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With the escalating urgency for sustainable energy alternatives, solar power in urban landscapes has gained prominence. Building‐integrated photovoltaic (BIPV) systems are pivotal in this shift, blending efficient energy generation with architectural aesthetics. This review casts a spotlight on BIPV technologies, with a special emphasis on the less‐explored semitransparent photovoltaics (PVs). These systems are not only energy generators but also natural light facilitators, setting them apart from their opaque PV counterparts. Advancements in both transparent and opaque PV, such as crystalline silicon, are discussed. However, the paper prioritizes semitransparent PV's unique benefits, including harmonious integration with building design and simultaneous energy and daylight management. An exhaustive examination of current literature and developments sketches BIPV's trajectory, highlighting applications, challenges, and technological strides. The narrative extols the aesthetic, financial, and efficiency merits of BIPV, particularly the semitransparent variants' blend of functionality and design. Performance optimization of BIPV systems is scrutinized across various environments and architectural styles. This meticulous discussion seeks to clarify the status quo, emerging research avenues, and future prospects of BIPV in fostering a greener energy transition. The review compares BIPV configurations with traditional solar PV systems, charting a path for enhanced energy production, cost efficiency, and aesthetic integration, with semitransparent PV as a key player. By exploring the interplay between architectural design, energy efficiency, and urban planning, this paper aims to solidify the groundwork for future research, reinforcing the sustainability narrative in urban energy infrastructure. [ABSTRACT FROM AUTHOR]

The problem of global warming has become a major global concern, and reducing greenhouse gas emissions is crucial to mitigate its effects. Photovoltaic power generation is clean, low-carbon energy. Photovoltaic products can convert solar energy into electricity, reducing CO2 emissions to an extent. This paper introduces the life cycle evaluation theory to assess the carbon emissions of photovoltaic curtain walls. PVsyst software allows for the simulation and calculation of power generation under different influencing factors, which provides valuable information about the carbon reduction potential of photovoltaic curtain walls. The evaluation of carbon emissions and their influencing factors using grey correlation analysis further enhances the understanding of the benefits and limitations of photovoltaic curtain walls. According to the results of grey correlation analysis, this paper concludes that the degree of various influencing factors on carbon emission of a photovoltaic curtain wall under different scenarios in descending order is as follows: orientation, location, inclination, shadow occlusion, and seasonal changes. The research findings of this paper provide a theoretical reference for the future development and application of photovoltaic curtain walls. By demonstrating the carbon reduction potential of this technology, this study contributes to promoting the adoption of photovoltaic curtain walls as a sustainable solution to mitigate the effects of global warming. [ABSTRACT FROM AUTHOR]

Building-integrated photovoltaics (BIPVs) and vehicle-integrated photovoltaics (VIPVs) receive solar irradiance through non-uniform shading objects. Standard scalar calculations cannot accurately determine the solar irradiance of BIPV and VIPV systems. This study proposes a matrix model using an aperture matrix to accurately calculate the horizontal and vertical planes affected by non-uniform shading objects. This can be extended to the solar irradiance on a VIPV by applying a local coordinate system. The 3D model is validated by a simultaneous measurement of five orientations (roof and four sides, front, left, tail, and right) of solar irradiance on a car body. An accumulated logistic function can approximate the shading probability. Furthermore, the combined use of the 3D solar irradiance model is effective in assessing the energy performance of solar electric vehicles in various zones, including buildings, residential areas, and open spaces. Unlike standard solar energy systems, the energy yield of a VIPV is affected by the shading environment. This, in turn, is affected mainly by the location of vehicle travel or parking in the city rather than by the climate zones of the city. [ABSTRACT FROM AUTHOR]

While colored photovoltaics are gaining popularity in the market for building-integrated photovoltaics (BIPV), several specific properties are not accounted for in standard PV performance models. This work shows how relying on the coloration efficiency alone can lead to significant errors regarding module temperatures. By comparing measured temperature data from a test installation featuring BIPV façade elements in multiple colors, little correlation is found between total optical losses (reflection and absorption losses) and module temperature. Instead, better correlation is found with total reflectance. This is attributed to the light absorbed in the pigment-based colored layers contributing to module heating, whereas reflected light does not. This is especially relevant for colors with high lightness, such as gray or beige, for which reflection losses are dominating absorption losses. When modelling colored BIPV products, it is therefore recommended to only consider reflection losses for the irradiance contributing to module heating, while continuing to also include absorption losses for the effective irradiance used in electrical performance modelling. [ABSTRACT FROM AUTHOR]

Building integrated photovoltaics (BIPV) is progressively achieving an advanced level of technical maturity and considerable market penetration. In the last kilometre for considerable market implementation, major challenges are today mostly related to improving cost‐effectiveness and product reliability. BIPV multifunctional products are still framed in complex and sometimes unclear qualification processes, in the grey area between electrotechnical and construction sectors, impacting commercialization and users' confidence. The EN 50583 part 1 and part 2 standards today represent the main regulatory framework in Europe for BIPV. However, acts in force for product certification, in the construction and electrical sectors, in most national and local contexts are not yet harmonized for BIPV and imply wide margins of interpretation. The product's qualification in the EU is therefore based on electrical standards for photovoltaics modules or, on the other hand, on standards for construction products. To overcome some of these barriers and challenges, the authors propose a newly developed procedure for testing the impact resistance of BIPV products, introducing a performance‐based approach with the goal of combining building and electrical‐related limit states and responding to the need for a harmonized assessment to ensure the product's safety in use. The methodology and preliminary findings resulting from the application of real test cases, taking also into account the effect of temperature, are presented and analysed. As a result, it is envisaged that the implementation will help operators and prospective normative upgrades, ensuring more outstanding product quality for BIPV's market and driving towards a drop in life cycle costs. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative concept for active wall-curtain façade modules aiming at high level of energy autonomy. The façade module consists of two opaque panels and one transparent panel integrating building integrated photovoltaics supported by façade integrated battery Peltier air-conditioning unit, active shading, and LED lighting. The developed demo-protype was deployed at testing facility and subjected to long-term experimental monitoring to assess the energy performance in real environment. The complex monitoring system captured key power and thermal fluxes, temperatures, mass flows and other operational states of the active wall-curtain façade modules. These measurements were assessed in form of monthly overview depicting total electricity consumption, on-site energy production, heating and cooling delivery as well as self-sufficiency and self-consumption indicators. [ABSTRACT FROM AUTHOR]

