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New model to assess effects of shading on crops in agrivoltaic projects

Publish Time:2023-10-06 Sources:
New research shows the importance of calculating the effects of shading created by PV panels on the photosynthetically active radiation (PAR) at the ground level, which is crucial to assessing crop yield in agrivoltaic projects. The proposed modeling considers different agrivoltaic project typologies across several sites in Europe.
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An Italian-Swedish research team has investigated the impact of shading created at ground level by different agrivoltaic system configurations, which the scientists said is necessary for accurate crop yield estimations.

They noted that previous research has been mostly interested in assessing the impact of shading on solar module production or global horizontal irradiance (GHI) distribution, while their study is mostly intended to analyze the effects of shading on photosynthetically active radiation (PAR) and crop yield.

“The developed model can be used as a starting point for accurately estimating crop yields at any location under the most common agrivoltaic system designs,” they explained. “It considers the agricultural part of agrivoltaic systems and can be integrated with existing PV power models to analyze crop yield and power production.”

Via the Matlab software, the scientists created a model that considers three different agrivoltaic system configurations: with fixed structures; with single-axis trackers; and with double-axis tracking systems. They then utilized the PVsyst and SketchUp software to validate the shading factors of the proposed model, claiming that both tools alone are not able to calculate beam and diffuse shading factors on the ground.

The group tested the model at three different sites in Europe: Lanna in Sweden; Estrees-Mons in France; and Klingenberg in Germany. It calculated PAR by decomposing it into its diffuse and direct components. “This decomposition of PAR is critical in AV systems due to the variable shadings caused by the panels on the crops, creating a non-homogenous PAR/diffuse PAR distribution during the day,” it further explained.

The testing showed, the scientists said, that the proposed model exhibited “high accuracies” compared to PVsyst and SketchUp. “The light homogeneity and PAR reduction could vary significantly depending on AV system configurations, from 86 % to 95 % and 11 % to 22 %, respectively,” they further explained. “The two-axis AV system showed the highest light homogeneity and lowest yearly PAR reduction in Lanna. The light homogeneity index was 95.15 %, and the annual PAR reduction was 11.01 %.”

The researchers emphasized that the model could be easily adapted to other types of agrivoltaic system layouts.

Their findings are described in the study “Direct and diffuse shading factors modelling for the most representative agrivoltaic system layouts,” published in Applied Energy. The team comprises academics from the Mälardalen University in Sweden and the Università Cattolica del Sacro Cuore in Italy.

Other researchers at Mälardalen University recently investigated how to optimize electricity yields in agrivoltaic installations with vertically mounted bifacial PV modules. They developed a techno-economic optimization model that purportedly outlines the ideal design parameters for an agrivoltaic vertical PV system by combining climatological data with figures on expected solar power generation, shading distribution, water for irrigation, and agricultural yield.

Other scientists from Università Cattolica del Sacro Cuore have also recently investigated different shade depth treatments on soybeans grown under an elevated agrivoltaic system in Monticelli d'Ongina, Italy.
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