Sun-tracking solar panels power Japan’s rice fields without crop loss

A University of Tokyo study demonstrates that dual-axis sun-tracking solar panels installed three meters above rice paddies in Nagano Prefecture can generate substantial renewable electricity without significantly reducing rice yields. By adjusting panel angles daily and seasonally, the system balances sunlight for crops during growth periods and maximizes power generation in the off-season. Over two growing seasons, rice output under the panels reached 75-85% of that in uncovered fields, with grain quality meeting Japan’s top standards. The array produced nearly 44,000 kWh annually, achieving efficiency comparable to European agrivoltaic projects and a levelized cost of electricity roughly equal to Japan’s residential rates without subsidies. Japan’s limited flat land and mountainous terrain create challenges for expanding solar energy without compromising farmland. Conventional solar farms require large areas, whereas agrivoltaics—stacking food production and power generation on the same land—offers a promising solution. The pilot project aligns with Japan’s goals to increase solar capacity and energy security, including