Science Friday
Hosted by Ira Flatow
Original podcast
Agrivoltaics combines solar panels and agriculture on the same land. It’ll be an uphill battle for it to hit the mainstream.
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Hey, I'm Ira Flatow, and you're listening to Science Friday. In America's heartland, some farmers are experimenting with technology to make their farms more environmentally and economically sustainable. One practice called agrivoltaics involves solar panels, farmers growing their harvests under the panels. The panels create shade for the plants, and the evaporation from the plants cools the panels, making them more efficient. Seems like a win-win. My next guest has been reporting on how agrivoltaics is working for small farmers across the Midwest. Jana Roche-Schleis is a news producer at KBIA in Columbia, Missouri.
Her podcast series, The Next Harvest, is available to listen on podcast platforms. Welcome to Science Friday.
Thank you so much for having me.
Nice to have you. Okay, did I get agrivoltaics right on this one?
You did, totally. What it is, is sort of in its name. The word itself, agrivoltaics, is a combination of agriculture and the term photovoltaic, as in a PV panel. So it's the idea of doing these two activities, farming and generating solar power, simultaneously and on the same piece of land.
So farmers are getting two harvests out of this, the traditional crop and then the solar energy, and making money on that, too?
They could, yeah. A farmer has said to me in the past, "It's sort of like farming the sun."
Well, can they make more money on the solar side than on the farming side?
Potentially, and that kind of gets into the minutia of how the energy is used. A lot of farmers will lease land to a solar developer or a utility for one of those large-scale solar projects. And in that case, they would receive like essentially a rental payment for providing land to the solar power plant. But on a smaller scale, a farmer might just build a ground-mounted solar array that provides enough energy for them to use, you know, to power their homes or barns. And that would be similar to a rooftop solar system on a house.
Well, don't the plants need the extra sun? Or is it actually beneficial to the plants to get some shade?
Yeah, I should say this is still very much in early research stages, but the farmers I talked to in Missouri, as well as research of agrivoltaics in hotter climates like Arizona, they're actually finding that the shade of the panels is benefiting some crops, herbs and produce, which might be not what we would usually assume because when you garden, you want to make sure that those plants get full sun.
Hmm. So how common is it to see agrivoltaics on a farm? Is it still a novelty, I would imagine?
Oh, it's certainly still a novelty. Like I said, it's being researched and experimented with across the country, but I don't think it's happening anywhere where it's common or on a large scale, with the exception of one variety of agrivoltaics. Perhaps the biggest agrivoltaic success story is actually sheep grazing.
Really?
Yeah. A solar developer told me flocks of sheep are sort of the easiest plug-and-play option into the most common type of solar design. For one, sheep are the right height to graze under and around panels, and they eat grass, which is generally what's growing within the array. And unlike goats, which are similarly sized, sheep don't necessarily have the tendency to chew on wires or jump on panels or anything like that.
Right. So you're talking to farmers. Let's, tell us what you're hearing from farmers about their incentive for trying this.
Yeah, there were two huge incentives that I found among my reporting for the farmers I spoke with. One of them is land. When a solar array is built, the operators need to find out what they're going to do, how they're going to manage that land under the panels. And farmers need land, and they're also uniquely qualified to manage it. So kind of a potential for collaboration here. But another reason farmers are trying this out is for the shade. And that was the case for Linda Hetzel in Kearney, Missouri. She grows herbs and produce and to sell to Kansas City restaurants. And she began working under the shade of her ground-mounted solar array last year.
Okay, let's hear what Linda had to say.
So in the drought of 2012, I started experimenting with growing things under a short-leaf pine in the backyard. And I can grow tomatoes and pole beans and various herbs underneath a tree.
Yeah, Linda said she's been farming on that same piece of land for 30 years, and she's noticed a change in the intensity of the heat she's experiencing each summer, to the point where she's getting up at first light to harvest before it gets too hot, both for herself as a human working into those outside conditions, but also for the produce that she's harvesting. It can wilt the hotter it gets. So there might be a benefit both to humans, the farmers themselves, and to what they grow, just to have a little bit of shade.