Photovoltaic modules are integrated into rooftop buildings, canopies, solar carports, bus stops, greenhouses, known as Building-Integrated Photovoltaics (BIPV). Rooftops may have curved surfaces. The incident diffuse irradiation on curved surface is not uniformly distributed along the surface because the slope of the surface varies with the distance along the curvature. The non-uniform diffuse irradiation stems from the variation of the local sky view factor along the curved surface, resulting in mismatch power losses. The variation of local sky view factors of curved surfaces, in presence of obscuring structures, was not investigate in the past. The purpose of the present study is to develop a methodology for calculating the local sky view factors and the annual incident diffuse irradiation along the curvature of the surfaces. The demonstrations apply to convex and concave parabolic and elliptic surfaces, including curved surfaces obscured by flat, convex and concave nearby rooftops. The effect of an obscuring building near a curved parabolic rooftop results in a decrease of the annual incident diffuse irradiation by 9 percent for 10 m separation between the rooftop and the building. The present study may assist the designer of BIPV systems to assess the generated electric energy on curved rooftops. [Display omitted] [ABSTRACT FROM AUTHOR]

• Long-term operational monitoring of a Zero Emission Building (ZEB) in Beijing. • An existing building being retrofitted into a Zero Emission Building (ZEB). • Key Building Mounted Photovoltaic (BMPV) technologies are practically utilized and their effects are estimated. • The ZEB realized its own net-zero carbon emission and net energy production. • The ZEB could be a comprehensive experimental platform. Building mounted photovoltaic (BMPV) technology is a promised way to achieve carbon peak in building sector. Focused on the influence of heat from PV modules on building envelope's heat transfer and energy saving performance, and the power generation, the coupling mechanism of power generation and heat transfer of integrated photovoltaic technology on building façades has been investigated. The synergy of solar energy generation and building energy consumption have been studied in this paper. The installation method of building PV system was proposed, with which can achieve the maximum energy saving. Furthermore, the achievements have been applied in Zero Emission Building (ZEB) of China Academy of Building Research (CABR), demonstrating way to realize zero carbon building by integration of photovoltaic technology. Total of 236.1 kWp PV systems were installed in ZEB. Monitoring data shows that the annual power generation of ZEB could reach 212,382 kWh, and the power generation per building area is 73.79 kWh/m2, which could meet all the energy demands. In addition, it can supply extra power to surrounding buildings. The ZEB can provide experience and practice data supporting carbon peak in building sector. [ABSTRACT FROM AUTHOR]

Building fenestrations are the key components maintaining the connection between building exterior and interior. However, they are also the weakest allowing heat loss, gain and light. To tackle the enhanced building energy demand, active and passive both ways must be included. Benign energy-generating components and passive energy-saving are both concomitantly possible using photovoltaic (PV) window fenestration. In this work, three different generations PV based fenestration integrated photovoltaics (FIPV) have been reviewed to understand how effective FIPVs are for low energy building. Later advanced technologies suitable for FIPV applications are also discussed. [ABSTRACT FROM AUTHOR]

The authors optimized the thickness of the layers in the 1.67‐eV‐bandgap‐perovskite sub‐cell of a 2‐terminal perovskite/silicon monolithic tandem solar cell under standard test conditions to get the current matching between the top and the bottom sub‐cells. Based on that optimized structure of the tandem cell, we characterized, calculated, and analyzed the annual output energy and the annual efficiency of the tandem cells on the facades and the rooftop of buildings under realistic conditions composed of module temperature, realistic illumination irradiance, and incident angle directly measured in Gifu, Japan in 2015. Consequently, the obtained annual output energy is 279.52, 238.89, 129.99, and 115.21 kWh/m2 with the corresponding annual efficiency of 22.42%, 19.70%, 10.50%, and 9.19% for the tandem solar cells mounted on the rooftop, the south, east, and west facades of the buildings, respectively. Thus, the rooftop and the south face of the buildings are the preferred directions for the BIPV application to gain higher energy. [ABSTRACT FROM AUTHOR]

Recently, greater research attention has focused on the application of solar power generation technology in building construction to reduce building energy consumption and encourage increased sustainable development. An emerging solar power generation technology is in the use of Building-integrated Photovoltaics (BIPVs), where photovoltaic materials are used to replace conventional building materials. In order to map the development of BIPV technology over time and explore technology paths, this study retrieved a total of 4914 patents dated from 1972 to 2016 from the Derwent Innovations Index patent database. This study applies patent co-citation analysis to map the patent co-citation network in three periods based on Ucinet tool. Evolutional path and three key technology frontiers were identified using Social Network Analysis (SNA) and text clustering. The results of this study provide an informed reference for future researchers in understanding the historical development of BIPV, as an emerging and important solar power generation technology in the built environment. At the same time, big data of patents are analyzed using SNA and text clustering, which overcomes the limitation of previous methods of frontiers study that have depended on expert opinion or peer review. [ABSTRACT FROM AUTHOR]

The existing evaluation of Building Integrated Photovoltaic systems (BIPV), limit to the system's electrical performance, similar to conventional PV ground-mounted systems. BIPV has to deliver on both the roles of building and PV alike while catering to the needs of the society, economically. The current paper introduces the concept of Integrability, which is an attempt towards a holistic approach in evaluating BIPV systems. Integrability Methodology for BIPV evaluation has been proposed, for urban localities, which can be adopted for various PV configurations, building typologies and climatic zones. An Integrability Index has also been devised, considering various building performance factors, to evaluate and compare the performance of BIPV structures. The methodology has been applied to a 5.25 kWp BIPV system and the index has been computed to be 0.17 (on a scale of 0–1) and the various strategies that improve the index (up to 0.56) have also been discussed. [ABSTRACT FROM AUTHOR]

This study numerically investigates the thermal behavior and airflow characteristics of the building-integrated photovoltaic (BIPV) façade. A three-dimensional model is developed based on the typical BIPV façade. Computational fluid dynamics (CFD) with the shear stress transport (SST) -omega turbulent model is used in the study. The effects of geometric configurations on the BIPV cell temperature in steady state are evaluated including the sizes of the bottom and top openings and the depth of the back air cavity (or so-called cavity depth). When the sizes of the inlet and outlet openings are the same, the effects on the decrease of cell temperature are limited. By enlarging the bottom (inlet) opening, the impact of ventilation in the cavity behind is more significant and the cell temperature decreases. Cavity depth is also a vital factor affecting BIPV cell temperature. The paper identifies the optimal cavity depth of approximately 100-125 mm. Flow disturbance and a vortex may be observed at the bottom and top of the air cavity, respectively, as the cavity depth increases which negatively affects the ventilation causing these flow disturbances to increase the cell temperature. Thermal effects of environmental conditions are compared with regard to two selected BIPV configurations. The wind velocity and the attack angle also have an obvious impact on cell temperature. Ambient temperature and solar irradiance exhibit a linear relationship with BIPV cell temperature as expected. [ABSTRACT FROM AUTHOR]

