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In the context of offshore floating photovoltaic systems (FPVs), this paper explores the use of bifacial photovoltaic modules installed in the vertical position. The energy harvested from the rear face of vertically configured bifacial PV modules compensates for the reduced production at the front face of the module, and this demonstrates the potential of bifacial technology for offshore applications. By comparison, most existing horizontally tilted bifacial FPV systems gain only a small benefit in production from the rear face of the module due to the minimum radiation received, and what also must be taken into consideration is the negative effect of significant soiling owing to the low tilt angle of the PV modules. Hence, to overcome these drawbacks, we have developed the innovative "PVSail" concept, which explores the deployment of vertical FPV systems on floats, buoys, or poles/minipiles. Floating vertical bifacial PV systems (VBPVs) have huge potential to harness all the energy generation capabilities enhance by reflected light, especially from snow‐covered surfaces in northern regions. Our analysis considers a patented mooring and vertical PV system that allows the VBPV structure to align with the prevailing wind direction to shed wind loads, and our numerical analysis explores the potential of VBPV applied to Catania in Italy and Nigg Bay in the United Kingdom. Our analysis study has revealed that across an azimuth angle range (0°–180°), vertical bifacial modules experience roughly a 9% decrease in energy yield at Catania and about a 5% energy yield gain in higher latitude regions like Nigg Bay. Additionally, increasing the latitude of the installation location of VBPV reduces the energy yield sensitivity to the orientation, that is, azimuth angle. The PVSail concept opens the door to novel deployment possibilities in offshore renewable energy projects. [ABSTRACT FROM AUTHOR]

The recent advancements in the solar photovoltaic technology is bifacial panels. These panels are capable of producing higher energy than their conventional panels by capturing from both front and rear sides. By harvesting solar energy from both the front and rare surfaces of the panels, the load on the inverters can increase. This affects its reliability performance. Nevertheless, inverter is reported as the critical component in the photovoltaic (PV) system. Hence this work presents reliability-oriented performance evaluation of PV inverter with bifacial panels is proposed. A 3-kilowatt photovoltaic system has been considered with yearly mission profile data at Hyderabad, India. This evaluation is carried out under various albedos. Finally, a comparison between monofacial and bifacial PV panel are presented. The results show that the albedo significantly impacts the lifetime of a PV inverter and therefore, the albedo should be considered when designing a bifacial panel's inverter. [ABSTRACT FROM AUTHOR]

The stricter requirements for the energy performance of buildings are creating a market for several building‐integrated photovoltaic (BIPV) technologies, including photovoltaic (PV) windows. Herein, an innovative multifunctional PV window concept designed to enhance energy generation while providing overheating protection for better indoor thermal and visual comfort is presented. This concept utilizes bifacial c‐Si solar cell strips combined with venetian blinds, all embedded in a unique insulating glazing unit. The bifacial technology increases the energy yield by using the blinds as reflectors, directing more irradiance to the cells' rear side. The goal of this study is to analyze the outdoor performance of this concept under real operating conditions. Twelve demonstrators are installed and monitored. Various measurement campaigns are conducted, examining the impact of different blind types, tilt angles, sun positions and sky conditions. The highest energy boosts occur when the blinds are fully closed at a 75° angle with their convex side facing outward. Blinds with the highest specular reflectance achieve a maximum performance increase of 25% on sunny days and a daily average increase of 12% compared to the case of no blinds. [ABSTRACT FROM AUTHOR]

In this paper, the concept of a collector-reflector system consisting of a bifacial solar collector and a single flat-plate reflector separated and placed in parallel below the collector but moveable only in the direction normal to the collector plane is investigated. The developed mathematical model was used to optimize the size and position of the planar back reflector. The optimal hourly, daily, monthly and annual distances between the collector and reflector were determined. In addition, the daily, monthly and annual energy performance of the optimized bifacial collector-reflector system was estimated and compared with that of the corresponding monofacial solar collector. Based on the obtained results, two ways of use of the reflector are recommended, either according to the optimal hourly (moveable reflector) or optimal annual (fixed reflector) reflector positions. With optimally positioned moveable or fixed reflector the total solar radiation incident on the bifacial solar collector can be significantly higher than that for a monofacial solar collector. Its largest daily and monthly as well as average annual increase is: 74% (59%), 65.91% (46.21%), and 54% (39.4%), respectively. The proposed model can be applied to evaluate the energy performance of flat-plate bifacial thermal, photovoltaic or photovoltaic-thermal solar collector, of arbitrary size and position, which is in this arrangement with a planar reflector. [ABSTRACT FROM AUTHOR]

Bifacial solar technology has experienced exponential growth in recent years and its trend is increasing for the coming years. Considering the advantages that it offers over monofacial technology such as its current price equivalence, the increase in performance thanks to the production of the rear face and the consecutive reduction of the LCOE, it is logical that more and more photovoltaic plants with this technology are been installed. Nowadays, there are some regulatory gaps regarding bifacial technology and, due to this growing trend, it is necessary to study, research and implement the optimal way to evaluate these systems. This article has experimented with a 3.3 kW bifacial photovoltaic system, divided into two strings with different configurations, whose monitoring system has all the instrumentation included in the IEC 61,724 standard, with the addition that it has several rear irradiance sensors arranged in different locations of the system to evaluate the variability of this parameter. After an experimental campaign of 9 months, a power estimation analysis and the calculation of the PR and PR25°C have been carried out using the different rear irradiance sensors. The variability of this parameter depending on the location of the sensor has affected the results in such a way that the RMSE committed in the power estimation has varied between 10.22% and 2.63%, while the PR and PR25°C of the system has oscillated between 0.84 for the most unfavorable case and 0.95 in the most favorable case. Assumed the great variability between performance ratios, it is necessary to establish a specific normative standard for the evaluation of Bifacial PV systems. [ABSTRACT FROM AUTHOR]

