Estimating solar irradiance to predict crop yield on northern agrivoltaic farms

As solar panel popularity grows, they are increasingly being built in multi-use areas. For example, agrivoltaic systems combine solar panels above farming land, maintaining agricultural activities. While this maximizes land usage, it comes at a cost. Instead of crops receiving mainly direct light, the panels can cause a significant amount of diffuse irradiation, which could decrease crop yield.

Ma Lu et al. studied how panels in an agrivoltaic system can impact the solar irradiance reaching the crops beneath in order to better predict crop yields. Building on previous work, the researchers developed a novel decomposition model to measure the diffuse irradiance component from the global photosynthetically active radiation — essentially the light plants use to grow — which can be derived from meteorological data.

To increase predictability, their model incorporates four additional variables: atmospheric optical thickness, vapor pressure deficit, aerosol optical depth, and surface albedo. The researchers tested and validated their model, which focuses on previously-neglected high-latitude environments, using in-field experiments in Sweden and found it outperformed previous models. If the needed measurements at the site are not available, a simplified version of the model can make an approximation using data collected from a nearby station or via satellite.

“We hope our findings will prove valuable to the agrivoltaics research community, especially in modeling the solar irradiance reaching crops in these systems, commonly referred to as ground-level or crop-level light distribution,” said author Silvia Ma Lu.

The authors plan to expand their model to include shading and validate it spatially and temporally, including both the shaded and non-shaded crop conditions of an agrivoltaic system.

Source: “Photosynthetically Active Radiation Separation Model for High-Latitude Regions in Agrivoltaic Systems Modeling,” by S. Ma Lu, D. Yang, M. C. Anderson, S. Zainali, B. Stridh, A. Avelin, and P. E. Campana, Journal of Renewable and Sustainable Energy (2024). The article can be accessed at https://doi.org/10.1063/5.0181311 .