• The harvesting related to the electrical energy production of a BIPV as a shading device and roof top photovoltaic (PV) system was simulated by "SolCel (Ver.2019)" which can consider also an influences of obstacles against a reflected irradiance around a BIPV and evaluate a thermal comfort characteristic of an adjacent room, and a solar irradiance for bifacial PV module, etc. • And this paper describes the ecological criteria to optimize the solar architecture through an ecological convergence of a passive solar architecture and photovoltaic system and newly suggested simulation model for solar architecture, considering results from a remodeling process of a small or medium-sized public building by an ecological application of the photovoltaic system. The solar architecture is defined as a kind of building integrated photovoltaic (BIPV) which the Photovoltaic (PV) modules are deployed to passive solar concepts, to minimize the heating & cooling load, to upgrade the indoor environmental quality and to be adjustable for regional weather and to continuously succeed architectural culture and history. The most ideal form of a BIPV is a multi-functional and ecological convergence through a passive concept application of a photovoltaic module for a building. The solar architecture needs to consider the architectural culture and history of the region through an ecological convergence which is applicable to a passive concept if the environment, energy and comfort problems will be effectively mitigated. The evaluation standard is needed to fulfill these requirements of solar architecture. The renewable energy sources are getting very hot issues, due to the environmental pollution, global warming, and energy shortage, etc. It is reasonable to disseminate the representative energy systems which could be ecologically convergent with the regional architecture. Most renewable energy systems including PV could not be activate or not be environmentally friendly if the systems are planned simply without multi-functional and ecological convergence. This paper describes the ecological criteria to optimize solar architecture through an ecological convergence of a passive solar architecture and photovoltaic system. [ABSTRACT FROM AUTHOR]

• Electrical-thermal modeling of power converter as part of a BIPV library in Modelica. • Power converter integration in BIPV module frame in a 'plug and play' configuration. • Experimental validation using a converter prototype tested in a climate chamber. • Improved accuracy compared to TRNSYS power conditioner across all KPIs. • Converter placement inside the frame strongly a?ects the components temperature. European legislation on building performance and energy efficiency pushes the shift towards minimizing the environmental footprint of buildings. Building-integrated photovoltaics (BIPV) is a promising technology that can accelerate the transition to energy-neutral buildings. Quantifying the potential of BIPV is crucial and one means of obtaining those results is through simulation. The state-of-the-art tools offer either thermal or electrical specialization; in particular, balance of system components (BOS) such as power converters have not been studied in detail within the building simulations BIPV domain. In this paper, a multi-physics model of a BIPV integrated DC/DC converter is developed in the Modelica language, taking into account the thermal and electrical couplings inherent to power electronic systems. The model has been validated using representative outdoor BIPV measurements and a DC/DC converter prototype. It has been found that the proposed model provides reasonable accuracy and outperforms an equivalent power conditioning model in TRNSYS. To demonstrate the model's functionality, two case studies are performed. First, the temperature-dependence of the converter's efficiency and losses is quantified and analyzed and, second, the prominent contributors to the converter losses are identified and discussed. [ABSTRACT FROM AUTHOR]

Highlights • Bifacial PV cells are used increase the surface area in urban BIPV applications. • Film-based optics provide back side illumination of the bifacial cells. • The dimensions of the optical elements impact the amount of energy generated. • An inexpensive, film-based solution functions as a passive solar concentrator. Abstract In this work, film-based optical elements are used as a passive solar concentrator for Building Integrated Photovoltaic (BIPV) window applications. Micro-facets are used to induce total internal reflection allowing window glass to function as a wave guide, thus redirecting light onto the back side of bifacial photovoltaic (BFPV) cells. Seasonal variations in the incident angle at solar noon were considered for Chicago, IL. Three optical models were developed using commercial optical software, validating that the optical elements have a significant impact on the amount of light energy allowed to reach the back side of the bifacial cell. Further, an experimental validation was conducted using two commercially available films. Using a 1:1 film to PV-cell ratio, the first film demonstrated a maximum of 26.3% increase in power on the back side of the bifacial cell. The second film type allowed a maximum of 30.2% increase. Both films allowed solar energy to reach the back side of the cell over the range of incident angles that were evaluated, making it useful as a passive solar concentrator. Finally, both 2:1 and 3:1 film to PV-cell ratios were evaluated for each of the two film types. A maximum power increase of 35.1% was observed. The results indicate that film-based optical elements have potential as a passive solar concentrator for BIPV applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Data recorded in Burgos, Spain, from January 2014 to September 2017. Highlights • Potential PV production from vertical façades are calculated from GVI. • Data were compared to the energy production of a horizontal facility. • Four classic decomposition models were tested to predict GVI. • The results highlighted the economic viability of BIPV. Abstract Potential photovoltaic (PV) production from vertical façades facing the four cardinal points of the compass are calculated from daily average vertical global insolation readings measured in Burgos, Spain. Ten-minute data sets are collected over forty-five months, from January 2014 to September 2017, in the experimental campaign to produce estimates of daily average insolation levels, from which the PV potential of the vertical surfaces was calculated. Given the scarcity of data on Global Vertical Insolation (GVI), the main sky-related variables were processed in four classic decomposition models (Isotropic, Circumsolar, Klucher, and Hay) to predict the insolation values. Both the experimentally measured GVI values and those calculated with the models were then compared using the statistical indicators RMSE and MBE. The results highlighted the economic viability of Building Integrated PhotoVoltaic (BIPV) facilities, even on the north-facing façades, in comparison with the horizontal facility at the same location. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Rh/v is defined to estimate the potential of solar energy on the vertical area. • Sun-tracking PV shading elements integrated with windows are modeled and analyzed. • Novel optimum sun-tracking methods and cell layout are first proposed. • Annual energy generation and average efficiency are improved by 27.40% and 19.17%. • Optimum sun-tracking methods reveal great ability to protect glare from the sun. Abstract Vertical space bears great potential of solar energy especially for congested urban areas, where photovoltaic (PV) windows in high-rise buildings can contribute to both power generation and daylight harvest. Previous studies on sun-tracking PV windows strayed into the trade-off between tracking performance and mutual shading, failing to achieve the maximum energy generation. Here we first build integrated models which couple the performance of sun-tracking PV windows to the rotation angles. Secondly, one-degree-of-freedom (DOF) and two-DOF sun tracking are mathematically proven to be not able to gain either maximum power generation or non-glare daylighting under reasonable assumptions. Then we derive the optimum rotation angles of the variable-pivot-three-degree-of-freedom (VP-3-DOF) sun-tracking elements and demonstrate that the optimum VP-3-DOF sun tracking can achieve the aforementioned goals. When the restriction of the proposed model is relaxed, the same performance can be achieved by the optimum one-DOF sun tracking with extended PV slats and particular design of cell layout, requiring less complicated mechanical structures. Simulation results of nine global cities show that the annual energy generation and average module efficiency are improved respectively by 27.40% and 19.17% via the optimum VP-3-DOF sun tracking over the conventional perpendicular sun tracking. The proposed optimum sun-tracking methods also reveal better protection against sun glare. The optimum VP-3-DOF sun tracking is also demonstrated to be applicable to horizontal PV windows, as those applied in the sun roof of a glass greenhouse. [ABSTRACT FROM AUTHOR]

