The bifacial passivated emitter and rear-side contact cells (PERCs) are capturing a growing photovoltaic market share, with a trend to replace monofacial device. Here, we reported five different rear ...pyramidal light trapping structures prepared by acid etching, with the monofacial counterparts as a comparison. The impact of the rear pyramid angles on the efficiency between under front and rear illumination shows an opposite trend due to a wavelength-dependent optical performance. To accurately optimize devices in real outdoor environments, the photovoltaic performance of mofacial and bifacial PERCs at different incident angles is simulated and integrated with an omnidirectional efficiency. Consequently, a significant improvement in bifaciality under omnidirectional incidence is obtained compared to vertical incidence, and a rough surface structure yields the maximum bifacial gain when the albedo is greater than 30 %. Furthermore, the power yield of monofacial and bifacial devices was predicted for every day in 2022.
•Preparing the industrial bifacial PERCs with different rear structures.•Effect of rear pyramid structure on optical and electrical properties revealed.•Recalculating the efficiency and bificiality based on omnidirectional incidence.•The daily energy yields obtained and compared between Shanghai and Beijing.
Bifacial solar photovoltaics (PV) is a promising mature technology that increases the production of electricity per square meter of PV module through the use of light absorption from the albedo. This ...review describes current state-of-the-art bifacial solar PV technology based on a comprehensive examination of nearly 400 papers published since 1979 (approximately 40% are referenced in this work) focused on illuminating additional research and development opportunities to enhance and assess performance and expand bifacial technology׳s overall contribution within a rapidly expanding global solar market. Research and development efforts on bifacial PV should continue to emphasize improved efficiency in cells, module reliability and deployment configuration of bifacial arrays in a PV plant to co-optimize front-backside energy production during the entire day for fixed and tracking systems. Research on improved conversion efficiencies associated with monofacial PV cells will also continue to benefit bifacial PV performance. Standardization of certification procedures for bifacial PV technology performance efficiency and expansion of niche applications is required to promote wider deployment worldwide.
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•First commercialization of bifacial PV modules for terrestrial applications.•Manufacturing of bifacial PV cells and modules in Spain in late 70′s - early 80′s.•Evolution of bifacial ...PV technology throughout the last 30 years.•59 bifacial PV modules manufactured in 1987 have been recovered and tested.•A 3.79 kWp generator has been made up with these modules and it is in operation.
A pioneer experience with the production and first commercialization of bifacial PV modules was developed by ISOFOTON, a Spanish academic spin-off established in 1981. Bifacial modules based on n-PERT cell technology were produced until 1989. 59 modules from that time were recovered from real installations after about 20 years of outdoor exposure. After cleaning and testing, 56 of these modules were connected to the grid at an IES-UPM terrace in Madrid on the 5th May 2021, constituting a 3.79 kW PV generator (nominal power of the frontal side), which is now in routine operation. The good health of these modules translates into yearly Performance Ratios of 88% (referred to the frontal side irradiation) and 81% (referred to the frontal plus rear irradiation). The comparison of the design and features of old and modern bifacial modules allows the evolution of PV technology throughout the last three decades to be appreciated.
•Bifacial solar PV module generates power through direct front irradiance and also through reflected irradiance (Albedo).•The additional power generated from the rear surface depends on the albedo of ...the reflective surface.•Five different reflective surfaces are used in the experiment namely, aluminum, white paint, cement, sand, and grass.•Comparatively, the aluminum reflective surface is producing more albedo, bifacial gain, and thus the peak power output.
