3 (Europe) generates 6338.33 GWh/yr of electricity and accommodates more than 50% of globally operational CSP plants. Parabolic trough/Thermal oil is the most preferred combination of CSP technology/Heat Transfer Fluid (HTF) and is used in 46 plants globally. Region 5 (Australia) produces the lowest annual electricity generation of 3900 MWh/yr but still holds great potential for numerous upcoming plants. Annual electricity generation of plants when plotted with area occupied displayed a linear trend for all the regions. Linear pattern observed also included 2–3 outliers indicating significant under or over performance of specific sites. Regional distribution enables a modular study and analysis, aiding future research and development in solar thermal energy. Accumulated information and data presented serve as a brief guide reducing the gap between social structures and latest technological advancements.

Mapping 30 Years of Sustainability of Solar Energy Research in Developing Countries: Indonesia Case

Research into converting solar light energy into electricity using so-called photovoltaic (PV) technology or solar cells (SCs) was started a long time ago. However, most developing countries tend to lag behind. The present work delivers a bibliometric mapping analysis of 30 years of Indonesian solar energy research papers in the Scopus database. A multidisciplinary point of view is used to cover the findings comprehensively, highlighting the emerging gaps, orientation, and promising future research that will benefit many researchers, governments, and industry. Two essential keywords, “photovoltaic” and “solar cell”, were used to harvest the data. A total of 1886 documents were finally investigated. The VOSviewer was utilized as a proper complement for visualizing and analyzing the publication trends based on the keywords and authorships. Many aspects of solar research have been explored, including the basic science of semiconductors, simulation, lab-scale device fabrication, and the application of technologies and policies. The findings show that the two keywords determined the research characteristics. It also reveals that the geographical location had a remarkable impact on publication distribution. The most striking result is that a minimum of 1146 documents are centralized on Java Island. In addition, the policies related to renewable energy show a strong impact: two years after the policies were announced, the publications exhibited a two-fold increase. The results also suggest that future research should focus on the increasingly significant domestic component of silicon-based solar cells, the various multidisciplinary approaches for making PV utilization more affordable, and on shifting towards the use of perovskite solar cells. Solid national and international collaboration should be continued for the sustainability of Indonesian solar energy research.

Prognozowanie wytwarzania energii słonecznej w systemach energetycznych w celu przyspieszenia implementacji zrównoważonego rozwoju gospodarczego

1. Alawaji, S.H. 2001. Evaluation of solar energy research and its applications in Saudi Arabia – 20 years of experience. Renew. Sustain. Energy Rev. 5, pp. 59–77, DOI: 10.1016/S1364-0321(00)00006-X. CrossRef Google Scholar

The Future Is Open and Shapable: Using Solar Speculative Fiction to Foster Learner Agency

Speculative fiction is a powerful medium to explore possible futures, inviting literacy researchers and educators to consider the value of futures thinking as a tool for eliciting learners’ hopeful narratives about equitable, sustainable futures for their communities. Yet, when asked to imagine the future, adults and youth alike often envision dystopian stories and fail to consider the interdependencies between technological innovations and the social, economic, and environmental contexts they shape. Moreover, current pedagogic strategies for thinking about the future encourage globalized perspectives rather than stories localized in learners’ lived contexts. Using design-based research methods and informed by ecological theories that assume learners exercise agency through their actions that bring together past, present, and future, our team developed conjectures about how futures thinking might support learners’ agency in relation to sustainability activism and environmental justice. Data analyzed to test our conjectures were 18 solar futures narratives written by adult and youth participants in a solar energy research program. Findings show promise for writing practices that foster sustainability and climate change learning.

Performance assessment of bare and anti‐reflective coated CdTe photovoltaic systems in comparison to multicrystalline Si in Brazil

AbstractThe performance of three ground‐mounted fixed‐tilt photovoltaic (PV) systems installed at the Solar Energy Research Laboratory Fotovoltaica/UFSC in Florianópolis, southern Brazil (27°S, 48°W, Cfa Köppen‐Geiger climate classification), were analyzed in this paper. This study compares the performance of cadmium telluride (CdTe) thin‐film PV modules (both with and without an anti‐reflective coating [ARC]) and multicrystalline silicon (mc‐Si) PV systems over two full years of continuous operation. Furthermore, the paper presents a literature review on previous studies that investigated the main environmental parameters that affect the performance of CdTe and m‐Si PV systems. Results revealed that throughout the period analyzed, the CdTe with ARC PV system presented the best performance, with an overall annual energy yield 5% higher than the reference mc‐Si PV system. In order to evaluate the performance behavior of the three PV systems under study, the main environmental parameters that affect the efficiency of PV systems were analyzed: temperature, spectrum, angle of incidence, weak‐light responsivity, and soiling impact. Irradiation levels for all PV systems were identical, as they are all operating at the same site. Temperature followed by spectral content of sunlight presented the highest impacts on performance, resulting in estimated overall performance gains of 1.9% and 1.5%, respectively, for the CdTe systems. These findings are consistent with our previous research, showing that CdTe has a performance advantage over traditional monofacial crystalline silicon technologies in warm and sunny climates.

