## 1 Introduction  
In the context of increasingly global energy demands and the vital importance of sustainable renewable energy sources, photovoltaic (PV) technology continues to play a pivotal role in meeting these challenges. Bifacial photovoltaic (bPV) technology has emerged as a promising solution, capable of converting sunlight from both the front and rear sides, potentially enhancing energy conversion efficiency compared to traditional PV modules. Two facts illustrate the relevance of bPV technology: the development of a specific IEC Standard to characterize bifacial devices (IEC 60904-1-2:2019 [1]) and the fact that Task 13 of the International Energy Agency (IEA) Photovoltaic Power Systems Programme (IEA PVPS) published a detailed report on bPV in recent years [2]. Production gains in the range of 6-10% under normal conditions have been reported [3; 4; 5], but considerable increments can be obtained with a proper design (+15-30%) and can be as high as 40% with optimal design parameters [6]. In order to take advantage of this potentiality, a thorough understanding of bPV technology is crucial, especially as a significant increment in worldwide bPV installation is expected. By 2030, the installation rate increased to 30%, while it was about 12% in 2020 [2]. Bifacial technology presents a promising avenue for sustainable land use and renewable energy generation. This innovative approach combines the benefits of both systems, leveraging the dual-sided energy capture capability of bPV modules and the land productivity enhancements offered by agrivoltaics. By deploying bifacial PV panels above agricultural fields, agrivoltaic systems can harness sunlight from both the front and rear sides of the panels while simultaneously providing shade to crops or livestock below. This dual-use configuration increases the energy generation potential while optimizing land use efficiency [7]. Additionally, the presence of vegetation beneath the solar panels can enhance the performance of bifacial modules by increasing the amount of reflected and diffused sunlight reaching the rear side of the panels [8]. On the other hand, from an urban perspective, bifacial technology has a high potential of being integrated into energy-sustainable buildings [9]. Bifacial modules can be used as transparent or opaque facades, skylights, sunshades, and curtains or integrated into rooftops [9]. However, despite its architectural features, the energy production contribution of the bifacial modules requires a thorough analysis, paying special attention to the particularities of each installation. Different parameters have been detected as crucial contributors to bPV performance. The main contributor is ground albedo (the percentage of incident sunlight that a surface reflects), as it proportionally increases the incident rear-side irradiance and, as a consequence, the rear power contribution. Daily albedo experiments [10; 11] and seasonal variations [11] can be as high as 0.9 (fresh snow) [12; 13] or as low as 5% (gravel) [11]. Another influential design parameter is the panel ground clearance height (GCH), which is the closest distance between the module and the ground. It has been found that its positive effect tends to saturate in the range of 0.4-1 m, depending on the location [14; 15]. Module orientation (tilt and azimuth) can also have a positive effect, but the optimum is highly dependent on each specific site and may not coincide with the optimum for conventional modules [6; 16]. Additionally, it has been highlighted that bifacial contribution increases when the diffuse to global radiation ratio is high [10], i.e., in overcast conditions. As a counterpart, the bifacial contribution is reduced by the non-uniformity of the rear-side irradiance. Since the performance of any PV cell string is heavily influenced by the worst cell in the string, the increase in said non-uniformity, at the parity of the average component, would reduce the performance of the worst cell, diminishing the overall operation.