MSU Extension MI Ag Ideas to Grow With

Hello, wherever you
are, and welcome to My Ag Ideas to Grow With
virtual conference. My name is Charles
Gould, and I'm a bioenergy educator
in the Agriculture and Agribusiness
Institute with Michigan State
University Extension. It's my pleasure
to welcome you to this session, Where Veggies Meet
Volts, Commercial Vegetable Production
in a Solar Project. This session is
the second of four agrivoltaic
sessions this week. Today, we'll hear
from A.J. Nair. A.J. is a
professor and chair of the Department
of Horticulture at Iowa State University. He will share his
experience in growing vegetables on a
commercial scale in a solar park and share
data on crop growth, yield, and quality. He will also talk
about the process of working with Alliant
Energy to enable vegetable production
on the solar site. Before we get
started, we'd like to take a moment
and thank our sponsors who are
shown on the screen. Due to their generous
support, we can offer this event at no
charge to participants. Now, let's jump into this evening's presentation. If you have any
questions during the presentation, please
type them in the chat. So let's go
ahead and begin, AJ. The floor is yours. Thank you so
much, Charles, for inviting me to present
in this webinar. My name is Ajay
Nair. I'm a professor and chair in the
Department of Horticulture at Iowa State
University and also a proud alum of Michigan
State University. I graduated from
the Department of Horticulture in 2011
and so had the honor of working with many
commercial growers in the state of
Michigan and learned a lot there. and then
trying to, you know, implement some
of the things I learned in Michigan
here in Iowa. So this project is
focusing on growing vegetable crops within
a solar production system, a solar
farm. And I'll tell you how it worked
out and show you some examples, some
experiments and results and finally open it
up for questions. So first thing, first,
I want to define what agrivoltaics is. I
know there are several definitions that
are out there, but agrivoltaics is basically
two words combined together, which is
agriculture and solar energy production.
So how can we grow vegetables and fruits
and other crops within a solar farm? So that's
basically what we are testing here at
Iowa State University. So when it comes to agrivoltaics,
some of the basic that are discussed
under this topic are crop production,
which is vegetable, fruit crops.
In our case, we grew broccoli,
tomatoes, and peppers, squash. So crop
production could be an opportunity
to combine agriculture with the
solar production, animal agriculture.
And this is what we primarily
hear about, and that is grazing of
sheep. That's very common and well
adapted in this system. In this project, we
are not excluding animal agriculture,
but I know there are several
projects that are looking into it,
and I think that's a great idea to see
how we can include pasture-raised
animals in the system. Okay. I also want
to acknowledge the team which is working
with me on this project. It's not
just me. This study and results which
I'm going to share with you is part
of a bigger grant from the U.S.
Department of Energy. The title is reflected
there, leveraging a public-private
partnership to address technical and
socioeconomic factors of an agrivoltaic system.
So you see my team members there. We have
different tasks built in this project. Task
one is horticulture and beekeeping. So
myself, Matt O'Neill, an entomologist and
several other people, Suzanne Slack, who's
a fruit specialist. We have task two,
which is farmer and landowner surveys,
economic analysis, because I think this
is something which is front and center
and kind of the foundation that we need
to address is what's the perspective of
agrivoltaic out there. I know it could be
a polarizing topic because growers
and farmers are concerned about losing
good farmland to solar production.
And on the other hand, that's a
great way of using land, like a dual
use, a coexistence. So that's task too,
talking to farmers, talking to growers,
talking to county people. Task three is the
energy efficiency. Are there differences
in microclimate within the solar farm,
which we can document and see whether it
promotes the growth of our fruit and
vegetables. So what is the temperature look
like? What does the humidity look like in
that system? And of course, task four is
outreach, where we are trying to disseminate
information, what we learn. So we have
been farming in this system for two years
now. So we have two years of data and we
have learned a lot, you know, just getting
into it and the ins and outs, the
challenges that arise. And I'll share all of
that with you today. uh so uh simplifying
the concept just the same uh image here but
this is a figure or image which my daughter
uh gave me an idea to draw when we were
pitching this idea to us department of energy
so you see some of my drawing skills out
there with microsoft paint but basically
using sun as a source of energy to produce
uh power and at the same time using some
of the energy from the sun between the panels
and also under the panels to grow vegetables
and fruit and see what is the feasibility
of growing crops. And when I say feasibility,
it was important for us that we are
able to farm on a commercial scale, not
as a small hobby farm, but more as a commercial
production system. So within agrivoltaics,
if you ask me what the current situation
is, many of the solar developers when they
install a solar farm one thing that comes
kind of second hand is after the installation
what do we do with the land should we
keep it bare should be you know seed grass
out there if the grass is seeded out there
who manages that grass how many times we have
to mow it all those practical questions I
see your hands up there so Suzanne do you
have a question Maybe not. Okay, I'll keep going. How do we mow and how
do we manage? That's a very important
question to address, not after the
construction of the solar farm, but before
that. And because many times people think
of how the vegetation is managed, it
reflects what the crop could be under that
system. And we don't want any bad aesthetics
to the system. What are the
possibilities? Of course, we can use it for
food crop production. It's a modified
microclimate which can benefit
the crops. Often when we talk about
fruits and vegetables, we consider them
as full sun, which is true. But at the
same time, is there a benefit of getting
some shade that can reduce the stress during
those months when the sun is shining too
bright? It's too hot, like July and August.
Could there be benefit of that shade? So we
wanted to evaluate that. it's a great
habitat for pollinators so in our projects
I'll show you some treatments where we
have pollinator mixes where bees can come
and and forage and we also have beekeeping
part of this project so can bees be utilized
at a solar farm and the grower can benefit
that way also and of course animal husbandry
and grazing which we are not studying
in this project but it definitely fits
well within the system. Because we all know
on a hot summer day, who does not like
shade? I mean, look at this picture
where the sheeps are. And I visited the
Jack Solar Garden. Byron Kominek is the owner
and the operator of that farm. They
do a fantastic job. They are kind
of the pioneers when it comes to agrivoltaic.
