Systematic Analysis of Meteorological Irradiation Effects

Since installation in 1997, the weather profiles as well as the performance of a 1 MW PV system in Munich have been recorded in second intervals and have shown effects of unexpectedly high irradiances. This study investigates this phenomenon, which is the effect of cloud enhancement. Cloud enhancement refers to increased solar irradiation values due to cloud reflection. The sharply defined edges of cumulus clouds lead to reflections and thus to cloud enhancement effects. Monitored irradiance and temperature profiles clearly demonstrate this effect and its correlations. The systematic analysis of these profiles in high resolution meteorological data records indicate on the basis of time period, frequency and energy yield the importance of the review of these weather characteristics. Spectral distribution recordings of the entire courses of cloud enhancement incidents display the influence on the wave lengths. Up to now cloud enhancements effects in PV are largely underestimated and should be incorporated in system sizing and design to ensure optimal performance.