Land management & conservation practices provide options for ag and solar integration - Agrivoltaics - the Future of Farming?
March 9, 2022More Info
This program includes three presentations describing each practice and how it can be implemented in Michigan.
Pollinator Habitat in Solar Energy Sites
Conservation Cover in Solar Energy Sites
Agrivoltaics - the Future of Farming?
'Dual use' is the integration of solar modules in an agricultural system in a way that enhances?a?productive, multifunctional landscape. This low-impact?energy system employs one or more of the following land management and conservation practices throughout the project site:
Pollinator Habitat: Solar sites designed to provide habitat for pollinating insects using the Michigan Pollinator Habitat Planning Scorecard for Solar Sites.
Conservation Cover: Solar sites designed in consultation with conservation organizations that focus on restoring native plants, grasses, and prairie with the aim of protecting specific species (e.g. bird habitat) or providing specific ecosystem services (e.g. carbon sequestration, soil health).
Agrivoltaics: Solar sites that combine raising crops for food,fiber, or fuel within the project area to maximize land use.
- Okay, welcome everyone. This is the Agrivoltaics presentation, where we're expanding out the understanding of what the dual use concept means in solar systems. My name is Charles Gould and I'm with Michigan State University extension. I'm housed in Ottawa county, but I work with farmers across the state on renewable energy and energy conservation issues. And one of the areas that I'm really focused in right now is how do we better utilize the land that goes into solar energy systems? And so we've talked about conservation cover. We've talked about pollinator habitat in previous presentations, and now we're gonna segue into Agrivoltaics. So I wanna begin here because this is really, this really sets the table for those individuals who are trying to understand how agriculture and solar fit together. I've said for a long time now that ag and solar is not a zero sum game, it's really not. And so this guidebook helps local planners, officials, legal counsel, policy makers in the state to figure out how to make ag and solar work together. The guide was put together by experts with Michigan State University extension and the Michigan State University school of planning, design, and construction in partnership with the University of Michigan Graham Sustainable Institute. So I put the URL in the chat box, so you can download it. And I hope that you will take the opportunity to read through it. What you'll learn today will expand on the content as it relates to Agrivoltaics in the guide. So here's the place though that I wanna start because we make reference to the fact that the master plan is so important, that it is developed in a way that supports community goals. And those goals really can be anything from resiliency to economic development, farmland preservation, climate action, energy generation, and there's more goals that a community can set that can welcome solar energy systems. So sometimes communities zoned first and plan second, and really want to get us thinking about the right way to do this. So the community's master plan sets the vision and high level goals for the community, and the local policy related to renewable energy generation is established first in the master plan with an explanation of how solar energy systems can fit into the unique landscapes and characteristics of whatever jurisdiction that is. So if we've got a master plan and it's meeting the community goals, then the next thing that really happens is we put the zoning in place that meets the tenants of the master plan. So zoning ordinances can be amended to include regulations for various configurations and scales of solar systems, solar energy systems, and the zoning regulations protect the community's health, safety, and welfare, and are based on the policies that are outlined in the master plan. So zoning regulations define the location, the scale, the form, or configuration of a solar energy system that's allowed in the community and establish the permits and processes by which solar energy is allowed and even incentivized. In talking with solar energy developers, they're not against zoning ordinances, but what is really frustrating to them is they don't know the parameters of the sandbox that they have to play in. So, they would really rather have a community say, okay, here's the parameters, and we welcome solar, but here's the area that you get to play in so to speak. And so that area, as I've mentioned before, is gonna be dictated on that master plan that's dictated on the goals of the community, and then the ordinances enable the master plan to be enacted. Okay so with that frame of reference here, now I wanna go into the dual use concept, where it's just not, where a piece of land is just not growing solar arrays, it's growing other things. And the land is utilized in a more useful way. So we have in the guide book, four different types of dual use land and conservation practices, grazing and forage, pollinator habitat, conservation cover, and then Agrivoltaics. So just a brief overview of grazing and forage, that simply means grazing