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

Abstract

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. • 5+ years of 8 PV technologies' IV curves from Lima's coastal, low-latitude site • Avg. daily loss for mono-Si modules: Thermal ≤ -4.4%; Spectral ≤ -1.5% • The combined nine pipelines generated a time-consistent mean PLR • mono-Si modules exhibited mean PLRs ranging from -1.6 to -0.9 %/year • Estimate: 2016-HIT long-term perf. may exceed 2018-IBC and 2019-PERT