How Does Neural Network Model Capacity Affect Photovoltaic Power Prediction? A Study Case.

The use of models capable of forecasting the production of photovoltaic (PV) energy is essential to guarantee the best possible integration of this energy source into traditional distribution grids. Long Short-Term Memory networks (LSTMs) are commonly used for this purpose, but their use may not be the better option due to their great computational complexity and slower inference and training time. Thus, in this work, we seek to evaluate the use of neural networks MLPs (Multilayer Perceptron), Recurrent Neural Networks (RNNs), and LSTMs, for the forecast of 5 min of photovoltaic energy production. Each iteration of the predictions uses the last 120 min of data collected from the PV system (power, irradiation, and PV cell temperature), measured from 2019 to mid-2022 in Maceió (Brazil). In addition, Bayesian hyperparameters optimization was used to obtain the best of each model and compare them on an equal footing. Results showed that the MLP performs satisfactorily, requiring much less time to train and forecast, indicating that they can be a better option when dealing with a very short-term forecast in specific contexts, for example, in systems with little computational resources.

Green or not? Environmental challenges from photovoltaic technology.

The booming demands for energy and the drive towards low-carbon energy sources have prompted a worldwide emerging constructions of photovoltaic (PV) solar energy facilities. Compared with fossil-based electrical power system, PV solar energy has significantly lower pollutants and greenhouse gases (GHG) emissions. However, PV solar technology are not free of adverse environmental consequences such as biodiversity and habitat loss, climatic effects, resource consumption, and disposal of massive end-of-life PV panels. This review highlights the benefits and potential environmental impacts of implementing PV technologies. To the end, some proposals are recommended to improve this new technology's sustainability.

Future research tendencies for solar energy management using a bibliometric analysis, 2000-2019.

Using the Scopus database between the years of 2000 and 2019, a bibliometric study was done to analyze the scientific publications in the area of photovoltaic solar energy management. From the preliminary analysis of future research tendencies, ten possibilities of study topics were developed; and due to that it was possible to assume that even though many studies of technological development are found, some insights can still be approached in a way that the practical implementation of solar systems photovoltaic is better used. This data was validated by the analysis performed with the Scimat scientific mapping software under a longitudinal structure, verifying the future tendencies researches mentioned previously.

Photovoltaic Cell Temperature Estimation for a Grid-Connect Photovoltaic Systems in Curitiba

Abstract The photovoltaic solar energy has been growing in installed capacity worldwide year by year, and Brazil has also been investing in this renewable source of energy generation. The conversion of light into electrical energy occurs in the photovoltaic cells, which are sensitive to the increase of the temperature. A considerable amount of the energy incident on the module is transformed into heat, rising its temperature and decreasing its efficiency. This study aims to estimate the temperature in photovoltaic cells (Tc) for polycrystalline silicon modules from a grid-connected photovoltaic systems through several equations proposed over the last decades by researchers. This estimation will occur in the municipality of Curitiba, using data from INMET's automatic station, located in the same city. The estimation was calculated hourly, throughout the day for one year. The validation of the estimated results was performed by measuring the cell temperature of a photovoltaic system installed in Curitiba, where it was observed that the equation proposed by Duffie and Beckman (2013) was the one that most approached to the measured value.

Current Panorama and 2025 Scenario of Photovoltaic Solar Energy in Brazil

Abstract The photovoltaic solar energy in Brazil was boosted by Normative Resolution No. 482/2012 of ANEEL, which regulated the micro and mini generation in the compensation system, and by the specific auctions for photovoltaic plants carried out by the federal government. However, the country still has little representation of the solar energy in its electrical matrix, about 0.13%, with approximately 1% of the installed capacity of electric power generators considering all the sources, both values ​​refer to the year 2017. In the initial moments of a technology, its growth occurs irregularly and because there is little installed capacity, any added value can cause abrupt variations in the percentage from one year to another, that is, its growth still does not follow a sustainable standard, which should be regularized around the year 2025, following the worldwide trend of growth of approximately 30% each year. As a scenario for 2025, the total power of the PVSGC in Brazil will be approximately 75.6 GWp which will represent 98.3 TWh of electric energy produced by this source, considering the estimated electric energy demand for 2025 of 800 TWh, will result in the contribution of 12.3% of the energy by solar photovoltaic source.

