Monitored data from 100 PV systems were used to study effects of combined power generation of these systems, compared to the characteristics of an individual system. The standard deviation curve of an average dairy power generation profile of 1 month is significantly decreased for the ensemble and corresponds to predictions based on cross-correlation characteristics of the radiation field. Power fluctuations between the monitored time intervals of more than 58 of the installed power have disappeared. The analysed energy spectrum of the combined power generation reveals that the produced energy is generated in a range below 65% of the overall installed power. The ensemble of PV systems supplies a calculable fraction of PV power within a certain time window around noon in the summer period, underlining the capability of reliable power production of a PV ensemble.