Evolution of agrivoltaic farms in Japan

Development of agrivoltaics in Japan started in 2004 in Chiba Prefecture initiated by Akira Nagashima. Today, 1,992 agrivoltaic farms (560 ha) exist throughout Japan except one prefecture out of 47 prefectures. Most agrivoltaics in Japan is small-scale less than 0.1 ha. It is estimated that total power generated by agrivoltaics is 500,000 to 600,000 MWh or 0.8% of the total power generated by photovoltaics in Japan in 2019. Farmland must be converted to non-agricultural use to install photovoltaics, in which agrivoltaics has an advantage over solar parks applicable to all 5 classes of farmland. Increase of devastated and abandoned farmland is a grave concern for the Japanese agriculture and agrivoltaics is expected to contribute to solve this issue. Over 120 crops are grown in agrivoltaics in Japan and for 69% of cases, cultivated crop is changed upon installation of agrivoltaics, which is causing concern that it may disrupt small, fixed markets of those crops. Shading rate in agrivoltaics ranges from 10 to 100% with its median at 30 to 40%. The choice of shading rate is made according to light saturation point of the crop, but a high shading rate is often determined first to maximize profit from electricity sale, because it is much greater than the one from agriculture itself, then suitable crop for that shading rate is chosen. Agrivoltaic development in Japan took off after the introduction of feed-in tariff (FIT) in 2012. FIT was significantly effective in policy impact compared to RPS system previously acquired in Japan, increasing renewable energy supply in Japan by 76% from 2012 to 2019. Photovoltaics has been a driving force increased from 7,600 GWh to 77,000 GWh during the same period. Two directives from the Ministry of Agriculture, Forestry and Fisheries (MAFF), one in March 2013 and another in May 2018, institutionalized agrivoltaics and promoted its development. The second amendment of FIT Law in June 2020, which will be enforced in April 2022, further paved the way for agrivoltaics preferentially treating it. Agrivoltaics is expected play an important role to revitalize the Japanese agriculture including reclamation of devastated or abandoned farmland, as being included in the above-mentioned policies. If all abandoned farmland were converted to agrivoltaic farms, 280 GW of electricity could be produced. The potential of agrivoltaics in 8 prefectures in Kanto region is estimated at least 15 to 39 GW. Emerging innovative agrivoltaics, such as one we see in a high value-added tea agrivoltaics in Shizuoka prefecture, is an economically and environmentally sound business model, which we may want to replicate elsewhere.