At his farm, I did see sheep.
And I think sheep suit the system well.
They do not damage any of the panels or
the wires. They graze underneath it as
compared to goats, which would like to climb
anywhere and everywhere. But again, for
animal husbandry, for animal crop production,
you can see shade can benefit. It can
reduce stress on those animals during
those hot months. What are some potential
benefits? we are looking into habitat
conservation like beneficial insects and pollinators
we can reduce crop stress by growing
underneath and between the panels crop
protection so this is something we experience
here in Iowa I'm sure in Michigan too you know
the weather is very unpredictable we have
hail we have storms a lot of dust being
pulled I know soil being pulled up in the air
and the plants are sandblasted or soil blasted.
Is there a protection from those occurrences
when we are within a solar or an agrivoltaic
system? So could there be protection
there? Of course, soil conservation, because
we can seed a pollinator mix or a grass, and
that can help with the runoff and reduce
erosion. And of course, the economics, whether
this will pan out of growing crops within and under
the solar panels. I need to be very
clear here is that in this system where we
have agrivoltaics, the main moneymaker
is energy. So there should not be
any doubt about it. We can grow crops.
We can look at the feasibility of these
crops, but that is not the moneymaker.
The moneymaker is the solar panel
and the energy. And I like to use the
example or analogy which my colleague,
Dr. Matt O'Neill from Entomology here
at Iowa State, also a Spartan, graduated
from Michigan State, made one time and he
said, agrivoltaic, if you think of it,
it's like a burger. And so the meat in
the burger is the electricity. That's
equivalent to the meat. And so what
are we? Fruits and vegetables and any
other thing, what are we? We are the
sesame on the bun. So it's not the
main moneymaker, but yes, we help with
the aesthetics, the optics of it. And then
if we can grow crops profitably and
sustainably, we can make money of the
crops as well, but it won't make as much
money as the solar. That's the energy.
That's what I wanted to say. But we can
definitely coexist. So could specialty crop
be a viable option? And that is what
our premise was, our hypothesis was, that
we should be able to grow these crops
without any challenges, without much insect
disease pressure. And that's when
this DOE grant came and we started
our project. Now, as Charles
mentioned, you know, we
need a partner. This site or this
experiment, this study would not have
happened without partnership with
Aligned Energy. So the way we
think of, you know, for a successful
agrivoltaic system is you need
three components. You need a landowner
who owns the land where the solar
panels will go. We need a utility
company that will be installing those
and selling the power, producing the
power. And we need a farmer who will
practice agrivoltaics. That is how
agrivoltaics would work. So these are
the three pillars. And for us at Iowa
State, the landowner is Iowa State. So
what we did is we leased the land,
this 10-acre land, to Alliant Energy for
20 years. So the land has been leased
to Alliant Energy. Alliant Energy
is a utility company. And
that's our second stake or second
pillar there. And without them,
this project wouldn't be possible.
So thank you so much to Alliant
Energy for this. And the farmer. And
in this case, the farmer, our students
and the faculty at Iowa State, we are
experimenting. So Alliant leaves the land,
set the solar, and then they invited us
back, say, hey, do you want to do some
research? And we said, yes, absolutely.
And we wrote the grant. We got the
grant. And here we are. And eventually, there
is a fourth ingredient here as well, which we
are not experimenting or asking much of,
is the consumer. is there an incentive
to grow produce or honey in an agrivoltaic
system and get an incentive and the
farmer could sell it and say hey this is this
is what the innovative form of farming is
where we have an energy company and
we are working with them and dual use of
land and more sustainable use of land so
consumers could come and play a major role
in this partnership. Okay. So here,
this is an aerial view of our site.
This is Iowa State University campus,
south of campus. And what you see here
is our solar farm, aligned energy solar
farm at Iowa State. This is a 10 acre site
and it produces 1.3 megawatt of energy.
What you see, the hoops on the right here
are the, it's the ISU compost facility
where we make compost. And a lot of the waste
that comes out of this actually goes into the
compost pile up here. And the north of this
facility up here, what you see is the Ag
450 farm. It's a farm that's owned by Iowa
State University. So we can store our machinery
there, tools there, which is a great resource
for us. So we don't have to go back to the
Horticulture Research Station and bring
stuff and use it here. So this is the
1.3 megawatt energy production farm. I will quickly take
you through the configuration of this
farm because Alliant Energy really helped
us to configure this farm and provide input
so we can install different types of
panels and different configuration of
panels. So what you see here is this one
major site up here. This section is section
area one, then we have area two and i'll
explain what these areas are so area one
and area two are single axis tracking panels
which means these panels track the sun east
to west so the panels will be all facing the
east in the morning and as the sun moves
to the west the panels will track the sun
so these are single axis tracker this has
now become the industry standard earlier that
was not the case it was the fixed panels.
But now the single axis tracking panel has
become that standard. There are two sides
here on the right and those are fixed
panels. So we do have a mixture of
both and we have two different heights
for those panels. One is a two feet, the
leading edge is two feet high, the other
is about four, four and a half feet high.
And then what you see that small box at the
end outside with some white plastic that's
actually plastic mulch out there that's an
open field production because we wanted to
compare what we are growing inside versus
what the crop is producing outside so there is
a fair comparison of the yield and the quality
and insect and all other data those are
the control plots we call it the area five
we also have a small dot here these are
our beehives and so we are rearing honeybees
here that go out and forage in the pollinator
mixes which we have seeded and we are
keeping track of how much honey a solar site
like this can produce and then of course we
have some more site out there which is we
planted in prairie there was some water
standing there it was originally be supposed
to be part of the solar but because of standing
water I think we decided let's put into
prairie and try to regenerate that land a
bit so that's a prairie habitat. We seeded
some seeds out there, prairie plants, to again
help the pollinators. So fixed panels,
this is just to show you how when
the construction was happening
in 2023 summer, the contractors were
slowly building the fixed panels here.
