LAUSR

Despite being a tropical country with great potential for solar power, knowledge about the actual performance of photovoltaic (PV) systems in Indonesia remains limited. In this paper, using 5-minute resolution data from 2016 to 2018 obtained from a 1 MW Copper Indium Selenide (CIS) and a 5 kW crystalline silicon (c-Si) PV plant in West Java, we aim to answer the question of how a CIS PV plant performs and degrades in Indonesia's tropical climate and how it compares to a PV system that contains c-Si technology. The methodological approach used includes performance analyses of these PV systems according to IEC standard 61724 and an investigation of the degradation rate using NREL/RdTools. The following results were derived from the analyses: the total annual Hi was 1500 kWh/m2 or around 4.2 kWh/m2/day. The daily-averaged performance ratio, PR, was 91.7 % ± 4 % and 87.4 % ± 7 % for the CIS system with string inverters and a central inverter, respectively. The mean PR of the CIS systems was 12 % higher than that of the c-Si system, which was 79.8 %. Concerning the final yield, Yf, the CIS system with a mean Yf of 3.85 kWh/kWp outperformed the c-Si system by 14 %. The CIS system degraded by 1.53 % per year, which is less than the c-Si system with a degradation rate (Rd) of 3.72 % per year. From these results, it can be concluded that, in this case, CIS technology performs better than c-Si in Indonesia's tropical climate. Uncertainties in the calculation and high values of Rd could be areas for further investigation.