At standard test conditions (STC), the performance of photovoltaic modules is compared using efficiency. As irradiance and module temperature fluctuate over the year and STC efficiency does not assess the performance of the module accurately in real world conditions, the annual energy yield is used instead as performance metric. Perovskite/silicon tandem solar cells are being massively researched and sought after in PV industry for their efficiency well above 34% with further growth perspective. In this work, to evaluate and compare performance of different perovskite/silicon tandem photovoltaic (PV) modules based on different bottom cell technologies, we use a hybrid modelling approach. Such approach, combining experimentally obtained and simulated current-voltage curves, flexibly predicts the annual energy yield of novel tandem PV modules via our PVMD toolbox and enables their optimization in any location. In particular, considering (i) mono- and bi-facial architectures, (ii) 2-terminal and 4-terminal module configurations, and (iii) silicon heterojunction or novel poly-SiOx passivated c-Si solar bottom cells, we compare the annual energy yield of different perovskite/silicon tandem modules and we optimize their performance in different locations with respect to different perovskite thickness and bandgaps@en

The tandem PV technology can potentially increase the efficiency of PV modules over 30%. To design efficient modules, a quantification of the different losses is important. Herein, a model for quantifying the energy loss mechanisms in PV systems under real-world operating conditions with a level of detail back to the components and their fundamental properties is presented. Totally, 17 losses are defined and divided into four categories (fundamental, optical, electrical, and system losses). As example, a system based on a > 29% two-terminal perovskite/silicon tandem cell is considered. The loss distribution at standard test conditions is compared to four geographical locations. The results show that the thermalization, reflection, and inverter losses increase by 1.2%, 1.1%, and 1.4%, respectively, when operating outdoors. Additionally, it is quantified how fill factor gains partly compensate the current mismatch losses. For example, a mismatch of 7.0% in photocurrent leads to a power mismatch of 1.2%. Therefore, the power mismatch should be used as indicator for mismatch losses instead of a current mismatch. Finally, herein, it is shown that solar tracking increases not only the in-plane irradiance but also the efficiency of the tandem module.

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We introduce a novel simulation tool capable of calculating the energy yield of a PV system based on its fundamental material properties and using self-consistent models. Thus, our simulation model can operate without measurements of a PV device. It combines wave and ray optics and a dedicated semiconductor simulation to model the optoelectronic PV device properties resulting in the IV-curve. The system surroundings are described via spectrally resolved ray tracing resulting in a cell resolved irradiance distribution, and via the fluid dynamics-based thermal model, in the individual cell temperatures. A lumped-element model is used to calculate the IV-curves of each solar cell for every hour of the year. These are combined factoring in the interconnection to obtain the PV module IV-curves, which connect to the inverter for calculating the AC energy yield. In our case study, we compare two types of 2 terminal perovskite/silicon tandem modules with STC PV module efficiencies of 27.7% and 28.6% with a reference c-Si module with STC PV module efficiency of 20.9%. In four different climates, we show that tandem PV modules operate at 1–1.9 °C lower yearly irradiance weighted average temperatures compared to c-Si. We find that the effect of current mismatch is significantly overestimated in pure optical studies, as they do not account for fill factor gains. The specific yields in kWh/kWp of the tandem PV systems are between −2.7% and +0.4% compared to the reference c-Si system in all four simulated climates. Thus, we find that the lab performance of the simulated tandem PV system translates from the laboratory to outdoors comparable to c-Si systems.

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