Well, we touched on this a bit about folks talking about the solar side of things. What's the incentive for them to have panels used for agrivoltaics?
Yeah, Ira, farmers and solar developers, they need exactly the same thing. And that's pretty large swaths of land that are cleared and flat and get a lot of sun. So solar projects, as they're being proposed and built, especially in rural and agriculture communities, they face a little bit of pushback because of that competition it's creating for land. So AgriVoltaics is saying, is there a way we can reduce that competition? Is there a way we can do both? And the developers I've talked to have told me straight out that they're interested in finding ways for AgriVoltaics to work. So their projects are, one, better suited for, and, two, potentially more accepted by the communities that they'd like to build in.
You mentioned having sheep under the panels. What about cattle or other ranches? I mean, they're a little bigger animals, aren't they? But more of them.
Completely. And that's something I'm really interested to see how that plays out. There are some significant modifications you'd have to make to a solar, the typical solar design, for it to work with a herd of cattle, right? It'd have to be taller, and then that means costs go up. You know, the higher you get on the panel, the more steel you need in the ground. They don't really know how cattle might interact with this infrastructure, or what impact it could have on the cow itself. And plus, cattle need, they're bigger than sheep, they need more grass. So what does this look like as far as moving them around and just having enough space for cows? But I'm really interested to see if there's any way that shade can similarly benefit cattle. I'm from Wisconsin,
so I'm interested in the dairy industry. Dairy cows can face heat stress, just like a human, and then that can negatively impact their milk production. So I'm really looking to see researchers and farmers who are experimenting with this, whether that shade might provide some release for the cows, and whether they can come up with some sort of design that's suitable for a herd.
Well, when you keep an eye on this, will you come back and tell us what you found?
It would be my pleasure.
Yeah, well, it's nice to have you. Jenna Rose Schleis is a news producer at KBIA in Columbia, Missouri. Her podcast series, The Next Harvest, is available to listen to on podcast platforms everywhere.
We have to take a quick break, but don't go away. More on this when we come back.
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So, we've learned that agrivoltakes can work well on small farms with smaller crops. But more than half of U.S. cropland is dedicated to commodity crops, like corn and wheat and soybeans. Could agrivoltakes work on this larger, more industrial scale? My next guest researches what it's going to take for agrivoltakes to hit the mainstream. Dr. Madhu Khanna is professor of environmental economics at the University of Illinois in Champaign and director of the university's Institute for Sustainability, Energy, and Environment. Welcome to Science Friday.
Thank you very much for having me.
Nice to have you. You've studied how well agrivoltakes works under a variety of conditions across the U.S. Did you find success was different depending on the environment where the farm was?
Absolutely. So we have studied the impact of agro voltaics in arid conditions in Arizona, semi-arid conditions in Colorado where grassland is common, and then the rain-fed conditions in Illinois. And what we find is that having these solar panels can really be beneficial in arid conditions like in Arizona with specialty crops that need to be irrigated, or even say in Colorado where irrigation is needed for these types of crops. Having panels can significantly reduce evaporation and therefore preserve soil moisture, and this can reduce the need for irrigation with panels.
And we've also observed that it can improve the quality of the produce so that it tastes better because it is able to preserve moisture.
What are the big challenges to using agro voltaics for commodity crops, like I say, wheat or corn?
Well, one of the big challenges is that the height of the panels would have to be raised beyond the level that is typically found in a conventional solar farm. In a typical solar farm, the height is around four feet from the ground. And in order to grow crops next to panels or even underneath panels, then the height would have to be raised to six, eight, or even 10 or 12 feet, depending upon the height of the crop that is being grown, so that the crops don't shade the panels.
Is that feasible?