livestock, raising the right kind of forages for livestock production, such that the height of those forages don't overtake that bottom lip of the solar array. And this is a real useful management tool because the solar developer gets to have the benefit of forage management. And then the sheep producer gets the benefit of having extra land to graze on. And what we're finding is that there's 87,000 head of sheep in Michigan. And right now the sheep industry is at equilibrium. In other words, the sheep industry can't expand because there's not any more land. Now, if we could take these solar energy systems and utilize them in a way that we could bring more sheep on, then we move out of equilibrium and into our land, we can expand the production of sheep in the state and the acres that the sheep came off of, in other words, the pasture that they came off could be hayed. And so sheep that come off, the solar arrays in the wintertime go be back to the farm. And the hay that has been cut then is fed to the sheep during the wintertime. So this picture really is to demonstrate the effectiveness of sheep in a grazing system. And this picture was taken in August. Six weeks before I took this picture, the lambs quarter and the foxtail, well, the lambs quarter was above my waist, and the foxtail was about my knee, around my knee. And you can see there that the sheep came in, the site, that's a 10-acre site near the Herbrook organic poultry farm. And the shepherds carved up the solar energy site into paddocks, and they moved the sheep from paddock to paddock. So they had a rotational grazing system. And you can see that they did a really nice job of mowing the lambs quarter and the foxtail down and keeping it under control. And that's really the design of a grazing system here. And sheep will eat just about anything. They're very efficient and very effective forage, consumer of forages. Pollinator habitat. What we really wanna see in the state of Michigan is, we wanna see habitat, the pollinator habitat that goes in that meets at least 76 on the scorecard. That ensures that we're gonna have a successful pollinator habitat established. We want to make sure that the right plants are put in, plants that are native, plants that will grow here. And so we have a site that has utility in terms of appearance, but also can benefit the insects that will come and visit these forts. We want a pollinator habitat that is maintained over the life of the solar project, and in areas where there's not pollinator habitat, that land should go into standard 327, which is put out by the natural resources conservation service. It's a conservation cover practice. And then conservation cover really is just putting vegetation in place, native plants in such a way that you are protecting specific species. Like you're creating a bird habitat, or you're creating a specific ecosystem service, for example, carbon sequestration of poor soil health. And you're, and these projects can be done with conservation organizations. Now, here's what we've been waiting for, Agrivoltaics. And this gets me really excited because the opportunities here are tremendous. And I wanna say up front here that I'm defining Agrivoltaics more narrowly than perhaps the industry does, the solar industry. And the reason that we did it this way is, and I'm going back to the guidebook, is we wanted, when planning and zoning board members look at what their options are for ag and solar, we could have said, okay, you can choose Agrivoltaics but really what does that mean? Well, it does incorporate grazing, this definition is kind of broad, and it incorporates some pollinator habitat and cover crops or conservation cover, but we wanted to be specific because we wanted to give individuals who are trying to make solar and ag work, we wanted to give them more to choose from. That they could really focus on. And we felt like we have the expertise that allows us to provide the help that is necessary in order to put these conservation and land practices in. So Agrivoltaics really is where we are specifically using a site to grow crops for food, fiber, and fuel. Well, what might that look like? I wanna take us in two different directions, fixed tilt solar array, and then what we call a vertical solar array. And so fixed tilt solar arrays look like what you're seeing there on the screen. They don't move. They have, when the solar array was put in, the modules are tilted such that they can capture the maximum amount of solar radiation so that the it's the most efficient way to produce electricity. And that's where they stay, 365 days a year, 24 hours a day. They don't move. Now, there are solar arrays that have modules that tilt, that move on an axis, and they follow the sun as it crosses the sky. And so efficiencies increase when you're able to track the sun across the sky. And that's what they call 'em. So there's fixed tilt and there's trackers. So trackers have the advantage of being able somewhere can hit a key on a computer and the trackers can go vertical. But for our purposes today, we're going to assume that a fixed tilt solar system is, or we're gonna talk about this fixed tilt solar array first, because that's what we have here in the state of Michigan. These are what you see typically, as you travel across the