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Hosted by members of the University of Minnesota Extension Beef and Dairy Teams, The Moos Room discusses relevant topics to help beef and dairy producers be more successful. The information is evidence-based and presented as an informal conversation between the hosts and guests.
00;00;11;03 - 00;00;37;06
Brad
And welcome to The Moos Room, Brad. Today. Kind of one of those unusual times where both Emily and Brad are gone. So I'm recording this early. I'm actually going to Germany, going to visit some farms, go to a farm show. Speaking at a conference there so needed to put something together. And this one's going to be on gravel.
00;00;37;08 - 00;01;07;20
Brad
It's a presentation that Anna Claire Mines woman from Colorado and myself did on Gravel techs, where we talk about some of our cattle grazing agro voltaic work. And I think it's pretty important to kind of discuss that as we move out of the grazing season this fall and into winter. But hopefully you learned something new and learn about what actually is going on in Colorado and other parts of the US from a gravel tax and solar grazing standpoint.
00;01;07;21 - 00;01;35;19
Brad
And then at the end is mine. It's kind of a rather long one, but I think I put Anna Claire first, and she'll give you lots of good information about Agro Voltaic and some of the projects that they're working on from that perspective. And hopefully you enjoy it. And I'll be back and give you a travel vlog all about agriculture and dairy cattle in Europe when I get back.
00;01;35;23 - 00;01;36;23
Brad
So we'll see you next week.
00;01;36;26 - 00;02;09;09
Anna Clare
I titled the presentation research on the Solar Savanna. And, this is a term that comes from one of my colleagues on this, this research project. Nick de Vries. And, I'm going to explain what this means. Let's see here. All right. So first, I just wanted to introduce myself a little bit less formally and say that I've been a fan, of grassland ecosystem since pretty much I ever laid eyes on a horse.
00;02;09;09 - 00;02;36;02
Anna Clare
I think was really when I. When I fell in love with grasslands and all the herbivores, and animals that inhabit them. And so, in adult life, I get to, work in grasslands every day. I dream about them. And so I get to work sometimes as a research scientist, sometimes as a consultant, as a, kind of partner.
00;02;36;07 - 00;03;13;06
Anna Clare
Advisor to ranchers and landowners, large landowners, mostly. This is in the West. And I get to develop programs that support ranchers and all kinds of great things. And so the question is, what is she doing in the energy? Where did she come from? So the the reason why I'm working in energy, as of the last few years, is really these guys, and this herbivory cycle, is really the foundation for, what we're calling grazing arable takes and why we're even considering this.
00;03;13;06 - 00;03;50;23
Anna Clare
And if you've heard me speak before, I'm really passionate about the fact that, our solar sites, if they're going to be installed on, on grasslands, pasture lands, then we have the opportunity to really, manage them as these whole ecosystems, these grazing systems where there are my, healthy soil microbiome and roots and nutrient cycling and pollinators and of course, our large herbivores that without them we really don't have, healthy grasslands.
00;03;50;26 - 00;04;20;09
Anna Clare
So, this relationship between cattle, you know, our other large herbivores, zebra, wildebeest, bison, elk, deer, this relationship is really, is as old as time. And there's there's no reason why we shouldn't, really insist on on managing solar sites that are built on grasslands, as grazing lands, as rangelands. So here's where the savanna comes in.
00;04;20;12 - 00;04;58;01
Anna Clare
So if you picture a savanna right there, it's primarily grasslands, with some trees, some shrubs, and if you picture transform this picture into a solar savanna, we can think of those shade structures of, of trees, these large trees, being in some way substituted by, by solar modules. We may take those wild herbivores and consider substituting in this kind of manmade system, domestic livestock.
00;04;58;01 - 00;05;46;08
Anna Clare
Right? Sheep and cattle. And this is the, the metaphor or really the concept of the solar savanna that, we know there are very vast differences between solar panels and trees. I realize this, but if we think of them as, as modifying the the shade and radiation dynamics of a pastured or grassland system, and the interaction of, of herbivores with those, those structures, that canopy, in other words, then we do have some, you know, commonalities that we can consider, maybe positive, and some dynamics that were positive and in fact, as Brad was talking about this, this has been going on with sheep.
00;05;46;08 - 00;06;15;08
Anna Clare
And so we, this is what it looks like. We have very, you know, we can we can have very healthy, biodiverse, grassland, landscapes, with large herbivores, and we can actually and the research, over the last 14 ish years is actually showing us that there is this symbiotic, relationship that we can observe.
00;06;15;10 - 00;06;42;03
Anna Clare
And there's, there are components of this that, that we're understanding, you know, the this sheep utilize the solar panels or cattle, for shade, for example. And the grass actually may, depending on the grass species, may actually be more productive and have an advantage with the access to shade or with shade of the panels. The grass and the sheep have a relationship.
00;06;42;03 - 00;07;16;08
Anna Clare
And this is, kind of the system that we're working in. But what happens here, right. We're pretty comfortable, I would say, in the United States and, and globally, we're getting we're nice and comfy with sheep. But what happens with cattle that are much larger, more massive, taller. It would that change, you know, the balance here that we are finding pretty pretty regularly in a sheep and solar system and that is exactly what the project is looking at that I'm working on with Silicon Ranch.
00;07;16;08 - 00;07;40;14
Anna Clare
And this is the, the homepage of our website. So on this website you can find lots more information on the project. Please visit it. And the project is called Cattle Tracker. And some of the comments in the chat we're asking about tracking systems. And so I will this is a project that is, using tracking systems.
00;07;40;16 - 00;08;04;26
Anna Clare
I really just love, the organic nature of the work that University of Minnesota and Brad's team has done, because it just was just born out of this curiosity and the opportunity that was captured. Right. Like you said, we just looked at how tall the cattle were. We we thought they would fit in that. And, you know, you just start trying things and I, I love that.