This is a close-up of what the fixed panels
look like. This is not at our site. This
is at the City of Ames site, which is a
site about two miles away from us. City of
Ames has a solar farm where they produce
energy. But this is typically what the
solar, the fixed panels look like. Now, this
is our fixed panel. And one of the biggest
things which I learned when I entered this
site to establish plots and work was the
amount of space between the leading edge of
one panel, which is out here, till the back
end of the other panel which is here so which
is kind of ending here so this is about 21
feet and often I think people have this
perception that the panels are stacked close to
each other and there's no space to move or you
can't move a tractor or even you can't move
a cedar or a tiller but that's not the case
there's about 21 feet in which you can
easily you know with a tractor lay plastic mulch
do all the commercial operation which you do
for growing vegetables so this is quite
possible 21 feet there and there's about three
to four feet under the back of that panel
too so if we want to do something there we
can do that so i think that's the number one
surprise or at least people think of it oh
i did not expect that there was so much space
between these panels so the single
axis tracker again this tracks
east to west this is our single
axis tracker you can see they
are on the on this pole here
this whole panel whole panel will
move east to west another thing i want
to highlight is these panels are bifacial
which means they make energy from the
top and they also make energy from the
bottom now i think the percentage of energy
they make from from the bottom which is
the reflected light might be 10 or 15
percent of what they make from the top,
but still it's energy. So again, industry
is moving to bifacial panels.
Earlier it was just on one side, but now
most of the panels that are used for
solar production, energy production
are bifacial. We were very particular
that no topsoil should be removed when
the site was being constructed and the solar
panels were going up. So Align did the exact
same thing. They did not remove the topsoil
and we did not do any grading of the land
either. So that's why you will see our panels
are not very straight. They do a little
bit up and down, but that's fine. It's working,
no problem at all. And that was something
which the growers and the farmers in Iowa
are very particular about that nobody should
remove the top solid. And that's kind of the
topic when we start agrivoltaic and
that's the first thing farmers want. And we did
the exact same thing. So the distance
between the top, the bottom of the panel
and the ground varies because we did not
level the ground. So it's a little bit
undulating, which is fine. We were
able to make it work. There is also this
pie-shaped structure, which you don't see
in the previous image, but this pie-shaped
structure is the fulcrum, which actually
turns the single-axis tracker. So every
two to three minutes, they will slowly move
again they're just tracking the sun and
it's quite fascinating to see that you see
stand there for some time you hear them
all creaking and slowly the panels moving
in from the morning till evening they'll
move east to west and then in the evening
at the night they move back you know
east so they're ready for the capturing the
light in the morning uh here you can see
this angle of uh of that panel so uh i don't
want to make it very complex or complicated
for you but this is what our treatment
design was and you can see the top uh labels
are the crops which we grew in the system
strawberry squash broccoli we have a
pollinator mix one which is uh more once a month
we have pollinator mix two later on which
is more twice a month we have raspberry
we have bell peppers and then we have a
grass which is a control and we have three
blocks here in which we randomly assigned these
treatments just so that we follow the
proper statistical method and technique and each
section each block is 64 feet long you
can see that here this 64 feet long and if
there's red for example number one there are
two rows of pepper on of strawberry on
this side and two on the other side if it's
yellow there are two rows of squash on one
side of it and two rows on the other.
And you'll see that in the images I'll show
you as we move on. But this is what our plot
design looked like. I want to maybe go back
and talk about this pollinator mix one and
pollinator mix two. What does that
pollinator mix mean? What it means is this
pollinator mix, which we got from the Bee and
Butterfly Habitat Fund. It has, you can see,
different seeds, different plants in
there, grasses, clover. We have, you
know, the asters, the columbine,
the goldenrod. So this is a mix. They
call it the bulletproof mix, which means
it will germinate and it will establish.
And so we went with this one for our
project. You can buy it from the Bee and
butterfly habitat fund. So let's get into
the farming task. So how did it look like?
So this is early spring of 2024. This
is the first season. JC is a grad student,
and we took some soil samples to figure out,
you know, what does the fertility look like
so that we can provide the right amount of
nutrients, NPK and any other sources which
the crop would need. It was all done on
a commercial scale. That's very important.
We use a 65 horsepower tractor and not any
small garden tool or anything, just a
regular tractor which we use at the farm and
no niche tools or equipment. Again, feasibility
is very important. Then only it will
be adoptable. This technique, growers will
adopt it if they see that they don't have
to change any of their practices to go into
agrivoltaic system. We also measured
the soil compaction. This is the first
season in the spring in 2024, and the soil
was quite compacted. As you can imagine, I
mean, there was heavy machinery loading
the panels, you know, moving around and
drilling these, putting these pylons into the
ground. There was a lot of traction there.
So what we did, you know, since we
found that traction, compaction, we went with
a soil spader at first to ***** the ground
so that we make sure we break the compaction
and we can grow our vegetables because
for vegetables we use plastic mulch for
which we need good tilt and so here you can
see the spader working with the tractor did
a great job you know broke broke down
whatever it could I mean didn't go all
the way deep but yeah it did it did well
that we could lay a plastic mulch so we
used a spader and after the spader we
did go with a tiller a regular tiller and
before that we did a fertilizer which was
broadcasted we just use a spreader out here
after that we used a tiller and after the
tiller we used the regular plastic mulch
layer this is steve jonas he's our farm
the farm manager at the compost facility you
can see steve here so you can see how this
was plastic was laid. Nothing special
just like how we do it in an open
field condition and using again a 65
horsepower tractor. We laid the plastic
mulch and we grew the transplants in
the horticulture greenhouses. This
is broccoli for you. Broccoli was transplanted
by hand. We could have used a water wheel
planter but this was only since this is
research and we only had 64 feet and we had to
randomized plots. So we decided to just
plant by hand, but you could have used, one
could have used a regular water wheel planter
to plant. The broccoli was planted in double
rows on raised beds. This is summer
squash that was planted later.
