Describe the impact of using bifacial PV modules on system design and modeling, including considerations for ground albedo and rear-side irradiance capture.

Bifacial PV modules generate electricity from both the front and rear surfaces, which impacts system design and modeling in several ways. Ground albedo, which is the reflectivity of the ground surface, becomes a crucial factor. The higher the albedo, the more sunlight is reflected onto the rear side of the modules, increasing energy production. Surfaces like snow, sand, or light-colored gravel have high albedo, while dark soil or vegetation have low albedo. Rear-side irradiance capture is another important consideration. The amount of sunlight that reaches the rear side of the modules depends on several factors, including the module height above the ground, the row spacing, and the tilt angle. Higher module heights and wider row spacing allow more sunlight to reach the rear surface. System design optimization involves finding the optimal combination of module height, row spacing, tilt angle, and ground albedo to maximize energy production. Performance modeling for bifacial systems is more complex than for monofacial systems because it requires accurate modeling of the rear-side irradiance. Traditional PV performance models only consider the front-side irradiance. Bifacial models must account for the spatial distribution of irradiance on the rear surface, as well as the bifaciality factor of the modules (the ratio of rear-side to front-side power generation). These models typically use ray-tracing techniques or view factor calculations to estimate the rear-side irradiance. Furthermore, the electrical configuration of the modules and inverters needs to be carefully considered to account for the different current-voltage characteristics of the front and rear sides. Monitoring is more complex, requiring sensors to measure irradiance on both sides of the module. Factors such as shading from the mounting structure need to be taken into account, as the rear side can be affected differently than the front.