Heavy rainfall that can damage crops is also on the rise, due to the warmer weather. Holds more moisture. says Madhu Khanna, an economist at the University of Illinois, Urbana-Champaign, who also received funding from the new USDA Agriculture Grant. “That’s another factor we want to look at.”
Khanna will study what the ideal solar array is for a particular crop, for example, if it needs larger or smaller gaps between panels to let sunlight through. Height is also a problem: corn and wheat will need taller plates, while bush soybeans will do well with a variety of squats.
Thanks to these gaps, crops grown under the solar panels are not immersed in darkness. But in general, light is more diffused, which means it bounces off surfaces before it hits plants. This replicates the natural forest environment, where all plants, except for the tallest trees, hang out in the shade, absorbing any penetrating sunlight.
Barron-Gafford found that forest-like shading under solar panels elicits a physiological response from plants. To collect more light, its leaves grow larger than if they were planted in an open field. He has seen this happen in basil, which increases the yield of this crop. Baron Gaford also found that pepper potatoThat grows in the shade of trees in the wild Three times the amount of fruit in the agricultural system. Tomato plants also grow more fruit. This is likely because the plants are less stressed by the constant bombardment of sunlight, to which they have not been evolutionarily adapted.
But every crop will be different, so scientists have to test each crop to see how they react to shade. “For example, we probably wouldn’t recommend that someone plant summer squash directly in the deepest shade, directly under a panel,” says Mark Ushansky, a horticulturist at Colorado State University who studies voltage farming and tests this exact scenario. “The best location for that might be further toward the edges where you’re likely to get a little bit more sun, because in this case we’ve seen a drop in yield.”
While creating the panels does entail some upfront costs, they may actually make some money for farmers, such as Kominek Tell Grist in this 2020 story before his paintings were in place. They would produce the energy to run the farm, and the farmer could sell any surplus back to a utility. And since some plants—like the salsa ingredients in Baron Gavford’s experiments—will use less water, this can reduce watering expenses. “If we can really allow farmers to diversify their production and get more of the same land, that can benefit them,” Khanna says. “Having crops and solar panels is more beneficial to the environment than solar panels alone.”
This type of setup also cools the solar panels in two ways: water evaporating from the soil rises toward the panels, and the plants release their own water. This is great for the panels’ efficiency, because they actually perform worse when they get hotter. They generate an electric current when the sun’s photons knock electrons out of atoms, but if they get hotter, the electrons get overexcited and don’t generate much electricity when they’re displaced.