Procedure for the quantification of the degradation index of Photovoltaic Generators

A procedure is presented for the quantification of the degradation index of Photovoltaic Generators, based on the quantification of the operational losses inherent in the system, which allows maintaining the nominal operating conditions and by the warranty terms of the photovoltaic generator. A photovoltaic generator connected to the network with a nominal power of 7.5 kWp, installed in the Solar Energy Research Center of Santiago de Cuba, is used to evaluate and validate the procedure. The starting point is the mathematical model of the photovoltaic generator, then the operational losses of the photovoltaic generator are quantified and the mathematical model is adjusted to real conditions, through a polynomial adjustment. The results obtained show that the photovoltaic generator presents deviations in terms of the nominal power generation, because the operational losses are 7% with respect to the values ​​given by the manufacturer.

Fault Diagnostic Methodology for Grid-Connected Photovoltaic Systems

This research focuses on the design of a fault diagnosis methodology to contribute to the improvement of efficiency, maintainability and availability indicators of Grid-Connected Photovoltaic Systems. To achieve this, we start from the study of the mathematical model of the photovoltaic generator, then, a procedure is performed to quantify the operational losses of the photovoltaic generator and adjust the mathematical model of this to the real conditions of the system, through a polynomial adjustment. A real system of nominal power 7.5 kWp installed in the Solar Energy Research Center of the province of Santiago de Cuba is used to evaluate the proposed methodology. Based on the results obtained, the proposed approach is validated to demonstrate that it successfully supervises the system. The methodology was able to detect and identify 100% of the simulated failures and the tests carried out had a maximum false alarm rate of 0.22%, evidencing its capacity.

Quo Vadis Solar Energy Research?

In this paper, solar energy research trends and their publishing evolution are presented in terms of bibliometric analysis tools applied to the existing publications within the Web of Science Core Collection. Publishing evolution shows a clear interest in solar energy topics, as 50% of the total number of publications have been published within the time period between 2015 and 2020; most of them at journals and conference proceedings. A results analysis shows that China, the United States and India were the most productive countries in terms of solar energy research publications, and the list of the 10 most productive countries accounted for 83% of total publications within 2019 and 2020. The study pointed out as well that the main thematic areas in solar energy research in 2019–2020 were related to particular topics such as solar cells and optical properties, nanoparticles and composites, TiO2 and photocatalysis, and more general topics such as performance, simulations optimization and renewable energy. Based on paper findings, the research future of solar energy is bright, with continued growth in the publications record and a wide variety of research topics.

A Low-cost System for High-frequency Solar Imagery and Power Data Acquisition

With advances in solar energy research and increasingly accurate forecast techniques, intermittency no longer stands as a barrier to the adoption of solar energy. Coupling reliable data and knowledge on the inherent variability of the solar resource with advanced learning and forecast models, renewable energy can take an even bigger role in today’s energy paradigm. The objective of this work is to develop and test a low-cost data acquisition system able to provide relevant data for solar energy forecast models. The results yielded from the performed tests indicate high correlation between image derived attributes and power measurements 20 s ahead.

