Vineyard dynamic agrivoltaics reduces canopy temperature and can increases soil water content

Abstract

Marketed as a way to protect crops against increasing temperature and drought induced by climate change while producing sustainable energy, agrivoltaic systems are undergoing a rapid expansion globally. They consist of photovoltaic panels affixed above crops. The present design includes dynamic photovoltaic panels (DPV) equiped with motors controlled by an algorithm. This system allows to change the angle of the DPV over time, providing maximum shade (solar tracking: DPV perpendicular to the rays of the sun) to minimum shade (solar antitracking: DPV parallel to the rays of the sun). It enables to control the microclimate in the crop and a potentially optimize the electricity production (Dupraz et al. 2011). However, these DPV have been observed to create uneven shading patterns, manifested as alternating shaded and illuminated strips along the crop (Tahir and Butt 2022). This phenomenon leads to the occurrence of microclimatic variations throughout the day. Furthermore, the physiological adaptation of plants to shading can also alter the microclimate. In order to ascertain the effect of solar panels on plant processes, crop yield and quality, it is therefore necessary to finely characterize the microclimate under the panels in an agronomic context.

In a non-irrigated pilot vineyard of 0.2 hectares of Merlot, planted in 2011, a controllable agrivoltaic shade structure was installed in 2022. The microclimate (i.e., incident light, air temperature, relative humidity, and soil water content) was measured continuously from 2023 to 2025 under the DPV and on an adjacent control (C) plot. The angle of the DPV relative to the sun’s rays is controlled as a function of grapevine phenology.

The data demonstrated an average of 50% light reduction under the DPV, with variations ranging from -35% to -60%, depending on the choice of angle of the DPV. During days when the temperature exceeded 30°C, an average of -1.5°C, +5% relative humidity, and -25% VPD were observed under the DPV at the hottest point of the day. During periods of drought, defined as a lack of precipitation for a minimum of 14 days, an increase in soil water content of up to +12% has been observed at a depth of 150 and 250 mm. Deeper probes did not show significant difference.

References

Dupraz, C., H. Marrou, G. Talbot, L. Dufour, A. Nogier, and Y. Ferard. 2011. “Combining Solar Photovoltaic Panels and Food Crops for Optimising Land Use: Towards New Agrivoltaic Schemes.” Renewable Energy, Renewable Energy: Generation & Application, vol. 36 (10): 2725–32. https://doi.org/10.1016/j.renene.2011.03.005

Tahir, Zamen, and Nauman Zafar Butt. 2022. “Implications of Spatial-Temporal Shading in Agrivoltaics under Fixed Tilt & Tracking Bifacial Photovoltaic Panels.” Renewable Energy 190 (May): 167–76. https://doi.org/10.1016/j.renene.2022.03.078

Acknowledgements

EDF power solutions as a project leader and EDF R&D as deputy. This project was supported by “ADEME” (Environment and Energy Management Agency), “Conseil Régional de Nouvelle Aquitaine” and “European Union”.