Rain concentration and sheltering effect of solar panels on cultivated plots

• Published in: Hydrology and earth system sciences 2018-02, Vol.22 (2), p.1285-1298
• Main Authors: Elamri, Yassin, Cheviron, Bruno, Mange, Annabelle, Dejean, Cyril, Liron, Francois, Belaud, Gilles
• Format: Article
• Language: English
• Subjects: Agricultural land; Atmospheric precipitations; Clean energy; Coefficient of variation; Computer simulation; Controlled conditions; Dimensions; Earth Sciences; Environmental aspects; Environmental management; Environmental Sciences; Fluxes; Heterogeneity; Hydrology; Interception; Irrigation; Irrigation efficiency; Irrigation systems; Irrigation water; Land use; Measurement; Patchiness; Photovoltaics; Rain; Rainfall; Rainfall simulators; Renewable energy; Renewable resources; Resource management; Sciences of the Universe; Soil; Solar energy; Solar panels; Spatial heterogeneity; Water resources; Wind speed
• ISSN: 1607-7938; 1027-5606; 1607-7938
• DOI: 10.5194/hess-22-1285-2018

Agrivoltaism is the association of agricultural and photovoltaic energy production on the same land area, coping with the increasing pressure on land use and water resources while delivering clean and renewable energy. However, the solar panels located above the cultivated plots also have a seemingly yes unexplored effect on rain redistribution, sheltering large parts of the plot but redirecting concentrated fluxes on a few locations. The spatial heterogeneity in water amounts observed on the ground is high in the general case; its dynamical patterns are directly attributable to the mobile panels through their geometrical characteristics (dimensions, height, coverage percentage) and the strategies selected to rotate them around their support tube. A coefficient of variation is used to measure this spatial heterogeneity and to compare it with the coefficient of uniformity that classically describes the efficiency of irrigation systems. A rain redistribution model (AVrain) was derived from literature elements and theoretical grounds and then validated from experiments in both field and controlled conditions. AVrain simulates the effective rain amounts on the plot from a few forcing data (rainfall, wind velocity and direction) and thus allows real-time strategies that consist in operating the panels so as to limit the rain interception mainly responsible for the spatial heterogeneities. Such avoidance strategies resulted in a sharp decrease in the coefficient of variation, e.g. 0.22 vs. 2.13 for panels held flat during one of the monitored rain events, which is a fairly good uniformity score for irrigation specialists. Finally, the water amounts predicted by AVrain were used as inputs to Hydrus-2D for a brief exploratory study on the impact of the presence of solar panels on rain redistribution at shallow depths within soils: similar, more diffuse patterns were simulated and were coherent with field measurements.