Bifacial photovoltaic systems have become a mainstream technology in utility scale and complex PV projects. Their performance depends not only on irradiance incident on the front side of the modules, but also on reflected and diffuse irradiance reaching the rear side from the ground and surrounding surfaces. LuciSun provides technical advisory and advanced modelling services for bifacial PV projects, supporting feasibility studies, design optimisation, and risk-informed decision-making in contexts where simplified bifacial assumptions are no longer sufficient.
LuciSun delivers dedicated simulation studies for bifacial PV systems across a wide range of applications, including ground mounted plants, carports, vertical PV, building-integrated photovoltaics (BIPV), agrivoltaics, and sites with complex terrain or surroundings. These services have been delivered to a wide range of clients across multiple projects, covering utility scale installations and complex configurations where standard bifacial assumptions were not sufficient. The studies are carried out by LuciSun experts using LuSim as a core modelling tool to explicitly assess rear side irradiance, bifacial gains, and their sensitivity to design and environmental parameters.
Unlike monofacial systems, bifacial PV performance is strongly coupled to its environment. Ground properties, surrounding objects, terrain geometry, and shading conditions all influence the amount and distribution of irradiance reaching the rear side of the modules. Uniform bifacial gain factors or simplified albedo based corrections often fail to capture these interactions accurately, especially in non-ideal or heterogeneous environments. LuSim addresses this challenge through explicit 3D representation of geometry and materials.
LuSim évalue l'irradiance du côté arrière en utilisant le même cadre 3D physiquement cohérent appliqué au côté avant des modules. L'irradiance réfléchie par le sol et les surfaces environnantes est calculée explicitement plutôt qu'approximée par des coefficients empiriques de gain bifacial. Le côté arrière de chaque module est discrétisé spatialement, permettant aux contributions d'irradiance de varier localement sur la surface du module et dans le temps, reflétant l'hétérogénéité spatiale et temporelle réelle.
La réflectance du sol joue un rôle central dans les performances des PV bifaciaux, pourtant les installations réelles présentent rarement un albédo uniforme. La végétation, les conditions du sol, le gravier, le béton, la neige ou les traitements réfléchissants dédiés peuvent créer une forte variabilité spatiale. Au-delà des simples hypothèses Lambertiennes, la distribution angulaire de la lumière réfléchie, couramment décrite par des fonctions de distribution de réflectance bidirectionnelle (BRDF), peut influencer l'irradiance du côté arrière dans des configurations spécifiques.
LuSim représente le sol explicitement en 3D et permet d'attribuer des propriétés matérielles variant spatialement. Cela permet d'analyser les distributions d'albédo hétérogènes, les traitements partiels et les configurations de sol localisées, et d'évaluer leur impact sur les gains bifaciaux de manière cohérente, tout en restant compatible avec différentes hypothèses de réflectance en fonction des besoins du projet.
Beyond global albedo assumptions, bifacial PV design may involve the use of highly reflective ground treatments, such as white gravel or reflective membranes, applied only on specific areas of the site. LuSim enables the assessment of the position, extent, and geometry of such reflective surfaces relative to the PV rows, allowing LuciSun studies to determine where high reflectance materials are most effective in increasing rear side irradiance.
This type of analysis is applicable to both fixed structures and tracking systems, where the optimal placement of reflective surfaces depends on shading patterns, row spacing, and system geometry.
In bifacial systems, shading affects not only direct irradiance on the modules but also the reflected component by modifying which parts of the ground and surrounding surfaces are illuminated. Support structures, mounting elements, and nearby objects can significantly alter rear side irradiance distributions and introduce localised electrical mismatch. LuSim captures this interaction coherently by evaluating shading, illumination, and reflected irradiance within a single 3D framework, allowing rear side contributions to change consistently with geometry and solar position.
Rear side irradiance computed by LuSim is integrated directly into the PV energy yield modelling chain. Front and rear contributions are combined at the module level and converted into electrical power using validated photovoltaic performance models. Spatially resolved rear side irradiance enables consistent assessment of bifacial gains alongside electrical behaviour, mismatch effects, and system losses, supporting robust energy yield assessments without relying on fixed bifacial assumptions.
The bifacial modelling approaches implemented in LuSim have been applied and validated in industrial studies and research projects, including large scale utility PV plants, carports, agrivoltaic systems, and European research initiatives such as SERENDI-PV and dedicated bifacial PV research projects. These applications have supported comparative analyses, sensitivity studies, and discussions of modelling uncertainty under real project conditions.
Accurate bifacial PV modelling is not only a design optimisation issue, but also a prerequisite for robust uncertainty assessment and bankability analysis. Small changes in geometry, ground treatment, or shading configuration can lead to significant differences in bifacial gains and overall energy yield. LuciSun’s bifacial PV advisory services provide a physically consistent and spatially resolved basis to compare design options, assess risks, and support informed technical and financial decision-making in complex bifacial PV projects.
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