Purdue University doctoral students Geoffrey MacRae Sanchez (left) and Varsha Gupta (center), with plant breeding professor Mitch Tuinstra (right), visit their research plots where solar panels stand over soybeans and corn on Sept. 1, 2022 in West Lafayette, Ind.
Purdue University doctoral students Geoffrey MacRae Sanchez (left) and Varsha Gupta (center), with plant breeding professor Mitch Tuinstra (right), visit their research plots where solar panels stand over soybeans and corn on Sept. 1, 2022 in West Lafayette, Ind.
Acres of corn stand tall on both sides of a narrow country road in northwest Indiana. It’s late August and the corn is tasseling, its golden crown coated in dew droplets that are glinting off the morning summer sun. Then there is a different gleam on the horizon, one that’s brighter.
Sprouting out of the corn like a super crop are four arrays of solar panels standing 20 feet high and towering above the stalks growing below. Both corn and panels are harvesting the sun.
“Either way, they are storing solar energy,” said Mitch Tuinstra, a professor of plant breeding and genetics at Purdue University. “One is storing them as electrons and the other in the plants.”
Tuinstra is one of several Purdue faculty and graduate students studying these solar arrays on the university’s research field, just a few miles off campus in West Lafayette, Ind.
Farmland is well suited for solar development of all kinds, for the same reasons it’s good for growing crops – it’s largely flat, drains well and gets lots of sun. What makes these Purdue research panels different is that they haven’t taken farmland out of production – they’re built overtop of the corn itself.
It’s a practice known as “agrivoltaics” or “agrisolar,” where active farming and solar happen in the same place instead of separately. The approach brings many complications that researchers are still trying to address – but they see big benefits in trying to hone in on best practices.
Farmers who want to lease their land for solar as an extra income source will reap even more economic benefits if that land stays in production – and some approaches to agrivoltaics may even help the crops themselves, researchers say.
“We want to see if we can devise systems that have minimal losses in terms of crop productivity, while maximizing their electricity output,” Tuinstra said.
Moreover, he said, researchers want to see how the co-location strategy could be a salve to a growing strain between solar and farming in the Corn Belt – where residents and towns are pushing back on what they see as industrialization in rural communities. That includes communities in Wisconsin, where University of Wisconsin-Madison researchers are working with Alliant Energy to pursue similar research on university-owned land near Stoughton.
Solar potential in farm country
The stakes behind this effort are high: Solar power has a key role to play in reducing the greenhouse gas emissions, chiefly from fossil fuel-fired power plants, that are driving the increasingly deadly effects of climate change.
The U.S. Energy Information Administration estimates that by the year 2050 – when the Paris Climate Accords say the world must reach net-zero carbon emissions to avert further climate catastrophe – solar generation will account for 20% of net electricity generation in the U.S., up from a mere 3% in 2020. The Biden administration is investing to get to that point, including billions under the Inflation Reduction Act for solar production and investment tax credits.
But panels can’t be concentrated in one region – such as the deserts of the Southwest – because of the high cost of transmitting the energy to other locales. Instead, Tuinstra said, localized renewables buildout will help utilities and consumers reap the benefits close to home.
A 2021 Department of Energy report concluded that by 2050, land equal to a maximum of 0.5% of the contiguous United States’ surface area would be required for solar projects to help meet climate change goals. By comparison, farms account for approximately 40% of all land in the United States. Still, that 0.5% of U.S. land would represent nearly 9.5 million actual acres, close to that of all the corn and soybeans planted in Indiana alone.
In the Corn Belt, the majority of land that could be used for solar is tied up in row crops. For some residents in these areas, solar represents an eyesore and a threat to crops and culture.
In late August, the corn surrounding the Palo Community Center in Palo, Iowa, was more than six feet tall, on its way toward harvest season. But this year, something else was sprouting up nearby: signs with a red X through the words “industrial solar.”
In the community center, residents waited to hear the fate of a proposed 200-megawatt solar installation – a traditional design, not agrivoltaics – that would be sited on farmland near town. Some attendees supported the project; many condemned it, most citing objections to taking cropland out of production. The projects were approved the following week.
When several meeting attendees were asked if layering solar arrays over active farmland could be a viable compromise, many were skeptical.
Robert Little, a 74-year-old electrician who said he has worked on farms throughout his life, said agrivoltaics could put generational practices in jeopardy.
“The biggest concern would be old family traditions,” Little said. “And the other conflict is that I don't think it could ever work.”
Similar concerns have popped up in Wisconsin. In Iowa County, for instance, Invenergy’s Badger Hollow Solar Farm, whose first 150 megawatts went online in December 2021, sparked debate between farmers who welcomed the benefits of leasing their land and residents who feared the 5.5-square-mile project would make the area a “solar wasteland.”
Communities and counties across the Midwest are saying no to solar — like in Indiana, where nearly a third of counties have ordinances restricting, if not prohibiting, renewable projects. This skepticism is a big motivator for researchers who see agrivoltaics as a win-win approach.
But there are unresolved challenges – like the shadows produced by solar panels. Tuinstra at his team at Purdue are studying this, hoping to model the optimal spacing between arrays and develop technology to keep excessive shadows from interfering with crop production.
Building agrivoltaic in cooler environments could even be good for both the panels and the plants below, according to Bowman.
In the Southwest and Northeast, one federal program is looking at co-locating solar with specialty crops such as lettuces, tomatoes and berries. These smaller plants are better suited for an agrivoltaic environment because they benefit from shade and require smaller equipment.
But in the Midwest, corn and soy acreage far exceeds that of specialty crops – and it requires more sun and bigger equipment for planting and harvest. So some studies are also looking at how to engineer different types of seeds and crops that are better suited for growing under solar.
Social scientists on the Purdue team are also researching public concerns surrounding agrivoltaics and how to communicate about them with farmers using facts, Tuinstra said. And solar companies are getting involved, reaching out for advice on designing a system that can fit around planting and harvesting.
But trying to optimize both crops and technology is putting researchers and developers in a chicken-and-egg loop: To get funding for projects and lower development costs, you need years of proof that they work. But to build those proofs of concept, you need money and affordability.
“It’s the Catch-22,” said Andrew Poor, the CEO of Midwest Agrivoltaic Systems. “I’m always looking for funding.”
Poor’s company is doing its own research on cost-effective ways to build taller, wider-spaced solar panel racks that can accommodate taller crops and bigger equipment. He’s pursuing smaller agrivoltaics projects with partners willing to pay for the cost of materials, hoping to eventually ramp up to more expansive production as data rolls in.
But it’s tough to attract development partners in a field that remains relatively unproven.
“They seem just as leery as the farmers are when it comes to signing up for a project,” said Tyler Lloyd, the solar operations director of Midwest Agrivoltaic Systems.
Still, not every farmer is opposed. Those with combinations of row crops and livestock have proved more receptive to the idea of agrivoltaics, Bowman said. Newer farmers less tied to traditional growing and harvesting tactics may also be interested in the tech.
“The trend has been to get this big equipment, to farm a lot of acres, and to farm it fast in a timely fashion to get the maximum yields,” he said – so to see solar proliferate on conventional farmland, “it may take a different mindset.”
This story is a product of the Mississippi River Basin Ag & Water Desk, an editorially independent reporting network based at the University of Missouri School of Journalism in partnership with Report For America and funded by the Walton Family Foundation.
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