L R AS Published on Monday 17 January 2022 - n° 389 - Categories:agrovoltaic

Agrivoltaics: panels, sunlight, energy production per m².

Spanish researchers have developed a new modelling technique for assessing the performance of semi-transparent photovoltaic systems used to cover greenhouses. They have included crystalline silicon (c-Si) solar panels in the modelling.

However, these panels introduce disturbances that affect crop growth. They have therefore also studied thin-film technologies (a-Si, CdTe), perovskite and dye-substrate panels. Thin-film and organic photovoltaic panels are flexible and lightweight. They will be easier to integrate than c-Si-based products.

This modelling takes into account two main aspects: the energy generated by the photovoltaic system; and the rate of crop photosynthesis as a function of the transparency of the photovoltaic system. The model also takes into account three characteristics: a°) the broadband and spectral content of the irradiance, b°) the solar cell technology and its performance parameters, c°) the relationship between the rate of photosynthesis and the effective photon flux falling on the crops.

The optimum PV system for greenhouses is one that reduces the annual net photosynthetic rate by no more than 10% and has only a marginal impact on crop yields. The system should also have a total spectral transmittance (TRF) of 0.68.

The researchers also found that photovoltaic systems could generate around 135 kWh/m². Total energy yield is significantly affected by the type of crop selected.


PV Magazine 13 January

Editor's note It may be that this breakdown to determine the factors influencing crops is already known. In any case, they have not been published until now. The main points are that silicon panels are not the best technology, that the rate of photosynthesis (of sunlight?) should not exceed 10%, and that the panels provide 135 kWh per square metre, but the surface of the greenhouse is not completely covered with panels. It would be good to know how much energy is produced per square metre in the areas not covered by panels. Finally, it seems that not all plantations require the same degree of sun or protection. It would have been useful to know the extreme sunlight characteristics of two very different species.

This study clearly shows that we are at the dawn of knowledge about agrivoltaics.

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