Performance loss rate and benchmarking of c-Si and thin-film PV modules considering thermal and spectral effects at a low-latitude site

Field-based assessment of photovoltaic (PV) module performance provides key insights for accurate lifespan prediction and reliability analysis. However, two significant research gaps remain: the scarcity of long-term evaluations in low-latitude regions and the limited application of established ensemble methods under diverse climatic conditions. This study presents a long-term field performance analysis of eight PV technologies installed in Lima, Peru, a subtropical desert climate at low latitude. Module Performance Ratio (MPR) was evaluated considering the effects of measured temperature and spectral variations. For c-Si-based modules, thermal losses ranged from −2.7 % to −4.3 %, while thin-film modules exhibited smaller thermal impacts (−2.2 % to −2.6 %). Spectral losses in c-Si modules ranged from −0.7 % to −1.5 %. Conversely, a-Si modules recorded spectral gains of 5.7 %. Additional analysis of open-circuit voltage, short-circuit current, and fill factor revealed distinct performance degradation pathways across technologies. Ensemble-derived Performance Loss Rates (PLR), combined with climate-influencing factors, enabled benchmarking and 25-year energy yield projections. Our reported PLRs of up to −1.61 %/year for c-Si slightly exceed reported global-median PLRs, suggesting detrimental effects of Lima's high humidity and UV exposure. Projections indicate that in Lima HIT modules may outperform IBC and PERT technologies, underscoring the value of region-specific, long-term PV performance studies.