When food crops are better in the shade of solar panels

Strengthening the resilience of renewable energies and food production remains a fundamental challenge in today's world, especially in regions sensitive to heat and drought.

Agrivoltaics, - term grouping agriculture and photovoltaic solar panels - would offer research by the University of Arizona, positive impacts on food production, water economy and the efficiency of productionelectric.

Agrivoltaics is an idea that has gained ground in recent years;However, few studies have followed all aspects of associated food, energy and hydraulic systems, and none have focused on arid areas - regions that eXperience food production problems and water shortages, but which have aSunfall of solar energy.

"Many of us want more renewable energy, but where do you place all these panels?As the solar installations take up space, they tend to find themselves on the outskirts of cities, and this is where we are already cultivating our foods, "said Greg Barron-Gafford, associate professor at the Schoolof Geography and Development and principal author of the journal which was published in Nature Sustainability.

A recent study in Nature has shown that current cultivable land has “terrestrial covers with the greatest potential for photovoltaic solar energy”, according to the in -depth analysis of solar light, air temperature andEntering relative humidity.

“Also, what use of land do you prefer-food or energy production?This challenge is at the intersection of the links between man and the environment, and this is where the geographers 'shine', "said Barron-Gafford, who is also a researcher in the Biosphere 2.“ We haveStarting to ask us: 'why not produce both in the same place?' And since then, we have cultivated tomatoes, peppers, chard, cabbage and herbs in the shade of solar panels. ”

Using photovoltaic solar panels and regional vegetables, the team created the first agro-voltaic research site at the Biosphere 2. The teachers and students have measured everything, from the germination period until theA quantity of carbon that they aspire in the atmosphere and in the water they release, via their total food production throughout the growth season.

The study focused on chiltepin chili, jalapeno and cherry tomato plants that have been placed under a PV network.Throughout the three-month-old summer growth season, the researchers have continuously monitored the levels of light, air temperature and relative humidity using sensors installed above theground surface, as well as temperature and humidity on the surface of the ground at a depth of 5 cm.The traditional planting area and the agrivoltaic system have received equivalent irrigation rates and have been tested using two irrigation scenarios - one daily and one every two days.

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They found that the agrivoltaic system had a significant impact on three factors that influence the growth and reproduction of plants: air temperature, direct sunlight and atmospheric water demand.The shadow provided by photovoltaic panels has made it possible to obtain cooler daytime temperatures and warmer night temperatures than in the traditional open -air plantation system.There was also a lower steam pressure deficit in the agrivoltaic system, which means that there was more humidity in the air.

"We have found that many of our food crops are better in the shade of solar panels because they are spared by the direct sun," said Baron-Gafford."In fact, the total production of Chiltepin was three times greater under the photovoltaic panels of an agri-photovoltaic system, and the production of tomatoes was twice as important!"

"At the same time, we found that each irrigation action could support the growth of crops for days, not just hours, as in current agricultural practices.This observation suggests that we could reduce our water consumption while maintaining our levels of food production, "added Mr. Barron-Gafford, stressing that soil humidity remained around 15 % higher in the agrivorma system than in theWitness plot when we irrigate every other day.

In addition to the advantages for plants, researchers also found that the agrivoltaic system increased the effectiveness of energy production.Solar panels are intrinsically sensitive to temperature - as they warm up, their efficiency decreases.By cultivating crops under the PV panels, the researchers were able to reduce the temperature of the panels.

"These overheated solar panels are in fact cooled by the fact that crops below emit water by their natural sweating process-just like the scorers on the patio of your favorite restaurant," concluded Barron-Gafford."All in all, it is a win-win in terms of improving our way of cultivating our food, using our precious water resources and producing renewable energy."

Un jardin traditionnel à ciel ouvert est situé à côté d'un système agrivoltaïque, dans lequel les plantes sont cultivées sous des panneauX solaires photovoltaïques. L'étude a été menée à la Biosphère 2, que l'on peut voir en arrière-plan. Credit photo : "Patrick Murphy/University of Arizona"

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[ Traduction Enerzine ]Lien principal : www.arizona.edu Autre lien : dX.doi.org/10.1021/jacs.9b07295