The output energy produced by the photovoltaic system strongly depends upon the amount of solar radiation harvested by the photovoltaic panels. Varying the tilt of photovoltaic panels at the optimal angle and/or cleaning the photovoltaic panels at regular intervals are some of the techniques that could enhance the photovoltaic system performance albeit at the cost of increased labor and water budget. Here, we explore a farm-level study to investigate the effect of different tilt angle adjustment schedules on the performance of conventional north/south ( N / S ) tilted monofacial photovoltaic farms. We further compare the performance of optimally tilted N / S photovoltaic farms with that of east/west (E / W) faced vertical bifacial photovoltaic farms for various dry periods for Lahore, Pakistan. We show that for a dry period of one month, the performance of N / S tilted farm is decreased by ∼ 40 kWh/m2 as compared to that for E / W farm that exhibits a performance degradation of ∼ 3 kWh/m2. Further, N / S farm performs better than E / W vertical farm if the cleaning is performed on (or before) fortnightly basis. Further, if cleaning is delayed for one month, then E / W vertical farm performs better than N / S tilted farm. The results presented in this work are beneficial for the development of E / W faced vertical bifacial farm in dusty climates and regions with scarce water supply. [ABSTRACT FROM AUTHOR]

Bifacial PV modules are increasingly used in commercial solar PV projects. With the use of the solar energy available at the module’s rear surface, the correct estimation of the albedo during the pre-construction phase of commercial projects becomes more important. The intention of the study is to determine the impact of the duration of a short-term albedo measurement campaign to reduce the uncertainty with respect to satellite albedo, thus providing a ‘beneficial campaign’. Albedo measurements from seven sites in the USA have been used to estimate the impact of 1-day and 7-day measurements (short-term measurements) on the simulated annual electrical energy production. Simulations based on monthly albedo data obtained from a recognised satellite provider have been compared with simulations where the albedo has been corrected based on short-term measurements. The study found that a 1-day campaign is often not beneficial, causing an increase in uncertainty with respect to satellite albedo. Measurement campaigns in winter do not generally reduce the error of the annual electrical energy production simulation, however, a 7-day campaign undertaken in summer appears to often reduce the uncertainty. It should be noted that the climate conditions, ground vegetation and measurement setup of the analysed seven sites in the USA may not be representative for other sites in the rest of the world.

Perovskite solar cells have become promising candidates for thin‐film photovoltaics (PV), but many record cells suffer from losses in current (≈3–4 mA cm−2). This is due to the choice of superstrate configurations (i.e., glass‐side illumination) and thin absorber layers, typically on the order of ≈500 nm. Illumination through a top transparent conductive oxide electrode (substrate configuration) using LiF and Al2Ox as anti‐reflective coatings leads to reflectance losses below 1% is demonstrated. When combined with 1 µm thick absorber layers, substrate configurated bifacial devices have power conversion efficiencies >20%, with minimized reflection losses approaching 98% of their detailed‐balance limits and higher Jsc than their monofacial counterparts. Further analysis is conducted to show there is still a significant fraction of current lost due to poor charge‐carrier extraction (e.g., resistive or low mobility contacts). This is studied by a direct comparison of photoluminescence at short‐circuit versus open‐circuit estimating a 4.5% loss in charge‐carrier collection. [ABSTRACT FROM AUTHOR]

The evolving landscape of Floating Photovoltaic (FPV) systems is marked by ongoing advancements, particularly in the refinement of floating structures and the arrangement of photovoltaic modules. Furthermore, the increasing adoption of bifacial PV modules, attributed to their capacity for heightened production densities, underscores a notable trend within the field. Concurrently, the development of specialized software tools capable of simulating bifacial floating PV systems (BFPV) is progressively unfolding. This paper seeks to contribute to the field by conducting a comprehensive assessment of the experimental and numerical energy performance of a bifacial East-West Floating PV system (EW-BFPV) leveraging bifacial modules. The evaluation entails meticulous environmental and system measurements executed over a ten-month duration at the “Enel Innovation Lab” in Catania, Italy. Moreover, the study endeavors to validate numerical results generated by two specialized photovoltaic software tools, namely PVsyst and SAM, in which models of the EW-BFPV system have been implemented. Central to this validation is the examination of the Energy Performance Index (EPI) and the Baseline Energy Performance Index (BEPI). This assessment integrates both observed performances based on measured meteorological data and predicted performance to ensure a comprehensive evaluation. Significantly, the research includes specific analyses aimed at assessing the influence of varying irradiance inputs on the calculation of PV module temperatures within the simulation tools. Despite inherent disparities in modeling approaches between the software tools, our findings suggest that harmonizing loss percentages can yield comparable outcomes. This observation underscores the robustness of the proposed methodology and its potential for facilitating accurate assessments of FPV system performance, thus contributing to the advancement of this burgeoning technology.