00;08;04;26 - 00;08;45;06
Anna Clare
And because of that work, that we reviewed very closely and we were able to look at and, and, you know, in retrospect in terms of time, we were able to build our, our research design from that. So you've heard the cliche, you know, standing on the shoulders of giants. Well, there are not very many giants on planet Earth that, in the cattle agro tech world, but I would I would call this team, one of the giants that we were able to stand, on the shoulders of and and elevate, you know, you know, and do something different, and build upon the work that they did.
00;08;45;09 - 00;09;13;11
Anna Clare
So, I want to recognize the team because I'm here speaking and you're seeing my face, but there are many faces behind this work. Our research team is made up of a really diverse group that is, it's international. It's a combination of scientists and students and engineers and ranchers. And and it's, you know, men and women of different backgrounds and all kinds.
00;09;13;15 - 00;09;42;17
Anna Clare
So we are the science team, and then we're led and we're guided by this advisory committee, from across the country who really provide, an expertise, type of backbone. We can lean on these, on these guys to review our work, to, ask questions, to provide feedback and lots of wisdom and experience. So, shout out to our advisory committee.
00;09;42;19 - 00;10;11;17
Anna Clare
So we started this project and, it really was launched. The project was was envisioned, earlier, but it was really launched. We're in our third year now. So in 2020, the end of 2022, and one of our first task was to conduct a very comprehensive literature review. Specifically on cattle approval text. Well, guess what? There was hardly anything other than the University of Minnesota's work, right?
00;10;11;24 - 00;10;34;11
Anna Clare
So we we, we designed, you know, worked on a literature review that really kind of branched out from just, cattle and solar. And I'll explain that in a minute. But this is a publication that has gone through a peer review. It is not published, but we are supposed to hear, like literally any minute now, for a publication date.
00;10;34;11 - 00;11;08;24
Anna Clare
So keep your eyes and ears peeled for this title. And this work that's coming out in Earth's future Journal of AGU. It's almost there. And so what what this literature review did was, looked at these intersections of what makes up an agreeable tick grazing system. And what we the way we structured the literature review was to look at the intersections of livestock and solar, solar and land and land and livestock.
00;11;08;27 - 00;11;36;20
Anna Clare
So we drew from the animal sciences, literature, from the rangeland science literature from sheep and solar, because there's a little bit more literature out there on that. And then solar and land. So soil, forage crops, all of those micro climatic kind of dynamics, including evapotranspiration and things like that. So, we identified through this literature review all of these intersections.
00;11;36;20 - 00;12;01;28
Anna Clare
So just tons of complexity here in those, those intersections of livestock, solar and land. We have all of these sub sections and connections across disciplines, and across areas of study. And that is all housed. And that's all surrounded by this context of, society and policy and economics. And so there are also pieces of literature out there on that.
00;12;02;00 - 00;12;20;26
Anna Clare
So we integrated all of this into this giant literature review, and we came out with, what we ended up doing with it was a gap analysis because we wanted to since since this is a very nascent field, we wanted to help guide future research. Right. So where what's missing? What do we still really want to ask?
00;12;20;26 - 00;12;51;17
Anna Clare
What do we still really want to study? What do we need in order to expand, commercialize? You know, cattle and solar. And so our gap analysis resulted in these six categories. And this is this is the first time this is ever being shared publicly, by the way. So, it's exciting. And we hope this would be like, you know, something to, to come back to if you are in a research setting.
00;12;51;19 - 00;13;25;19
Anna Clare
So we identified that, more research in just photovoltaics and livestock integrated right integrated systems. And I want to recognize also how our project is addressing these gaps. So we did the literature review. Then we really develop and start to conduct a study that addresses the gaps. That was the whole point of the literature review. So in this, this PV livestock integration, is our cattle tracker research.
00;13;25;22 - 00;14;04;00
Anna Clare
We also identified that there, that there is a need for more layered ecological impact. So not looking at, you know, myopic, my myopic, cause and a factor like, you know, one dependent variable and or one independent variable and one dependent variable, but having this kind of holistic or like layered, understanding of ecological dynamics and in fact, we are looking at this kind of multi dimensional, ecosystem research in Georgia and Tennessee, which is where our research is taking place.
00;14;04;03 - 00;14;33;23
Anna Clare
Biogeochemical and economic modeling is another area, being able to make predictions, based on a particular geographic context. For example, and we're working with the De Saint biogeochemical model. And all of our data is going into the parameterization, of a model that is tuned to an aggregate take system. Management best practices is another one.
00;14;33;25 - 00;15;09;27
Anna Clare
We are definitely using our our work as a case study for understanding this. And being able to provide learning on that social dimensions. We have part of our, our project is a stakeholder survey, that we just got IRB approved. So it will be kind of officially, launched and available. So if you keep touch with us on LinkedIn or on that website, you'll be able to, participate in this survey, understanding social opinions and perspectives on cattle approval, text barriers, things like that.
00;15;09;29 - 00;15;41;04
Anna Clare
And then we identify that, there's just a need for collaborative science. This is a very cross-disciplinary area. And, and we wanted to build a project that was a living model for this collaborative science. And not just that it's, you know, collaborative in terms that are different people are involved, but that it's truly across disciplinary, but also cross-sector because that's what energy and agriculture is.
00;15;41;07 - 00;16;06;17
Anna Clare
Policy economics, government private. And, and we really want to cross those boundaries. That's the best way we can learn. And so that's what we set out to do. So our, our timeline, that, looks kind of like this for, for our research. So the, the x axis is, is time. It's the number of years that our project is slated for.
