Performance of Bifacial PV Arrays With Fixed Tilt and Horizontal Single-Axis Tracking: Comparison of Simulated and Measured Data

Berrian, Djaber; Libal, Joris; Klenk, M.; Nussbaumer, Hartmut; Kopecek, Radovan

doi:10.1109/jphotov.2019.2924394

Cited by 57 publications

(40 citation statements)

References 13 publications

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“…higher GCR) leads to greater mutual shading by adjacent PV structures, thereby permitting less light to reach the backside of the array [46, 47]. The difference in bifacial gains observed between the systems with differing GCR is consistent with the simulations performed by [7], which showed about a 3% reduction in bifacial gain when GCR is increased from 0.25 to 0.5.…”

Section: Resultssupporting

confidence: 68%

“…The BEG is attributed to light reaching the backside of a PV system, which typically consists of diffuse (scattered) light from the ground, sky, or neighbouring PV rows, but the contributions of direct beam light are possible when the sun is behind a fixed‐tilt system. In utility‐scale PV parks, BEG is typically between 5 and 12%, depending on the configuration and the ground albedo [5–8]. Bifacial PV has potential to reach the lowest levelised cost of energy ( LCOE ) of any commercially available PV technology because such bifacial energy gains are achievable using the same land area that is used for monofacial PV designs while maintaining comparable upfront costs [9, 10].…”

Section: Introductionmentioning

confidence: 99%

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Value of bifacial photovoltaics used with highly reflective ground materials on single‐axis trackers and fixed‐tilt systems: a Danish case study

Riedel

Poulsen

Jakobsen

et al. 2020

IET Renewable Power Generation

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The energy produced by bifacial photovoltaic (PV) arrays can be augmented via albedo enhancements. However, the value of the additional energy must outweigh the costs for such modifications to be economically viable. In this work, the electrical performance and economic value of six 13 kWp crystalline‐silicon (c‐Si) PV arrays with distinct configurations are evaluated. The system designs include horizontal single axis trackers (HSAT) and 25° fixed‐tilt structures, monofacial and bifacial PV panels, and low and high ground albedo. The value of the system designs is assessed using onsite electrical measurements and spot prices from the Nord Pool electricity market. We find that HSAT systems increase the annual value factor (VF) by 4% and decrease levelized cost of energy (LCOE) by 3.5 EUR/MWh relative to fixed‐tilt systems. The use of bifacial panels can increase the VF by 1% and decrease LCOE by 4.0 EUR/MWh. However, a negligible VF increase and modest LCOE decrease was found in systems with bifacial panels and ground albedo enhancements. Although our results show that albedo enhancements result in lower LCOE than designs without, the uncertainty in upfront and ongoing costs of altering the ground in utility‐scale PV parks makes the solution presently unadvisable.

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Section: Resultssupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Value of bifacial photovoltaics used with highly reflective ground materials on single‐axis trackers and fixed‐tilt systems: a Danish case study

Riedel

Poulsen

Jakobsen

et al. 2020

IET Renewable Power Generation

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“…In addition, VFs have analytical or numerical solutions depending on the problem that has to be solved. The VF model has been used by the MoBiDiG simulation tool, and the detailed description of that model has been discussed in our previous work . We recall the most important equation in our irradiance model that counts for the ground reflected irradiance received by the rear side of the bifacial module in order to show the most important dependencies:

E_{ref,rear} = ρ \times GHI \times F_{A_{nsh} \to A_{normalm}} + ρ \times DHI \times F_{A_{sh} \to A_{normalm}},

with

ρ

being the albedo of the ground surface, GHI the global horizontal irradiance, and DHI the diffuse horizontal irradiance.…”

Section: Research Methodology and Proceduresmentioning

confidence: 99%

“…The MoBiDiG simulation tool has been developed by ISC Konstanz, which uses VF concept to model the rear irradiance; ie, the rear irradiance is determined for each cell within the backside of PV module, unlike for the 2D VF, which is more suitable for large PV systems and is able to calculate the irradiance change along a direction that is perpendicular to the unlimited rows. In addition to VF concept, RT has been adopted in the current work to determine the backside irradiance of bifacial modules.…”