We planted them single row, two
feet spacing. Again, we planted
it by hand. We also planted bell
peppers later in the season, double row,
12 by 12 so 12 inches between plants within a
row and 12 inches between rows so as the season
progressed uh you will see this is uh
the broccoli was uh transplanted uh end of
april at 24th 25th of april uh this is what uh
broccoli looked like in in june about getting
ready to be harvested first week of june
i would say and as i was mentioning we have
two rows of broccoli on one side and two
on the other and there is a reason we had
this because the electrical engineers
who are working with us on this project they
are measuring the amount of energy that
these panels are producing based on the vegetation
under them so they are doing the
calculations of if you grew strawberry or if
you grew bell peppers or broccoli did that
change the energy production and the
hypothesis is that it should because the humidity
and the temperature under the panels
will be different because we have different
crops out there. So that's why engineers
were an important part of this grant. And
we have the Electrical Power Research Center
here at Iowa State. And Ann Kimber is
the director. And Ann and her team and
researchers, Hugo Villegas from the
Electrical and Computer Engineering, they
are all helping us to figure that out.
So that's why it's It's an integrated
project, not only on crop production,
but also on energy. So this is broccoli. This is squash in
July. And you can see the students
out there. We are harvesting the squash,
grew really well. Yes, there is
shading that comes on these plants depending
on the time of the day. So maybe
some rows are shaded in the morning, but
during the middle of the day, they
all get full sun and some get shaded
more in the evening. but we did not find
any detrimental effect of the chit
on crop growth. Harvested good quality
summer squash. You can see some of the
squash that we have harvested and graded
based on, you know, insects and disease and
all that. But overall, no worry, no problem
with production. This is bell
pepper, transplanted end of May,
beginning of June. And so this is about a
month after transplanting. You can see double
rows there. uh on white plastic much uh
we we want to mitigate some of the heat
stress if possible and also to reflect some
heat light back which could benefit the
panels you know uh since we are interested in
energy production also uh this is bell pepper
harvest uh in august uh students you know
out there we are all harvesting and those
buckets and calculating all that you know
yield with number marketable non-marketable
but just to show you as an example that
there's no problem in growing high quality
crops under an agrivoltaic system. These are the
peppers out there. Another thing I want
to highlight is you will notice we have used
the black weed fabric between the rows.
And I think that's a great tool, especially
in this system where we can manage the
weeds in the row using the plastic piles, but
between the row, when it rains, it will be
challenging to go in there. It could be
muddy and we have to manage the weeds by
hoeing or spraying. Put pre-emergent herbicide
and post is very difficult. So we decided
to put more energy and effort in installing
these four feet wide weed fabric so that
there is no issue with weeds throughout the
season. And that was the case. We had no
problem with the weeds, did not have to weed
at all entire season because of the weed
fabric being there. You can see that this
is in August growing peppers I collected
a lot of data and students are working
on it you know for broccoli the stem
diameter plant height average head diameter
a number of leaves marketability of course
for summer squash and bell peppers flowering
data so we have amassed a lot of data
typically do that and the students are
working on analyzing that and I'll share
some of that with you. This is Raymond
here who's the grad student looking at
the height. These are some plants
that are growing outside the agrivoltaic
system, so open field condition.
So we wanted to see what are the differences
there. And we also are interested in
technology. And this is Dr. Peter Walter from
the National Resource Ecology Management
Department who actually works with drones and
captures images of the plant so he flew drones
multiple times on on our on this system and
what he did was find out what is the height
of the plant and what's the area of the plant
based on drone images by my image analysis
and this is what a drone image looks like
when the drone flies over it you can see the
broccoli or the peppers out there and then
the image is captured and looks at the
vegetation and it spits a number of what is the
percentage out there. So this is broccoli. I think I should
highlight one more thing here. So if you look
at the broccoli data, this is the panel
broccoli on the x-axis here. And this is
the maximum height of the plant and the
volume. You can see the broccoli that is under
the panel have higher, the height is more
as compared to the outside field. And
same thing with the volume, the broccoli
volume of the plant was higher when the plants
were grown between the panels, say the
panel broccoli versus the control. So
definitely growth is more in plants that are
between those panels. This is the broccoli at the time of harvest. So comparing the
yield of broccoli, you can see here that
the solar produced a little bit less
as compared to the outside
broccoli when you look at the
marketable produce. And our hypothesis
behind that is, yes, the plants did
well in that solar treatment, but they
produced more biomass, maybe more vegetative
growth and not much energy spent in
the head formation. And also in the spring,
you know, being a little cooler in the
solar day, when they were maturing, maybe there
was more heat. And because of that, maybe
they were a little bit more non marketable
produce in broccoli in that system. But overall,
not a big difference in yield when we
grow broccoli within the solar treatments
versus the open field. So that's a big thing
to take home that we are not compromising
yield significantly when we grow in this
agrivoltaic system. Because growers are more concerned
about, will there be anything? What
will be the reduction? Will I get
anything out of it? Will there be
more insects or disease? We did
not find that. This is the drone
mapping for the squash plots. When we ran
the drone and you can see, we clearly
see here again, the solar treatments
up here on the x -axis, the height and
the volume both are more as compared
to these gray bars. So plants are bigger. The volume of the
plant is more. This is squash. So very similar
result, what we found with broccoli. But
when it comes to yield, it was flipped. and
we found that the yield on squash which
is growing in that solar treatment is higher
than the one in the control so that this
is a positive thing we did not expect this
to happen but this has now happened almost
two years this is a 2024 data 2025 maybe
the gap is not this high but the plants in
that solar treatment are doing much better
and they're yielding more so we feel that
the solar panels are reducing the stress
on the plant. And because of that, you
know, the plants are able to do well as
compared to the plants that are outside. So squash
did really well. When we look at pepper,
look at the SPAD values of plant height
and stem diameter. And if you compare
those two treatments, both solar and open
field, you will see that statistically,
those numbers are significantly
higher in pepper when they are grown in that
solar panel treatments. The SPAD is higher,
the plant height is more, and also
the stem diameter. And when it comes
to marketable yield, again, not significant
difference, but the outside did produce a
bit more. And again, they're getting full
sun. Obviously, they have more photons they
can use, but growing them inside doesn't
impede the crop significantly, that
you can't even harvest anything. So this is
a good thing that we showed that the
feasibility of growing these crops in a
commercial manner in the solar agrivoltaic system
is quite possible. Just a few slides from
Suzanne Slack. She's our fruit specialist
in our department. And Suzanne did some
work with raspberries. And these raspberries
were grown directly under the panels, not
between the panels like you saw with
squash and peppers and broccoli, but this is
right under the panels. So she chose the ever
-bearing raspberries that produce all
season, Anne, which is a yellow type, and Joanne
J, which is a red. They collected a lot
of data on harvest and berry quality and
brand productivity, ambient air temperature
and light. You can see in these
pictures, raspberries growing under the
panels. And so what does the yield tell us?
