at Jack’s Solar Gardens in Boulder County, Colorado, owner Byron Kominek covers 4 of his 24 acres with solar panels. The farm is growing a vast array of crops beneath them – carrots, kale, tomatoes, garlic, beets, radishes, lettuce, and more. It is also generating enough electricity to power 300 homes. “We decided to go about figuring out how to make more money for the land, which we thought should do more,” Kominek says.
have roofs Therefore 2020 If humanity is going to prevent the worst climate change, people will need to be creative about where they put solar panels. Now scientists are wondering how to cover the canals with them while reducing evaporation while generating electricity. Airports are filling their open spaces with sun eaters. And the place doesn’t get much more open than on a farm: why not stick a solar array in a field and plant crops below? It’s a new scientific (and literal) field known as photovoltaics—along with agriculture—and it’s not quite as counterintuitive as it might seem.
Yes, plants need sunlight, but some require less than others, and actually become stressed by too many photons. Shading those crops means they will require less water, which evaporates faster in an open field. In addition, the plants “sweat”, which cools the panels upwards and increases their efficiency.
“It’s a rare win-win,” says Greg Barron-Gafford, an Earth system scientist at the University of Arizona who is studying agrivoltaics. “By growing these crops in the shade of solar arrays, we reduce the amount of intense sunlight that soaks up water and stresses the plant.” Barron-Gafford is among the recipients of a new $10 million grant from the USDA’s National Institute of Food and Agriculture for Research Agriculture for a variety of regions, crops and climates.
Barron-Gafford is running experiments measuring several variables – such as growth, water use and energy production – to determine which crops may benefit the most. For example, she has grown salsa ingredients – cilantro, peppers, and tomatoes – and found that they grow even better, if not under solar panels, than under the open. They also use only half the water. (“Think if you dropped your water bottle in the shade versus in the sun,” says Barron-Gafford.) They also found that the panels significantly reduce the air temperature, allowing farmers to take care of the plants. Will benefit. Their work suggests that the panels can act as a protective bubble to protect crops from the extreme heat associated with climate change, which affects crops and reduces their yields.
Heavy rainfall that damages crops is also increasing, as warmer climates hold more moisture. “By protecting plants in this way at a time when there is extreme heat or extreme rainfall, it can actually benefit them,” says economist Madhu Khanna of the University of Illinois, Urbana-Champaign, who received funding from USDA’s new also won. Agrivoltaics Grant. “So that’s another factor we want to look at.”
Khanna will be studying what might be the ideal solar array for a particular crop, for example, if large or small gaps are needed between panels to allow sunlight to pass through. Height is also an issue: Corn and wheat will require taller panels, while bushier soybeans will be fine with a more squat variety.
Thanks to those gaps, crops grown under solar panels are not bathed in darkness. But, generally speaking, light is more diffuse, which means it is bouncing off surfaces before hitting the plants. It mimics a natural forest environment, in which all plants, except the tallest trees, hang in the shade, soaking up any sunlight that breaks through.
Barron-Gafford has found that a forest-like shading beneath solar panels elicits a physiological response from plants. To collect more light, their leaves become larger than when planted in open ground. He has seen this happening in Tulsi, which will increase the yield of that crop. Baron-Gafford also found that black pepper potato, which grows in the shade of trees in the wild, produces three times more fruit In an agricultural voltaic system. Tomato plants also produce more fruit. This is probably due to less stress on plants from the constant bombardment of sunlight to which they are not evolutionarily adapted.
But every crop is going to be different, so scientists will have to test each one to see how they react to shade. “For example, we probably wouldn’t recommend that someone plant summer squash in the deepest shade, directly under a panel,” says Mark Uchansky, a horticulturist at Colorado State University. “The better location for this might be towards the edges where there’s likely to be a little more sun, because we’ve seen a decrease in yield in that case.”
While there are some upfront costs when panels are installed, they can actually make farmers some money, as Kominek told Grist in this 2020 story before their panels were implemented. They will produce energy to run the farm, and the farmer can sell any surplus back to a utility. And since some plants—such as the salsa ingredients in Barron-Gafford’s experiments—use less water, that could reduce the cost of irrigation. “If we can really allow farmers to diversify their production and get more out of the same land, it can benefit them,” says Khanna. “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 up toward the panels, and the plants release their water. This is dandy for the panels’ efficiency, as they perform really poorly when they get too hot. When the Sun’s photons kick electrons out of atoms, they generate an electric current, but if they overheat, the electrons become over-excited and don’t generate as much electricity when they are displaced. Huh.
And as with installing solar panels over canals, using the farm does the neat trick of not taking up any additional land. To deploy a conventional solar array, you must first free up space. But canals and agricultural fields are already in use. “It’s a big macro-trigger to get people to the table and think about: What does rural economic development look like, and what is the future of agriculture?” Andrea Gerlak, a social scientist at the University of Arizona who is working with Barron-Gafford on the deployment of agrivoltaics. “If it allows smart agriculture, sustainable agriculture, and it uses less water, that’s a big trigger for people to talk.”
But Agrivoltaics will not work for every farm. Solar panels remain a significant investment, especially on a scale the size of an area. It would also be a challenge to maneuver around them with heavy harvesting equipment, so Khanna says the arrays should be designed as flexible systems. “The idea would be that you have these panels that are not going to be fixed at a given angle and constant,” says Khanna. “They’ll be able to actually rotate and become vertical, and let the instrument pass through.”
Kominek says the United States is witnessing a massive transfer of agricultural land from an older generation to a younger generation, who have to decide what to do with their heritage. Faced with the hardships of drought and heat, it can be tempting to say, “To hell with the crops,” and cover a field entirely with solar panels. But he and Baron-Gafford don’t think it should be a one-or-one proposal.
“The question for policy makers and landlords is whether we are going to take a lot of arable land – land where we can have chickens, cows, vegetables, perennials and other things – and just put solar panels and grow weeds. them down?” Kominek asks. “Or are we going to create regulations that keep that soil active, allowing it to keep doing productive work, like it’s been doing for decades or centuries?”
Baron-Gafford also points out that agro-voltaic should not be limited to the types of crops eaten by people. A farmer can allow native grasses to grow wild under the panel, providing food for livestock, which will also benefit from shade. Or they may promote the growth of plants for native pollinators, such as bees. With the right management, that land can pull double duty as a synthetic forest—just because it’s shaded doesn’t mean life can’t thrive beneath it.
“I think everything likes a little shade,” Kominek says. “There are quite a variety of crops that enjoy it. And when it’s 100 degrees outside, I Enjoy the shade.”
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