Field Performance of Advanced PV Module Technologies in Desert Climates: Contrasting Results and Insights

Tunnel Oxide Passivated Contact (TOPCon) and Silicon Heterojunction (SHJ) solar cells are emerging as leading photovoltaic (PV) technologies, poised to replace Passivated Emitter and Rear Cell (PERC) technology. This study evaluates the field performance of SHJ and TOPCon modules in Qatar's extreme desert climate using two datasets collected over distinct time periods: medium-power modules (<450W) and high-power modules (>550 W) from different manufacturers with varying bills of materials (BOM). While TOPCon modules consistently outperformed SHJ modules in terms of both performance ratio (PR) and specific yield, the first dataset revealed SHJ modules (19.4% efficiency and PTC of 0.28%/°C) adapting well to seasonal variations. However, the second dataset highlighted a significant decline in SHJ performance, despite superior nameplate specifications (22.1% efficiency and PTC of 0.26%/°C), with diminished PR and specific yield values compared to TOPCon modules. Electroluminescence (EL) imaging confirmed notable degradation in SHJ modules in both data sets. The results presented clearly emphasize the critical role of operating module temperatures in desert climates and underscore the variability in SHJ performance compared to the consistent reliability of TOPCon technology. This study also highlights the need to benchmark emerging PV technologies under real-world conditions, as nameplate specifications alone may not guarantee superior field performance in harsh environments.