So if we look at Ann, for berry count, the
plants under panels were similar in
production to the non -panel. So this is a good
thing, no difference. When it came to
total weight, as you can see in this
particular graph here, the plants under the
panels consistently produce larger berries
throughout the season. So that's a plus
that the berries are doing well. Actually,
the raspberries are performing well
under that shade as compared to the outside
growing conditions. When you look at
Joange, which is the red cultivar out there
uh berry count uh plants under the panels
began fruiting earlier and were producing
more or similar uh to the non-paneled
or the outside plants and when it came to
total weight we saw the same thing plants
under the panels consistently produce
larger berries throughout the season so uh
when you're growing these berries under the
panels the panels are actually benefiting
them you know in terms of total weight
so um that that's a this is two year data.
So we are very happy how things are looking
with the system. We have Dr. John
Tindal with us from the NREM department and Hong
Lee Feng in the econ department here at
Iowa State, who are helping us with the
economic tasks and keeping track of our budgets,
creating enterprise budgets and figuring
out which crop is more profitable and also
doing the stakeholder engagement piece of
it so they did a 2025 growing season budgeting
and you can see the crops are labeled
based on the color so pepper is that orange
one broccoli is the green yellow squash
strawberry is the red and raspberry is the pink
and you can see as the months go up like
from february march april may you can see
we are getting busy in the field and this is
labor and you can see a lot of labor in
strawberry in April, May, and June, and then
slowly dies down in terms of the bandwidth
here. If you look at squash, May, June, not
much, but then July and August, a lot of
harvest is happening. Look at peppers, you
can see May, June, July, and then August
and September, you know, harvest happening.
So they divided the labor put into
these crops, again, trying to develop
the enterprise budget for individual crops
so that growers can decide which crop
is more profitable. So between the 2024 and
2025 labor analysis, they did find that
the labor went down by 28% in second
year because the first year we are
establishing things, we are figuring things
out, we are fine-tuning things. And again,
this is research. The commercial system
will be different. But as a farmer,
as a grower, they definitely want to know
what is the revenue that can come out
of this. Of course, markets dictate
that. If there's a market for bell
peppers, a grower will grow bell peppers.
That's totally fine. But we are interested
in, as a research point of view,
which crop, what is the feasibility if
somebody wants to go in and decide on
which crop to grow. A lot of numbers
here, but this is between area one and
area five. So area one is the single
axis tracker. Area five is outside
field production. And we are seeing
that you see different numbers out here
of the material costs, for example,
for peppers, for summer squash, for
broccoli, raspberry. And we are finding the
change. So for example, between 2024 to
2025, there was a 49% decrease in material
cost because, again, once we fine-tune
things, we know how to manage things within
that agrivoltaic system. And raspberries,
again, one-time investment in terms
of trellising, strawberry also,
a lot of planting. Second year, they
produce the fruit. So, a lot of numbers
in there, a lot of calculations, and we
will be, we are working actually on some
extension publications to streamline this and make
it easy as a summary. So John is working on
that two-year data. We are also interested
in the microclimate within the agrivoltaic
system. What is the temperature?
What is the light intensity when we
grow crops in there? So Michael Kielewald,
who is our outreach coordinator, he
made these graphs. This is from 2024. This is actually not
the microclimate. This is actually
the energy produced from those panels.
And now we are not comparing crops
here. We are just comparing fixed standard
versus tracking. So if you see the
fixed standard, which is the fixed
panel, which is two feet leading edge versus
the tracking standard, which is five feet, we
can see why the solar developers are going
to single axis tracker because the energy
produced is more in that system. Of course,
the area dictates what panel to put. What
I've heard from our contractors and our solar
developers here in Iowa is that when the land
area is anywhere between less than four or
five acres, they will go with fixed, but
anything over four or five acres, they will go
with a single-axis tracker. but energy
production is definitely higher if you compare
green and this purple in the single axis tracker
similarly the tracking tall is higher than
the fixed tall so there's a reason why
the developers are using the single axis tracker
this graph actually shows you the comparison
of temperature across time open field
and under solar panels what does that temperature
look like. So on the x-axis, we have the
months, May to August, and you have the
temperature on the y-axis. No difference in May,
but if you move on from May to June, July,
August, September, October, you will see
that the temperatures are about, you know,
one to two degree lower in the solar agrivoltaic versus the open field. So there's also a myth
out there that these agrivoltaic systems
are super hot and crops won't grow there
or it's unbearable, but that's not the case.
What we are finding here is the temperatures
in the open field are higher and actually
the temperatures in that solar agrivoltaic
system is lower. And so it's actually a
buffering temperature. So that's something
which we found unique. And we
have this data from two years
now. This is 2024. If you look at the
soil temperature, here you see the, we
also, it's kind of replicating or following
the same pattern. The light green one is
the solar and the dark green one is the control.
