Crops for autumn were harvested on October 17 and 18, 2019, at a rice field in Tenri City, Nara Prefecture (Fig. 1). A rice harvester traveled back and forth through the rice field efficiently cutting rice plants – a scene witnessed in rice fields throughout Japan. But this rice field is characterized by something rarely seen in other rice fields.
Two-axis tracking-type mounting systems, each supporting about 40 solar panels, are moving arrays (units for mounting solar panels) of solar panels automatically responding to the motion of the sun. The rice harvester travels under the mounting systems for harvesting.
In solar sharing, the sunlight is shared by crops and solar panels. In this project, rice, which is the main crop in Japanese agriculture, is grown in the field. Crops that grow comparatively well in shade, such as Japanese cleyera trees and garlic, are generally selected for solar sharing. In solar sharing, idle farmland is normally used, with a focus on power sales and reducing the farming workload as much as possible.
If solar sharing where rice is grown takes root and becomes popular, solar power generation may spread rapidly because the impact of solar power generation on rice fields is much more significant, unlike the case for other crops.