We present a radiative cooling material capable of enhancing albedo while reducing ground surface temperatures beneath fielded bifacial solar panels. Electrospinning a layer of polyacrylonitrile nanofibers, or nanoPAN, onto a polymer-coated silver mirror yields a total solar reflectance of 99 %, an albedo of 0.96, and a thermal emittance of 0.80. The combination of high albedo and high emittance is enabled by wavelength-selective scattering induced by the hierarchical morphology of nanoPAN, which includes both thin fibers and bead-like structures. During outdoor testing, the material outperforms the radiative cooling power of a state-of-the-art control by ∼20 W/m2 and boosts the photocurrent produced by a commercial silicon cell by up to 6.4 mA/cm2 compared to sand. These experiments validate essential characteristics of a high-albedo radiative-cooling reflector with promising potential applications in thermal and light management of fielded bifacial panels.

This study investigates the performance of agrivoltaic systems employing bifacial photovoltaic modules. A comparison between yield in Sweden and Italy was carried out. Three agrivoltaic system designs were evaluated: vertical fixed, single-axis tracker, and dual-axis tracker. The results showed that the specific production varied between 1090 to 1440 kWh/kWp/yr in Sweden and 1584 to 2112 kWh/kWp/yr in Italy, where the lowest production was obtained with the vertical fixed agrivoltaic system while the highest production was obtained with the dual-axis tracking agrivoltaic system. The vertical fixed design had a higher electricity production during low solar elevation angles, while the single-axis and dual-axis tracking designs had significantly higher power production during mid-day. The electricity production gain using a dual-axis tracker design was mostly during mid-day, but the increase compared to the single-axis tracker was only 1-2%. The study concludes that low-height, fixed agrivoltaic systems without tracking are well-suited for high-latitude countries like Sweden, while elevated systems with tracker solutions are more suitable for locations like Italy. The findings suggest that the performance of agrivoltaic systems with bifacial photovoltaic modules is highly dependent on geographical location and the specific characteristics of the crops grown beneath them.

We present a radiative cooling material capable of enhancing albedo while reducing ground surface temperatures beneath fielded bifacial solar panels. Electrospinning a layer of polyacrylonitrile nanofibers, or nanoPAN, onto a polymer-coated silver mirror yields a total solar reflectance of 99 %, an albedo of 0.96, and a thermal emittance of 0.80. The combination of high albedo and high emittance is enabled by wavelength-selective scattering induced by the hierarchical morphology of nanoPAN, which includes both thin fibers and bead-like structures. During outdoor testing, the material outperforms the radiative cooling power of a state-of-the-art control by ∼20 W/m2 and boosts the photocurrent produced by a commercial silicon cell by up to 6.4 mA/cm2 compared to sand. These experiments validate essential characteristics of a high-albedo radiative-cooling reflector with promising potential applications in thermal and light management of fielded bifacial panels. [ABSTRACT FROM AUTHOR]

Compared with monofacial solar cells, the development of bifacial solar cells has garnered considerable attention for achieving higher power output by simultaneously harvesting direct and diffused light while incurring fewer additional manufacturing costs. Perovskite light absorbers, given their outstanding optoelectronic properties, present great opportunities for fabricating bifacial solar cells. However, one of the challenges in designing bifacial perovskite solar cells (PSCs) is that they suffer from optical and electrical losses due to insufficient light absorption in the perovskite layer. In this respect, in this work, a hot‐pressing transfer process is developed to fabricate a diffraction‐grating (DG) perovskite layer to form a bifacial PSC. The constructed DG structure on the perovskite layer improved its light‐harvesting efficiency, reduced its charge recombination, and enhanced its charge extraction properties. The bifacial DG PSC achieved power conversion efficiencies of 14.01% and 10.04% for the bottom and top illuminations, respectively, resulting in a bifaciality factor of 0.71. Therefore, the newly developed hot‐pressing transfer process for fabricating DG structures on perovskite layers is a promising technique for fabricating high‐efficiency bifacial PSCs with high bifaciality factors. [ABSTRACT FROM AUTHOR]

Photovoltaics (PV) is a cost-competitive and scalable technology for electricity generation that plays a crucial role to accelerate the European energy transition and achieve carbon neutrality. Large-scale installation of rooftop PV, as well as innovative PV applications such as floating PV coupled with hydropower and bifacial PV along roads and railways, offer multi-benefits, not least in reducing competition for land. In this study, we present a geospatial approach to assess the pan-European technical potential of these three applications, using publicly available datasets. The findings reveal that the PV total installed capacity could exceed 1 TWp, which is far larger than the total PV capacity for 2030 in the EU Solar Energy Strategy (720 GWp) and would be a significant contribution to the several TWs needed for the overall transition to net-zero by 2050. The evidence presented is a useful starting point for policy-setting at national and regional level, as well as for research and detailed analyses of location specific solutions. [ABSTRACT FROM AUTHOR]

