Under patches of shadow, Greg Barron-Gafford crouched to check on a row of artichokes. It was mid-April in the southern Arizona town of Oracle, which had already seen a string of 90-degree days in the previous few weeks, plus a 100-degree spike. Still, the plants appeared robust, their leaves lush and perky. Other plants — herbs, garlic, carrots — seemed to be thriving, too, despite the heat. The garden’s bounty had even drawn wild animals: Recently, gophers had raided the site, so Barron-Gafford and his colleagues were considering installing a buried fence to thwart them.
Part of the garden’s vitality was thanks to the 30 3-meter-high solar panels overhead, which provide crucial shade that keeps the crops underneath from drying out. About 30 feet away, another garden — that’s a generous word for it — sprawled forlornly under the full heat of the sun, its plants wilted and shriveled.
Barron-Gafford studies agrivoltaics, the practice of combining agriculture with solar energy generation. He and his team planted these experimental gardens at the Biosphere 2 research facility, seeking to better understand both the benefits and the practical challenges involved in implementing agrivoltaics. He has also helped develop agrivoltaics projects all around the world, working with communities in Kenya, Mexico, Morocco and elsewhere.
But while agrivoltaics seems to be gaining traction around the U.S. and worldwide, Arizona is still an agrivoltaics desert. Aside from Barron-Gafford’s pilot projects, solar fields and farmland tessellate across the Sonoran Desert, as unmingling as oil and water. Significant practical challenges have prevented the widespread adoption of agrivoltaics, from solar-unfriendly state policies to the entrenched skepticism of both farmers and utilities.
Barron-Gafford, of course, wants to change that.
AGRIVOLTAICS is often touted as a win-win for both solar generation and agriculture, especially in summer. Shade reduces crops’ heat stress and helps farmers save water: In one of Barron-Gafford’s studies, crops under panels needed 50% less irrigation than those fully exposed to the sun. In turn, the plants release water from their leaves, which cools solar panels and boosts their efficiency.
Agrivoltaics should be a shoo-in for Arizona, given its abundant sunshine and dwindling water supplies. By late June, 97% of the state faced moderate to exceptional drought, conditions that are becoming more frequent and intense with climate change. Agriculture alone consumes three-quarters of the state’s water. Now, mandated water cuts are making farming increasingly untenable, forcing farmers to sell their land for less thirsty enterprises, including solar development and generation.
Agrivoltaics could extend the lifespan of Arizona’s farms and bridge the two competing land uses. “Maybe we can change the conversation from ‘food versus energy’ to ‘sustaining food production because of energy,’” Barron-Gafford said.
Other locales have embraced agrivoltaics. One poster child for the practice is Jack’s Solar Garden in Longmont, Colorado. Once a hay farm struggling with water shortages, it now boasts 3,276 solar panels that power 300 homes and shelter a diversity of produce, from corn and raspberries to medicinal herbs. The panels stand 17 feet apart and about 6 feet off the ground, leaving enough room for the farmers to maneuver in between and underneath.
“We do better now selling electricity than we did growing hay,” said owner Byron Kominek. The business’s agricultural arm is also flourishing: His leafy greens grow 2 to 5 times larger than they did under the open sky.
“We do better now selling electricity than we did growing hay.”
Colorado’s solar-friendly policies have made Jack’s Solar Garden possible. In 2019, Gov. Jared Polis unveiled a plan to eliminate greenhouse emissions in the next few decades, spurring utilities to procure clean energy en masse, including from community solar projects like Jack’s Solar Garden. Kominek has a 20-year business agreement with Xcel Energy, the state’s largest utility, to sell clean energy to its customers. On top of a multitude of regional incentives, Colorado also exempts property taxes associated with the value of solar installations.
Arizona’s starkly different policy landscape makes it hard for farmers to replicate Jack’s Solar Garden’s success. The state lacks incentives for non-utility entities such as community parties to enter the solar playing field. Starting in 2017, Arizona slashed the margins of small-to-medium solar installations that sell surplus power back to the grid. Now, the credit for energy sales is 30% to 70% of the retail price, unlike in Colorado, which allows the same type of providers to sell at the buying rate.
“It takes a really long time to pay off the up-front investment in solar panels,” said Kate Bowman, regulatory director of the policy advocacy organization Vote Solar, of the state of Arizona’s non-utility-scale solar. “No project could ever pencil out.”
OVERALL, HOWEVER, solar is booming in Arizona, feeding a rise in energy demand. But it’s largely driven by the utility-scale development that is rapidly usurping the state’s prime farmland, drawing resentment from the remaining farmers. By 2040, nearly 90,000 acres of land in Arizona that currently grow crops are projected to be covered in utility-scale solar panels, according to a report by the American Farmland Trust.
And many Arizona farmers say they doubt that solar is compatible with farming. For Nancy Caywood, a 71-year-old alfalfa and cotton producer in Casa Grande, water is her biggest headache, but putting up solar panels to save on irrigation is out of the question, because the farming machines she uses are over 14 feet tall. “There’s no way that you could physically put those panels up that high,” Caywood said. “We don’t want solar on our farm, period.” Even if it were possible, erecting lofty-enough panels would be cost much more than installing lower ones.
Nearly 200 miles west, produce farmers in Yuma County, the winter vegetable capital of America, are also shrugging at the idea. John Boelts, a co-owner of Desert Premium Farms which specializes in salad crops, said that his primary concern is food contamination. Overhead structures might invite birds to perch or roost, then defecate on the crops below. “Foodborne illness is such a big risk,” Boelts said. As a precaution, his team doesn’t even harvest anything under power lines. (According to Kominek of Jack’s Solar Garden, bird droppings shouldn’t be an issue, since USDA standards require all produce be washed before sale.)
“We’ve let the agrivoltaics conversation be dominated by engineers and folks who have a more technical interest in agrivoltaics without asking a lot of hard and critical questions around who stands to benefit,” said Carrie Seay-Fleming, a sociologist who has worked with Barron-Gafford at the University of Arizona. “It’s not a silver bullet.”
IF FARMERS aren’t willing to put solar panels in their fields, could solar companies instead bring farming to their facilities?
Barron-Gafford aims to demonstrate that it’s possible. For another project, his team plans to grow desert crops and vegetables on 10 acres of a 100-acre solar array in Casa Grande.
This solar-centric model may be the key to scaling up agrivoltaics, given the swaths of solar already present in Arizona. But in Barron-Gafford’s experience, utilities worry that farming might interfere with energy production. Solar panels are usually fairly low-slung, often placed directly on the ground. For this experiment, his team made several concessions to the landowner, the energy company AES: Crops must be less than 4 feet tall, the average height of the panels, and grown between the rows of panels rather than directly underneath them. That means the plants will be shaded only during early morning or just before sunset.
Moreover, retrofitting utility-scale solar installations to be agrivoltaics-ready is no easy task. The ground beneath the panels is usually cleared of vegetation to simplify maintenance. For the new project, Barron-Gafford’s team spent a grueling few weeks in April laying down irrigation lines, tilling and adding compost to the compacted soil around the panels.
Then, in May, the team hit a fresh obstacle: Most of Barron-Gafford’s research funding, which had come from the Departments of Agriculture and Energy, was axed. Still, the team is committed to squeezing out one harvest by summer’s end, to avoid two years of preparation ending with nothing to show for it.
“We’re hoping that that (people) will care once they see what’s possible,” Barron-Gafford said. “I do think that humans have a great capacity to work through problems and figure out a way.”
