Spatial interpolation of the solar irradiance; A study from the smoothing effect of irradiance fluctuations

In the near future, short time fluctuations of the power generation from grid-connected photovoltaic (PV) power generation systems will become an important issue in the utilities. The smoothing effect that the fluctuations of the power generation from scatteringly installed PV power generation systems cancel out is well known. In this study, we have demonstrated the smoothing effect for short time fluctuations from analyses of the solar irradiance in an area of an about 10km square. Additionally, the spatial interpolation of the solar irradiance is also discussed. A good agreement between the measurements and the predictions of the spatial interpolation is obtained in fluctuation cycles longer than 8 minutes.