Optimal tilt angles for bifacial photovoltaic plants across Europe based on cumulative sky and Typical Meteorological Year data

The European targets for the Energy Transition by 2030 are strongly oriented toward the massive diffusion of PV plants, both at the building level and in large-scale utility systems on land. The expected PV capacity in Europe by 2030 is 900 GW, 4.3 times the 2022 level. Bifacial modules are currently the best solution for utility-scale PV systems, offering higher solar energy yields with minimal additional costs. This paper helps improve the efficiency of bifacial PV power plants at the European scale through the optimization of tilt angles in various configurations. Typical Meteorological Year data are retrieved from the PVGIS platform for a series of 2382 points uniformly distributed across Europe according to a regular 50 km × 50 km grid. A cumulative sky radiance is built for each location and an iterative search for the best tilt angle is performed to maximize the annual energy yield (on both front and back surfaces considering direct, diffuse and reflected energy) of south-facing modules, with both ground albedo and PV row spacing taken as parameters. Latitude is the primary influencing factor for optimal tilt angles, with an average value ranging from 26° for Greece to 36° for Finland. The results indicate that the Ground Coverage Ratio is also a significant parameter, while albedo has only a minor effect. The study of an Alpine region with a finer grid shows that mountainous terrain leads to reduced optimal tilt angles. A free web-based tool has been developed to provide optimal tilt angles for any location in Europe.