Energy Payback Time (EPBT) and Energy Return on Energy Invested (EROI) of Perovskite Tandem Photovoltaic Solar Cells

Two-terminal tandem perovskite (PK) cells are considered a promising option for future photovoltaic (PV) market due to the rapid improvements in their power conversion efficiencies. However, their large-scale adoption requires a better understanding on the energy performance of these PVs. In this paper, the life-cycle energy consumptions of two-terminal tandem solar cells consisting of lead-based PK top cells prepared on bottom cells of copper indium gallium selenide, copper zinc tin selenide, and monocrystalline silicon are evaluated. The energy payback time (EPBT) and the energy return on invested (EROI) are the two use-fulmetrics for examining the energy generation performance of PV systems. EPBTs of the current state-of-the-art devices range from 7 months to 12 months, while the EROI of the cells is in the reverse order as the EPBT and ranged between 5.2 and 9.2. These two energy indicators of tandem devices are expected to improve as the tandem PV technologies mature, with an EBPT as low as similar to 27 day (0.9 month) and the EROI as high as 105 for high-efficiency long-lifetime devices.