state. Okay. So what can you grow under a fixed tilt solar array? There are actually a lot of things that you can grow. It would, it was just before Christmas, I got a call from a brewery and an organic farm in Berrien county, who were wanting to put in a, and they had a business relationship where the organic farm was providing greens for salads and sandwiches in the brewery. The brewery had put on rooftop solar, they were just ecstatic with the rooftop solar, and they were seeing the benefits on their electric bill from having rooftop solar. They were really excited. And so they had talked with the organic grower who's providing greens, and they had thought that a two-acre site on the organic farm would be really nice, 'cause it would augment or provide electricity for the farm use. And so they called me and we talked about this. And I did a little bit of research on that, and greens will do very well in partial shade. And what happens physiologically is the leaf area begins to expand because of the shade. So the quality, the taste does not diminish, but the plant adapts to the decrease in light. And you can see here on the list here, and these are all things, all crops that could be grown under and around a solar or under a solar array. So let's talk about, so we have these crops, but what might be some things to consider if you wanna grow crops under a fixed tilt solar array. Well, most, for a smaller farm, you're gonna wanna use the electricity on the farm. So that fixed tilt solar array the first thing that I think that you're gonna look at is where can we use that electricity? Typically solar, typically utilities are looking for large, amounts of electricity. Really don't wanna mess with the smaller arrays unless or smaller solar projects unless they're grouped together. So the first thing that you would look at is can I use that electricity in a packing shed? Can I, are there other uses that I, we've got electric tractors out there for example, batteries now, the efficiencies of batteries are increasing. The prices are coming down. So can we use the solar array to charge a battery? Can we use it to run equipment? Those kinds of things. And this is something that I hadn't thought about, it was brought to my attention, that if we're growing crops underneath the solar array, they're gonna be protected from frost, drought, and hail damage. And over the last five years or so, 10 years, we've had early frost, and we've had drought, and there's a growing body of research that really shows the benefit in water conservation underneath those solar arrays. So if you can put crops in that are shade tolerant, and you've got the moisture there because it's not being evaporated, you've got a pretty good system there. The other thing that happens is you increase the efficiency of your solar panels to convert solar radiation into electricity, because those plants through the evaporation, the transpiration process, cool those solar arrays down, and increase the efficiencies of power production. This is another concept that I hadn't thought about, but was pointed out to me is that those solar arrays provide shade for workers who are harvesting crops. And I mean, I've been out picking strawberries and other fruit, blueberries, for example, when it's been hot, and it's not very comfortable. So this would be an incentive for workers to harvest crops, and it would be an incentive for a you pick operation. Coming in and picking crops on hot summer days, it's gonna be a little easier when you've got some shade there from those solar arrays. So I thought that those were some really valid reasons from a farmer and a consumer standpoint of putting crops underneath those fixed tilt solar arrays. So I wanted to present this concept to you of efficiencies. So if we look at a two-acre or in this case, a two hectare piece of land, and on one hectare we have a hundred percent wheat and that wheat could be, it could be any crop. And we have an adjoining acre, a hundred percent solar. What we have over that two acres is we have a hundred percent wheat and we have a hundred percent solar electricity. But now if on that same piece of land, we have 80% wheat and 80% solar on one hectare, and we have 80% wheat and 80% solar on the other hectare, then we get an efficiency increase of 60%. Okay? So that dual use concept really maximizes the value of the land, where those two crops, if you will, harvesting solar radiation, harvesting wheat are located. So let's move into the second type of solar array, and this is called a vertical bifacial solar array. And so if you'll take a look at that top picture, what you're seeing here is on the east side, you have solar cells that are collecting solar radiation, on the west side, you have solar cells that are collecting solar radiation. Okay? So as the sun moves across the sky, you're collecting solar radiation. The other cool thing about this, and the reason that I put this particular picture in is all of us know that snow reflects the sunlight. Well, during the wintertime, when you've got cover, when you've got a snow cover out there and that sunlight is out, and you're reflecting that sunlight, that vertical bifacial solar array is gonna capture that energy. That's another bonus for having this type of bifacial solar. So the vertical