Growing crops under solar panels: agrivoltaics takes off

Crops growing under rows of solar panels (agrivoltaics)
Image: Aaron Bugaj

In the new field of agrivoltaics, researchers are showing how panels can increase yields and reduce water use on a warming planet, according to a report in Wired.

Garden in Boulder County, Colorado, owner Byron Kominek has covered four of his 24 acres with solar panels and is now growing a huge array of crops underneath them—carrots, kale, tomatoes, garlic, beets, radishes, lettuce, and more.

The solar panels are generating enough electricity to power 300 homes.

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“We decided to go about this in terms of needing to figure out how to make more money for land that we thought should be doing more,” Kominek said.

Using a solar farm for, well, farming, is a new scientific (and literal) field known as agrivoltaics—agriculture plus photovoltaics—and it’s not as counterintuitive as it might seem. 

Plants need sunlight, but some need less than others, and indeed get stressed by too many photons. Shading those crops means they will require less water, which rapidly evaporates in an open field. Plus, plants “sweat,” which cools the panels overhead and boosts their efficiency. 

“It is a rare win-win-win,” says Greg Barron-Gafford, an earth system scientist at University of Arizona who’s studying agrivoltaics.

“By growing these crops in the shade of solar arrays, we reduce the amount of that intense sunlight that bakes off the water and stresses out the plant.”

Barron-Gafford is among the recipients of a new $10 million grant from the USDA’s National Institute of Food and Agriculture to research agrivoltaics for different regions, crops, and climates.

Barron-Gafford has been running experiments to quantify several variables—like growth, water use, and energy production—to determine which crops might benefit most. For instance, he’s grown salsa ingredients—cilantro, peppers, and tomatoes—and found that they grow just as well, if not better, under solar panels than in the open.

They also only use half the water. (“Think if you spilled your water bottle in the shade versus the sun,” says Barron-Gafford.) He also found that the panels significantly reduce air temperatures, which would benefit farmworkers tending to the plants. His work suggests that the panels might act as a protective bubble to shield crops from extreme heat associated with climate change, which overwhelms crops and decreases their yields.

Heavy precipitation that can damage crops is also on the rise, since a warmer atmosphere holds more moisture.

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“In times when there is extreme heat or extreme precipitation, by protecting plants in this manner, it can actually benefit them,” says Madhu Khanna, an economist at the University of Illinois, Urbana-Champaign, who also won funding from the USDA’s new agrivoltaics grant.

“So that’s another factor that we want to look at.” 

Read the full article here.