The soil is warmer or hotter in the open
field condition as compared to the
solar, the agrivoltaic panel. So definitely
the it's a bit cooler in that system as compared
to the open field. We did actually Michael
also did the growing degree days
calculation and you can see those that that
light blue section which you see at the top
is the open field that's area five and
the orange or the pink whatever color you
call this it's at the bottom one which is
the area one again showing same result
but in a degree day model that there was
between June 6th to October 14th, 3,654
degree days in the solar agrivoltaic versus
4,083 which is in the open field. And
this is based on the HOBO sensors which we
installed out there. So definitely the micro
climate is different, it's cooler and in
that system as compared to open field. Now
one thing I want to invite you all if you
are in iowa anytime starting june this is
from last year but we had several open houses
in 2025 actually and you can see those
examples here the dates we have june 27 12 and so
we are going to do the exact same thing this
year we have a website which i will share
with you if you are in this area in ames in
iowa in des moines close by if you want to check
out the system check out this research
plot please feel free to come or reach out to
me if you are not able to come during the
open houses day i will still be happy to show
you around we hosted a lot of field days we
hosted a lot of people solar developers county
officials elected officials our senators
congresswomen congressmen chamber of commerce
folks growers consumers everybody was welcome
because not many had gone into an
agrivoltaic farm so we are very open outreach is a
big part of this project so we are very happy
to host anybody who's interested to visit
again you can see we have sometimes we have
lunches right under the shade out there works
out great when we have open houses and and
field days it's a natural place to rest
you know we have engaged the 4-H part of this
activity, high schools, done a lot of field days to also engage the youth in this agrivoltaic
programming. A big thank you again
to Alliant Energy, without whom this
project won't be possible. This is
our website at the bottom, agrivoltaics
.research.iastate .edu. So you can go
there. We have a lot of information out
there, pictures. And also, I need to
thank the U.S. Department of Energy who funded
this project to evaluate the feasibility
of agrivoltaics here at Iowa State
at the Aligned Energy Solar Farm. So thank
you to all the other partners, the Practical
Farmers of Iowa, the Iowa Specialty Crop
Growers Association, the Iowa Department
of Agriculture. Everybody provided
input and everybody plays a key role as we
learn the system more and fine tune it. So
with that, I'm more than happy to answer
questions. And I hope I was able to share
things in a clear manner and please ask
questions. Thank you. All right. Thank
you very much. You have provided
us with a lot of food for
thought here. We do have some
questions here. Danielle has a question.
I know Danielle is a student at michigan
state university and she is uh working with
me on a on an aggravate project and i think
she has a really good question here in
terms of scaling solar with commercial farming
what have been some of the biggest barriers
and what feedback have farmers provided about
working within solar array uh environment
yeah so uh i would not say barrier but i
would say challenges and some of them for
example you know these are smaller plots we can't
use a tractor mounted like a sprayer for
example a boom sprayer you can't use that
you know it's uses so we have to use a backpack
sprayer for spraying fungicides or insecticides
that is something many farmers ask can
you till in there both directions like
crisscross are there wiring down there and
so I tell them there is no wiring in the ground
except in the front of the panel, right
in the front where the inverters are. And even
that wiring is about three to four feet
down. So you can till, no problem. You can
go either ways, east and west, under the
panels. If you want to till under the
panels, totally fine because the wire or
the wiring is running right beneath the
panel. Instead of in the ground, it
is right beneath it. So that is something
which growers ask. Other challenges I would say, I mean,
we can use all the machinery, no problem
with our weed fabric. We had to lay by a
hand, which is, I think that's the best way to
lay the weed fabric. Insects and diseases, squash wine border,
squash bucks, we did see them. We saw
tomato hornworm, which is very, very
common when it comes to outdoor production
also. So apart from spraying, I don't
see there's any challenge as such to
manage these systems. So what kind of
feedback have you heard from farmers, though,
that have come and visited the
site? Yeah. What are they saying about
what you're doing? Yeah. One of the reasons why
many of the farmers are visiting is that
many solar developers are reaching out
to our farmers and asking them, are they
interested in a solar farm? Maybe they have
a 10-acre site. Can they install an
established solar farm? And our farmers are
like, I'm happy to do that or I'm interested
to do that, but I don't want to lose agriculture
or growing my produce. So can we
grow it? And when they come and see the site,
one of the biggest take home for them
is that, yes, it is possible without
compromising on the scale. they ask questions
about how's the quality of the produce and we
find no difference in the open field production
and the inside. In fact we find less
sun scalding in some of the produce that
is in that solar panel because the sun is not
directly hitting the fruit all the time
especially for peppers. They are interested
in irrigation and that's something I need
to point out here is that we had to install
irrigation so we put underground piping
because this was a site where it was
primarily corn and soybean before we put this
agrivoltaic. So we, the college, put in
money about $25,000, $30,000 to install
irrigation. So this cannot be replicated
anywhere in the farm country out there
because there has to be irrigation. And as we
all know, for fruit and vegetables, without
irrigation, it's difficult to grow high
quality produce. So I think farmers have
to be cognizant of the fact that they
need to use irrigation. All right. Lee is asking, has
anyone measured wind velocity at the soil
surface based on panel height,
direction of wind and position of panel?
Yeah, Lee, excellent question. We have
not done that. But what I have heard
from the students is, you know, who work in
both the single axis tracker system versus
the fixed panel, it is much hotter in
the single in the fixed panel system versus
the single axis tracker because the
fixed panel, the panel completely blocks the
wind from one end and they're working
behind it. So it gets really hot when they're
harvesting as compared to a single axis
tracker, which is up there, it moves back
and forth. And so it's much cooler. So apart
from that information, we have not measured
the wind velocity, but there is less
wind moving in the fixed panel versus the
single axis tracker. Patrick is asking one
of the more common anti-solar arguments,
particularly on farmland, is that solar
panels will leak PFOS, cadmium and other
chemicals into the soil, permanently
making the land unusable for farming. Has this
research addressed this concern or
are there solid resources on this topic?