Section: Introductionmentioning

confidence: 99%

A comparison of ray tracing and view factor simulations of locally resolved rear irradiance with the experimental values

Berrian

Libal

2020

Progress in Photovoltaics

Self Cite

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One of the prerequisites for a reliable energy yield prediction of bifacial photovoltaic (PV) systems is the capability of modeling the backside irradiance of those systems with high accuracy. Currently, the most important optical models used to quantify the reflected irradiance on the backside of a bifacial solar panel are view factor and ray tracing. The MoBiDiG simulation tool has been developed at ISC Konstanz uses the view factor (VF) concept to model the rear irradiance. In addition to the VF concept, ray tracing (RT) has been adopted to determine the backside irradiance of bifacial modules by using the open-source tool bifacial_radiance that has been developed by the National Renewable Energy Laboratory (NREL). A customized monocrystalline silicon solar panel has been built in order to evaluate the accuracy of the existing optical models by locally resolved rear irradiance measurement. The performance of rear irradiance has been investigated along the rows of the customized PV module during sunny and cloudy days with typical back irradiance values of ≈50 and ≈ 150 W∕m 2 . The comparison of measured and modeled data has been carried out on hourly, daily, and monthly basis, and the results show lower deviations for solar cells located in the center of the PV module than on the edge. Moreover, the concept of decisive solar cells has been introduced and applied to both measured and modeled data, solar cells located in the center rows were found to act as the most decisive solar cells. Finally, considering the installation configuration studied here, ie, bifacial mounting with low clearance height (below 0.2 m), both hourly RT and VF approaches are able to model long-term cumulative irradiance received by decisive solar cells with a very high accuracy ranging from ±0.5% to ±2%.

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“…The other investigated aspect is the impact of the use of horizontal solar trackers, an issue not yet well studied in the case of bifacial PV modules. Indeed, although several studies in the literature analyzed the effect due to solar trackers on a traditional mono-facial PV system and solar collector performance (for instance, see Reference [15][16][17][18][19][20][21][22][23][24][25][26][27][28]), currently few studies exist (see Reference [29][30][31]) for bifacial PV systems, and further studies are required. Such a need arises because, for a bifacial system, the benefit on the performance determined by the use of solar trackers could be sensibly different from that observed on traditional mono-facial PV systems.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Bifacial PV String Performance: Perimeter Effect and Influence of Uniaxial Solar Trackers

et al. 2020

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The bifacial photovoltaic (PV) systems have recently met large interest. The performance of such systems heavily depends on the installation conditions and, in particular, on the albedo radiation collected by the module rear side. Therefore, it is of crucial importance to have an accurate performance model. To date, in the scientific literature, numerous models have been proposed and experimental data collected to study and optimize bifacial PV system performance. Currently, 3D and 2D models of bifacial PV devices exist. Though the former are more mathematically complex, they can lead to more accurate results, since they generally allow to fully consider the main aspects influencing a bifacial PV system performance. Recently, we have proposed and validated through experimental data a 3D model tested as a function of module height, tilt angle, and ground albedo. In this work, through such a model, we studied the role played by the perimeter zones surrounding the PV string, by considering PV strings of 30 or 60 modules. We considered the cases of fixed installation with optimal PV module tilt and of installation with uniaxial horizontal solar tracker. We evaluated the PV energy yield as a function of the size of the perimeter zones for the two cases, i.e., both with and without the solar tracker. In optimal perimeter conditions, we then studied the behavior of bifacial and mono-facial PV strings by varying the geographical location in a large latitude range.

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Performance of Bifacial PV Arrays With Fixed Tilt and Horizontal Single-Axis Tracking: Comparison of Simulated and Measured Data

Cited by 57 publications

References 13 publications

Value of bifacial photovoltaics used with highly reflective ground materials on single‐axis trackers and fixed‐tilt systems: a Danish case study

Value of bifacial photovoltaics used with highly reflective ground materials on single‐axis trackers and fixed‐tilt systems: a Danish case study

A comparison of ray tracing and view factor simulations of locally resolved rear irradiance with the experimental values

Numerical Modeling of Bifacial PV String Performance: Perimeter Effect and Influence of Uniaxial Solar Trackers

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