00;16;06;17 - 00;16;33;02
Anna Clare
And here in the middle this dotted yellow line is where we are now. The y axis are those those ecological layers that I talked about in that gap analysis and how we're addressing this. So we are really looking all the way from 50cm below the soil surface all the way to six meters. At the that the sensors mounted on an eddy covariance flux tower.
00;16;33;02 - 00;17;07;19
Anna Clare
So we're looking at this kind of a micro atmospheric layer. We're looking at the vegetation layer. We're looking at the multiple layers of soil depths. And we're looking at different, layered variables that all are correlated in some way, that we're figuring out. So from, from the air, meaning, you know, carbon dioxide wind, wind speed, wind flow, humidity, above and below the solar array, forage, soil, subsoil.
00;17;07;19 - 00;17;26;05
Anna Clare
We're also, looking at economics and, and building a financial model for a, cattle tracker, looking at animal behavior and a lot of that. We are building off of the work of, of Brad and his team. And so we've we're about in the middle. We've got a long ways to go, but that's where we are.
00;17;26;05 - 00;17;49;03
Anna Clare
Just to give you an idea, and so in, in the cattle portion of the study, the cattle tracker portion, aside from the ecosystem dynamics portion, I kind of think of them in two different buckets sometimes, we're really looking at, you know, how do we safely, humanely regenerative li like supporting land health, and profitably integrate cattle.
00;17;49;09 - 00;18;16;23
Anna Clare
So this is a little bit different than, Brad's work. He called it demonstration. And that's so, so important. And it makes sense in the context of an educational institution. But the, the leader of our project is a, is a solar developer company. It's a for profit entity and, and a leader in research and demonstration, but in the kind of the utility side.
00;18;16;26 - 00;18;37;25
Anna Clare
So what we're really looking at all along the way is how do we prove or how do we make it make sense to scale this up to commercialize it, to make it insurable, to make it bankable? And, and those are the things we continue to kind of ask. And those are the things that guide kind of what we're doing.
00;18;37;25 - 00;19;06;16
Anna Clare
So we're kind of looking at this being something, build it, creating something and studying something that is scalable AI and all of those different dimensions. And so we're doing this in two phases. The first phase already happened, and this first phase was really looking at the different heights, right. So it's great to have the, the case studies and have the demonstrations that okay, at an eight foot, you know, talk to height and a six foot leading edge height.
00;19;06;22 - 00;19;29;29
Anna Clare
The cattle are not wrecking the panels that that is a great, anecdote. Right. That's and to have that studied and to have that, demonstrated for so for a really the longest study that we have on that is, is this one, so we, we took that and thought, okay, that makes a lot of sense. And in fact, the rancher that we're working with, Mr..
00;19;29;29 - 00;19;46;01
Anna Clare
Will Harris a of white oak pasture, said, yeah. You know the browse how do we go out into the woods and look at where the cattle browse? The browse height is about, you know, seven feet. Anything taller than that is just not even going to be an issue. So we started asking, you know, what is the range of height that we want to test?
00;19;46;01 - 00;20;12;09
Anna Clare
And we really wanted to test this and it and it also affects, you know, different, ambient kind of conditions for the cattle regarding airflow and humidity. And like I was talking about heat stress and things like that. And our lead scientist on this portion of the study, actually did a, a not quite a meta analysis, but she the citation is here.
00;20;12;09 - 00;20;42;29
Anna Clare
And, and Lily Edwards Calloway, has this, really great tables and summary data on the literature thus far about shade structures and cattle and kind of where the heights, how the different heights affect these aspects of cattle health and welfare. So we designed a trial and the trial took place in pens. We needed to control the environment, in order to, to zero in on height of the panels.
00;20;42;29 - 00;21;07;13
Anna Clare
Right. So we studied three different heights, two meters, 2.5m and three meters. This was a mock up. So these panels were not electrified. There's no electricity running through anything. But we did create a very realistic scenario. So we had dampers, we had cables strung. We had real panels, real talk tubes, real IBM piles. Everything was real.
00;21;07;13 - 00;21;32;27
Anna Clare
It just wasn't electrified. We made sure that it was designed to be failsafe. So in case the cattle did try to wreck a panel or try to ram into the I-beam or something, that it wouldn't come tumbling down and hurt the animals. We had to get this this research approved by I a cook review. And so we designed it to be safe, in a, in a test situation.
00;21;32;27 - 00;21;58;17
Anna Clare
So what we were interested in learning is what is the frequency of physical engagement per height, what body part does the animal engage with. And three, with what part of the module does the animal engage. And we tracked either you know, the module or the panel itself. The talk to the controller, the cable, the damper, the brackets, the piles we looked at, where they engaged, what were they curious about?
00;21;58;17 - 00;22;22;29
Anna Clare
What were they wanting to to nose or lick or head scratch or whatever it was that they were doing? And then fourth, our fourth kind of variable was with what intensity did they engage with the mock ups and here's an example of what this kind of looked like. And we used bulls. So we tested 144, bulls.
00;22;22;29 - 00;22;46;20
Anna Clare
Half of them were adult bulls and half of them were yearling bulls. And we had it we classify them by weight. I think this was a group of yearling bulls. And, you know, those scratch, but you can see them also hanging out, in the shade and pretty, kind of not really interested in the panel. So what did we learn?
00;22;46;23 - 00;23;19;24
Anna Clare
We learned that, there is a significant kind of inverse relationship, but direct between the interaction frequency. So how much they engaged and the height. And you can see that in the graph on the left. The lower the height the higher the interaction frequency. And that's the y axis. We also saw that there is a significant relationship between interaction frequency and the num, the number of days in the pen.
