By Sarah Bowman and Brittney J. Miller et.al
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. They look both out of place, technology amid nature, and as though they have always been there. After all, both the corn and the 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. Grazing land for animals like sheep can also be a good fit for solar. But 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.
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 that some analyses predict will kickstart massive growth in the sector.
According to Tuinstra, these new panels can’t all be concentrated in the desert regions of the Southwest, for instance, because it would be highly inefficient to transmit that energy throughout the rest of the country. Instead, there needs to be localized buildout so that utilities and consumers can reap the economic and reliability benefits of renewables close to home.
That federal report said a focus on “disturbed lands,” such as capped landfills and old parking lots, could help prevent over-reliance on “high-value lands in current use.”
But in the Midwest and the Corn Belt, the vast majority of viable land that could be used for photovoltaic energy generation is tied up in agriculture – specifically row crops, Tuinstra said, or corn and soy in much of the Midwest and wheat and barley further west.
Concern for tradition
For some residents in areas where farmland is being eyed for this kind of conversion, solar is viewed as an eyesore and a threat to crops and the agrarian character of their communities.
In late August, the corn surrounding the Palo Community Center in Palo, Iowa, was more than six feet tall. Farmers would harvest the crop over the next month or so, just like any regular season.
But this year, something else joined them in the field: 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 that would be sited on agricultural land near town – not agrivoltaics, but a more traditional approach where the panels would not sit above any crops.
Some attendees supported the projects; many condemned them, most citing objections to taking cropland out of production. In the end, the complaints didn’t matter: 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.
“I doubt it very seriously,” said Robert Little, a 74-year-old electrician. He worked on farms his whole life and comes from a farm family. Agrivoltaics could put those generational practices in jeopardy, he said.
“The biggest concern would be old family traditions,” Little said. “And the other conflict is that I don’t think it could ever work.”
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. Further south, a Louisiana parish recently approved a commercial solar moratorium in an area that’s home to both dense petrochemical industry and sugarcane fields.
Better together
This skepticism is a big motivator for researchers who see agrivoltaics as a win-win approach – crops and panels working in concert on the same sites at the same time, instead of competing.
But there are unresolved challenges – like the shadows produced by solar panels. That’s part of what the team at Purdue is studying, Tuinstra said, to model the optimal spacing between arrays, along with technology to keep excessive shadows from interfering with crop production.
To that end, farmers in the Midwest may have an advantage over their peers in the Southwest because solar arrays tend to work more efficiently in less heat-intensive environments, said Dennis Bowman, a digital agriculture specialist at Illinois Extension.
“Having a cooler environment [with] plants underneath the solar panel that are transpiring moisture and providing a cooling effect will actually help increase the efficiency of the panels,” he said.
One federal program is exploring different types of agrivoltaics through roughly two dozen projects across the country. Some, such as in the southwest and northeast, are 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 for planting and harvesting.
But since farmers across Indiana, Illinois and Iowa plant roughly 56 million acres of corn and soy each year, versus just a few hundred thousand acres of specialty crops, professors like Tuinstra and Bowman want to know if these row crops can work for solar too. At first glance, it seems unlikely: Planting and harvesting require more sun and bigger equipment.
So some studies are also looking at how to engineer different types of seeds and crops that are better suited for growing under solar. And Tuinstra said 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.
‘A different mindset’
Midwest Agrivoltaic Systems and its CEO Andrew Poor are doing their own research on developing cost-effective solar panel substructures – known as racking – that stand taller and farther apart than normal arrays, enough to accommodate row crops and farm equipment.
Poor’s company is currently working on 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. And it may take a different mindset” to see solar proliferate on conventional farmland, he said.
Social and economic scientists on the Purdue research team are researching concerns surrounding agrivoltaics and how to address them with farmers using facts, Tuinstra said.
“If the communities are concerned philosophically [and saying], ‘We don’t want to see these arrays in our space,’ that’s entirely valid,” he said. “What the social science and economics groups need to be able to say is, ‘This is the value of having the system, this is what it does to your farms, this is how it improves sustainability of these communities.’”
For agrivoltaics to win a place in the typical farmer’s heart — and their fields — some attendees at the Palo, Iowa, meetings said they’ll have to see it to believe it.
“There’s no way it’s gonna work. There’s no way,” said Doug Hanover, a 62-year-old carpenter who started working on farms as a teenager. “I’d want to see it proven.”
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