Comparison and Selection of Solar Radiation Data for Photovoltaic Power Generation Project

Based on the measured solar radiation and power generation data of a 5.6 kW PV grid-connected system in Beijing from June of 2012 to December of 2016, the differences between the measured data and the data provided by solar energy databases are analyzed. The results show that the measured data is lower than 80–90% of the data provided by Meteonorm and NASA databases. The actual output of PV system is less than 60–75% of the estimated power generation according to the databases. Considering the errors between the database and the measured value, it is suggested to reduce the radiation data in the selected database by 10–20% during the PV power generation project feasibility research and design stage, and ensure that the estimation of power generation is closer to the actual power generation.