Weather Effects on the Efiiciency of Photovoltaic Systems in Medellín, Colombia

Shortages of electricity in Colombia associated with negative precipitation anomalies during El Niño-Southern Oscillation warm events led the government to seek diversification of the electricity matrix, which is mainly based on hydropower (66%). Additionally, wind and solar power generation are also alternatives to climate change. Potentially, solar radiation levels are high year-round in Colombia due to its low latitude location; however, cloudiness in the region is likely the most critical limiting factor for photovoltaic development. In this work, we analyze the variations in photovoltaic efficiency and their dependence on weather variables. Toward that end, we monitor three simple photovoltaic systems located in three different zones of the valley, and simultaneously, we analyzed some of the limiting factors which influence solar energy generation. The efficiencies on each location were calculated considering the power output data, as the ratio among the horizontal global radiation and the area of each solar panel. We also considered radiation from a pyranometer network, air temperature and relative humidity from meteorological sensors, water vapor density, liquid water content from a microwave radiometer, and reflectances as a proxy of clouds from GOES 16. To identify clouds, we estimated radiance thresholds from the GOES information in the three locations of interest based on changes in the surface radiation data. These thresholds allow identifying the most sensible hours for radiation and photovoltaic energy generation.