The Effect of Different Levels of Shading in a Photovoltaic Greenhouse with a North–South Orientation

Abstract

Photovoltaic greenhouses have been claimed to be a solution to cover the energy demand of the protected crops sector. Thus, there is a need to know what is the maximum percentage of shading produced by roof-top photovoltaic panels that does not affect crop yields. The present study analyzes the effects of increasing percentages of shading in a greenhouse tomato crop located in the southeast of Spain. For this study, photovoltaic panels have been simulated with opaque sheets located in the roof-top of a north–south oriented greenhouse. Three treatments of top roof shading percentage (15%, 30% and 50%) where studied and compared with the control treatment without shading (0%). During the study, parameters registered were radiation, temperature, pH and electric conductivity of the substrate, crop yields and fruit quality. Results of the analysis show that higher percentages of shading in the roof-top of greenhouses reduce so much available radiation for the crop causing a reduction in the yield and fruit quality, even in Mediterranean areas where radiation is not a limiting factor.

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

“…This would reduce the temperature value and additionally obtain an energy benefit through the collection of solar energy that can be used for other daily tasks on the farm. This has also showed in several studies that this alternative is economically and technically feasible, although it must always be accompanied by studies that allow establishing the optimal level of shade that does not negatively affect the yield and quality of the crops [73,74].…”

Enabling Year-round Cultivation in the Nordics - Agrivoltaics and Adaptive LED Lighting Control of Daily Light Integral

“…Plant species with a low (5-10 mol•m -2 •d -1 ) and moderate light needs (10-20 mol•m -2 •d -1 ) are more tolerant to shading compared to plants with high (20-30 mol•m -2 •d -1 ) or very high (DLI > 30 mol•m -2 •d -1 ) requirements [28][29][30][31][32]. Greenhouses in southern Europe with a PVR,% between 10% and 15% showed a very small decrease in the crop yields, even when cultivating shade-intolerant plants like tomatoes [66,69]. Roof coverage ratios between 20-25% showed minimal negative effects on the yield of low and moderate light demanding species [59,70].…”

Agrivoltaic Systems Design and Assessment: A Critical Review, and a Descriptive Model towards a Sustainable Landscape Vision (Three-Dimensional Agrivoltaic Patterns)

“…The following figures (Figures 10 and 11) show the state of art with designs for increasing the overall performance of the APV systems by varying the PV pattern (geometry and density) and the modules' height (besides the technologies used for the PV systems and modules). [154]). (c) tunnel greenhouse, up: 37% PV density [122][123][124], down: checkerboard arrangement [51,155].…”

“…(a) Gable roof, dynamic system. (b) Gable roof fixed system, different densities 15%, 25% and 50% (adapted from[154]). (c) tunnel greenhouse, up: 37% PV density[122][123][124], down: checkerboard arrangement[51,155].…”