LCA of greywater management within a water circular economy restorative thinking framework.

Greywater reuse is an attractive option for the sustainable management of water under water scarcity circumstances, within a water circular economy restorative thinking framework. Its successful deployment relies on the availability of low cost and environmentally friendly technologies. The life cycle assessment (LCA) approach provides the appropriate methodological tool for the evaluation of alternative treatments based on environmental decision criteria and, therefore, it is highly useful during the process conceptual design. This methodology should be employed in the early design phase to select those technologies with lower environmental impact. This work reports the comparative LCA of three scenarios for greywater reuse: photocatalysis, photovoltaic solar-driven photocatalysis and membrane biological reactor, in order to help the selection of the most environmentally friendly technology. The study has been focused on the removal of the surfactant sodium dodecylbenzenesulfonate, which is used in the formulation of detergents and personal care products and, thus, widely present in greywater. LCA was applied using the Environmental Sustainability Assessment methodology to obtain two main environmental indicators in order to simplify the decision making process: natural resources and environmental burdens. Energy consumption is the main contributor to both indicators owing to the high energy consumption of the light source for the photocatalytic greywater treatment. In order to reduce its environmental burdens, the most desirable scenario would be the use of solar light for the photocatalytic transformation. However, while the technological challenge of direct use of solar light is approached, the environmental suitability of the photovoltaic solar energy driven photocatalysis technology to greywater reuse has been demonstrated, as it involves the smallest environmental impact among the three studied alternatives.

Projection of the Demand of Electricity in the State of Paraná for 2050 and Proposal of Complementarity of the Electrical Matrix through the Solar Photovoltaic Source

ABSTRACT Energy is essential for human activities and, considering the prospect that the demand for energy increases, it is necessary to carry out studies of new technical solutions so as to make the use of the available sources feasible. Greater participation of renewable energy sources in the electricity matrix has been stimulated worldwide and a number of public policies have been adopted by different countries in order to seek greater energy security and sustainability. In this context, photovoltaic solar energy potentially plays an important role in the evolution of the participation of alternative sources in the world energy matrix, considering its abundance and wide availability in the terrestrial surface. This work proposes a methodology to model a scenario that estimates the consumption of electricity in 2050 in the State of Paraná and how it can contribute to the complementarity of the Brazilian electricity matrix. In addition, it indicates, based on decision factors, which are the most indicated mesoregions for possible deployments of grid-connected photovoltaic systems in Paraná to meet this demand.

Determination of the Ideal Time for Cleaning of Photovoltaic Panels Aiming at Better Productivity - Case Study of the Implanted Grid-Connected Photovoltaic System at the Federal University of Technology of Paraná

ABSTRACT Considering the development of new technologies in the electricity generation sector, such as solar photovoltaic energy, some studies are made necessary to obtain the best performance of these systems. This generation model consists of modules, which are exposed to adverse climatic conditions, they receive direct influence of the dirt, according to the environment from which they were installed, which directly influences the performance of the system since, due to the disposal of waste on the module, a smaller portion of the solar radiation can reach the photovoltaic cell effectively. The objective of this work is to determine the ideal time for cleaning photovoltaic panels, aiming at high system productivity, having as object of study the photovoltaic panels of the Federal University of Technology - Paraná (UTFPR) Campus Curitiba, installed in the Green Office (GO) and at Neoville´s headquarters. Within this objective, it was necessary to verify its merit indexes, parameters used to compare grid-connected photovoltaic systems. The study shows the importance of frequent cleaning of panels, especially when they are installed in urban areas and close to high traffic access roads.