Photovoltaics (PV) is a cost-competitive and scalable technology for electricity generation that plays a crucial role to accelerate the European energy transition and achieve carbon neutrality. Large-scale installation of rooftop PV, as well as innovative PV applications such as floating PV coupled with hydropower and bifacial PV along roads and railways, offer multi-benefits, not least in reducing competition for land. In this study, we present a geospatial approach to assess the pan-European technical potential of these three applications, using publicly available datasets. The findings reveal that the PV total installed capacity could exceed 1 TWp, which is far larger than the total PV capacity for 2030 in the EU Solar Energy Strategy (720 GWp) and would be a significant contribution to the several TWs needed for the overall transition to net-zero by 2050. The evidence presented is a useful starting point for policy-setting at national and regional level, as well as for research and detailed analyses of location specific solutions. [ABSTRACT FROM AUTHOR]

Abstract Compared with monofacial solar cells, the development of bifacial solar cells has garnered considerable attention for achieving higher power output by simultaneously harvesting direct and diffused light while incurring fewer additional manufacturing costs. Perovskite light absorbers, given their outstanding optoelectronic properties, present great opportunities for fabricating bifacial solar cells. However, one of the challenges in designing bifacial perovskite solar cells (PSCs) is that they suffer from optical and electrical losses due to insufficient light absorption in the perovskite layer. In this respect, in this work, a hot‐pressing transfer process is developed to fabricate a diffraction‐grating (DG) perovskite layer to form a bifacial PSC. The constructed DG structure on the perovskite layer improved its light‐harvesting efficiency, reduced its charge recombination, and enhanced its charge extraction properties. The bifacial DG PSC achieved power conversion efficiencies of 14.01% and 10.04% for the bottom and top illuminations, respectively, resulting in a bifaciality factor of 0.71. Therefore, the newly developed hot‐pressing transfer process for fabricating DG structures on perovskite layers is a promising technique for fabricating high‐efficiency bifacial PSCs with high bifaciality factors.

Bifacial solar cells are gaining popularity due to their compactness, space‐saving property, and higher photoconversion efficiency (PCE) than mono‐facial solar cells. Bifacial dye‐sensitized solar cells (BF‐DSSCs) are fabricated and characterized utilizing D‐205 as a dye sensitizer in combination with I−/I3− and Co2+/Co3+ redox electrolytes. BF‐DSSCs using iodine‐based electrolytes demonstrate a cumulative PCE and bifaciality factor (BFF) of 13.05% and 85%, respectively. The hampered PCE under backside light illumination is attributed to the absorption of photons by the electrolyte itself. Contrary to this, BF‐DSSCs fabricated using cobalt‐complex‐based redox electrolyte exhibits an exceptionally high BFF of nearly 100% with a PCE of 4.77% and 4.75% under the front‐ and rear‐light illumination, respectively. Although the open‐circuit voltage of the BF‐DSSCs fabricated using cobalt electrolyte (with deeper redox potential) is slightly higher than that of BF‐DSSCs fabricated using iodine electrolyte, their cumulative PCE (9.52%) is much lower than that of iodine‐based device counterparts (13.05%). This decrease in PCE is attributed to the relatively fast charge recombination in the cobalt‐electrolyte‐based BF‐DSSCs. [ABSTRACT FROM AUTHOR]

Bifacial photovoltaics (BPVs) are a promising alternative to conventional monofacial photovoltaics given their ability to exploit solar irradiance from both the front and rear sides of the panel, allowing for a higher amount of energy production per unit area. The BPV industry is still emerging, and there is much work to be done until it is a fully mature technology. There are a limited number of reviews of the BPV technology, and the reviews focus on different aspects of BPV. This review comprises an extensive in-depth look at BPV applications throughout all the current major applications, identifying studies conducted for each of the applications, and their outcomes, focusing on optimization for BPV systems under different applications, comparing levelized cost of electricity, integrating the use of BPV with existing systems such as green roofs, information on irradiance and electrical modeling, as well as providing future scope for research to improve the technology and help the industry. [ABSTRACT FROM AUTHOR]

In view of the increasing interest and market share of bifacial cells and modules, suitable substrates such as glass and transparent backsheets along with ethylene vinyl acetate (EVA) and polyolefin elastomer (POE) encapsulants were examined in combined‐accelerated stress testing (C‐AST) to evaluate and compare degradation modes. Testing with both monofacial and bifacial cells, we found that glass–glass modules with monofacial cells led to greater grid finger breakage than those with polymeric backsheets. This is attributed to previous X‐ray topography and modeling work showing higher stress in cells and interconnections in glass–glass modules than glass backsheet modules. Consistent with the objectives of C‐AST, which stresses modules at levels corresponding to the limits seen in the natural environment, we observed the UV‐fluorescence signatures of modules tested in C‐AST (considering the degradation associated with developing chromophores, moisture penetration, and photobleaching effects) to be like those in fielded modules, more so than other chamber stress testing implemented for comparison. We found light‐induced degradation (LID) in module types with regenerated (inactive) cells with C‐AST, suggesting the possibility of LID destabilization in some field conditions. We could also distinguish potential‐induced degradation (PID) on the back of the bifacial passivated emitter and rear cells (PERC) in C‐AST. Confirming with ex situ tests, we found polarization‐type PID most prevalent in glass‐glass modules with EVA as would be anticipated considering the greater leakage current through such module encapsulation. Unlike PID tests performed in the dark, which can lead to false positive PID test results, field‐representative illumination is experienced by the modules on the front and back sides while −1200 V system voltage is applied in C‐AST, supporting the conclusion that this module type with glass‐glass construction would be susceptible to PID in the field. [ABSTRACT FROM AUTHOR]

