Vegetables can flourish when co-located with solar projects, said researchers at the Iowa State University.
Their research is a year into a four-year study examining how varying heights and designs impact crop production in agrivoltaic farms, where solar installations and farmland are co-located on the same land. The study hopes to determine whether higher solar arrays create better growing conditions for horticultural crops and beekeeping production.
The research team began by growing crops in the standard solar panel configuration for utility-scale solar farms, Ajay Nair, the lead principal investigator told pv magazine USA. After focusing the study’s first year on the project’s tilting panels that track the sun, the researchers are now incorporating land between fixed-angle solar panels into research plots.
“In an attempt to have the biggest bang for our research buck, we focused our initial farming efforts on the industry standard,” Nair said. “If we can make it work there, then we can make it work at the many current and future utility-scale farms,” he said. “In this way, we hope to more quickly translate the research into recommendations for farmers interested in agrivoltaic practices.”
Image: Christopher Gannon, Iowa State University
(See also: Solar grazing supports healthier soil, food for sheep, study finds)
Nair said that after last year’s crop yields, they identified some crops, such as strawberries, that appeared to do well in the single-axis tracking configuration. Now, the researchers have planted the same crops around the panels with fixed-angle configurations to determine whether the crops can handle the more consistent shadow patterns from the solar panels, he said.
The solar array was built in two parts. One part is an 811 kW fixed-tilt array facing south. Six fixed-tilt rows have a standard leading edge of two feet off the ground in front and three rows have a five-foot leading-edge height. The second array is a 946 kW single-axis active tracker array, which is the most common configuration for modern utility-scale solar projects. Eighteen of the active-tracker rows are the standard above the ground by about five to six feet. The other five rows are between eight to nine feet above the ground. All solar panels on the site are bifacial, meaning they generate power from both sides.
For both the single-axis tracking and fixed tilt configurations, Nair said they are also testing a mix of plants they selected for their attractiveness to pollinator and comparing the pollinator mix to an industry-standard mix of grass and clover. They will then use seed mixes when comparing how the crop’s different vegetations grow between and under panels compared to an open-field control garden.
Image: Christopher Gannon, Iowa State University
“This comparison helps us determine how the plants are affected by the shadows and microclimate of the solar farm,” Nair said. “From our first field season, we have some preliminary evidence that some crops produce as much, if not more, harvestable products when grown between the panels than in the open-field control.”
During the project’s first year, summer squash and peppers produced better in the solar panel area, he said. However, Nair said this is not true for all crops, such as broccoli, which did not grow as large as the crops in the control plot.
Image: Christopher Gannon, Iowa State University
“These results are why this research is important, as we need to inform farmers of what their best options would be if they explore agrivoltaic practices,” he said.
“We are exploring how each establish and the extent to which they are used by pollinators, including honey bees kept at the farm,” he said. “The clover has really established, resulting in a early nectar flow at the farm. This has resulted in our honey bees being more productive in the first month of the summer than in the entirety of our first growing season.”
“This data set will help us better understand the economic potential of agrivoltaic practices to not only be a stand-alone source of income for farmers, but also a form of reducing operation and maintenance costs for the solar developer,” Nair said.
Built, owned and operated by Alliant Energy, the solar installation is made of 3,300 panels that generate 1.38 MW of capacity. The installation was completed in 2023 and provides Iowa State University with clean energy via renewable energy credits. The project was Alliant’s first agrivoltaics endeavor.
The project was funded by a $1.8 million grant from the U.S. Department of Energy Solar Energy Technologies Office as part of the $8 million Foundational Agrivoltaic Research for Megawatt Scale (FARMS) funding opportunity in 2022.
Read about the research the other recipients of the FARMS grant are doing here.
This article was corrected on June 4, 2025 to state the researchers are from Iowa State University and not the University of Iowa.
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I think this is an Iowa State University program, not a University of Iowa program?
You are correct! I realized I had incorrectly said it was the University of Iowa during the editing process, but must have forgotten to change it in the subhead. Thank you for pointing this out, we appreciate you!
The sub headline incorrectly says “University of Iowa” This is happening at Iowa State University, in Ames. The University of Iowa is in Iowa City. I attended the latter.
You are correct. Thank you very much for the correction. We’ve amended the article. Go hawks!