bifacial panel reduces snow and dust accumulation. You do get some of that on those fixed tilt, but what's really interesting here, and the last two bullet points come from this study that I've listed down at the bottom by Kahn and Hanna, Sun and Alam. The vertical bifacial solar array provides two output peaks during the day, with the second peak aligned to when peak electricity demand is highest. So this really gets me excited to think about this and what the opportunities are. So this study points out, which is summarized in this third bullet point that regardless of geographical location, and they looked, the study looked at location around the globe, a vertical bifacial farm will yield 10 to 20% more energy than a traditional monofacial farm, or a practical row spacing of six and a half feet with four feet high panels. Okay? So I'm gonna provide some additional context to this here in just to minute, but the bifacial is what makes this work, because if it was not bifacial, then you wouldn't have the yield increase. Okay, so the thing about the bifacial solar arrays that really lights my fire is the fact that it reduces competition of land use for food versus land use for electricity. And I hope that I can show you this in a way that makes sense to you. And I wanna do this with a series of graphs, and this information is gonna come from this study that's referenced down at the bottom of the slide. It was done, the research paper was published last year. So this is new data. And so if you look at the graph up here, this table here on on the Y axis, you have, this is power production per year, on the X axis, you have row distance. And then on the Y axis here, you have crop yield. And what you see here is that crop yield, and these are oats and potatoes. So this is the oat yield, and this is the potato yield. Okay? So the study came from, I believe Italy, I think is where this came from. So the significance here is when you look a power production. So as the rows get further apart, your power production starts to flatten out. Okay. And that makes sense, right? Because when they're closer together, you have the shade effect, as they get farther apart, you lose that shade effect, and they're all identical, so they're just producing electricity based on the solar radiation that they receive. So here you have your potato yield and you have your oat yield. And what this suggests is that your yield, if you look at the row distance here, and this is in meters, which would be about 65 feet versus this five meters would be around 16 feet. So it decreases by 50%. All right, the closer your modules are together, those rows, then you take a yield hit, and that would stand a reason because you have some of the shading effect, right? So your shading effect then gets diminished as your row distance increases. Okay. So keep that in mind. Now, I know this is a busy slide, and I hope that I can and help you through this. So what this study is pointed out and came to the conclusion is that land equivalent ratio, and that's this right here, this land equivalent ratio, simply means it's an indicator of the productivity of land used to assess the value of mixed cropping systems. So the study took a look at the effect of solar, the effect of solar on row distance, and then the effect of yield, and this is potatoes right here, and this is the solar. So what they've kind of done is taken the yield the yield of the potatoes and this land equivalent ratio, and they've put 'em together, so we have a land equivalent ratio for solar and potatoes, and they did the same thing with oats. So it allows researchers to compare the productivity of mixtures of crops on the same land versus monocultures, and is used for both mixtures of annual crops and mixtures of trees and crops. Okay. So, but going back again, this involved the production of electricity and crop production. So we have three systems here that they used, that they tried to determine what the land equivalent ratio is. So in this, by increasing the row distance, the land equivalent ratio decreases. Okay and that's what we see here. Although a lower distance between the mutual rows reduces the crop yield and PV production, in other words, the production of electricity, the land equivalent ratio increases since the specific electricity production per unit of area increases, and the PV contribution is more significant than the crop production to the land equivalent ratio. So that's what we're seeing right here. So this is the crop yield over row distance and the land equivalent ratio. And so this was basically, this shows us where that sweet spot is right here. And what we see here is that in the year that this data was taken, the optimal row distance was 9.2 meters for oats. So that's the intersection of this line right here, which is about 30 feet. And for, or excuse me for potatoes was about 30 feet here, 9.2 meters and there was 9.7 meters for oats, which is still about 32 feet. So what this suggests here is for the optimum amount of power production and the optimum amount of, or the optimal yield, what is that row distance. where we maximize power production, we maximize yield. And what this study suggests is that for potatoes, it was 30 feet, for oats it was 32 feet. Okay. So we can use this same