Case study of rice farming in Japan under agriphotovoltaic system

The performance of an agriphotovoltaic system was studied from the viewpoint of both the crop yield of Japanese rice in a paddy field plant and the photovoltaic (PV) electricity production cost. The PV panels with a total rated output of 45,760 W were integrated onto a cost-effective dual-axis sun-tracking system and positioned at 3 m above the ground at the rice paddy field of 830 m2 area. We show that the crop yield is strongly correlated with the amount of solar irradiation. By optimizing the operating mode and shading rate of PV panels, a crop yield of higher than 80% as compared to the average crop yield in the surrounding area has been satisfactorily achieved. The annual PV electricity produced amounted to an estimate of 43,995 kWh in the case-study period, and a specific yield of 961.4 kWh/kW was obtained.