00;23;19;24 - 00;23;41;06
Anna Clare
So we left groups of animals in the pens under the solar module mockups for two days. And what we saw was in day one, there was a lot more frequent engagement they were exploring. It was like, I don't know, a honeymoon period. Right? By day two, they really didn't care. There was less the frequency of engagement dropped off.
00;23;41;11 - 00;24;15;04
Anna Clare
They arbitrated. They they just kind of got used to it being there, just like a shed or, anything else that cattle have in their environment. There is a significant relationship between height and then the location on the animal that they engaged with. So in this lower table, lower right table, the in with the two meter height, they were much more engaged with their head or neck, than the two and a half or three meter height, if that makes sense.
00;24;15;06 - 00;24;42;11
Anna Clare
And then looking at the table on the top right, we see a couple things. We see that above two meters, we saw, significant reduction in interaction frequency by 43%. If we went from a two meter height to a 2.5m height, we also saw that then the three meter height reduced the interaction by 59%. So this is this is, you know, makes sense.
00;24;42;11 - 00;25;05;17
Anna Clare
But it's good to see the numbers. It's good to see the data. And to see also in this last bullet that even at a two meter height, at the lowest height that we tested. And this is lower than what's built at University of Minnesota by some feet, that the solar panels were never even touched. They were really engaged more with the dampers.
00;25;05;17 - 00;25;27;06
Anna Clare
And so if you're a solar engineer, designer or someone looking at building something for cattle, I would look at the dampers, in a and this is of course in a tracking system, because that was the, the part of the modules that they were the most engaged with. And those also happened to be kind of more delicate pieces of, of the structure.
00;25;27;09 - 00;26;10;15
Anna Clare
So something to consider. What are we doing next? We're doing phase two. Let me check myself on time. Yeah. So we're doing phase two. Phase two is a 4.5MW solar installation. It's being built in, Tennessee. It's being built as we speak. And hopefully that mock up trial that you saw looking at three different heights. So we will be replicating that study on this site to what we're calling an outdoor test lab, in December or so, November, December, kind of at the end of this year, this outdoor test lab, as it is, is designed to be a research site.
00;26;10;17 - 00;26;34;10
Anna Clare
It's it's designed, it's going to be producing energy. It's the energy has an off taker already. Everything is moving forward, but it is also in everyone on board. All the collaboration knows that this is also a research site and there will be ongoing research here. So I want to want to let you know too, that with, you know, it's kind of an important issue these days, but very a very cool thing.
00;26;34;10 - 00;26;59;04
Anna Clare
And, and something to consider if you're in the, on the solar side of this is that, the majority of all the components of this solar installation come from within 500 miles of the site. So it's it's domestic, USA made, content. And, and that's just something that we're very proud of and it's able to move forward.
00;26;59;06 - 00;27;24;25
Anna Clare
What are we going to study. What are we going to do. Now in phase two. And so we have we have organized our research plan into three buckets. One is behavior looking at activity time. Two is behavior looking at use of space. And three is health and performance. And so again standing on the shoulders of giants, we did not this did not just come out of nowhere.
00;27;24;25 - 00;27;48;11
Anna Clare
We we reviewed literature. We looked at what other researchers had done, and we looked at our own context and our own questions and our own interests, and we melded all that together. And this is what we've come up with. So this is what we plan to study on the outdoor test lab. And using instrumentation similar to what Brad talked about and some other things.
00;27;48;11 - 00;28;08;09
Anna Clare
And, and we're really interested in and how they interact with the space, what they do, where they spend time, and also in proximity to other animals. And this is all compared to this control. So you see how the site is divided into a control pasture and then the array. So we will have cattle in the control.
00;28;08;09 - 00;28;32;09
Anna Clare
It's just an open pasture. Same grasses, same kind of land, same soils and things like that. And then we'll, we'll have cattle simultaneously in the array. And so we'll be able to compare cattle in and out of the array. We will be using a rotational grazing system. This is the third bullet here where we'll develop, subdivisions of the array.
00;28;32;09 - 00;28;52;09
Anna Clare
So paddock a paddock kind of rotational grazing system and we'll replicate that, but on a smaller scale in the control pasture. So as much as we can apples to apples, management and stocking density and things like that of the cattle. But we're just either they've got access to panels or they don't basically. And then we'll be tracking all of these variables.
00;28;52;11 - 00;29;17;19
Anna Clare
In addition to that, we will be replicating all of our ecosystem dynamics research that we've been conducting for two and a half years in Georgia. This is what that research design looks like. And it will be we'll use our control in on the Tennessee site similarly to this bottom right hand corner in the reference. So we have basically three comparisons.
00;29;17;21 - 00;29;42;20
Anna Clare
I'm not going to be able to spend time on this and I've presented on it before. So if you've never seen any other presentations, I'm going to have to fly through this. But we basically are comparing mode array to grazed array to a reference pasture that has no array on it. And, and in this part of this study we are looking at plant species composition.
00;29;42;23 - 00;30;09;23
Anna Clare
We're looking at solar radiation precipitation, soil moisture, soil temperature. We're looking at soil carbon. So nitrogen, and we are learning some things. So I'm highlighting some things and in yellow boxes and some of the things that Brad was saying, we are seeing the same thing. So we're seeing higher soil moisture content, under the panels versus between the panels.
00;30;09;25 - 00;30;36;07
Anna Clare
Soil temperature is consistency consistently lower? This is supporting those cool season grasses like the orchard grass and things like the, the, the clover, those look at the legumes that are going to do well in that, in that situation. So, let's see here. We're also looking at soil carbon. We're looking at biomass, as well. And we're also looking at regrowth rates.