That is certainly feasible, and there are many examples of that being done. But the cost of raising the panels goes up exponentially because not only do you need more steel in order to raise the panels, but the foundations have to be much deeper. The all the cabling has to be buried under the ground in order to protect it from equipment. And so all of that significantly raises the cost of setting up an agro voltaic farm. The second challenge is that the typical space between panels is fairly narrow in a conventional farm. It's about 18 feet. But in order to allow Now for typical, you know, conventional farm equipment to operate,
uh, as is the case with uh, our conventional corn and soybean farming, we would need to increase the space between panels to about forty feet or so. And so the amount of panels in a field would go down and that would affect the amount of energy that you can get from a forty acre field, for example.
Hmm. So also, could the shade from solar panels be a negative for some of these commodity crops?
Yes, that is exactly the other uh, issue as the crops that we're talking about love full sun. And so having them next to panels poses shade on them. And that has been found to reduce the amount of uh, crop yields that we can get. This, of course, varies depending upon the distance between the panels. Some rows will be under full sun and may not be affected, but the rows closest to the panels are more likely to be impacted. Now, all of this really depends also on the design of the panels. So if the panels are fixed in their tilt, you know, the impacts will be more negative on certain uh, parts of the field.
If the panels rotate and track with the sun, the impacts will, will differ. And then depending upon the material that the panels have been made out of, that also impacts the amount of the radiation that can pass through the panels to the crops underneath. And so many factors are going to impact the, the effect that it's going to have on crops.
So far, I've heard just negative things about this idea. More expensive to build the solar panels, uh, more expensive to maintain them. Not as much use from them as we would in smaller crops. This doesn't sound very hopeful, or, or am I reading this wrong?
Well, I think we are still at really the early stages of investigating the performance of this technology and most of the studies have really looked at trying to fit agriculture into a solar farm setting rather than thinking about how we can optimize a field in order to produce both food and energy better, what kind of spacing, what height. The other thing to keep in mind is that we're looking at impacts under current climate conditions, but as the climate changes and becomes more variable as is expected in the future with extreme heat days and extreme precipitation, then in fact, our research
shows that these having panels to provide protection to the crops might actually be beneficial.
Is there a lot of community opposition to solar panels on farmland because I've driven through some farmland where I've seen, "Don't put solar panels here." Do you see that happening in other places?
Yes, that is happening more and more. There's many, you know, counties that have put bans or restrictions on converting cropland to solar farming and, you know, the restrictions are growing and this causes delays for solar developers in getting their projects approved as well as many projects get canceled. And it also raises the costs of producing solar energy because solar developers may not be able to access the land that is the most suitable and the closest to the grid where you can produce it at the lowest cost.
Is this an aesthetic thing? People just don't want to see these ugly quote-unquote solar panels among all their beautiful farmland?
Yes, that is certainly one of the reasons for this opposition, but I think it's more than just that. I think it's also there is a sense of identity within an agricultural community and a sense of place and what they do and farmers like to produce and the solar farming, you know, takes away from all of that and I think. That is really one of the reasons. Also, small agricultural communities, if they happen to be located next to a transmission grid, they would be a prime spot for solar farming and a lot of land could get converted relative to the amount that's currently under crop production.
This can also then impact other businesses that rely upon agriculture. And so this can have cascading effects on that community and surrounding businesses.
What do you think the solar industry can do to ease these tensions?
Well, I think the solar industry can actually work with the farmers and try to co-develop the idea of producing food and energy on the same land. And rather than, you know, coming in from the outside and expecting to lease this land and use it, they can work with the community to figure out the best business models that would appeal to the community and benefit the local community as well as benefit the solar industry and solar energy development. Right now, there is this sense that the solar developers are coming in from the outside and, you know, converting this land and the benefits are going to urban areas and the users of energy.