The additional gain in the energy yield of a bifacial solar photovoltaic (PV) module is mainly due to its ability to absorb the ground reflected irradiance (Albedo) through the rear surface of the module. Albedo is the critical characteristic that depends on the surface of the ground, the position of the sun, module clearance, module spacing, tilt angle, etc. The higher the value of albedo, the more is the bifacial gain and so the energy yield. This work investigates the performance of the ELAN series N-type passivated emitter rear totally diffused (PERT) bifacial PV module installed at latitude 9.673° N and longitude 77.964° E under diverse albedo conditions. The ground surface under the module is covered with different reflective materials and the performance parameters like albedo, bifacial gain, and the peak power output are calculated and compared. For aluminum reflective surface, the value of albedo is high and in the range of 0.50–0.57, with an average bifacial gain of 21.4%. The white reflective surface stands next with the value of albedo between 0.37 and 0.42, and an average bifacial gain of 18.9% followed by the reflective surfaces of cement, sand, and grass with an average bifacial gain of 12.8%, 7.8%, and 4.8% respectively. Depending upon the albedo and the bifacial gain, the bifacial solar PV produces the additional power gain. Overall, from the experimental results, it is observed that different reflective materials with different albedos produce different bifacial gain and peak output power depending on the operation conditions.
•Data from a string of bifacial PV modules were monitored for a full year.•A filtering method is described and has been applied.•Models for voltage and current at the maximum power point, originally ...developed for monofacial modules, have been applied.•Modified empirical models for bifacial photovoltaics have been proposed and applied.•The method can be replicated using experimental datasets from other sites.
The bifacial photovoltaic (PV) modules are able to convert the irradiance that hits both the front and the back side of the modules into electrical energy, this allows to increase the output power compared to monofacial modules. However, the mathematical models used for traditional PV modules do not consider the contribution of rear irradiance, even recent works deal with the modeling of the rear irradiance influence on bPV power output. In the present work some empirical models capable of estimating the current and voltage at maximum power point conditions are unveiled; the models consider only the front irradiance, as monofacial PV modules, or the back irradiance through the concept of equivalent irradiance and module temperature. In addition, some modifications to the current and voltage models have been proposed. In all cases, the optimal parameters of the models are obtained starting from a dataset of experimental data acquired from a string of bifacial photovoltaic modules installed in Catania (Italy). The PV plant under study was monitored for an entire year, thus allowing the use of data acquired in different weather conditions.
The method description includes the filtering of the input signals and the searching method of the empirical coefficients in order to estimate the current and voltage at the maximum power point (MPP) for bifacial photovoltaic modules.
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•HOCl reacts with its UV irradiation products Cl• and •OH to generate ClO• at Ru-IrO2.•The Cl• and •OH generated at TiO2 accelerate the generation of ClO•.•TiO2/Ru-IrO2 (UV) system ...exhibited a synergistic effect on NH4+ oxidation.•The system achieved a TN removal rate of 98.4% in the actual wastewater treatment.
Photoelectrocatalysis is effective for the oxidation of ammonium (NH4+) due to the ability to produce oxidizing species such as •OH and Cl•. Compared to •OH and Cl•, ClO• is a more robust species capable of oxidizing NH4+, which can be produced by the combination of •OH and Cl• with free chlorine. However, the conventional photoelectrochemical (PEC) systems generally prefer to produce Cl• for NH4+ oxidation due to the lack of sufficient HOCl. Herein, a UV-driven PEC system consisting of TiO2/Ru-IrO2 bifacial electrode has been constructed for the enhanced ClO• generation for NH4+ oxidation. Large amounts of HOCl can be generated at the Ru-IrO2 interface, which can be further activated by UV irradiation to generate Cl• and •OH, and then rapidly react with HOCl to generate ClO•. The Cl• and •OH generated at the TiO2 interface could also react with HOCl, further accelerating the generation of ClO•. Under UV irradiation, the oxidation rate of TiO2/Ru-IrO2 was 6.7 times than TiO2, 1.5 times than Ru-IrO2, and even 1.24 times than the sum of individual TiO2 and Ru-IrO2. In addition, the bifacial electrode achieved highly efficient NH4+ oxidation for the treatment of actual wastewater, eliminating 81.0 mg L−1 of NH4+ in 120 min with a TN removal rate of 98.4%. The UV-driven PEC system with TiO2/Ru-IrO2 bifacial electrode is a promising potential technology for NH4+ oxidation due to its ability to rapidly produce ClO• and oxidize NH4+ to N2 without the addition of chemical reagents.