This paper presents an integrated bottom-up approach aimed at helping those dealing with strategical analysis of installation of Building Integrated Photo Voltaic (BIPV) to estimate the electricity production potential along with the energy needs of urban buildings at the district scale. On the demand side, hourly energy profiles are generated using dynamic building simulation taking into account actual urban morphologies. On the supply side, electricity generated from the system is predicted considering both the direct and indirect components of solar radiation as well as local climate variables. Python-based Algorithm editor Grasshopper is used to interlink four types of modelling and simulation tools as 1) generation of 3-D model, 2) solar radiation analysis, 3) formatting weather files (TMY data set) and 4) dynamic energy demand. The method has been demonstrated for a cluster of 20 buildings located in the Yasar University in Izmir (Turkey), for which it is found the BIPV system could achieve an annual renewable share of 23%, in line with the Renewable Energy Directive target of 20%. Quantitatively-compared demand and supply information at hourly time step shows that only some energy needs can be met by BIPV, so there is a need for an appropriate matching strategy to better exploit the renewable energy potential. [ABSTRACT FROM AUTHOR]

India receives sun's energy over 300 days a year most of the time. About 5000 trillion kWh per year sun's energy is incident over India's land area. Theoretically, a small fraction of total incident solar energy can meet the entire country's power requirements. There are many government schemes to promote solar power generation. The government of India initiated solar PV/BIPV policies to encourage industries and individuals to use solar energy powered systems for electricity generations. This article provides an overview of the solar energy status and application of BIPV system in India. It includes an assessment of the region's solar energy potential and solar PV/BIPV installed capacity. This paper gives a brief description barriers and challenges facing solar BIPV development in India. This study also provides the solar PV/BIPV policies and recommendations with reference to the Indian context. [ABSTRACT FROM AUTHOR]

Color management of integrated photovoltaics must meet two criteria of performance: provide maximum conversion efficiency and allow getting the chosen colors with an appropriate brightness, more particularly when using side by side solar cells of different colors. As the cooling conditions are not necessarily optimal, we need to take into account the influence of the heat transfer and temperature. In this article, we focus on the color space and brightness achieved by varying the antireflective properties of flat silicon solar cells. We demonstrate that taking into account the thermal effects allows freely choosing the color and adapting the brightness with a small impact on the conversion efficiency, except for dark blue solar cells. This behavior is especially true when heat exchange by convection is low. Our optical simulations show that the perceived color, for single layer ARC, is not varying with the position of the observer, whatever the chosen color. The use of a double layer ARC adds flexibility to tune the wanted color since the color space is greatly increased in the green and yellow directions. Last, choosing the accurate material allows both bright colors and high conversion efficiency at the same time. [ABSTRACT FROM AUTHOR]

Building integrated ETFE foils are used as the absorbing structure in the solar energy targeted applications. These foils as a building transparent material have been drawing much more attention for the past decades. In addition, integration of amorphous photovoltaic cells with these ETFE foils is taken into account due to the low production cost and its resistance to high operating temperatures. In the present study, a Building integrated Photovoltaic thermal (BIPV/T) ETFE cushion roof was numerically modeled and the thermal and electrical performances of this system were obtained in two cases: the cushion with the steady state mass flow and the cushion with the air pressure regulator system. Verification of the modeling was performed by comparing the model's results with the available experimental data in the literature. The main strength of the present modeling is consideration of the air pressure regulator system in the modeling process which has not been studied yet. The result of the present study showed that the present model predicts the BIPV/T ETFE cushion performance with a reasonable accuracy and can predict the system performance under different operating conditions. The results also showed that in case of the cushion with the steady state mass flow, the power generation is 15% higher than that of the cushion with the pressure regulator system. However, the cushion with the steady state mass flow has a low net output generated power due to the high consumed power of the blower. [ABSTRACT FROM AUTHOR]

• The low-loss and aesthetic solution of building integrated photovoltaics (BIPVs) is explored with dot-matrix patterning technique. • The mismatch loss and temperature distribution of dot-matrix patterned (DMP) photovoltaic module are analyzed. • The circuit modeling of PV module takes the transmittance of pattern shading into consideration and thus improves the accuracy. • The electrical characteristic of dot-matrix patterned (DMP) photovoltaic module is experimentally and numerically investigated. • The short-circuit current of the series-connected photovoltaic module is found to be determined by the most shaded cell, which provides a theoretical minimum for the patterned PV module's out-put design. PV modules with customizable appearances have become attractive due to the falling cost of PV cells and the increasing demand for BIPV projects, whereas the impact of patterns on module performance has not been studied in terms of mechanism. This paper introduced a circuit simulation method for PV modules with various pattern styles, and its robustness was validated extensively through custom PV mini-module that allow for I-V curve measurements and analysis. The electrical and thermal characteristics of dot-matrix patterned (DMP) module, including short-circuit current, fill factor, peak power, energy efficiency and temperature distribution, were analyzed in detail. The results demonstrated that pattern shading decreased the module power but slightly increased the fill factor and relative efficiency, in addition to which, the power reduction of dot-matrix patterned module was less than that of continuous patterned module. When the cells of DMP module correspond to different pattern shading, the current and power of module were limited by the most shaded cell, with the lowest percentage values of 53% and 49% in this paper. Inhomogeneous pattern distribution caused additional power loss (e.g., measured 7.74% in our work) and local temperature rise for modules with same shading area. To reduce losses, the principle of using the smallest possible dot size and configuring the dot-matrix evenly was suggested to designers. [ABSTRACT FROM AUTHOR]

