From bifacial PV cells to bifacial PV power plants - the chain of characterization and performance prediction

摘要

Bifacial PV technology raises new challenges for the characterization and modelling of solar cells and modules, as well as for the yield predictions of power plants, as the contribution of the rear side can significantly affect the performance of these types of device. Reliable measurements and simulations are essential for gaining the trust of investors in this new and powerfully emerging technology. This paper covers the entire field of bifacial device characterization, from the additional demands on the measurement of bifacial solar cells and modules, through the modelling of cell-to-module losses, to the simulation of bifacial gains at the system level. An overview of different measurement set-ups and procedures for bifacial solar cells and modules is given, and the way in which the major influences can be controlled in order to achieve highly precise measurements is explained. With regard to yield predictions, the paper discusses how the existing models need to be extended to consider the additional site- and mounting-related factors that influence the available rear irradiance. It is shown that a combination of raytracing and electrical modelling allows accurate yield predictions of bifacial PV systems. The advanced tools presented in this paper for modelling cell-to-module losses and yield prediction outline the possibility for optimizing module and system design, and thus for increasing expected gains.