This study presents a comprehensive performance assessment of a bifacial photovoltaic (PV) system and real-time validation of a new energy estimation model. The system consists of 18 bifacial PV ...modules installed at a test site with a total capacity of 6.8 kWp. The system’s performance was evaluated based on its energy yield over one year. The energy estimation model was validated in real-time using data collected from the bifacial PV system. The results show that the bifacial PV system achieved an annual energy yield of 1569 kWh/kWp. The energy estimation model was accurate and reliable, with correlation coefficients of 1.04 and 1.40 for the front and rear sides, respectively. This study provides valuable insights into the performance of bifacial PV systems and the development of precise energy estimation models, which can help design and optimize PV systems in different environmental conditions.
•Firstly, the proposed energy estimation model for bifacial PV systems is validated through an experimental setup, which utilizes the solar geometry concept to estimate the rear-side irradiance.•Secondly, the validated model is utilized to analyze and determine the most effective configuration of a bifacial PV system.•Lastly, we introduce a customized bifacial PV structure and evaluate the optimal tilt angle for south-north panels. Furthermore, we employ two different methods to calculate and extensively discuss the albedo of the installation site. By considering these factors, we aim to provide practical insights into the design and installation of bifacial PV systems.
Bifacial solar cells hold the potential to achieve a higher power output per unit area than conventional monofacial devices without significantly increasing manufacturing costs. However, efficient ...bifacial designs are challenging to implement in inorganic thin-film solar cells because of their short carrier lifetimes and high rear surface recombination. The emergence of perovskite photovoltaic (PV) technology creates a golden opportunity to realize efficient bifacial thin-film solar cells, owing to their outstanding optoelectronic properties and unique features of device physics. More importantly, transparent conducting oxide electrodes can prevent electrode corrosion by halide ions, mitigating one major instability issue of the perovskite devices. Here, the theory of bifacial PV devices is summarized and the advantages of bifacial perovskite solar cells, such as high power output, enhanced device durability, and low economic and environmental costs, are reviewed. The limitations and challenges for bifacial perovskite solar cells are also discussed. Lastly, the awareness of bifacial solar cells as a feasible commercialization pathway of perovskite PV for mainstream solar power generation and building-integrated PV is advocated and future research directions are suggested.
•Performance evaluation of bifacial PV systems incorporating dynamic albedo.•Study of the optimal installation angle of bifacial PV systems in the Chinese grid.•Prediction of carbon reduction ...potential for bifacial PV systems on life cycle.•Comparison between optimal fixed tilt and biannual tilt angle adjustment.
Bifacial PV modules, capable of generating electricity from both sides, are highly efficient but vulnerable to environmental factors. This study investigated the photovoltaic performance characteristics and carbon emission reduction potential of bifacial PV systems, considering China's regional power grid independence, environmental diversity, variations in carbon emission factors, and daily fluctuations in albedo. When the installed capacities of bifacial and monofacial PV systems are 253.80 Wp/m2 and 235.00 Wp/m2 respectively, the initial annual electricity generation of the bifacial PV system installed in Beijing is 461.11 kWh/m2, which is only 83.95 % of that in Lhasa, but the corresponding carbon reduction in Beijing exceeds that of Lhasa by 11.13 %, amounting to 407.75 kgCO2. These indicate significant regional disparities in both the electricity generation capacity and carbon reduction potential of PV systems. Furthermore, compared to fixed installations, adjusting the tilt angles twice a year can increase the annual electricity generation of bifacial PV systems by approximately 2.37 %-3.17 % and monofacial PV systems by approximately 2.23 %-3.83 %. The research findings offer valuable insights regarding the impact of regional climate and grid characteristics on bifacial PV systems, thereby providing a reliable reference for optimizing their design and enhancing performance.