To ensure the cost effectiveness of photovoltaic power plants (PVPPs) it is needed to keep the level of yearly energy production as high as possible. In this context, efficiency and availability of a PVPP have to be checked continuously. The section of a PVPP which deserves more attention is surely the PV array, where many fault conditions can happen (shading, by-pass diode faults, cable interruptions, and so on). A diagnostic tool to detect faults in the PV array is desirable, even if its implementation is critical owing to: the fluctuation of the operating conditions (mainly irradiance), which complicates the instantaneous response investigation and costs and implementation constraints to implement a distributed (at PV module level) or semi-distributed (at string level) monitoring/diagnostic system. Particularly, for BIPV systems, further constraints related to the regular access for inspection and maintenance operations have to be considered. In this paper, the procedure adopted to develop and validate a diagnostic tool can be summarized in four steps: (1) using real data to model the PV array; (2) introducing several fault scenarios on the real PV string and analyzing the relative modifications of the I – V curves; (3) assessment of the meaningful parameters useful to discern the different faults by means of a PV generator (PVG) simulator based on a metaheuristic technique denominated ABC-DE ; (4) proposition of several fault signing tables to assess the PV plant fault diagnostic. [ABSTRACT FROM AUTHOR]

Solar irradiation in Brazil is favorable for electricity generation, yet this energy source represents less than 0.1% of the Brazilian energy matrix. This article presents photovoltaic solar panels as an important alternative in the context of the Brazilian energy crisis. Solar irradiations levels were considered to calculate the number of solar panels necessary to supply the average electricity demand of social housing programs. A scenario approach and an OFAT sensitivity analysis were used to evaluate feasibility (IRR, NPV, cash flow and payback) based on existing electricity charging policies and usual long-term financing plans for social housing programs. The results for all the proposed scenarios indicate that photovoltaics are an environmentally and economically feasible alternative. Deploying between four to seven 217 W photovoltaic panels onto each house would meet the needs of all solar irradiation zones considered, making dwellers significantly less dependent on the grid and capable of up to 47% grid feedback for up to 30 years. Finally, feed-in tariff policies and a trust fund for maintenance and reinvestment costs are suggested in order to stimulate the use of photovoltaics as a sustainable alternative. [ABSTRACT FROM AUTHOR]

• The study compared two BIPV ventilated facade technologies in three orientations. • Effects of PV module's characteristics, temperature, and orientation were analyzed. • The c-Si modules' yields were higher than CIGS in all periods and orientations. • The east facade performed better than the west due to less heat accumulation. • Combining BIPV in the south and west facades best fits Dubai's daily peak demand. Buildings, especially mid- and high-rise ones, offer the opportunity to incorporate Photovoltaics (PV) on their vertical surfaces in addition to their roofs. This is achieved through Building Integrated Photovoltaic (BIPV) solutions. Ventilated facades in buildings can facilitate PV integration and improve the envelope's thermal performance. However, research on BIPV ventilated façades is lacking in the Gulf and MENA regions. Considering the area's harsh climate, investigating these facades is critical. Therefore, the authors of this paper conducted comparative experimental research on the energy performance of BIPV ventilated facades in the hot climate of Dubai. For a year, they monitored the energy yield and temperatures of Copper Indium Gallium Selenide (CIGS) and monocrystalline silicon (c-Si) modules on the south, east, and west facades. In addition, the study analyzed the effect of the modules' characteristics, orientation, temperature, and solar angle on the energy yield. Despite the hot temperatures, the monthly area-normalized energy yields of the c-Si modules were consistently higher than the CIGS modules across all orientations, with an average difference of 13.6%. The modules in the south facade produced the highest annual yield. Also, from October to February (the coolest period), the energy yield of the south modules surpassed the east and west modules by 41.6% and 48.5%, respectively. However, from April to August (the highest energy demand period), the east and west energy yield exceeded the south by 40.9% and 32.5%, respectively. In addition, the west-facing modules experienced higher temperatures than those in the east, resulting in an average of 12% lower energy yields. Hence, the east façade has performed the second best. The west façade production, nevertheless, closely coincides with Dubai's peak periods curve. Thus, the combination of modules on the west and south facades achieved the strongest generation-consumption correlation. [ABSTRACT FROM AUTHOR]

• Representative cities regrouped for energy-saving potentials upon STPV integration. • Coupled STPV integration scenario induced energy-saving effects got validated. • Energy-saving effects of STPV photo-thermal-electrical property variations examined. • Design strategies for both integration concerns got proposed accordingly. Semi-Transparent Photovoltaics (STPVs) have received increasing popularities as they conform to the architectural design trend of large-area glass curtain walls and expand the application scenes of building integrated photovoltaics (BIPVs). However, their high sensitivities toward extreme thermal and radiation climate conditions as well as the potential key integration scenario--skylights for large footprint buildings, have rarely been highlighted. Meanwhile, in context of the low energy glass application consensus as well as varieties of commercial module typologies with diverse photo-thermal-electrical properties, designers are still in lack of key understandings regarding actual energy performances and appropriate design solutions of STPV integrations upon diversed climate conditions. In this work, the actual energy-saving disparities, occasioned by distinct climate conditions of both thermal design and solar radiation resources, have been investigated in detail through simulation validations over representative large footprint railway station building prototypes. 14 representative cities covering most concerning climate zones, as well as seven STPV modules based on different PV technologies or featured photo-thermal-electrical properties had been examined for their climate responsivenesses. All engaged cities have been re-grouped from the new perspective into four categories (Low, Medium, High, Ultra-high energy-saving beneficial) with corresponding energy-saving rates (ESRs) (<15%, 14%∼20%, 20%∼22%, >24%) to reveal their true energy-saving beneficial potential levels. Design strategies on basis of applicable integration scenarios as well as appropriate module properties and typologies have been proposed corresponding to each reclassified city categories, to achieve the best conjugated energy-saving effects. This research can provide essential knowledge for finalizing STPV integration designs under the premise of a best energy-saving performance, in response to diversified and complicated climate conditions. [ABSTRACT FROM AUTHOR]