[Display omitted] Perovskite solar cells (PSCs) have achieved remarkable progress in the past decade and become the most powerful challenger of traditional silicon photovoltaics. Among the many designs, bifacial PSCs have received widespread attention these days due to their ability to fully utilize environmental reflection and scattering light to enhance energy yield. They also can provide better aesthetic design for building-integrated photovoltaics (BIPVs). However, the potential of bifacial PSCs is not limited to these traditional applications. Importantly, such architecture also serves as a universal component for multi-junction cells and photon engineering, which are both critical for further efficiency improvement. In this review, the requirements of different functional layers under various applications are described in detail, starting from the structure of bifacial PSCs. The application developments are introduced, including albedo utilization, semitransparent PSCs (ST-PSCs), TSCs. The present issues (such as stability, large area, recombination of carriers at the back electrode and toxicity etc.) and the extra challenges of bifacial PSCs are highlighted. It is hoped that this review can provide new ideas for the future development and further improve the competitiveness of PSCs. [ABSTRACT FROM AUTHOR]

Throughout this article, we explore several generations of photovoltaic cells (PV cells) including the most recent research advancements, including an introduction to the bifacial photovoltaic cell along with some of the aspects affecting its efficiency. This article focuses on the advancements and successes in terms of the efficiencies attained in many generations of photovoltaic cell and discusses the challenges of each generation. Monocrystalline silicon dominates the solar cell market, and other technologies are still being developed in order to commercialize them. As an illustration, recent solar cell technology, known as the fourth generation and containing graphene, has been discussed. To determine if the damaged solar panel pieces would function or not, a test was conducted, it showed that even after being cut into small pieces, the open circuit voltage had not changed. The bifacial photovoltaic technology has been briefly reviewed in the review, including the substrates used, cell texturing, antireflection coating, cell reflectors, etc. Bifacial photovoltaic (PV) performance will continue to profit from studies on higher conversion efficiencies linked to monofacial PV cells. It is important to do studies within the area of bifacial PV modules in order to boost their performance, efficiency, and market value globally. [ABSTRACT FROM AUTHOR]

Key message: We examined leaves of a suite of microphyllous woody plants and describe a little-known form of leaf peltation for the first time and also investigate strongly reflexed leaves in two distantly related lineages. Plants cope with a range of environmental conditions, especially related to water relations, and have developed an array of physiological and structural solutions to maintain a functional water balance. There has been considerable recent work on physiological solutions to water deficit but little attention paid to leaf characteristics. In many species there is a change in leaf form from seedlings to adults. We examine such changes in several small-leaved species from the distantly related Asteraceae and Myrtaceae, some of which develop micropeltate or reflexed leaves as adults. All are native to dry or seasonally dry sites. Three major morphological groups were recognised as follows: (1) leaves erect, nonpeltate and scale-like (Ozothamnus hookeri), (2) leaves erect and peltate (Phaenocoma prolifera, Regelia inops), (3) Leaves reflexed (Olearia lepidophylla, Ozothamnus scutellifolius, Ozothamnus reflexifolius, Melaleuca diosmifolia). The microphyllous peltation in P. prolifera and R. inops in the absence of a meristematic fusion/bridge differs from typically peltate leaves. These small-leaved taxa occur in open, high light environments which are very different from the mesic, shaded understorey habitats of typical peltate-leaved plants. Many small-leaved species have leaves closely appressed to the stem and often with recurved margins. The erect leaves are functionally similar to reflexed leaves. Environmental filtering leads to superficially similar plant forms that may have somewhat different ontological origins. Such morphological forms are examples of convergent evolution in distantly related species but within each family are likely phylogenetically related. [ABSTRACT FROM AUTHOR]

[Display omitted] • Optimal PV system row spacing presented considering land-use and latitudes 15–75°N. • Latitude-based formulae given for optimum tracked, fixed-tilt, and vertical spacing. • Optimum tilt of fixed-tilt arrays can vary from 7° above to 60° below latitude-tilt. • Similar row spacing should be used for tracked and fixed-tilt PV arrays >55°N. • Bifacial arrays need up to 0.03 lower GCR than monofacial, depending on bifaciality. General guidelines for determining the layout of photovoltaic (PV) arrays were historically developed for monofacial fixed-tilt systems at low-to-moderate latitudes. As the PV market progresses toward bifacial technologies, tracked systems, higher latitudes, and land-constrained areas, updated flexible and representational guidelines are required. Using our 3D view-factor PV system model, DUET, we provide formulae for ground coverage ratios (GCRs –i.e., the ratio between PV collector length and row pitch) providing 5%, 10%, and 15% shading loss as a function of mounting type and module type (bifacial vs monofacial) between 17-75°N. Fixed-tilt arrays span a wide range of GCR (0.15–0.68, 5% loss) compared to single-axis tracked arrays (0.17–0.32) and vertical east–west arrays (0.11–0.16). We additionally optimize fixed-tilt module tilt, finding that the optimum tilt can vary from 7° above latitude-tilt to 60° below latitude-tilt in certain cases. We demonstrate that tracked and fixed-tilt PV arrays should have similar GCRs >55°N, but tracked systems are more sensitive to row-to-row shading losses <55°N. The GCR of fixed-tilt arrays at lower latitudes can reach 0.55 without introducing >2.5% shading loss, whereas tracked and vertical arrays reach 2.5% shading loss by GCRs <0.22 and <0.10, respectively. We additionally find that bifacial PV arrays require GCRs up to 0.03 lower than monofacial GCRs. These results can inform future deployment designs for latitudes >15°N. [ABSTRACT FROM AUTHOR]

