Increasing Focus on Agrivoltaics

Researchers Look at Ways to Farm as Solar Expands in Rural America

Chris Clayton
By  Chris Clayton , DTN Ag Policy Editor
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A 10-acre solar farm at Iowa State University is a partnership between the university and Alliant Energy to develop more agrivoltaics projects that allow fruits and vegetables to grow between rotating solar panels. (DTN photo by Chris Clayton)

AMES, Iowa (DTN) -- As solar leases are becoming a more popular option for farmers, researchers are studying ways agriculture and solar power can coexist.

The term is "agrivoltaics," which basically means creating a dual use of land for both solar power and agricultural production.

A 1.37-megawatt solar farm near Ames, Iowa, started generating electricity last month with a mix of fruits and vegetables growing between and under the panels. The solar array, which produces roughly enough energy for 200 homes, is a joint project between utility company Alliant Energy and Iowa State University.

Such research projects will draw more attention as solar leasing continues to expand on farm ground nationally.

Some of the panels at the ISU site are fixed in place, while others rotate to follow the sun throughout the day and adjust the shade below the panels.

"They are following the sun and generating as much energy as possible," said Matt O'Neal, a professor of entomology at Iowa State University. "If they track the sun, they can produce more energy than if they are fixed in place."

O'Neal is part of a team from ISU that planted broccoli, squash, peppers, as well as strawberries and raspberries on the 10-acre site. They also are starting to plant grapevines on the site. O'Neal said Alliant Energy set up the site with a few different configurations of solar panels to see what would work best for farming at the facility.

"We think the infrastructure and growing conditions, if not ideal, are at least suitable for those crops," he said. "The scale at which we could work in this project fits fruit and vegetable agriculture."

While farming in Iowa is dominated by corn and soybean production, O'Neal said solar arrays are going to be more suited to develop fruit and vegetable production, as well as grazing livestock.

"A lot of the solar farms are going to be at a size where it wouldn't be profitable to grow corn and soybeans. They just aren't big enough, but fruit and vegetable farming are more likely to be profitable," O'Neal said.

Along with fruits and vegetables, there are also pollinator mixes growing underneath and to the sides of some panels. Clovers and other flowers will help support as many as 30,000 honeybees on site as well.

"It comes down to a question of profitability, not just for the farmer, but also for the solar-farm developer and their maintenance going forward," O'Neal said. "We want to know if maintaining those is cost-efficient for the site, as well as growing crops is cost-efficient for the farmers."

INTEREST IN SOLAR GROWING

Solar leasing remains controversial, but also continues to gain interest among farmers and landowners, whether agrivoltaics are involved or not.

Surveys by the Purdue University/CME Group Ag Economy Barometer in both April and May show 20% of respondents have discussed leasing farmland for solar energy production over the last six months. The May survey showed 55% of respondents had been offered long-term leases with rates of $1,000 per acre or more. As many as 27% of those surveyed had offers of more than $1,250 an acre. Roughly 30% of respondents have signed solar leases on farmland they control. Purdue's polling also indicates farmers are becoming more optimistic about solar and wind energy production.

"We are seeing a shift in how alternative revenue sources are impacting farmland value expectations," said James Mintert, director of Purdue University's Center for Commercial Agriculture.

One of the largest solar farm projects in the Midwest is the 6,000-acre Oak Run Solar Project just west of Columbus, Ohio. The project is being developed by Kansas City, Missouri-based Savion LLC, a subsidiary of the oil company Shell USA. Savion plans to develop what the company claims would make it the largest agrivoltaic facility in the country with plans to graze at least 1,000 sheep and grow crops on at least 2,000 acres, according to the Columbus Dispatch.

DTN reached out to Savion about its plans, but the company did not respond.

FARM BILL SEEKS STUDY

Still, farm groups and Congress have raised concerns about solar operations consuming more farmland. The House version of the farm bill includes language that would limit the use of any USDA funding for ground-mounted solar energy systems. The House bill also calls for USDA to study the effects of solar panel installations on farm ground, including looking at yields and land values, and food security, as well as the types of land best suited for solar energy and agricultural production.

UNIVERSITY WORK

As of now, multiple land-grant universities are already involved in research projects.

Alliant is leasing the land from Iowa State University for 20 years. The agrivoltaics work by ISU is being aided by a $2 million Department of Energy grant over four years to pay for the students and faculty at ISU to research the project and operate the farm.

"Four years is just going to scratch the surface on the questions we are interested in," O'Neal said. "We only started with (six) crops. There is a longer list of crops that can be grown under those (panels). There is some research showing leafy greens do better under the panels, for instance."

Along with Iowa State, Alliant Energy also is working to develop an agrivoltaics research site with the University of Wisconsin.

The University of Minnesota also has an ongoing project looking at solar production and grazing dairy cattle.

There are also groups at Purdue University looking at what it would take to grow crops such as corn and soybeans. Solar panels in those kinds of fields would have to be both higher off the ground and farther apart to work. That may not be practical for a solar developer looking to maximize energy production.

PANELS, HEAT AND SHADE

There's value to having vegetation under the solar panels, especially in the hottest times of the year. "As those panels get hotter, they generate less electricity. So having a cool microclimate under the panels that cool is really helpful in trying to generate as much electricity as possible. Regardless of whether you are farming or not, there is some benefit to having some vegetation under there," O'Neal said.

Research from Oregon State University also has found that potatoes grown under the shade of solar panels yielded 20% more than potatoes grown under the full sun.

O'Neal pointed to a group in France that has solar panels over apple trees. The orchard operators have discovered that trees under solar panels are less likely to suffer frost damage than trees without solar panels.

"That's in part because the panels trap the heat and provide a little bit of insulation -- just enough to be of some benefit," O'Neal said. "That was something that never came up when we were thinking about our project, but it's the kind of thing that got our horticulturalists interested."

O'Neal added, "It's just one way people who are thinking about creative ways to have this piece of technology help them farm a little easier."

View a short video at the ISU farm here:

https://www.dtnpf.com/….

Chris Clayton can be reached at Chris.Clayton@dtn.com

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Chris Clayton