Temperature-Related Energy Loss of Silicon PV Modules in Baku and Seoul

This preprint estimates the temperature-related energy loss of silicon PV modules in Baku (Azerbaijan) and Seoul (South Korea) from six years (2015-2020) of hourly PVGIS-ERA5 data: irradiance on a south-facing tilted plane, 2 m air temperature and 10 m wind speed. The irradiance-weighted annual loss relative to 25 °C operation is 1.74 % in Baku and 2.48 % in Seoul with a wind-dependent cell-temperature model (Faiman), but 5.42 % and 4.30 % with a model without wind (NOCT), so which city loses more depends on the thermal model. Mean daytime wind speed at 10 m is 6.15 m/s in Baku and 2.47 m/s in Seoul. In each city, switching the thermal model changes the annual loss more than varying the temperature coefficient (-0.30 to -0.45 %/°C) within one model. ERA5 irradiation for Seoul appears high compared with published Korean national means, so a sensitivity analysis with scaled irradiance is included. All results are modelled estimates and are not validated against measured PV output. The analysis code is open (see the repository link). The analysis code, study design and draft text were prepared with the help of an AI model (Claude, Anthropic); the author ran the code, checked the results and takes responsibility for the content.