00;30;36;07 - 00;30;58;11
Anna Clare
So what happens after the cattle do a grazing pass. Is does the grass regrow at a faster rate in the panel system or in the open pasture? Is there a difference in regrowth or recovery of forage, after a grazing event, for example. And we and our you know, after two years of continuous data, we are learning things.
00;30;58;14 - 00;31;25;27
Anna Clare
That's pretty exciting. Sorry to have to fly through. We're using all of this data to parameterize a biogeochemical model. Again, this will continue on in the outdoor test lab with cattle. So so this study, this ecosystem dynamics study that I'm giving a little review on is a sheep system. We will then add that forth kind of semi comparison with cattle.
00;31;25;29 - 00;31;56;20
Anna Clare
Similar same same research methods actually. But looking at a cattle system. So model parameterization, what this means quickly is that we take our, our ground, our data, our field data, where we're using different instruments that are testing, measuring soil moisture and temperature and all kinds of microclimate, information, as well as this kind of biomass fluctuation when there's grazing events and such.
00;31;56;23 - 00;32;32;17
Anna Clare
And, and we're calibrating basically a model, to predict in a way that we are seeing on the ground. And so in this slide, you see that our actual field measurements are in red, the model simulation is in blue. And you see that we are getting flows. We are very close. The, the simulation of the model, it is very well predictive of what we actually see in our field measures, in this system, of, of acrobatics.
00;32;32;17 - 00;32;41;22
Anna Clare
So just wanted to make sure that's understood. And thank you so much for the time. It's always hard to keep something like this in 30 minute.
00;32;41;24 - 00;33;10;26
Brad
Thanks everybody for joining us to to talk about cattle grazing underneath solar panels. Obviously, it's been quite the interesting topic that a lot of people are talking about. Obviously, it started a lot with, sheep in the past, but there's a lot of interest in cattle. And I'm going to kind of give a rundown about where we came from at the University of Minnesota and kind of some research that we've worked on, and then maybe where we're going in the future, as well.
00;33;10;26 - 00;33;41;09
Brad
So really, this is kind of our schematic where, where we what we really wanted to do. There were our goal and our research center. So we're at in western Minnesota, and we have about 300 milking cows on pasture. And we graze heifers, cows, you name it, under solar panels. But our goal was to actually utilize solar and have it be dual use and not just have a bunch of panels, on the ground.
00;33;41;11 - 00;34;05;07
Brad
And a lot of people were grazing sheep and we don't have any sheep at our research center. So the idea was, well, why can't we put cows under there? So we started that. Our goal was to actually utilize the solar energy, graze cattle and power electric cars. And that's where we sort of have gone. We have this, fast charger at our research center.
00;34;05;07 - 00;34;27;24
Brad
So actually, if if you ever come to western Minnesota and to our research center, you can charge your electric vehicle from the solar panels that the cows are grazing under. So that that was my concept when we developed this project. So let's talk about some of the solar, that we've actually started. This is a picture of our research center kind of in the middle.
00;34;27;24 - 00;34;51;28
Brad
You can see, kind of an each barn a little bit. We first started with solar on buildings just like everybody else did. That's a hog barn, 15 degrees. And in slope, doesn't work well in the wintertime because the snow load, the snow covers all of them. So our goal was to take them off of the barns and can we put them somewhere else?
00;34;52;00 - 00;35;16;29
Brad
And the large solar installation that we have, on the right hand side of the picture was our first one that we, we put up in 2015, actually. So ten years ago, we really didn't know what we were doing. I think we just put this 50 K solar system, about eight feet off of the ground and built it that way without ever thinking about cows.
00;35;16;29 - 00;35;35;27
Brad
That was not our goal. At the time, we were not thinking about grazing any cows or sheep or anything under the panels. We just wanted elevated panels, because we thought that we could produce more solar energy and kind of get it up. Away from some of the corn and trees and everything else that is on our research center.
00;35;35;27 - 00;35;58;29
Brad
So that's kind of where we went. But in 2017, we kind of had the idea of, can we put cows underneath the panels? And, a lot of people, especially here in the Midwest, some people were starting to graze sheep under those. And like I said before, we don't have sheep at our research center anymore, but we have lots of cows, so can we put cows under there?
00;35;58;29 - 00;36;24;29
Brad
So this is early spring of 2019. This is a the pasture actually that what it looked like before we put the solar installation in. So pretty flat. Some trees. In June of 2018 we started to build it. So we probably I would say we overbuilt the system. We were concerned that what were the cows going to do with the panels?
00;36;24;29 - 00;36;50;13
Brad
What were they going to do with the structure? Were they going to bother it? Were they going to wreck it, you name it? So we actually cemented those poles into the ground six feet. And because we, we just didn't know. And so they, they are cemented in there. Probably will withstand a category five hurricane if it ever came through.
00;36;50;13 - 00;37;14;22
Brad
I don't think they're going to blow over. But that's that's where we went. And then we started putting, the panels up. So this was our, our racking system that we used for, putting the panels up. These are fixed tilt. They're not single axis tracking. And, on one side, at least in this picture, the lower edge of the panel is six feet off of the ground.
00;37;14;22 - 00;37;35;21
Brad
So not very high. The other end is eight feet. Some of you have heard this before. No scientific reason why we pick that. We kind of went out and found the tallest cow in our herd, and tried to figure out how far she could reach up. And maybe touch panels if she wanted. And that was about six feet.
00;37;35;21 - 00;38;05;09
Brad
So, that's kind of where where we really settled and, we haven't looked back, I guess. So this was July of 18. So this was a obviously on a small scale. But by no means is this megawatts. We started with 30 kW. So this is, two banks of 15 kW. You can see very minimal disturbance of, of the ground, obviously some equipment, but and where we had to pour the concrete, things like that.