We present our own Interdigitated Back Contact (IBC) technology, which was developed at ISC Konstanz and implemented in mass production with and at SPIC Solar in Xining, China, with production efficiencies of over 24%. To our knowledge, this is the highest efficiency achieved in the mass production of crystalline silicon solar cells without the use of charge-carrier-selective contacts. With an adapted screen-printing sequence, it is possible to achieve open-circuit voltages of over 700 mV. Advanced module technology has been developed for the IBC interconnection, which is ultimately simpler than for conventional double-sided contacted solar cells. In the next step, we will realize low-cost charge-carrier-selective contacts for both polarities in a simple sequence using processes developed and patented at ISC Konstanz. With the industrialisation of this process, it will be possible to achieve efficiencies well above 25% at low cost. We will show that with the replacement of silver screen-printed contacts by copper or aluminium metallisation, future IBC technology will be the end product for the PV market, as it is the best performing c-Si technology, leading to the lowest cost of electricity, even in utility-scale applications.

The considerable growth of the renewables’ shares in the energy market paves the way towards United Nations Sustainable Development Goal 7. Solar photovoltaics (PV) are more economically viable amongst other renewables because of their lower, easier installation and reliability. However, the PV, like other renewables, is more vulnerable to climatic conditions. Currently, the monofacial leads the PV market; however, it is expected that the bifacial PV will be dominant as it offers more energy yield at a lower cost. It is thus crucial to analyze the PV performance concerning climatic conditions. The merits of this study include: (i) the performance of bifacial PV for the climate change scenarios is analyzed, which is lacking in the literature; (ii) detailed monofacial and bifacial PV mathematical models are developed to estimate the PV output; and (iii) the comparison is made between monofacial and bifacial PVs performance and their dependence on climatic conditions. The climate model is used to predict the ambient conditions for the years 2050 and 2080. The average hourly responses of solar irradiance and energy yield are presented and analyzed.

We present our own Interdigitated Back Contact (IBC) technology, which was developed at ISC Konstanz and implemented in mass production with and at SPIC Solar in Xining, China, with production efficiencies of over 24%. To our knowledge, this is the highest efficiency achieved in the mass production of crystalline silicon solar cells without the use of charge-carrier-selective contacts. With an adapted screen-printing sequence, it is possible to achieve open-circuit voltages of over 700 mV. Advanced module technology has been developed for the IBC interconnection, which is ultimately simpler than for conventional double-sided contacted solar cells. In the next step, we will realize low-cost charge-carrier-selective contacts for both polarities in a simple sequence using processes developed and patented at ISC Konstanz. With the industrialisation of this process, it will be possible to achieve efficiencies well above 25% at low cost. We will show that with the replacement of silver screen-printed contacts by copper or aluminium metallisation, future IBC technology will be the end product for the PV market, as it is the best performing c-Si technology, leading to the lowest cost of electricity, even in utility-scale applications. [ABSTRACT FROM AUTHOR]

Numerous aspects of performance assessment of bifacial PV have been undertaken over the years, however, an area where knowledge lacks, is concerning the negative impact of soiling on individual side of a bifacial module. An in-depth study has been presented where the soiling losses and rates for individual sides of a bifacial module have been quantified through experiments. A soiling rate of 0.328 %/day was observed for bifacial module, while the rear side soiling rate was measured to be equal to 0.031 %/day, which was significantly lower than the front of the module. The impact of wind speed and relative humidity was investigated on the soiling losses for the module, along with a detailed assessment of effect of wind direction on the soiling on individual sides of the module. A common metric to analyse bifacial modules against monofacial is bifacial gain which was observed to be greater for soiled module (13.98 %) compared to clean module (12.92 %) due to significant variation in available irradiance to the front side of the module. Finally, a comparative assessment of the impact of orientation on the soiling losses was conducted and the results showed that significantly lower soiling losses (∼2 %) and soiling rate (bifacial∼0.063 %/day and bifacial rear∼0.047 %/day) was observed for a vertically installed bifacial module. The results are significant as they direct towards the applicability of bifacial modules in regions with prevailing dust and will assist in deciding which type of mitigation strategies can be explored for individual sides of a bifacial module. • A soiling rate of 0.328 %/day was observed for bifacial module. • The rear side soiling rate was measured to be equal to 0.031 %/day. • Bifacial gain which for soiled module (13.98 %) compared to clean module (12.92 %). • Vertical installation of bifacial module resulted in lower soiling losses (∼2 %). • Wind direction plays a crucial role in determining soiling rate of individual side. [ABSTRACT FROM AUTHOR]