Assessment of the Potential Implementation of Solar Energy Generation in State Schools in Curitiba/PR

ABSTRACT Solar energy as a form of electric power generation is gaining ground in Brazil, being the subject of worldwide discussions on sustainability. The electric energy, a right of all citizens, represents a consumption of natural resources on a large scale. State schools in Paraná invested more than R$ 46 million to guarantee electricity and thus provide essential running conditions to the system in 2016. Through open data, 15 schools from "Regional Administrativa do Cajuru", in Curitiba/PR, were evaluated in consumption and expenses of electric energy from January to May of 2017 and a solar photovoltaic system was dimensioned to supply the demand of each school. From that, it was estimated the total saving from the electricity that would no longer be spent on electricity which could be directed to other educational programs and projects of interest to the community towards sustainability within the school. The savings estimated totalized more than R$ 435 thousand annually.

Mapping and Characterization of the Grid-connected Photovoltaic Systems in the City of Curitiba: Preliminary Results

ABSTRACT This work presents the mapping of grid-connected photovoltaic systems supported by the Normative Resolution (NR) of the National Agency of Electric Energy (ANEEL) Nº 482/2012 in the city of Curitiba. Firstly, a brief introduction was made justifying the reasons that led to the development of this study, followed by the explanation about the methodology, procedures and criteria adopted in the study. A general mapping of all on-grid photovoltaic systems supported by NR Nº 482/2012 installed in the city of Curitiba, identified by class, is presented, indicating how the urban distribution of these photovoltaic systems occurs, and it is possible to observe in which regions the highest prevalence of installations occurs. From this, the general characterization of these photovoltaic systems is performed, classifying them by class, number of installed systems, power, number of modules, total occupied area, average power of modules and average efficiency of photovoltaic systems. Considerations are also raised regarding the reliability of the Database of Distributed Generation Consumer Units made available by ANEEL.

Analysis of Production and Consumption of Electric Energy in the Green Office of UTFPR in Curitiba

ABSTRACT The increasing demand for electricity and the scarcity of resources, require renewable energy sources and efficient equipment that reduce the consumption of electricity. The Green Office (GO) of the Universidade Tecnológica Federal do Paraná (UTFPR) is a sustainable building that uses strategies to reduce impacts to the environment, one of them being the use of the grid connected photovoltaic system (on-grid). The on-grid was installed in 2011 and since then has been feeding the GO and another building (block V) belonging to UTFPR. This article presents a comparison between an estimate of energy consumption and the generation of energy through the on-grid. By means of the estimated consumption, a survey in loco of the scenario of expenditures of the electrical equipment used in the GO was made, estimating hours of use and power, so the consumption scenario was 145 kWh/month. The power generation of the EV is lower in the months May - July, period in which the solar irradiation is smaller, but according to the measurements the on-grid produces more energy than it consumes.

Earth-Abundant Cobalt Pyrite (CoS2) Thin Film on Glass as a Robust, High-Performance Counter Electrode for Quantum Dot-Sensitized Solar Cells.

We report a cobalt pyrite (cobalt disulfide, CoS2) thin film on glass as a robust, high-performance, low-cost, earth-abundant counter electrode for liquid-junction quantum dot-sensitized solar cells (QDSSCs) that employ the aqueous sulfide/polysulfide (S(2-)/Sn(2-)) redox electrolyte as the hole-transporting medium. The metallic CoS2 thin film electrode is prepared via thermal sulfidation of a cobalt film deposited on glass and has been characterized by powder X-ray diffraction and electron microscopy. Using the CoS2 counter electrode, CdS/CdSe-sensitized QDSSCs display improved short-circuit photocurrent density and fill factor, achieving solar light-to-electricity conversion efficiencies as high as 4.16%, with an average efficiency improvement of 54 (±14)% over equivalent devices assembled with a traditional platinum counter electrode. Electrochemical measurements verify that CoS2 shows high electrocatalytic activity toward polysulfide reduction, rationalizing the improved QDSSC performance. CoS2 is also less susceptible to poisoning by the sulfide/polysulfide electrolyte, a problem that plagues platinum electrodes in this application; furthermore, CoS2 exhibits excellent stability in sulfide/polysulfide electrolyte, resulting in highly reproducible performance.