Due to global climate change, building-integrated photovoltaics (BIPV) have been recognized as an effective solution to reduce the dependence on fossil fuels and achieve nearly zero-energy buildings. Nevertheless, BIPV implementation remains a niche development. Various studies have discussed the barriers to BIPV implementation. However, very few studies have endeavoured to investigate the complex interrelationships among the barriers to BIPV implementation in Singapore. In this study, the barriers to BIPV implementation in Singapore are first addressed by a literature review and then verified by local academics and industry experts. Additionally, the interpretive structural modelling (ISM) approach is deployed to investigate the contextual interrelationships among the identified barriers. Then, a hierarchical structure of the barriers is developed through the ISM method, and the barriers are categorized by clusters, with cross-impact matrix multiplication applied to the classification technique. In addition to the economic-related issues proposed by previous research, which has concentrated on nonspecific BIPV implementation barriers, the findings show that the lack of professionals and the absence of cost-effective BIPV products and design tools should be given specific attention for BIPV implementation in Singapore. The findings offer valuable information on the overall structure and interrelationships among the barriers to Singapore's BIPV industry, and a three-step plan for unlocking the potential of BIPV implementation is proposed. The findings also have implications for future research and for obtaining effective scientific and administrative solutions to facilitate BIPV deployment in Singapore. [ABSTRACT FROM AUTHOR]

Progress in development of building-integrated photovoltaic systems is still hindered by the complexity of the physics and materials properties of the photovoltaic (PV) modules and its effect on the thermal behavior of the building. This affects not only the energy generation, as its active function and linked to economic feasibility, but also the thermal insulation of the building as part of the structure's skin. Traditional modeling methods currently presents limitations, including the fact that they do not account for material thermal inertia and that the proposed semi-empirical coefficients do not define all types of technologies, mounting configuration, or climatic conditions. This article presents an artificial intelligence-based approach for predicting the temperature of a poly-crystalline silicon PV module based on local outdoor weather conditions (ambient temperature, solar irradiation, relative outdoor humidity and wind speed) and indoor comfort parameters (indoor temperature and indoor relative humidity) as inputs. A combination of two algorithms (Grammatical Evolution and Differential Evolution) guides to the creation of a customized expression based on the Sandia model. Different data-sets for a fully integrated PV system were tested to demonstrate its performance on three different types of days: sunny, cloudy and diffuse, showing relative errors of less than 4% in all cases and including night time. In comparison to Sandia model, this method reduces the error by up to 11% in conditions of variability of sky over short time intervals (cloudy days). • An AI-based approach is proposed for predicting PV module temperature for BIPV. • The obtained models show relative errors of less than 4% in all cases. • In comparison to Sandia model, this method reduces the error by up to 11%. • GE+DE is a reliable tool easily applicable to non-conventional PV applications. [ABSTRACT FROM AUTHOR]

Building-integrated photovoltaic (BIPV) panels are emerging as a useful technology for helping to achieve net-zero energy buildings. At this time, the main drawback with BIPV systems is the cost per kilowatt per hour of electricity generated. Besides cheaper production of photovoltaic panels, increases in their efficiency can be obtained by reducing panel temperatures. This is often achieved by adding a cavity beneath the panels to allow ventilation of the rear of the panel. However, the details of airflow in the cavity and the effect on cooling have not been rigorously researched. Life-time enhancement against degradation is also an effective technique to reduce the cost of electricity generated. Moisture ingress and thermal stresses are among the primary reasons for degradation of BIPVs; these processes are directly affected by air and moisture flow around the panels. The surface temperature thermography and airflow observations performed in this work helps to understand the transport mechanisms above and below the panels. For this purpose, a novel setup was developed consisting of a building model with a mock BIPV panel plus a solar simulator placed inside an atmospheric wind tunnel. Particle image velocimetry (PIV) and infra-red thermography were performed to simultaneously monitor the surface temperature and airflow above and below the panel. The study clearly shows how the accelerated airflow within the cavity increases the heat exchange between the PV and airflow and consequently reduces the PV temperature. It is also shown that the stepped open arrangement of panels is more effective in reducing the temperature comparing to a flat arrangement. This arrangement also has a better resistant against the air and moisture ingress. [ABSTRACT FROM AUTHOR]

Dirt accumulation ("soiling") on the surface of photovoltaic (PV) modules may cause significant energy output reductions ("soiling losses"). The adoption of suitable soiling mitigation strategies can make PV deployment more attractive, but it requires the assessment of the magnitude and the seasonal evolution of the soiling losses at local scale, as they are highly dependent on the regional climate, the meteorological conditions and the surrounding environment. For the purpose of estimating them for building integrated and building applied PV systems in Madrid city, Spain (i.e. under Mediterranean climate conditions), a systematic optical analysis was performed during a 15-month experimental campaign using a rooftop soiling test bench which allowed the exposure of multiple glass coupons at two tilt angles of interest (8° and 35°) in a semiurban environment. There was no cleaning schedule so that the exposed glass coupons were simply washed away by the rain. Broadband transmittance reductions (T loss) indicated the occurrence of low soiling losses with yearly-averaged T loss values of 1.49% at 8° and 1.04% at 35°. Regarding the soiling evolution, the local precipitation regime played a fundamental role. Soiling losses were negligible during frequent-rainfall periods, experienced a moderate increment in spring (March–April), and increased notably during the dry summer season, reaching annual maxima in July (5.13% at 8° and 3.89% at 35°). In order to minimize the local soiling losses, performing module cleaning operations at least during these two times of the year is encouraged. Concerning the soiling spectral effects, the optical loss increased towards shorter wavelengths, making wide-bandgap PV technologies more sensitive to local soiling. Finally, when applying PV performance prediction models which include soiling, the recommended local values for the daily soiling rate and the rain threshold are 0.11%/day and 5.3 mm at a tilt angle of 8° and 0.09%/day and 3.3 mm at a tilt angle of 35°. • BIPV-/BAPV-oriented soiling experiment. • Soiling test bench for the long-term exposure of glass coupons. • Assessment of the soiling optical losses on a yearly and a seasonal basis. • The annual rainfall regime played a fundamental role on soiling. • Daily soiling rates and rain thresholds estimated for PV yield prediction tools. [ABSTRACT FROM AUTHOR]

[Display omitted] In this manuscript we review research on the feedback mechanisms between photovoltaic energy production and the urban environment, with an emphasis on synthesizing what is known, while drawing attention to limitations, and indeed errors in, the literature on this topic. We include in our analysis studies on photovoltaic (PV) systems in urban settings – on buildings, as shade structures, or as stand-alone arrays within an urban environment. We further limit the review to studies that investigate how the urban setting affects the performance of PV systems or how PV systems affect their surrounding urban environment. Our review is based on a systematic search of the literature, which revealed 116 unique articles that addressed the underlying questions in a meaningful way. While there are conflicting results reported across this body of literature, our review and synthesis reveal two key findings: (1) PV can significantly warm the city during the day, provide some cooling at night, and potentially increase energy use for air conditioning of buildings in some climates and building types; and (2) placing PV in an urban setting can adversely affect PV efficiency, reducing overall power production up to 20% in comparison to PV applications in rural settings. It is recommended that future developments of PV technologies focus both on increased efficiency and the need to increase reflection of wavelengths of energy not converted to electricity by the PV cells. Furthermore, designs for urban PV systems should explicitly consider the effects of elevated urban temperatures, pollution, and shading on system performance. [ABSTRACT FROM AUTHOR]

