Performance assessment of bifacial c-Si PV modules through device simulations and outdoor measurements

Abstract

Bifacial solar cells are receiving increased attention in the PV market due to their higher energy yield compared to conventional monofacial modules thanks to additional light conversion through their back surface. This additional rear side energy gain creates a potential for significant reduction of the overall levelized cost of energy (LCOE). Despite this fact, wide deployment of bifacial PV modules is very limited because of the high unpredictability of their power output due to various factors such as ground reflectance, module elevation angle, orientation and tilt angle. Due to this complexity, modelling of bifacial modules and systems is currently not developed at the same level of maturity as monofacial ones, where established commercial tools have been developed for PV system designers. In this regard, a customized 2D device model has been developed to simulate bifacial PV structures based on the numerical solution of the transport equations by the finite element method. The model was used to simulate actual PV performance and energy yield based on measured outdoor environmental parameters including solar radiation spectrum and temperature. Bifacial device output was also compared with a monofacial one based on the industrial standard Al-BSF structure. Simulated results were also compared and validated with outdoor experimental data based on IV measurements of monofacial and bifacial modules installed at various tilt angles at a location near the Western coast of Saudi Arabia.