An overview of the Passivated Emitter and Rear Totally Diffused (PERT) solar cell is presented, which is a member of Passivated Emitter and Rear Contact (PERC) family. Due to its outstanding properties, n-type PERT is considered as a promising candidate in photovoltaics (PV). In recent years, research efforts have been devoted towards industrialization of PERT mostly based on n-type substrates to benefit from its inherent advantages. In particular, the IMEC's n-PERT developed with Jolywood, a 23.2% certified efficiency of the front side has been achieved which is almost the highest efficiency for industrial n-PERT. Currently research is focused on bifacial n-type PERT cells that are already manufactured industrially and are now in mass-produced in industry. This review is focused on the experimental approach towards monofacial PERT cells with a historical overview, PERT's structure, passivation scheme, contacts formation, light trapping and antireflection coating scheme and their corresponding process steps and approaches. [ABSTRACT FROM AUTHOR]

For the transition to sustainable energies to happen in a relatively safe manner, there has to be as many improvements to actual capabilities that allows us to convert solar and wind energy into electric energy. For this reason, in this paper, we present a potential solution to rise the efficiency of solar irradiation conversion by using a cheap, highly reflective membrane under the already installed solar arrays. This solution can be used in order to maximize the radiation that falls on the photovoltaic cell, especially under the panel, by using bifacial photovoltaic panels. [ABSTRACT FROM AUTHOR]

Bifacial perovskite solar cells (PSCs) have accentuated a great deal of attention to achieve a higher power output per unit area by utilizing albedo compared to conventional monofacial solar cells with a very low additional manufacturing cost. However, the design of the bifacial PSCs is very much challenging due to high rear side carrier recombination, ion migration, and electrode corrosion as well as electrical loss in transparent rear contact. In this paper, we have reviewed bifacial PSCs to explore and analyze their latest advancement. The bifacial device's performance varies with respect to the albedo from where the diffuse light gets reflected to the rear side which has also been discussed thoroughly. For the best performance of bifacial solar cells, the back contact electrode, transport layer, and perovskite layer of the device need to be transparent, for which various ways to make components semi-transparent have been discussed and explored. The transparent charge carrier layer helps in reducing the parasitic recombination, which directly affects the bifacial photoconversion efficiency. This extensive review of bifacial PSCs is presented here which will guide perovskite research for feasible commercial realization. [ABSTRACT FROM AUTHOR]

Brazil's cumulative photovoltaic (PV) installations have now surpassed 32 GWp. The fastest growing and most prevalent PV technology is the bifacial photovoltaic module, which is now being incorporated in more than 2/3 of new power plants. These modules collect solar radiation on both front and rear sides, providing gains in electricity production compared to traditional monofacial modules. The market acceptance and quality control of this technology requires standard methods to accurately determine the nominal power of the bifacial modules. But the specification of energy production from the bifacial backside is complicated due to critical factors that include the albedo, the separation, height, and positioning of the modules, the shading of the rear surface, and the specific geographic and climate conditions. This paper addresses these issues in determining the performance of bifacial PV modules in the tropical conditions of the State of Minas Gerais, Brazil. Specifically, the bifacial gain for modules and systems is evaluated, assessing the effects of albedo, site maintenance, climate/environmental conditions, thermal behavior, and back-surface shading. The special cases of tracking versus non-tracking systems are evaluated showing specific attention needs to the albedo changes and rear module shading constraints. These studies are performed on real power plants having different operating conditions (e.g., tracking, non-tracking, ground cover). The methodology includes I-V characterization of modules and string and thermal imaging/mapping under existing climate and meteorological conditions. Correlations with experimental albedo conditions is a special concern with these studies. These results are further compared to controlled laboratory measurements to establish information needed to better evaluate the developing standard for actual local operating conditions. This case study provides evaluation of the quality of the both the bifacial PV products being used and their installations in the rapidly emerging Brazil PV markets. [ABSTRACT FROM AUTHOR]

Degradation from ultraviolet (UV) radiation has become prevalent in the front of solar cells due to the introduction of UV‐transmitting encapsulants in photovoltaic (PV) module construction. Here, we examine UV‐induced degradation (UVID) in various commercial, unencapsulated crystalline silicon cell technologies, including bifacial silicon heterojunction (HJ), interdigitated back contact (IBC), passivated emitter and rear contact (PERC), and passivated emitter rear totally diffused (PERT) solar cells. We performed UV exposure tests using UVA‐340 fluorescent lamps at 1.24 W·m−2 (at 340 nm) and 45°C through 4.02 MJ·m−2 (2000 h). Our results showed that modern cell architectures are more vulnerable to UVID, leading to a significant power decrease (−3.6% on average; −11.8% maximum) compared with the conventional aluminum back surface field (Al‐BSF) cells (<−1% on average). The power degradation is largely caused by the decrease in short‐circuit current and open‐circuit voltage. A greater power decrease is observed in bifacial cells with rear‐side exposure compared with those with front‐side exposure, indicating that the rear side is more susceptible to UV damage. Secondary ion mass spectroscopy (SIMS) confirmed an increase in hydrogen concentration near the Si/passivation interface in HJ and IBC cells after UV exposure; the excess of hydrogen could result in hydrogen‐induced degradation and subsequently cause higher recombination losses. Additionally, surface oxidation and hot‐carrier damage were identified in PERT cells. Using a spectral‐based analysis, we obtained an acceleration factor of 5× between unpackaged cells (containing a silicon nitride antireflective coating on the front) in the UV test and an encapsulated module (with the front glass and encapsulant blocking 90% of the UV at 294 nm and 353 nm, respectively) in outdoor conditions. From the analytical calculations, we show that a UV‐blocking encapsulant can reduce UV transmission in the module by an additional factor of ~50. [ABSTRACT FROM AUTHOR]