Semi-transparent Building Integrated Photovoltaics provide a fresh approach to the renewable energy sector, combining the potential of energy generation with aesthetically pleasing, multi-functional building components. Employing a range of technologies, they can be integrated into the envelope of the building in different ways, for instance, as a key element of the roofing or façade in urban areas. Energy performance, measured by their ability to produce electrical power, at the same time as delivering thermal and optical efficiencies, is not only impacted by the system properties, but also by a variety of climatic and environmental factors. The analytical framework laid out in this paper can be employed to critically analyse the most efficient solution for a specific location; however, it is not always possible to mitigate energy losses, using commercially available materials. For this reason, a brief overview of new concept devices is provided, outlining the way in which they mitigate energy losses and providing innovative solutions for a sustainable energy future. [ABSTRACT FROM AUTHOR]

Compared with traditional photovoltaic (PV) cells, bifacial PV cells can generate electricity on both sides. The study aims to research the electricity generation improvement of bifacial PV module as building envelope, and to find factors affecting its power generation performance in order to optimize it. A prefabricated building was renovated with two facades and the roof installed with bifacial PV modules. A test rig was established to monitor the electricity generation of the bifacial PV facades and roof, as well the indoor illuminance. It was found that the roof had the highest power generation per unit area. The electricity generation of bifacial PV module was simulated and validated. Through the simulation, the electricity improvement of the bifacial PV module was about 4.7%–18.8%. Then the simulation model was used to research the important factors to improve bifacial PV modules. The correlation between indoor light environment and bifacial PV power generation improvement is found. With the increase of reflectivity of the inner surface properly, the improvement of electricity was increased until the reflectivity of the ceiling reaches 0.8. In addition, the best coverage of bifacial PV was found. This study will provide optimization guidance for the application of bifacial PV modules in buildings envelope. [ABSTRACT FROM AUTHOR]

This paper reviews and analyzes technological design options, which have become available to date for BIPV systems on roofs and facades, independently of specific products or building projects. This means that this survey does not analyze existing products or realized buildings, but provides an overview of the technologies for BIPV. The starting point is an analysis of the relevance of BIPV technologies for the decarbonization of energy systems, providing energy for direct use of electricity and sector coupling together with an analysis of the German BIPV market. The paper presents the wide range of technical design options for BIPV systems and categorizes and analyzes them to provide a structured overview. This comprises a detailed analysis of the design options for BIPV modules, in which not only the design options for the PV cell layer were comprehensively investigated, but also the different variants of embedding materials, front and rear cover materials, additional interlayers and electrical module layout. Two fundamental module-level design options were investigated in particular detail: The use of PV cells as basic elements of patterns and the use of color to conceal the PV cells. Subsequently, options for the design of complete electrical systems are reviewed, ranging from sub-module level design parameters to building energy systems. Design options for the constructional integration of BIPV modules in the building envelope complete the review of technological design possibilities. [ABSTRACT FROM AUTHOR]

• Solution-processed SnO 2 –SiO 2 layers were synthesized for use as distributed Bragg reflector. • SiO 2 thickness of SnO 2 –SiO 2 distributed Bragg reflector was adjusted to achieve various colors. • Colored devices were fabricated by incorporating SnO 2 –SiO 2 distributed Bragg reflectors into MAPbI 3 perovskite solar cells. • Maximum efficiency of 9.52% is achieved by a blue-colored solar cell. Organic–inorganic hybrid perovskite solar cells have attracted significant interest as a novel candidate for building-integrated photovoltaics (BIPV) applications. In particular, coloring methods for perovskite solar cells have been actively studied to meet the aesthetic needs for BIPV. To date, studies based on TiO 2 –SiO 2 -based distributed Bragg reflectors (DBRs) have been reported owing to their good color selectivity and low power conversion efficiency (PCE) loss. However, the application of TiO 2 layers as DBRs for building exterior can result in serious problem due to their high photocatalytic activity. Therefore, in this study, to overcome this problem, the TiO 2 layers in both DBR and electron selective layer in perovskite solar cells are replaced by SnO 2 films. SnO 2 –SiO 2 DBRs with various SiO 2 thicknesses were synthesized by a simple spin-coating process. By combining DBRs and TiO 2 -free perovskite devices, blue-, purple-, and yellow-colored perovskite solar cells were successfully fabricated and showed PCEs of 9.52%, 5.99% and 6.85%, respectively. [ABSTRACT FROM AUTHOR]

• Rooftop PV key driver in the PV market, thus modelled in IMAGE IAM. • Global estimated potential 8.3 PWh y−1: 1.5 times residential electricity demand. • Scenarios show key role for rooftop PV but regional characteristics crucial. • Income levels and grid electricity prices dominate regional deployment. • Low-irradiation western Europe better than high-irradiation Middle East. The use of solar photovoltaic has strongly increased in the last decade. A significant part of this growth comes from home owners installing rooftop photovoltaic. Despite this key role, most long-term model-based scenarios do not consider decentralized supply of rooftop photovoltaic but concentrate on utility-scale photovoltaic instead. In this paper, we implement rooftop photovoltaic in the Integrated Assessment Model IMAGE to study its possible role in energy and climate scenarios. We first calculated the global technical and economic potential to derive regional cost-supply curves for rooftop photovoltaic. Next, we have added a new decision in the IMAGE model allowing household investment in rooftop photovoltaic based on the comparison of the whole-sale electricity price with the price of rooftop photovoltaic. The global suitable roof surface area was assessed at 36 billion m2, or 4.7 m2 capita−1, leading to a potential for rooftop photovoltaic of 8.3 PWh y−1, roughly 1.5 times the 2015 global residential electricity demand. In the baseline scenario, adding rooftop photovoltaic could lead to a 80–280% increased share of photovoltaic electricity production in 2050 (i.e. from 6% to 17% in total power production). This increase depends on regional characteristics that are essential to the deployment of rooftop photovoltaic: differences in social-economic and policy factors (capital costs, household income, and electricity prices) are considerably more important than physical factors, such as solar irradiance. [ABSTRACT FROM AUTHOR]

