Renewable Energy Institute released a new report entitled "Shading in Solar Sharing Can Be Effective with Proper System Design and Cultivation Practices."
Since Japan introduced its solar sharing framework in FY2013, installations have expanded across the country, with the cumulative number exceeding 6000 by FY2024. As deployment has grown, stricter regulations have been proposed based on concerns that shading from solar panels may reduce crop yields and quality. The Ministry of Agriculture, Forestry and Fisheries (MAFF) has proposed limiting shading to less than 30% under its concept of "desirable agrivoltaics." However, crops differ in their light requirements depending on the species and variety. Appropriate system design and cultivation practices can effectively mitigate the impact of shading, and many projects have demonstrated that shading can even improve crop quality.
The report reviews domestic and international research together with case studies from across Japan to examine how shading affects crop growth. It covers a wide range of crops, including rice, soybeans, tea, coffee, and spinach. The findings show that crop yields and quality cannot be assessed solely based on shading rate. Instead, system design and cultivation practices tailored to the characteristics of each crop are essential. The report also highlights that shading can reduce soil moisture loss while mitigating leaf scorch and heat stress.
Solar sharing provides farmers with an additional source of income from electricity generation alongside agricultural production, contributing to more stable farm management, attracting new farmers, and revitalizing abandoned farmland. Rather than imposing a uniform shading limit, regulations should comprehensively evaluate regional conditions, crop characteristics, system design, and cultivation practices. The report also calls on national and local governments to collect and utilize performance data from projects across Japan to support the wider deployment of solar sharing under diverse local conditions.
＜Table of Contents＞
Introduction
Chapter1. How Shading Affects Crop Growth
・How Crops Grow Under Shading
・Issue 1. Shading Rates Suitable for Different Crops
・Issue 2. Reducing Soil Moisture Evaporation
・Issue 3. Poor Crop Growth Can Occur Even at Shading Rates Below 30%
Chapter 2. Lessons from Successful Projects with Shading Rates of 30% or More
・Success Factor 1. Designing Systems Tailored to Individual Crops
・Success Factor 2. Maximizing the Benefits of Shading through Cultivation Conditions
Conclusion: Toward a Better Regulatory Framework
＜Related Links＞
[Recommendation] Deregulating Solar Sharing to Expand New Agricultural Projects（5 March 2026）*in Japanese
[Special Contents] Solar