Review on solar water heating in Libya

This review paper aims to provide a comprehensive review of the history and the best practices of solar water heaters in Libya. Although, Libya is blessed with high solar potential, there is no wide-spread implementation of this technology due to many reasons such as: the cheap price of both electricity and electric water heaters, lack of clear and systematic policy, and lack of environmental awareness. The Center for Solar Energy Research and Studies (CSERS) has given attention to this technology since its establishment in 1978, and the solar water heating system field test project is one of the research projects in the Center. The paper has shown that there was no attention paid to this technology and even to renewable energy in general in the previous years. However, preliminary information clearly shows the importance of continuing research in this field. Numerous valuable information on solar water heating systems from literature were dedicated and made available for researchers and decision makers. The studies conducted in this field for Libya are arranged in this review on the bases of the topic studied: performance evaluation, optimization, on-site measurements and policies and strategies. One of the most important results retrieved from these studies show that the daily quantity of hot water withdrawn per capita at 45 °C is estimated around 60 liters. The estimated annual amount of energy consumed for water heating per person is 510 kWh. For average Libyan family of six persons, the annual amount of energy consumed per dwelling is estimated about 3060 kWh. The review also presented the history of solar water heaters implementation, manufacturing and testing facilities for quality control in Libya. The study calls upon the Libyan decision makers to take their responsibility and put an urgent action plan to help the wide-spread implementation of solar water heaters in the residential, services and industrial sectors. Such a plan will surely alleviate the ever increasing demand for electricity, save fossil fuel reserves and mitigate GHG emissions.

Towards Strategic Plan for Wide Spreading of Solar Water Heaters in Libya

Solar water heaters have been in use for decades in many countries in the world that have less favorable climatic conditions for solar energy as compared with Libya. However, still there is no usage of such technologies in the country. This could be attributed to many factors including, among others, lack of clear policy and/or serious plans to establish such technology, cheap prices of conventional energy, and lack of environmental awareness.The Center for Solar Energy Research and Studies (CSERS) of Libya has developed an excellent research and development program on national scale for domestic solar water heating systems. The national program started in the early 1990’s aiming at increasing public awareness. The program utilizes different ways such as pilot projects, studies, workshops, and reports to convince people and decision- makers of Libya about this subject and its benefits.This paper attempts to suggest a strategic plan (win-win situation between government and people) for encouraging and helping wide spread (replacement) of solar water heaters nationwide based on economic and environmental pointers in favour of the replacement.The suggested strategic plan is to provide 25% of existing houses in 2013 with solar water heating systems by 2022, with governmental subsidy of up to 65% of the system cost. The study has shown that every L.D. paid by the government will return with at least 2 L.D. after 10 years of investment without considering the money saved from the fuel savings, power plant installations to fulfill the demand, and the environmental benefits.

Simulation Study of the Thermal Performance of MSF Desalination Unit Operating by Solar Vacuum Tube Collectors

The Center for Solar Energy Research and Studies (CSERS) has a good experience in operating and evaluating the thermal performance of small scale 5 m3/day Multi-Stage Flushing (MSF) desalination plant connected to solar pond according to the local weather conditions of Tajoura area. However, a new project has been suggested to run the desalination plant with vacuum tubes solar thermal collectors utilizing available technology and experience. In this study an attempt was made to make the best use of readily available components to operate the MSF desalination unit with field of solar thermal collectors. Several configurations of collectors and tank arrangements were designed and examined through the use of simulation software, TRNSYS. The study has shown that the layout-3 (two 500 litre storage tanks each of them connected to 9x5 vacuum tube collectors) gives the best performance with an annual solar fraction over 77% at load temperature of 70 °C with flow rate of 2500 lit/hr, and over 68% at load temperature of 80 °C for working condition of 8 hours daily. The study has also shown that running the desalination plant for 24 hours a day reduces the solar fraction of the solar collector field to 25%

Design of photovoltaic system powered a small-scale SWRO desalination plant

This paper illustrates a proposed design to the Center for Solar Energy Research and Studies (CSERS) - Tajura, for the erection and testing of a stand-alone photovoltaic (PV) system for the powering of a small scale seawater reverse-osmosis (SWRO) desalination plant. The plant promises to deliver up to 0.25 m3/hour of potable water from seawater with a salinity of about 38,000 ppm and the osmotic pressure of 26.4bar.In the current paper, ROSA Software by Dow chemical company was used to establish suitable membrane unit at this capacity. A unit of 4 inch of SW30-4040, with a feed pressure of 48 bar, and a salt recovery (R) of 20% with total dissolved solids (TDS) of 190ppm was selected.Also results showed that, the electrical consumption of the SWRO plant was 2500 W, and the specific energy consumption was 10 kWh/m3. The size of the selected stand-alone photovoltaic (PV) system to power a SWRO plant with a mean production capacity of 1.5m³/day (6 hours operating per day), is 48V nominal voltage, 72 PV modules (shell SQ85-P), and 16 batteries with the capacity of 383Amp-Hour each.