Yeah, good question. I have confronted
this question before. I have not found
any, you know, solid research work that
has been been done. So far, my understanding
is it is minimal risk of leaching of
any of the heavy metals or the PFAS being
mentioned here. If that's the case, I
mean, we use so much of plastic and so much
of other things in our production system,
it will all end up in the soil. I mean, if
you ask me, will it end up there? Maybe in
several years, it might. But so far, I've
not come through any rigorous research work
that has been done. So far, most of
the research that has been done has
shown that no, there is no risk of that
contamination. So I would just
say that PFAS is not part of
solar modules. And the way that solar
modules are constructed makes it very,
very, very difficult for contaminants to
escape. And think about how a solar
module is constructed in the first place. It
would not be in the best interest of a solar
module manufacturer to make something that
is going to escape, especially when
they need those constituents in the
module to produce or to convert solar energy
into electrical energy. So, I mean, North
Carolina State University has come out with
information on panel safety. uh and i just
under i just heard just uh what last week
that they're revising um with new research
data the recommendations that they made when
that last report came out so the average
lifespan of the panel is 20 years so that's how
long that panel will be out there producing
energy so it's pretty tight pretty safe uh
and again pfas is more you know other the
forever chemicals that come out of you know
other things lee asks in in typical iowa whether
does it rain more in the afternoon or in
the morning and it's in reference to the
drip line yeah very good question yeah because
depending on where the how the panels are
and the heavy rain the rain will all flush out
and fall right in front of it and there could
be erosion that could happen because we have
grass we do not have any issue with erosion
and in terms of rain it's quite unpredictable.
I mean, it could be early in the morning,
morning or afternoon. So it's very hard to
figure out when it's raining more. But
the bigger picture is the rain doesn't impact
anything in terms of eroding the soil wherever
it falls and that drip line. And also
there's another question. I don't know if later
somebody asked, but whether we wash the
panels, whether the utility company wash the
panels. They don't. They do not wash the panels.
It's economically not viable for them. So
we are by the side of a gravel road. So there
is some, you know, dust that comes and
settles, but the rain takes care of it.
Because they said they start washing it, by
the time they started one and finished the
other, it'll be time to wash again. So
they do not do that. so in your economic
research have you found a large disparity in
cost for the higher panels and if so what
policies would mitigate the cost factor in
your opinion yeah so we use two different
configuration of the panels for if i did not
explain it clearly but in the single axis tracker
we had two different heights five feet
and eight feet in the fixed panel we had two
heights two feet and four feet so let's
look at the single axis driver so uh five feet
and eight feet eight feet definitely more
expensive the alliant energy didn't share
with us what the cost is to put that eight
feet they they bore that cost they but imagine
more steel the more it goes on top of the
ground the more it has to go under the
ground because it has to be installed uh safely
so that doesn't fly panels don't fly out
so definitely much more expensive expensive
to install an eight feet panel now we grew
one crop consistently across we grew peppers
under the five feet like between the five
feet and also between the eight feet panels
and we did not find any difference in yield
for peppers so there is no need to raise
the panels we can grow peppers uh profitably
uh under a between a five feet torque tube
panel versus an eight so uh and that was
another thing we wanted to experience or test
with the study is do we need to raise the
height we don't have to five feet is good
enough that is really good to know because
solar companies or solar developers or the
farmers might want it to be raised higher because
you know we want to grow we need enough
light in there yes you will get the same
amount of light and and no difference you know
uh obviously there'll be better wind movement
in that eight feet, but I mean, given our,
we didn't find any impact on yield as
compared to the height. Okay. Excellent. Candice asks, I have
been told that, but wondering if there
is a way to waive the economic costs and
community acceptance. I would wager developers
could save millions if they were able to
convince a community or a state to site and
permit the project within a year instead of
three to five plus by creating the opportunity
to continue specially crops raising and
grazing with sheep? Yeah, I think we did
the economic analysis mostly on the crop
production side of it. But I think another
underlying theme in our project was to
make everyone aware of what agrivoltaics
is. And so that acceptance piece is
something we were very particular
about. That's why we wanted people to
come to the site and take a look at it
and ask us questions. Anytime people
came, Aligned Energy was also there and creating
more awareness. And so I didn't
understand what three to five year plus question
was here, uh but no i think that gets at
the amount of time it takes to work through
the system by the time it is a system
is a solar project is proposed to when it is
built okay okay yeah yeah yeah here at
state it took them alliant energy when they
started this work it was somewhere in
march or april and by october they were done
like we had the ribbon cutting in october
although there were some delays in the
inverters. And so the whole site went into
production in March of 2024, but the construction
was very quick. Yeah. All right. Hopefully, Candice, that answers that
question. If not, type another one in
and explain yourself a little bit more
clearer. All right. Another young person
question here from Danielle. Was there an
existing tile drainage system before
development? If so, how did the installation
of the solar infrastructure affect
the system's performance? Good question, Daniel.
Yes, there was an existing tile drainage
system because this was a corn
-soybean rotation field. And when they installed
those pylons, they made sure that they do
not damage the tile. These pylons were
put, just pounded directly into the ground
no concrete poured and so we gave them
the the plan of the land lay of the land
so they had all the the plans and they
made sure that they do not damage the the
tiles all right right and i know lee lee lee
he's a troublemaker here and he's saying
that your squash graphic is is is
misleading lee why don't you unmute
yourself i think you can do that and just
explain what you meant So almost all the
graphs where you showed solar compared to the
control, the graph started at zero, and
you visually could actually see the
difference between the two. But on your squash one,
you started at 200. And it makes it
look like the production was
twice as much unless you go over and
read on the side and judge the math
and do the math. Yeah, so if you
look at this, even though it
started at 105, what you have to look
at is the difference. This is 119.7,
and this is 142.7. Yeah, but look at
the bottom. What's the bottom? It
doesn't start at zero. Yeah. So, yeah. So
that was just because when we created the
graph, we could have started with zero. This
all started at zero. Of course. We just fine-tuned
it such that, you know, you can see the
difference between 119 and then 142. I
understand what you're saying because it
should not be 105. How do you get to
119.7 from 105? Yes. So the
visualization makes it look like
it's a bigger difference than
it actually is. Yeah. So if you
look at the number, basically you
have to focus on the difference
between 142 and 119. Yeah. But thank you for
bringing that up, Lee. All right. Most solar farms
have outside fence. Does this aid reducing
various critter invasions or do they
dig, jump to access? And you don't have a
fence. Can you talk about why there wasn't
a fence and what kind of like deer damage or,
you know, things like that that you got?