calculation to figure out what that sweet spot is for vertical bifacial solar arrays and other crops. So if we want to grow alfalfa, we can figure that out. If we want grow wheat, we can figure that out. If we wanna put sugar beets in there, we can figure that out. If we want to grow tomatoes, we can figure that out. So we have the template now to figure out how we do this. Now there's one more point here that I need to make. Concerning the land equivalent ratio results achieved in this study, it's important to note that the implementation of an Agrivoltaics system can lead to equivalent ratios above 1.2, which means 20% more productivity for the same land as compared to a monoculture. So if we look at this intersection right here, and we just go up straight up and we looked at the land equivalent ratio here, we would say that this is what? Between 1.2 and maybe 1.3, let's just call it that. So regardless of whatever number that is, this particular system would show that they're getting, in this configuration, 20% more productivity out of their solar and out of their yield, combined for that piece of ground. You can look over here, this is this for oats. This is the same type of situation. I'd probably say this is about a 1.3, getting 30% more productivity for that same land as compared to a monoculture. So the point here is that these results can have a fundamental effect on the design of an Agrivoltaics system, especially farmers rotate their crops. So having said that, I know that, there's still more work. There's still more questions that need to be answered, but I think this has some real applicability to Michigan, especially when we have snow. Where we're able to still continue to produce electricity during the wintertime, by using the bifacial. And then during the spring summer and fall, growing crops. You as well as I do that, we grow more variety of crops here in Michigan than any other state in the United States. I mean, we are truly a bread basket of the United States here in Michigan. All right. So what are some uses for this? I mean, you just use your imagination here. Top left here, there's a piece of equipment going down a row, harvesting a hay crop. Next to it on the right is a dairy farm that has the vertical bifacial solar arrays used as a fence. And then on the bottom left, the configuration allows a poultry producer to put his chickens out as free range. So, I mean, that's just a few of the uses that, a few of the illustrated uses for this type of system. So what's the key? I've said this before really is planning up front. Before the first pylon is put in, the solar developer, all the parties, the farmers, whoever is involved need to sit down and talk about this. What is the end game? How does it fit to the community's goals? That master plan that I talked about earlier. I think that we're, I've said this before that if we're gonna see solar energy projects in rural Michigan, there has to be an ag component to it. And this very well could be the ticket here, where we have ag and solar together. But that's not gonna happen unless we're all sitting down at the table and we're talking about how that's gonna happen and what it's gonna look like. So, clear communications of expectations and outcomes before construction or engaging in a partnership that ensures a greater chance of long term productive partnerships is really, that's really the key to all of this. So in conclusion, dual use options are dictated by the community's master plan. They can include conservation, cover grazing and forage, pollinator habitat and Agrivoltaics. And Agrivoltaics, Agrivoltaics cropping systems can be developed for both fixed tilt and bifacial vertically mounted solar arrays, but to gain these benefits requires intentional planning. Wanna thank our sponsors, North Central SARE, Sustainable Agriculture Research and Education and Greenstone Farm Credit. And just to point out that MSU is, MSU extension programs are open to all, regardless of race, color, national origins, sex, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status, and veteran status. And there's my contact information. So let's see if we've got some questions here. Okay. Stephanie asks, would the plants get enough water from the rain under those arrays? Or would you need to supplement more water for them? My understanding is that there's sufficient water. And if you think about it, the fixed tilt solar arrays are gonna shed the rain and the snow. And if there's a proper amount, if there's forages that slow the flow of that rainwater coming off, then the rain water's gonna percolate down through the soil and it's gonna go, it's gonna disperse in a lot of different directions once it gets into the soil. And those crops, the roots of those crops are gonna go where that water is. And my guess is that they're gonna go where that drip line is. So they're gonna, automatically gravitate over to where that drip line is underneath that lip of the solar array. So, as I understand it, there's not a need for any additional, there's not a need for additional irrigation. Erika, I would agree that this looks like a great option for urban farm use. Here in Ottawa county, I know that we frequent the farmer's market during the spring and the summer, the fall. And I'm familiar with some of