Solar Air-Heated Humidification-Dehumidification Desalination Unit

A solar powered desalination unit which working on a humidification –dehumidification technique (HDH) is one of the most important techniques used in brackish and seawater desalination especially in remote and rural areas. In the present study, a test-rig was designed and constructed for conducting a set of experiments on a solar assisted desalination unit working on a HDH principle under the prevailing conditions of Tajoura-Libya. Experiments were carried out on specified days in March, 2019 at the laboratories of Center for Solar Energy Research and Studies (CSERS) at Tajoura. The effect of different design parameters and operating conditions on the performance of the unit and its productivity is closely investigated and interpreted. Results show that the productivity of the HDH unit decreases by increasing the process air mass flow rate. A significant improvement in the productivity of the unit is noticed when the feed water mass flow rate to the humidifier is increased. Furthermore, initial water temperature inside the tank has a remarked effect on the productivity of the unit. In order to obtain a reasonable amount of fresh water, the temperature of the water inside the tank should be increased. Increasing the cooling water mass flow rate to the dehumidifier leads to a corresponding decrease in the surface temperature of the cooling coil and hence the productivity of the unit is improved. The Productivity of the unit is varying from its lower value of (0.903 kg/m2.day) to a higher value of (6.47 kg/m2.day). These values are obtained for one meter square of solar air heater area. Gained Output Ratio (GOR) values range from a minimum of (0.082) to a maximum of (0.572). It is reasonable when compared to ones in literature for the water-heated HDH units.

Experimental Investigation of the Thermal Performance of a Solar Air Heater

Solar air heaters are widely used in many low temperature applications such as space heating, crops drying, desalination..etc. It collects solar radiant energy and transforms it into heat through a fluid (air) flowing inside the system. The outside cold air is heated through the system and delivered to the required application. It is simple, economic and clean. In this study, an experimental investigation is carried out using a test-rig installed at the laboratories facility for Center of Solar Energy Research and Studies (CSERS) in Tajoura-Libya equipped with all necessary measuring instruments and devices. The aim of this study is to investigate the effect of process air mass flow rate on the thermal performance of a solar air heater working at different operating conditions under the prevailing conditions of Tajoura-Libya. Experiments were conducted on specified days in August 2019, October 2019 and January, 2020.Results show that there is a noticeable increase in the air temperatures of the solar air heater as incident solar radiation values increase during the day time, especially at afternoon. The maximum average outlet air temperature measured reaches 60 oC which is suitable for space heating and crops drying applications. Useful heat energy collected is directly proportional to the incident solar radiation. Increasing air mass flow rates leads to a corresponding decrease in the temperature at different locations in the solar air heater. Furthermore, the average thermal efficiency values of the solar air heater range from 35% to 65%. Average overall heat loss coefficient values tend to decrease with the day time. Finally, the present study results coincide with literature and show a good agreement.

Graphene assisted crystallization and charge extraction for efficient and stable perovskite solar cells free of a hole-transport layer.

In recent times, perovskite solar cells (PSCs) have been of wide interest in solar energy research, which has ushered in a new era for photovoltaic power sources through the incredible enhancement in their power conversion efficiency (PCE). However, several serious challenges still face their high efficiency: upscaling and commercialization of the fabricated devices, including long-term stability as well as the humid environment conditions of the functional cells. To overcome these obstacles, stable graphene (G) materials with tunable electronic features have been used to assist the crystallization as well as the charge extraction inside the device configuration. Nonetheless, the hole transport layer (HTL)-free PSCs based on graphene materials exhibit unpredictable results, including a high efficiency and long-term stability even in the conditions of an ambient air atmosphere. Herein, we combine graphene materials into a mesoporous TiO2 electron transfer layer (ETL) to improve the coverage and crystallinity of the perovskite material and minimize charge recombination to augment both the stability and efficiency of the fabricated mixed cation PSCs in ambient air, even in the absence of a HTL. Our results demonstrate that an optimized PSC in the presence of different percentages of graphene materials displays a PCE of up to 17% in the case of a G:TiO2 ETL doped with 1.5% graphene. With this coverage and crystallinity amendment approach, we show hysteresis-free and stable PSCs, with less decomposition after ∼3000 h of storage under a moist ambient atmosphere. This work focuses on the originalities of the materials, expenses, and the assembling of stable and effective perovskite solar cells.

