Crop and Energy Production Merge in Iowa Project

Solar power may be the answer to the world’s future energy needs. But its benefit is limited if it hampers our ability to produce food.

Using farmland for solar panels, especially in the agriculture-heavy Midwest, is fraught with controversy. “There is concern that solar energy will prevent land from being used for farming,” says Matt O’Neal, professor of entomology and Henry A. Wallace Chair for Sustainable Agriculture at Iowa State University.

What if the two could co-exist?

A new study underway at Iowa State University seeks to answer that question.

“Solar panels don’t have to be disruptive. It doesn’t mean farming the land has to stop,” says O’Neal. “We want to look at possibilities and profitability.”

A multi-disciplinary team of ISU professors, graduate and undergraduate students is working with Alliant Energy through a public-private partnership to study the potential of agrivoltaics, the simultaneous use of areas of land for both solar panels and agriculture. The team includes horticulturalists, economists, environmentalists, sociologists, engineers and even entomologists.

The project is the first of its kind. “There has been research conducted, but not on a utility scale,” says Nick Peterson, Strategic Partnerships Manager with Alliant Energy, “and not in a public/private partnership with a land grant university.”

There has also been little research conducted in the Midwest, the heart of agriculture, where farmland is gold.

The solar farm

Alliant Energy completed construction on the 10-acre Alliant Energy Solar Farm on the ISU research farms near Ames, Iowa in the fall of 2023. Managed by the ISU College of Agriculture and Life Sciences, the research farms are used to study livestock production and the agriculture industry.

Alliant designed, built, owns and will operate and maintain the 3,300 solar panels and 16 inverters at an ultimate estimated cost of around $4 million.

The ISU team will plant fruits and vegetables beneath and among the panels to measure not only plant growth but the effect on energy production.

“One of the questions before the electrical engineers is the effect of the vegetation on the panels,” says Peterson. “Engineers know from previous study, particularly out of Colorado, that panels that are cooled can absorb more energy. What we’re studying now is how different types of panels and vegetation impact energy production.”

The solar array consists of two types of panels—fixed and single access tracker. 

Fixed panels are like those often found on rooftops. As the name implies, they stay in one fixed position. For scientific method purposes, the lowest edge of the panel sits at two heights, five feet or 2.5 feet. 

Tracker panels move with the sun. They are placed at five or eight feet. All panels are bi-facial, meaning they absorb sunlight on both sides.

Horticulturalists are growing raspberries, strawberries, summer squash, peppers and broccoli, along with control grasses. The first of the raspberries and the grass mix went in this fall. The remainder of the crops will be planted in the spring. 

Traditional Iowa crops such as corn and soybeans were avoided due to the need for large equipment and the small acreage. 

Issues such as harvest timing and growing season will be studied, as well as climatic impacts. O’Neal sees specific varieties eventually being developed for the environment.

The harvested crops will be sold to the university’s dining halls.

The crops, along with flowering perennials, were chosen with natural attraction of pollinators in mind, and the project will include beehives, with researchers studying how the bees develop and what kind of honey they produce. Other projects in various parts of the country have utilized sheep grazing in their agrivoltaics, but livestock was ruled out at ISU due to limited area and water availability.

“Bees are livestock, too,” says O’Neal.

More questions

While the bees, plants and energy production are under study, sociologists and economists will weigh in.

Sociologists will study public perception of agrivoltaics and solar power in general. Researchers will look at how such a project could affect a community and will track how information based on science leads to future community decisions.

“There are valid concerns about how land will be used in the future,” says O’Neal. “People are leery about ag land being used for recreation, urban development or energy production.” Wildlife conservation is a concern, including pollinators. Some see solar arrays as disruptive to agriculture, Iowa’s top industry. “This project will give the public a chance to see if various modifications to a solar farm make these sitings more palatable.”

“The bottom line is this is Iowa, and we should be growing things,” says Peterson. “For us to be good stewards of our customers, we need to be looking at how we can maximize land use.”

For Alliant Energy, the economics of power production are front and center. Peterson says 52 percent of Alliant’s energy comes from a mix of renewable sources such as wind and solar. The rest comes from natural gas and a few remaining coal plants set to retire by 2040.

A three-person economics team will study the cost and profitability of the solar farm. “Every step can be costly,” says Hongli Feng, assistant professor at the ISU Department of Economics, “from the land to the ground preparation, to the seeds and equipment and labor.” 

Based on the cost tracking, the team will create an enterprise budget tool for farmers and solar field developers.

The basic business model is based on reality. 

“The land lease agreement between ISU and Alliant Energy follows what landowners might experience if the energy company chooses a site on their land,” says O’Neal. “We want to look at what that relationship would be like.”

“Much of the existing research is regionally specific,” adds Feng. “We need to see how it applies to Iowa and the Midwest.”

The partnership

Alliant Energy has been active in research conducted by ISU’s Electric Power Resource Center for more than 60 years. According to EPRC director Anne Kimber, the center’s research focuses on integrating renewable energy into the existing structure that wasn’t designed for it.

In addition to the ongoing research, Iowa State University has a five-year strategic plan for operational sustainability, which includes goals for tripling the use of renewable energies and ultimately, carbon neutrality.

“ISU called Alliant to explore what sustainable energy production on the research farm might look like,” says Peterson. “ISU has added several new facilities to its research farm in recent years, including a feed mill and a turkey teaching and research facility. These projects give students the opportunity to learn agriculture and the agriculture industry firsthand, but they come with operating costs.”

The Alliant Energy Solar Farm will produce 1.375 MW of power at maximum capacity, enough to power the equivalent of around 200 homes. The renewable energy ISU receives will offset a portion of the university’s annual carbon emissions.

That alone is a pragmatic goal. But Ray Klein, director of partnerships at Iowa State University’s College of Agriculture and Life Sciences, saw more opportunity. He proposed leveraging the project for academic and ag industry research.

The result was a four-year, $1.8-million grant from the US Department of Energy, the largest grant awarded by the agency for such a project.

The research

Iowa State University is a land-grant teaching college, and the project includes surveys, seminars and field days to share findings with agriculture producers and the public through Iowa State University Extension and Outreach.

“When we first started this, ISU’s priority was that they be able to share what we learned,” says Peterson.

The information may be especially useful in the growing farm-to-table sector of ag production, where producers often operate on smaller tracts of land and sell locally, and food produced in agrivoltaics systems may more immediately go into local food systems impacting food availability.

“Local food systems are the next level of diversity in ag,” says Peterson. “This opens up a new avenue for farming that is coupled with renewable energy. I’m hoping we can develop the research base to show if agrivoltaics is viable, profitable and sustainable for this part of the world.”

“This is unbiased research,” adds Ajay Nair, an ISU professor of horticulture. “We will report what we find, and people can decide whether this is a system that is feasible or not.”

Kimber sees benefits beyond food and energy. “There are a lot of communities who are thinking about community solar arrays,” she says. “Imagine if the community also gets to have gardens associated with those arrays? You’re starting to build community around that. I think that’s worth working on.”