This paper presents the results of survey on 276 grid-connected PV generation systems and measurement of 7 systems in Kyushu area. The electricity generated for a year was in average 925.9kWh/kWp/year. It was found that the system with panels on one side of roof generates more electricity than the system with panels on plural side of roof. The electricity generated by the system with panels on one side of roof was approximately 10% more than that with panels on three sides of roofs. The amount of electricity generation from PV system is in general affected by the local solar radiation condition and the system efficiency. The relation between decrease in power generation and the shadow on the panel or the unbalanced solar radiation between panels was simulated using the data acquired by the experiment.