00;38;05;09 - 00;38;29;06
Brad
But the grass was still growing. And then we decided that we should put cows under there. And I only show this picture because this is what happens when it rains. And you leave the cows under the panels and they decide that they're going to stay under there during a rainstorm, and they really just muck it all up. And, I could not show you the picture, but I wanted to show you the reality of what?
00;38;29;06 - 00;38;48;03
Brad
What happens when you don't really know. We weren't we didn't know what we were doing. So we just put the cows out there and and let them go, and, they didn't really bother the panels at all. Maybe the first day or two, they were trying to reach them and see what it all was, but, they didn't bother them.
00;38;48;05 - 00;39;08;14
Brad
You can see that The wire is, up high underneath the panels. That's in some conduit as it comes down the metal pole and goes on underground into the inverters, and we'll show you those in a second. This is that fall. We didn't do anything. I didn't reseed anything. We just pulled the cows off, and the grass grows back.
00;39;08;17 - 00;39;30;06
Brad
Grass is pretty hardy, and, the land is quite resilient. The pasture land. So it grew back without, any issue at all. But we learned our lesson. Probably wouldn't, put the cows out there like that. What we did, during inclement weather, things like that. So these were this was kind of our learning process as as we went.
00;39;30;09 - 00;39;52;08
Brad
But as we go along, you can see the cows are utilizing the shade. Sorry, the solar as a shade mechanism. That is really what it is. It is for shading cows with the benefit of producing solar energy. In this picture you see that there's lots of space between the cows and the solar panels. They're really not going to reach it.
00;39;52;08 - 00;40;10;23
Brad
They're not going to bother it. Most of the cows during the hot part of the day are hanging out underneath the solar panels. I kind of maybe I'll make this a little bit slower so you can maybe see it online. It's kind of a video, but you can see a lot of the, the wires, that we have for the solar panels are up underneath.
00;40;10;25 - 00;40;39;28
Brad
So the cows can't touch them or reach them, or anything like that. There's a lot of, space in between, these two panels. We could actually drive a combine in between there. That sort of ulterior motives as well as what we have, was to grow possibly some crops in between these solar panels. But, that kind of gives you a schematic of of what, what it might look like in, in our design.
00;40;39;28 - 00;40;59;18
Brad
But everything is underneath. The cows can't bother it at all. You can kind of see the concrete, poles, but that's a good, way of making sure that the cows aren't bothering the wires. This next picture. So this is, our inverters. And that was one thing that we decided that we would do is keep the inverters on the outside of the fence.
00;40;59;21 - 00;41;20;23
Brad
We we just weren't sure. We didn't want to put more fencing inside. We we kind of had the luxury that we put the solar panels close to the fence so we could put the inverters on the outside of the fence. I've seen many different places where you have to, fence the inverters off, and it creates a probably a little more hassle and things like that.
00;41;20;23 - 00;41;47;24
Brad
But we decided on all of our solar installations and we have, five of them here at our research center. Now, all of the solar inverters are on the outside of the fence. Basically, the power line goes underneath, the, the grass here and over to the panel. So the wires are coming down. So obviously there was we dug the power line six feet under the ground to the solar inverters.
00;41;47;27 - 00;42;10;11
Brad
If you want to know, we, we monitor solar energy. Obviously, here in the Midwest, in Minnesota, we produce most of our solar energy in the summertime, kind of May, June, July and August. Not as much in December. That's probably the lowest time, obviously, because of the the tilt of the earth, we don't aren't exposed to most of the sunlight.
00;42;10;11 - 00;42;46;17
Brad
So we have quite a low production of solar in December and January, but that, we still produce. So, so then we, decided that we would go bigger. And, so we've partnered with the University of Minnesota, Morris campus, in our pasture where the cattle are. And we have a half a megawatt of, of solar. So this solar will power the, University of Minnesota campus that is here, obviously, again, smaller scale than what we're thinking about megawatts.
00;42;46;17 - 00;43;11;19
Brad
But this is is getting larger for, for, pasture grazing. A lot of this is demonstration. It's along the state highway. So, we put this in this is, actually this is half of it. So this is 250 kW. You can see it's in, kind of these different rows. There's a lot of space in between where we can drive tractors, things like that.
00;43;11;19 - 00;43;33;08
Brad
You could drive a mower if we wanted. We're. We're not interested in mowing. We want to put cows there. So this is kind of what it looks like. It's pretty green under there, actually. Sabrina, our host, this was her master's thesis project with, one of the solar panels. It looks a little green under there for different, species.
00;43;33;11 - 00;43;53;21
Brad
But this was the installation of of how they did it, and we kept it at fixed tilt. We we, we started with fixed tilt, so we kept it that way. Obviously, we're probably moving into single axis tracking and those type of aspects. But when we, built this system, that's what we used. It's eight feet off the ground.
00;43;53;23 - 00;44;18;28
Brad
You can see the poles that we used. They just pounded them into the ground. We didn't need any concrete there in about six feet. We didn't need any concrete anymore. We understood that we way overbuilt our 30 kW system. So these are just pounded into the ground and have no problem. So this is, how the grass grows underneath those panels does grow quite well.
00;44;19;00 - 00;44;47;08
Brad
It's probably a little more spacing, 20ft between the panels so we can drive equipment and machinery and things like that. Between. And obviously, like I said, we have, different, reasons for doing that, but there's lots of space, lots of ways that we can grow grass. We kind of built this 1 in 2 parts. You can see these are just, mono facial, panels, at least on the first part.
00;44;47;10 - 00;45;11;06
Brad
And then when we put the other, section in, we went bifacial. So you can see this is just this past summer. So this only got completed, last fall. So it's kind of a brand new one. And this is, cows underneath. These are actually heifers, underneath the panels. Being in the shade, you can see there's a little bit of dirt work, there where they created.
