Via EUREC Members, IMEC
Imec and EnergyVille recently presented a new simulation framework that can accurately calculate the energy yield of bifacial PV systems (also capturing reflected light from the ground). Compared to existing approaches, it not only computes the energy yield of the individual cells and modules based on local and varying meteorological conditions, but also takes into account the double-sided illumination and the way it is influenced by module frames, system components’ geometry, and varying albedo.
Bifacial PV systems can annually generate 5 to 20 % more electricity than their traditional monofacial counterparts on little or no extra cost. Because of this benefit, bifacial PV installations are gaining market share. However, the limitations of the current simulation tools to precisely determine their expected energy yield could hinder further deployment.
While the existing commercial energy yield simulation tools and approaches used for the design of PV power plants have become more and more precise for standard monofacial silicon solar modules, their estimations for bifacial systems still include high error margins. Calculating the energy yield of bifacial solar modules is more challenging because energy generation from light received at the rear side depends on many variables that are hard to determine and may vary during the day, e.g. self-shading, plant geometry, mounting structure, ground albedo (= the percentage of sunlight reflected by the ground to the PV module’s rear side).
Additionally, non-uniformity in rear illumination causes differing total energy generation at module level and consequently electrical mismatch losses at string level. This means that the string configuration also plays a role in the global solar power plant energy yield.
The new model enables the calculation of the energy yield of an entire system, while maintaining a low error margin of < 5% (daily RMSE) even in complex scenarios and at high speed of calculation. It is now ready to be validated on large scale installations in real-life conditions and in different climates across the world.