Yeah. So I would I would correct here, Charles.
We do have a fence. Oh, OK. And that is
a big plus, which the farmer gets free
of charge because the fence was installed
by Alliant Energy. And it is in their
protocol that whenever they have the
solar farm, because they have the inverters
or the machinery, it's always fenced.
So that's a bonus. And it worked for
us and it worked for any farmer
who's interested in agrivoltaics. If a
solar energy, if a solar developer
comes on the farm and sets up that, they
will put a fence. And this is an eight
-foot fence. And so it helped to keep all
the critters. I mean, occasionally there'll
be some, but deer, no problem with that. We
did not have any issues. so all right think
of it i mean think of the amount of money uh
we i mean the farmer can benefit you know
with that fencing around you know we definitely
saved a lot there all right selma has
a question and i know she's a university
of michigan student um how often do
sound or how often are excuse me how
often were the solar panels maintained
and have you noticed any damage
to the crops due to, I guess, the
maintenance schedule? Yeah. Throughout these two
years, there was only one instance where
because of a storm, one of the panels
came off, literally came off. But that
was it. No other problem. So in terms
of maintenance, the Alliant Energy
has not gone in there to do anything except
fix that one panel. And Patrick just
has a comment here. Your response
aligns with my own findings and
understanding, but I still face opposition
for farmers who are anti-solar. Thanks
for the responses. Yeah, thank you.
Thank you, Patrick. Selma has another
question. Have you observed any
erosion caused by rain running
off the panels? No, we did not
because we, one is we have the grass out
there and the pollinator mix out there. And
for the vegetable, you have that wheat
fabric, which is on the sides also.
So that takes the impact of the drip,
and it doesn't cause any erosion. We do
not have any problem. All right. Diana is another
student with the University
of Michigan, and she's asking, is the solar developer, okay, could the solar
developer handle the recycling or
replacement of the solar rays after its
expired lifespan? So I guess, what are
your decommissioning plans when this
project's done? Correct. Excellent
question. And so we have a lease
and the lease agreement lists
all these things. I should have also
mentioned that for us, for the
agrivoltaic, we have a lease agreement
with Aligned. It's not a lease
agreement. It's called the site access and data
sharing agreement. And so Aligned Energy
has allowed us free access anytime we
want. We have keys to enter. And so that's
the good part, what they have done. many of
the projects in many places fail because
of access issues, but Alliant has definitely
allowed us. So that is the site access
agreement. In addition, Iowa State University
has a lease agreement for this land. And
there are a couple of points and bullets
or riders out there. One is after 20 years, Alliant has to remove
everything and do whatever is needed
to give the land back to Iowa State in
the same state they found, if not better.
So that's one clause. The second thing is
they can decide to if and if Iowa State
agrees, they can donate those panels to Iowa
State and just leave. So we have covered
ourselves by making sure that if they remove,
if they do not, once the project is over,
they will remove everything, whatever
needs to be done, seeding of the grass, if it
needed to be under the panels, whatever,
they have to do that. And so that's already
been taken care of. All right. Lissa asks, did I
understand correctly that in general, the
yields and quality of the produce were
better under the panels than in the open
field control group? I would say for
broccoli, the results are mixed. Broccoli did
better outside as compared to inside. But when
it comes to squash and bell peppers, the
solar panel treatments, One year was statistically
higher, but one year, I think they are
almost the same. So there is no yield
drag. That is for sure. Whether the solar
will produce more, we are not saying that
because it is not consistent with
both the years. But definitely, it's not
producing less as compared to outside for
squash and peppers. All right. And then
I think this is the last question
that we have here. And Candace asks, my
question was actually a response to a previous
comment. Sorry for the confusion. The
common argument is that raised solar panels
are too expensive for utility skills, project,
and developers do not find them cost
competitive. But I was wondering if the money
saved in permitting faster would make up
for the increased cost. That's an
interesting concept. Yeah, that's true.
So I think the single -axis tracker has
become the standard now because I showed
you the graph where the energy produces
more in the single -axis tracker versus
the fixed. So I think that issue is going
away. Most of the solar developers
will come in with a single-axis tracker
and bifacial panels. Fixed is only for very
small-scale static small sites, but they
themselves see that there's more value in
the single-axis tracker. And with respect to
the height within, as I've indicated earlier,
five feet is good enough you don't have
to go with eight zoning you know siting
permits those kind of things are more county
based and you know in iowa there are some
counties that have outrightly banned solar
you cannot install solar panels whereas
some are supportive so we are trying to work
and again as from iowa state we are not
biased in terms of saying that hey this
is good this is bad we are showing the results
if it works please adopt if not that's
totally fine but we don't want to provide a
biased information in terms of no so put
agrivoltaic be fully supported i mean i see
value here based on the results what i
have produced but it's the grower who has to
decide it's the county which has to decide
so we are trying to work with some of the
counties to clear up some of the fog in
terms of what is being done how it is being
done what's the soil looks like is there
erosion is the top top soil being you know
taken away and so there is still some conversation
needed between the utility companies
and the county officials and the farmers
to clearly understand this concept and work
on this together. Thank you, AJ. This has been
a tremendously educational
presentation here. I'm so glad that
you were able to share your
insights on growing vegetables and
small fruits on a commercial scale. So, AJ, thanks again. Thank you. Sure,
appreciate it. And everyone, have
a good evening. Thank you so much,
Charles. This was a great opportunity. You
know, anytime I can help and provide
information, you know, go green. Go white. See you now.