| Work Detail |
Israeli scientists have tested three different photovoltaic technologies to power a greenhouse that houses 400 cucumber seedlings. Their analysis has revealed that the PV module cover on the greenhouse roof has a "negligible" impact on crop yield, but they also noted that the spectral transmittance of the greenhouse cover and accumulated dust can negatively affect crop performance. solar module.
A group of researchers led by Israels Triangle Research and Development Center (TRDC) investigated the impact of using photovoltaic power generation in a greenhouse housing cucumber crops and found that the impact on crop yields is negligible. .
"Our study compares the impact of opaque silicon photovoltaic technologies versus semi-transparent organic photovoltaic technologies installed at roof height in a Mediterranean polytunnel greenhouse on the growth of cucumber plants," Esther Magadley, corresponding author, explained to pv magazine. Of the investigation. «The proposed case study shows the potential of photovoltaic integration inside greenhouses. "However, more studies are needed that investigate the effect of altering the installation location on the lifetime of the PV and the effect of altering the light spectrum within the greenhouse for different greenhouse types and locations."
In the article “Examining the effect of different photovoltaic modules on cucumber crops in a greenhouse agrovoltaic system: A case study”, published in Biosystems Engineering , Magadeley and his colleagues explained that in their work they used three different semi-transparent photovoltaic technologies: glass-encapsulated bifacial PERC panels, plastic-encapsulated bifacial PERC modules, and semi-transparent organic photovoltaic (OPV) modules.
They compared the performance of the PV-powered polyethylene greenhouse to that of a reference greenhouse without solar power generation. They also compared the performance of the three photovoltaic technologies deployed in the greenhouse with that of reference solar panels installed outside the greenhouse.
Each greenhouse housed 400 cucumber seedlings, arranged in four pairs of rows with a separation of 40 cm between them. Irrigation was carried out for 30 minutes a day to obtain about 30 m3 of water per hectare. The photovoltaic system used glass and plastic encapsulated panels, each with an efficiency of 22.5%, and OPV panels with an efficiency of 4%.
For their analysis, the academics took into account parameters such as light transmission, plant growth and the performance of the photovoltaic modules. They highlighted that the diffusing nature of the polyethylene cover could improve the performance of bifacial PV modules and noted that periodic cleaning should be ensured to enhance this effect.
The team analyzed the impact of solar panels on crop growth taking into account plant height, internode length and stem diameter. He observed “significant” variations in the height of the plants depending on the photovoltaic technology and the conditions of the roof plastic.
Tests showed that plants under the OPV and plastic modules grew more, which may depend on better adaptation to capture more light in shady conditions. "Although both the plastic and silicon glass modules had separations between the cells to provide some transparency and the OPV modules had semi-transparent active material, the level of transparency of the modules are aspects that require further optimization to adapt to the needs greenhouse and cultivation," the scientists explained.
They also found that OPV, plastic and glass technologies achieved a real efficiency of 2.8%, 11.6% and 16.7%, respectively. "The glass-encapsulated Si-PV modules outperformed the others in terms of electrical output, but this came at the cost of a less favorable light spectrum for plant growth," they specified.
“Glass-encapsulated silicon PV modules offered higher crop yields and greater efficiency,” Magadley further explained. «However, the OPV modules, with lower efficiency, produced fruits of greater average weight, which suggests that their light transmittance could be more in tune with the efficient growth of plants. Although current results lean in favor of glass-encapsulated modules, the potential of advanced OPV technologies, especially those with spectral transmittance tailored to plant growth, remains an interesting prospect for integration in greenhouses, especially as the efficiency of IPOs increases.
Looking ahead, the scientists plan to apply custom-made photovoltaic modules, more efficient greenhouse materials and “innovative” designs to optimize light distribution within the greenhouse. |