00;45;11;06 - 00;45;37;08
Brad
But this is after they within two weeks after they put the the panels up, you can see their bifacial grass growth is wonderful. Lots of grass growth in the shade. I actually think the, the shade, the solar panels actually prevent evaporation of grass. So you can, grow more grass underneath. And then in wintertime, we don't have many issues with, snow on the panels at all.
00;45;37;08 - 00;45;55;12
Brad
So we have winter here. You can see, snow on the ground, but no snow on the panels. So a little bit about some of our research. I won't go too in-depth, but I wanted to cover some of the basics, so we've looked at, evaluating, solar grazing, in it, at least with our pasture based, dairy herd.
00;45;55;14 - 00;46;18;00
Brad
So we did this on a small scale in 2019, with 24 cows, where we allowed some cows to have shade from the solar system, and some cows did not have shade. And we had four periods. So the cows were not underneath the solar panels on a continuous basis. So they were only in there for about seven days.
00;46;18;00 - 00;46;40;24
Brad
So, they were rotated, in and out of, of the shade. Then we put a bunch of sensors on our cows because we were interested. Can the solar system reduce heat stress in cows? What is activity look like? You name it. So we we put a lot of sensors on these cows. We also were interested in animal behavior, so we counted flies on the cows.
00;46;40;24 - 00;47;06;19
Brad
Yes. Students, do know how to count flies on cows. So we we counted flies. We were interested from a pasture based standpoint. We counted respiration. So you can see no difference in fly load. Obviously, they're all exposed to the same environment in the same pasture. So we didn't necessarily expect flies to be different. There was maybe the increase in fly numbers underneath the shade but not any statistical difference.
00;47;06;21 - 00;47;30;17
Brad
The biggest thing was respiration rate. So not in the morning, but in the afternoon. The cows that didn't have shade from the solar system had more breaths per minute. So they which was indicative of heat stress. So they were more stressed breathing more. So we basically have reduced heat stress in cows by having them underneath our solar panels.
00;47;30;19 - 00;48;09;17
Brad
We also looked at, hygiene of these cows. If they stand underneath the solar system, do they create, mud or mess? There's maybe some indication that if I look underneath their belly in their lower leg, that maybe those cows are a little bit dirtier? Not much. You know, I don't know much of a difference between a 2.9 and a 3.2 on the lower legs, but there's maybe something there that if you leave the cows underneath the solar and don't provide them a lot more space, that they, they may be a little bit dirtier if they're maneuvering and because they're hanging out in the shade during the hot part of the day,
00;48;09;19 - 00;48;31;10
Brad
we didn't see any difference in milk production for these cows. Obviously a milk production was not our goal anyways, at least with this study, because the cows were only underneath the solar system, 28 days out of the 150 grazing days. So we were really interested in heat stress and, how we could reduce body temperature of cows.
00;48;31;10 - 00;49;01;05
Brad
And you don't see much overnight, but really during the hot part of the day, that's where we reduce body temperature. So about a half a degree Fahrenheit to one degree Fahrenheit, we've reduced body temperature. That's quite a bit. That's really significant for reduction of heat stress in cows. And it was really in the afternoon from noon until midnight, really is when you see the biggest benefit in reduction of heat stress for those cows.
00;49;01;10 - 00;49;29;16
Brad
And this is a graph of the this is internal body temperature. You'll notice that really it starts about 1:00 in the afternoon and really carries through until 11:00 in the evening. We see this huge, difference in body temperature. This is in Celsius. But you see a big difference, especially around three, 4:00 in the afternoon. When that is the biggest, the hottest part of the day, at least here in the upper Midwest.
00;49;29;18 - 00;49;47;22
Brad
Biggest reduction in heat stress. Those cows were underneath the solar panels getting out of the sun. It spiked a little bit here. This was milking time. So that's, cows had to go back to the milking parlor, so they got a little hot when they had to walk. So that was cows. The next question was, what do they eat under the panels?
00;49;47;22 - 00;50;15;23
Brad
And so Sabrina here, this was her master's thesis. And so she looked at forage, biomass and nutritive value of grasses and legumes grown under different, agro voltaic sites. So we used a 30 kW site, 50 kW site, and then had just kind of regular pasture to see, how, grasses and legumes grew underneath solar panels.
00;50;15;25 - 00;50;41;02
Brad
And you could see we grew alfalfa, peas, fescue, orchard grass, clovers and a bunch of mixtures to see how things grew. Well, what what does it tell you? Well, actually, things grow well underneath solar panels. That's the big thing. And obviously it depends on, grass here. If you look at the mixtures, grass, alfalfa mix, grass red clover mix, they were actually higher underneath the solar panels.
00;50;41;02 - 00;51;12;14
Brad
So we grew more forage underneath the solar panels than we did out in the open pasture for a couple of the mixtures orchard grass, meadow fescue, those grasses that were grown in monoculture alone had way more biomass underneath the solar panels than what they did in the open pasture. So we can grow good forages and probably more forages underneath the solar panels if you want to look at forage quality, actually not much difference in forage quality.
00;51;12;14 - 00;51;41;21
Brad
It's kind of basically that the forage quality is good underneath solar panels, no matter, where you're growing it, as well as the digestibility. So we can grow a lot more forage. That's probably the biggest thing, high quality forage and a lot more of it underneath the solar panels without really compromising any forage quality at all. So where where are we going to kind of go, is the question with our agri tags.
00;51;41;23 - 00;52;02;11
Brad
And one of the things that based on our, our fixed system, we decided that we would build our own, so we built our own agro voltaic system, from a modified combine trailer, that we used and, and this was kind of a prototype, you know, this is does it lead to some other things that we're thinking about as far as agro voltaic?