Experimental Investigation of the Thrmal Performance of a Solar Air Heater

Solar air heaters are widely used in many low temperature applications such as space heating, crops drying, desalination..etc. It collects solar radiant energy and transforms it into heat through a flid (air) flwing inside the system. Th outside cold air is heated through the system and delivered to the required application. It is simple, economic and clean. In this study, an experimental investigation is carried out using a test-rig installed at the laboratories facility for Center of Solar Energy Research and Studies (CSERS) in Tajoura-Libya equipped with all necessary measuring instruments and devices. Th aim of this study is to investigate the effct of process air mass flw rate on the thermal performance of a solar air heater working at diffrent operating conditions under the prevailing conditions of Tajoura-Libya. Experiments were conducted on specifid days in August 2019, October 2019 and January, 2020.Results show that there is a noticeable increase in the air temperatures of the solar air heater as incident solar radiation values increase during the day time, especially at aftrnoon. Th maximum average outlet air temperature measured reaches 60 oC which is suitable for space heating and crops drying applications. Useful heat energy collected is directly proportional to the incident solar radiation. Increasing air mass flw rates leads to a corresponding decrease in the temperature at diffrent locations in the solar air heater. Furthermore, the average thermal effiency values of the solar air heater range from 35% to 65%. Average overall heat losscoeffient values tend to decrease with the day time. Finally, the present study results coincide with literature and show a good agreement.

716 mV Open‐Circuit Voltage with Fully Screen‐Printed p‐Type Back Junction Solar Cells Featuring an Aluminum Front Grid and a Passivating Polysilicon on Oxide Contact at the Rear Side

This article reports the recent progress of p‐type back junction solar cells featuring an aluminum front grid and an n+‐type passivating polysilicon on oxide (POLO) contact at the cell rear side. The best cell has an efficiency of 22.6% and an open‐circuit voltage of 716 mV, independently confirmed by Institute for Solar Energy Research Hamelin (ISFH) CalTeC. The cell area is 244.5 cm2. The increase in the SiNx capping layer thickness at the cell rear side reduces the deterioration of passivation quality of the POLO contact by screen‐printed silver. This increases the open‐circuit voltage by 22 mV compared with cells with a thinner nitride layer thickness. The investigation with scanning electron microscopy shows that the damage of the POLO contacts underneath the screen‐printed metal contacts is avoided by increasing the SiNx capping layer thickness. A contact resistivity of 2 mΩ cm2 is measured using the transfer length method.

Economic Effect of Dust Particles on Photovoltaic Plant Production

The performance of photovoltaic panels decreases depending on the different factors to which they are subjected daily. One of the phenomena that most affects their energy production is dust deposition. This is particularly acute in desert climates, where the level of solar radiation is extreme. In this work, the effect of dust soiling is examined on the electricity generation of an experimental photovoltaic pilot plant, installed at the Solar Energy Research Center (CIESOL) at the University of Almería. An average reduction of 5% of the power of a photovoltaic plant due to dust contamination has been obtained, this data being used to simulate the economic effect in plants of 9 kWp and 1 and 50 MWp. The economic losses have been calculated, and are capable of being higher than 150,000 €/year in industrial plants of 50 MWp. A cleaning strategy has also been presented, which represents a substantial economic outlay over the years of plant operation.

Energy balance and performance assessment of PV systems installed at a positive-energy building (PEB) solar energy research centre

The energy balance and performance of all Photovoltaic (PV) systems installed at Fotovoltaica/UFSC solar energy laboratory (www.fotovoltaica.ufsc.br) in Florianópolis, Brazil (27° S; 48° W) were demonstrated over time, from Aug/2017 to Feb/2020. The laboratory was designed as a zero-energy building (ZEB) with PV systems installed on rooftops and façades, not maximising annual generation, but to achieve a compromise between aesthetic appeal and the energy output. Further PV systems were installed on the same site in the shapes of a carport, an electric bus (eBus) shelter and charging station, and different ground-mounted PV systems fixed at latitude tilt and single-axis tracking. Monthly analyses were carried out during the period, such as the solar irradiation availability on site, changes in the number of building occupants, the increase of installed capacity of PV systems, and energy generation and consumption. With 111 kWp, the total PV generation in the period could supply 148% of building energy needs and 97% of the Fotovoltaica/UFSC Laboratory (building plus eBus). However, there were some downtime events in certain PV systems due to R&D activities, which affected total energy production. If systems had operated at their optimal performance all the time, the laboratory could have generated 38% more energy, which means 134% of building plus eBus consumption. Therefore, the Fotovoltaica/UFSC Laboratory can be considered not only a ZEB, but a positive-energy building (PEB). The issues discussed in this paper apply not only to the particular case-study presented; they demonstrate the potential of BIPV in enabling energy positive buildings.