Energy flexibility in buildings is gaining momentum with the introduction of new European directives that enable buildings to manage their own energy demand and production, by storing, consuming or selling electricity according to their need. The transition towards a low-carbon energy system, through the promotion of on-site energy production and enhancement of self-consumption, can be supported by building-integrated photovoltaics (BIPV) technologies. This paper investigates the aesthetic and technological integration of hidden coloured PV modules in architecturally sensitive areas that seem to be the best possibility to favour a balance between conservation and energy issues. First, a multidisciplinary methodology for evaluating the aesthetic and technical integration of PV systems in architecturally sensitive area is proposed, referring to the technologies available on the market. Second, the experimental characterisation of the technical performance specific BIPV modules and their comparison with standard modules under standard weather condition are analysed, with the aim of acquiring useful data for comparing the modules' integration properties and performance. For this purpose, new testbeds have been set up to investigate the aesthetic integration and the energy performances of innovative BIPV products. The paper describes the analyses carried out to define the final configuration of these experimental testbeds. Finally, the experimental characterisation at standard test conditions of two coloured BIPV modules is presented and the experimental design for the outdoor testing is outlined. [ABSTRACT FROM AUTHOR]

As building integrated photovoltaics (BIPV) are becoming increasingly popular, the demand for optimized utilization will be increasing with respect to efficiency, aesthetics and reliability. In cold climate regions, we predict that there will also be a growing focus on how to avoid snow and ice formation on the exterior surfaces of BIPV. During the winter period there is substantially less incident solar radiation. This is also the period when the solar radiation is most needed for heating, lighting and power production purposes. The task to avoid accretion of snow and ice is challenging due to the fact that snow, ice and ambient weather conditions exist in countless variations and combinations. Snowfall, freezing of rain water and condensation of air moisture with subsequent freezing, are examples of aspects that have to be addressed in a satisfactory way. The present study aims to review the cold weather challenges facing BIPV, the strategies for overcoming them and the opportunities that follow from successfully overcoming them. • Overview of ice and snow mitigation strategies on BIPV. • Surface design of BIPV for snow and ice shedding. • Synergy effects offered by successful BIPV mitigation surface design. • Future research and development opportunities in mitigation of snow and ice for BIPV. [ABSTRACT FROM AUTHOR]

State-of-the-art reliability assessment typically starts from a given circuit topology, for which the most suitable components are selected using a Physics of Failure analysis. This paper, however, addresses the topology selection stage, which is the foundation in designing reliable converters. Based on an overview of the reliability performance of different components, a methodology is presented as a guideline for comparing topologies to one another. The focus is directed at practical consequences associated with certain designs. Furthermore, an overview is provided on the latest developments in component technology reliability improvements. The developed methodology is mainly intended for demanding applications, where long lifetimes are required or elevated ambient temperatures are present. After the topology selection, an overview of possibilities is given that allows further increasing converter availability. Finally, the methodology is applied to the design of module level converters for building integrated photovoltaics, which is a high temperature application with a high desired lifetime. A prototype and experimental results are presented. [ABSTRACT FROM AUTHOR]

Incident solar radiation modelling has become of vital importance not only in architectural design considerations, but also in the estimation of the energy production of photovoltaic systems. This is particularly true in the case of buildings with integrated photovoltaics (PV) systems having a wide range of orientations and inclinations defined by the skin of the building. Since solar radiation data at the plane of interest is hardly ever available, this study presents the analysis of two of the most representative transposition models used to obtain the in-plane irradiance using as input data the global and diffuse irradiation on the horizontal plane, which can be obtained by satellite-based models or ground measurements. Both transposition models are validated with experimental measurements taken in Murcia (southeast of Spain) and datasets provided by the photovoltaic geographical information system (PVGIS) and the National Renewable Energy Laboratory (NREL) for vertical surfaces facing the four cardinal points. For the validation, the mean bias deviation, root mean square error and forecasted skill were used as indicators. Results show that the error rate decreases slightly for clear days. Better results are also obtained by dismissing data with low solar elevation angles so as to avoid shadowing effects from the surroundings in the early and late hours of the day, which affects mainly the performance of the transposition models for west and east surfaces. The results highlight the potential of equator-facing façades in winter time when the received irradiation can be twice as much as the one collected by the horizontal plane. It is also noteworthy that the operating conditions of all façades are mainly low irradiance and medium temperature at these locations. [ABSTRACT FROM AUTHOR]

Since building-integrated photovoltaic (BIPV) modules are typically installed during, not after, the construction phase, BIPVs have a profound impact compared to conventional building-applied photovoltaics on the electrical installation and construction planning of a building. As the cost of BIPV modules decreases over time, the impact of electrical system architecture and converters will become more prevalent in the overall cost of the system. This manuscript provides an overview of potential BIPV electrical architectures. System-level criteria for BIPV installations are established, thus providing a reference framework to compare electrical architectures. To achieve modularity and to minimize engineering costs, module-level DC/DC converters preinstalled in the BIPV module turned out to be the best solution. The second part of this paper establishes converter-level requirements, derived and related to the BIPV system. These include measures to increase the converter fault tolerance for extended availability and to ensure essential safety features. [ABSTRACT FROM AUTHOR]

Photovoltaic electricity generation is growing at an almost exponential rate worldwide, reaching 400 GWp of installed capacity in 2018. Different types of installations, ranging from small building integrated systems to large plants, require different maintenance strategies, including strategies for monitorization and data processing. In this article, we present three case studies at different scales (from hundreds of Wp to a 2.1 MWp plant), where automated parameter monitorization and data analysis has been carried out, aiming to detect failures and provide recommendations for optimum maintenance procedures. For larger systems, the data collected by the inverters provides the best source of information, and the cross-correlated analysis which uses these data is the best strategy to detect failures in module strings and failures in the inverters themselves (an average of 32.2% of inverters with failures was found after ten years of operation). In regards to determining which module is failing, the analysis of thermographic images is reliable and allows the detection of the failed module within the string (up to 1.5% for grave failures and 9.1% of medium failures for the solar plant after eleven years of activity). Photovoltaic (PV) systems at different scales require different methods for monitorization: Medium and large systems depend on inverter automated data acquisition, which can be complemented with thermographic images. Nevertheless, if the purpose of the monitorization is to obtain detailed information about the degradation processes of the solar cells, it becomes necessary to measure the environmental (irradiance and ambient temperature), thermal and electrical parameters (I-V characterization) of the modules and compare the experimental data with the modelling results. This is only achievable in small systems. [ABSTRACT FROM AUTHOR]