00;52;02;12 - 00;52;28;29
Brad
Obviously on a small scale, you know, we're we're in the development stage trying to think about some of these things. This is 20 kW of portable, portable shade, for our cows. It has battery storage. You can see the battery boxes. The inverters are on, the solar system. The cows don't bother it at all. It kind of folds up and you can see that the cows are during the hot part of the day.
00;52;28;29 - 00;52;53;22
Brad
They're underneath the solar system so we can produce energy for irrigation or powering fences or all kinds of different stuff and be able to use that. As a way to cool our cows. So these are bifacial panels, that we use and, where this might lead us into the future of agro voltaic. So, who knows?
00;52;53;22 - 00;53;18;27
Brad
But it's a good concept of, we can build portable shade systems, with with power. This is a picture of the of the battery boxes that we use. We also have an electric tractor that we can move. So this solar system will actually power the the monarch electric tractor that we have. We we wanted to, invest in, electric vehicles as well.
00;53;18;27 - 00;53;41;26
Brad
So, we did that, and I was trying, trying to figure out this tractor as autonomous. So can I, control it from my app to move my solar shade system while sitting in my office or somewhere else? Well, we'll we're going to find that out this summer, but that that is the goal. So I can move my solar system, without having to go out there and do it.
00;53;41;28 - 00;54;10;09
Brad
If you want to know more, about some of our solar projects, and we'll probably share these, slides with, with people. But, you can see solar farms in agriculture. This was a PBS program out of Minneapolis here that, came out and looked at our solar on our research farm. And then we also went to, some farmers that we're working with that are actually growing corn underneath solar panels that they've developed themselves.
00;54;10;09 - 00;54;31;12
Brad
So that's in the in the program as well. So we're working with farmers that are growing corn underneath solar panels, and it can be done. And it's a unique way of doing it. So we're really exploring a lot of that as well. And if you want to know more about our mobile shade system, this actually this program just came out on Monday evening.
00;54;31;12 - 00;54;54;05
Brad
So or sorry, Sunday, two nights ago. It's, our so solar shade system gives you an idea of agro voltage and what that means. And you can see, our, our system in use. So as I end here with, the last couple minutes, of, of time that I have kind of these are my thoughts and where we're going.
00;54;54;08 - 00;55;20;24
Brad
So this is kind of our miss versus reality. A lot of some people have heard me talk before. I will tell you, the cattle are not going to wreck the solar panels. It just tractors. And people will, I have yet to see cows wreck solar panels. We've had solar on our research center here for ten plus years, and we have yet to see a cow jump on a panel.
00;55;20;26 - 00;55;44;21
Brad
Wreck the panels or wreck any wires or do anything. What sort? So it it's not going to happen. I think we need to think of the cow in mind when constructing solar farms. You know, if we're going to graze cattle under there, how do we have to build that? You know, I've talked to some solar developers as well that certainly are scared about putting cows under these solar panels.
00;55;44;21 - 00;56;05;08
Brad
Well start small. I spoke at a conference this, winter, and I think a solar developer was just going to go back and maybe put 20 cows underneath the solar panels just to see what would happen. I think that's where we're sort of seeing is believing. If you just start out small, just try it and I think you'll be surprised.
00;56;05;11 - 00;56;25;14
Brad
Obviously, working with the solar developers to do that is, a big thing. And again, don't worry, they're not going to break it. Haven't seen it yet. These are our kind of our opportunities. You can see our picture. This is in the winter time. So we utilize our solar system in the winter as well. We we've out wintered.
00;56;25;14 - 00;56;55;13
Brad
These are heifers, in early February here on pasture. You can see they like to be underneath the solar panels even in the winter time. So these are kind of some of the concepts that I think about. Obviously we want to build cattle tough structures. I don't think we need to go overboard, but obviously we want to think about the cow in mind, prioritize the animal safety kind of smart layouts to prevent injuries that they have.
00;56;55;15 - 00;57;18;23
Brad
Obviously it's it's for shade. Solar is shade benefits for cattle. And that's what we see. Obviously there's lots of liability that goes around. People are are scared. How do you reduce financial risk if cows happen to wreck the panels? Who's pays for that? Different things like that. I understand all of that. And there's, risk that goes along with that.
00;57;18;26 - 00;57;43;02
Brad
Obviously, we need more data to help debunk our myths with facts and and build confidence. So my last slide here, this is kind of the future of Agro Volt, at least for us. And where we're going obviously the height of the panels is something that we're, continuing to explore. And I think, Anna Claire will talk about some of that work that that they have done.
00;57;43;05 - 00;58;04;11
Brad
We're actually moving into some vertical bifacial panels. So this I've been out to Rutgers, in new Jersey, and they have a vertical, system where they're grazing cattle on, and we're going to try that at our research center, too, obviously on a small scale. But these are things that we want to think about as well. There's may be other unique solar designs.
00;58;04;14 - 00;58;30;17
Brad
Obviously, what kind of crops can we grow under the panels? Alfalfa, row crops, pasture, you name it. I'm exploring virtual fencing with solar panels so you can put cows underneath the panels, maybe exclude some different areas, that we have, and just let them graze and use it from a virtual standpoint. And we need long, more long term research and data that support that.
00;58;30;17 - 00;58;53;16
Brad
Cattle don't back the panels. So with that, thank you for your attention. And we are grateful for the funding from the Minnesota Legislature for a lot of these projects, that we we have, if you want to know more information, you can always contact me. And I'm glad to, help anybody out with, talking about solar and grazing.
00;58;53;19 - 00;58;57;02
Brad
Thank you.