Techno-economic assessment for the future design of multimegawatt PV plants with innovative Perovskite-Silicon Tandem modules

Currently, the most efficient Photovoltaic (PV) modules are based on silicon heterojunction technology with the integration of monocrystalline silicon and amorphous silicon layers, reaching module conversion efficiencies up to about 22%. In the future, the performance of photovoltaic modules might be further enhanced by manufacturing Tandem devices joining monocrystalline silicon layers and innovative layers based on hybrid organic-inorganic materials, like perovskite. This type of module might permit to reach conversion efficiencies higher than 30%. In this context, this dissertation provides a techno-economic assessment for future installations of multimegawatt PV plants with innovative perovskite-silicon Tandem modules as part of a collaboration with the Research, Development & Technological Innovation department of Edison S.p.A. This work investigates the modifications the design of such plants will require, and the most important energy and economic indicators of the plant will be evaluated. In particular, two installation sites, Piossasco (Piedmont, Italy) and Priolo Gargallo (Sicily, Italy), and three different typologies of modules will be considered: the reference module is a crystalline silicon module with a rated power of 547 W and efficiency of 21.2%. The other two devices are Tandem modules with different electrical connection of monocrystalline silicon and perovskite layers (two-terminal, 2T, with series connection, and four-terminal, 4T, with parallel connection). The modelling of the Balance of Systems (BoS) for plants equipped with these different PV technologies assesses the main differences and innovations in terms of design that perspective Tandem technology will bring with its future "early" adoption and consists of the following steps. First, string sizing is performed, considering an appropriate system voltage for tandem modules that might be affected by potential induced degradation phenomena and leakage currents. Then, coupling with the Inverter is evaluated by selecting the appropriate size and maximum power voltage range. After that, the optimal layout is evaluated to minimize the connections within the system, and, lastly, the topic of protections and the electrical connection with the grid is addressed. The Levelized Cost of Electricity (LCOE) for each plant configuration is evaluated, using Capex and Opex and energy yield data, derived from advanced optoelectrical modelling, provided by the Company. The study concludes with a sensitivity analysis based on two quantities: the manufacturing overcost of Tandem technology compared to crystalline silicon and its durability. Lastly, the dissertation includes some remarks regarding the issues the perovskite technology will face in the next years, like its durability and scalability.