The bifacial photovoltaics (PV) technology promises several advantages over monofacials, including improved energy yield, lower operating temperature, and easier integration with agrophotovoltaics. There have been various experimental or computational studies comparing bifacials to monofacials; however, a theory-experiment combined analysis for accurate worldwide extrapolation is missing. Literature review reveals that many reported experiments study standalone systems that overrepresent the yield performance obtainable in farms. Moreover, most reported experimental studies are for configurations that are not necessarily designed close to the optimum. In this work, we experimentally study and analyze the fixed-tilted bifacial farm configiurations, namely south-facing monofacial, south-facing tilted bifacial (TBF), and ground-sculpted vertical bifacial (VBF) arrays, at Dhaka, Bangladesh (23.7 °N, 90.4 °E). The optimal TBF configuration, for 0.5 albedo, yields 21.3% and 73.3% more than the optimal monofacial and the optimal VBF configurations, respectively. Through a combination of experimental and numerical analysis, we compare the in-array performance of the configurations under different albedo conditions to analyze the physics and consolidate the predictions. There is a growing interest in PV array configurations beyond the conventionally ground-mounted south-facing TBF, such as agrophotovoltaics, floating-PV, industry-roof PV array, etc. This necessitates a critical analysis of various array configurations for broader PV expansion.

Bifacial technology is attracting the attention of the photovoltaic community. Although considered premature, research and development activities still need to be carried out to improve bPV performance. In addition, the need for a standard test reference will aid bankability and increase confidence in this technology. This article describes the state of the art of bifacial technology, going through the bPV cell and its difference compared to conventional monofacial cells and listing the different sources of limitations, with an identification of different parameters that characterize the performance of the bifacial. Then, the paper reviews the different modeling methods that allow predicting the performance of bPV systems, and ends with the most important applications, whether for dual use of land to produce energy and food (agrivoltaic) or for placing bPV modules on water bodies instead of on the ground (aquavoltaics), or for vertical use as solar fences, acoustic barriers, or building-integrated photovoltaic modules. [ABSTRACT FROM AUTHOR]

Glass/glass (G/G) photovoltaic modules are quickly rising in popularity, but the durability of modern G/G packaging has not yet been established. In this work, we examine the interfacial degradation modes in G/G and glass/transparent backsheet modules under damp heat (DH) with and without system bias voltage, comparing emerging polyolefin elastomer (POE) and industry‐standard poly(ethylene‐co‐vinyl acetate) (EVA) encapsulants. We investigate the transport of ionic species at cell/encapsulant interfaces, demonstrating that POE limits both sodium and silver ion migration compared with EVA. Changes to the chemical structures of the encapsulants at the cell/encapsulant interfaces demonstrate that both POE and EVA are more susceptible to degradation in modules with a transparent backsheet than in the G/G configuration. Adhesion testing reveals that POE and EVA have comparable critical debond energies after the DH exposures regardless of system bias polarity. The results of this study indicate that the interfacial degradation mechanisms of G/G appear to be similar to those of conventional glass/backsheet modules. For emerging materials, our results demonstrate that POE offers advantages over EVA but that transparent backsheets may accelerate encapsulant degradation due to increased moisture ingress when compared with the G/G structure. [ABSTRACT FROM AUTHOR]

• The spectral behaviour of both front and rear sides of bifacial modules is analysed. • A bifacial spectral factor is proposed to assess the combined front and rear impact. • The model considers the impact of module-to-ground clearance and bifaciality. • Spectra of three cities and four grounds are modelled with SMARTS and AERONET data. • The bifacial spectral factor on green grass is up to 1.65% higher than for monofacial. The demand for bifacial photovoltaic modules is continuously increasing. However, some aspects of their behaviour under realistic operating conditions still require more in-depth investigations. Indeed, the long-term analysis of the spectral impact on bifacial modules remains pending. This is particularly true for the rear incident spectrum, which changes depending on the ground type. In this paper, the rear and front long-term spectral impact on bifacial modules is analysed for three locations (Tabernas, Spain; Solar Village, Saudi Arabia; Alta Floresta, Brazil) and four ground types (light soil, white sand, green grass, and concrete slab) at daily, monthly and annual timescales. The SMARTS model is used to generate front and ground-reflected annual spectra. The investigation leads to the definition of a novel metric, called bifacial spectral factor, which quantifies the combined front and rear spectral impact. Results show that the annual bifacial spectral impact differs from the monofacial one due to the influence of the rear spectral irradiance. Green grass is found to have the higher bifacial spectral benefit, leading to yields in between 1.19% and 1.65% higher than in the monofacial case. However, thanks to its high albedo coefficient, white sand is the most convenient ground among the analysed types in terms of bifacial spectral energy gains. The rear spectral factor shows a great range of variation as a function of ground type (between 0.989 and 1.150). However, this is only a non-negiglible second order effect compared to the bifacial spectral factor, which is mainly influenced by the front spectral factor. [ABSTRACT FROM AUTHOR]