Whereas the costs are really being borne by the agricultural community that is losing its land and getting displaced. And so, you know, one of the mechanisms could be to to take some of the benefits and the earnings and the revenue from solar generation and feed that back to benefit the local community through improvements, you know, schools or other things that the community cares about as a way to really benefit both the local community as well as the consumers of electricity that may be all over the country.
You know, we've talked to farmers and ranchers over the years on this show about renewable energy. We've talked to people with solar panels. I remember years ago, talking to a rancher in Oklahoma, who had one of the first wind farms, very small wind farms, and he said, "You know, I make more money doing renewables than I do ranching." Can farmers look at this as a source of income, or is it still not up to that point where they have to weigh the pros and cons of this?
Farmers can certainly benefit from converting a part of their land for solar energy. It is a much higher value, you know, commodity, and less risky than crop farming. So, from a farmer's perspective, even if the shading reduces some yield, but the higher income that they can get from solar energy would more than make up. And so, again, the relative trade-offs will depend upon how much is the loss in income from farming, and so on, and what portion of the land is put into energy versus agriculture. But there are many conditions under which farmers might actually benefit. And that's kind of another
aspect that I think is worth considering, that currently, all of the models that you're talking about for agriwill takes are ones where it's the utility that is owning the solar energy generation and the investment in it, and they are leasing land from the farmer. And in those cases, utilities may struggle to cover the costs of an agriwill take installation. But if we could think of alternative models, where it may be more farmer-owned as well, or farmers partnering with solar energy developers to co-develop this, then I think this might be more beneficial for both parties.
Yeah, because it doesn't take really much total farmland, does it, to meet solar energy needs here in the US?
Yes, absolutely. Currently, only about, you know, half percent or maybe half to one percent of of crop land is is being used for solar energy. And even up to twenty fifty, projections of the potential production that might take place of solar energy, it's expected would take less than two percent of crop land. So the total amount of land that's needed is not very large, given the land that we have in the U.S. However, these impacts can differ across different communities and some small communities where agriculture is already a small share of the overall county, you know, the amount of land might might be substantial as a percentage.
Mm hmm. Final question, what kind of research, I always ask, what do you think you need in the future to make something work? What kind of research do you want to do next on agrivoltaics?
Well, the the research that needs to be done is to see how we can optimize the use of land for meeting multiple needs. You know, we've we sort of focus very much on either one thing or the other, either solar energy or or agriculture, but there's a lot of benefits thinking about co-location and what what the advantages of that might be. But we really need to step back and think about what would be an optimal configuration of panels and crops and the height of the panels, the space between them. Also, we're looking at things with the current conventional equipment, but perhaps there
is the opportunity to have smaller equipment and that can operate under narrower spaces and still perform well. And with the growing use of A I. technologies and robots, you know, small robots that can operate between between rows of crops and so on, there may actually be a possibility to better use land and be able to produce crops productively as well as produce energy. And so, you know, much more research is needed in order to figure out how to do agrivoltaics well.
Yeah, you think that if there's a will, there's a way to make this work.
Absolutely. That's really been the cornerstone of U.S., you know, agriculture is to be always innovative and developing new approaches to be able to increase farm productivity.
Well, Dr. Kana, fascinating. Thank you for taking time to be with us today.
You're welcome. Dr. Madhukana is Professor of Environmental Economics at the University of Illinois in Champaign and Director of the university's Institute for Sustainability, Energy, and Environment. This episode was produced by Kathleen Davis.
That is me. And if all of this talk of farming has you craving getting your hands dirty, I have the perfect pitch for you. We are working on a story about how children's immune systems and microbiomes develop. You've probably heard that a little bit of dirt is good for your immune system. Do you make sure that the kids in your life are spending ample time rolling around on the playground? Do you get into arguments with your parents about cleanliness? You know what? We would even take a story about the grossest thing that your kid has ever done. We want to hear it, so give us a call at 877-4-CY-FRY. That is 877-4-CY-FRY. Thanks for listening. We'll catch you tomorrow.
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