those farms, and the smaller farms definitely could, I think it would be a benefit to them if they implemented something like that. Stewart asked, how does the cost of the vertical bifacial array compare to a standard fixed tilt array. Right at this point, it's more expensive. How much more expensive? I do not know. But we have seen the cost of solar modules come down, tremendously. I mean, they're still coming down. And so we expect that the same will be true with vertical bifacial arrays over time. So. Billy asked, what are the quality features of good solar panels for small property owners considering garden installation? I think, what are the quality features of good solar panels? Certainly you want them to have a guarantee. The solar developer that you buy from should be registered with the Better Business Bureau. You can, there's association called Great Lakes Renewable Energy Association. And if you are looking at, or looking for solar companies that sell modules, I would go to their website, the Great Lakes Renewable Energy Association doesn't have necessarily code of conduct, but it's a group that exhibits peer pressure, if I can say that. And so the companies that you find that are Great Lakes Renewable Energy Association members are gonna be reputable because they have a reputation to uphold as a member of that association, so I think those are places where I would start. I think, I don't think I would go to a mail order, I don't think I would go to some outfit that you find on the web that sells other kinds pumps and motors and nails and bolts and equipment and stuff like that. I think I would try to, I would go and investigate local companies, companies that are registered with Great Lakes Renewable Energy Association, companies that are Better Business Bureau affiliated, those kinds of things. All right. Stewart asks where can you find information on optimum spacing for various crops? For example, berries. So I would start with the paper that I referenced. I am asking that same question, because I'm looking for opportunities to work with growers to Michiganize the results of this paper. So I know we've got people on campus that can develop computer programs where you plug in the data and we can determine optimal spacing for Michigan crops. So I guess what I'm saying is, it's a work in future. Okay so Jennifer asks, if land is sold to a developer, rather than leased, can farmers arrange to use the land like reverse lease? I would assume so, but in it's really gonna be most, well, let me rephrase that. There are solar developers that do not want anyone on their land other than those who are authorized to be there. And that's typically gonna be someone who comes in and mows, and someone who does maintenance on the equipment. Then there are other solar developers that just welcome anyone to come in. And those are the solar developers that like to develop relationships with farmers, because they recognize that there are economic and social benefits to having relationship with someone who can increase the value of that piece of land. So you're most likely gonna, if you've got a solar developer that has purchased the land, that typically, you're probably not gonna get on that land. Now, the exception is Consumers Energy. Or at least one exception would be Consumers Energy because here in Ottawa county, there's an 11-acre site that's just south of the Grand Valley State University campus. And it's their community solar project. Consumers Energy has expressed interest in grazing that land. Right now, it's got three different types of turf species of grass. And I've done some research to know if the turf species will, the turf grass will support grazing sheep, and it will. And so later on this month, I have organized a meeting with Consumers Energy engineers, with a sheep producer and other individuals that are part of this project. So we can talk about how we make this happen. And One of the things that's come out of this is Consumers Energy has a 10-acre site in Saginaw county where they haven't done anything to it yet. And they have pulled us in as consultants to design it, such that it can support grazing sheep. So they've already taken soil tests of that land, sent it off to our MSU soils lab, so we know what the soil nutrient value is. And so when we look at the types of forage crops that we wanna put out there, we have the soil test results that'll maximize our ability to, or maximize the success of putting in a forage crop. That's gonna support sheep. So long way around of answering your question, Jennifer, but I appreciate you asking that. So we've got a few minutes left. Are there any other questions? And you can certainly unmute yourself, we're small enough now that if you wanna unmute yourself and ask your question, that's fine. Or you can type it into the chat box. Okay well, thank you. Well, I hope everyone has a good day. And if there's any questions that you have, please call me, shoot me an email. I'm just passionate about this. I just think that ag and solar, there's just no reason why I and solar can't work together. And that's what we're working for is to try to make that happen. So if you wanna further this conversation, call me, shoot me an email. I'd love to talk with you. And with that, y'all have a good day.