Agrivoltaics research: Solar panels prove to be good for saffron plants in Vermont

Courtesy of Energy News Network: As the growing season winds down at most New England farms, it’s only just gearing up at Golden Thread Farm, in Stowe, Vermont. The plants that fill the farm’s two plastic-covered high tunnels are just beginning to come out of their dormancy. Come October, they will bloom into purple crocuses with thread-like stigmas that will soon after be hand-harvested for sale as saffron.

More commonly associated with Iran and Spain, the cultivation of saffron, an expensive spice prized for its flavor and medicinal properties, is “a side project” for Brian Leven, a lawyer and the farm’s owner. He sells the dried stigmas online for $50 a gram — roughly the yield from 182 flowers — and supplies some local restaurants and stores.

“I charge a lot more than what you could find online, but it is a better product — I can vouch for its purity,” Leven said. “It’s a nice little business for someone who has the time and commitment for it.”

That’s what Margaret Skinner, a researcher at the University of Vermont, had in mind when she and some colleagues began experimenting with growing the crop back in 2015.

“We could see diversified vegetable growers growing lots of spinach and kale, but they weren’t making any money at it because everybody was growing the same thing,” she said. “We felt saffron offered an opportunity for these growers to add a high-value crop.”

It turned out the saffron plants were hearty enough to withstand the Vermont winters, even when planted in the ground. And Skinner and her colleagues at the university’s North American Center for Saffron Research and Development have since made another potentially lucrative discovery: Saffron can successfully be grown around a solar array.

A study released earlier this year summarized the results of their three-year experiment, conducted in cooperation with iSun, a solar energy and clean mobility infrastructure company based in Williston. Saffron was planted in both raised beds and in the ground at an iSun solar array in Burlington. Plants were placed in the aisles of the array, under the panels and around the perimeter.

The research concluded that, given the right soil conditions, saffron grows well in the aisles and at the edges of a solar array. The crop was most profitable when grown in raised beds.

Steven Yates, director of project development at iSun, said the study demonstrates that solar panels and crop production need not be mutually exclusive.

Dual use of farmland is the way forward,” Yates said. “Particularly in the more-urban farmland areas, where the infrastructure and distribution systems are there and can handle the load easily.”

One challenge with growing crops in a solar array is that the panels and mounts create obstacles for regular tending such as weeding and watering, Skinner said. But saffron is not a labor-intensive crop until harvest time.

Once you plant the corms — the underground stem base — you can leave them in the ground for three to five years, she said. The leaves remain green throughout the winter and don’t require any care.

After they bloom in the fall, “it’s very intensive for two to three weeks when you’re picking the flowers, and then you’re out of the array,” she said. “So you aren’t needing to put a lot of manpower into the solar array area.”

The crop is not for every farmer, however. For some people, the process of picking the flowers and separating the tiny stigmas by hand is “too fiddly,” Skinner said. “You need some fine motor skills.”

Yates is now working on another pilot project that will test a novel racking system between rows of arrays that will allow for different crops to be grown using mechanical equipment.

“Changing minds that installing solar on ag land does not exclude that land from agriculture is the path forward,” he said.

Some solar developers in Vermont — like the 2.49-megawatt Open View Solar Farm in New Haven — are already practicing agrivoltaics by partnering with farmers to use the land around arrays for grazing sheep. But there is a lot more potential, said Peter Sterling, executive director of Renewable Energy Vermont, a clean energy trade association. His organization has been lobbying to get the rules changed around net metering to make it easier to site solar on farms; currently, those rules favor brownfield sites.

“The bottom line is, in Vermont, it’s getting harder and harder every year to be a farmer,” he said. “Having solar on your land can help balance the books. But it’s not easy for a farmer to get something sited, and it should be. If neighbors raise objections, they can drag out the permitting process for so long that the developer finally walks away.”

Given the pace of climate change, combining solar with agricultural uses is going to be essential, Skinner said.

“There’s a part of me that doesn’t like the way an array looks on a field — I’d like to see cows out there,” she said. “But cows are not going to save us from the climate crisis we’re in.”


Lisa Prevost is a longtime journalist based in Connecticut. She writes regularly about housing, development and business for the New York Times. Her work has also appeared in the Boston Globe, CNBC.com, Next City and many other publications. She is the author of “Snob Zones: Fear, Prejudice and Real Estate.” A native New Englander, Lisa covers Connecticut and Rhode Island.

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