Modernizing our Agricultural System with Agrovoltics

by LAUREN GONZALEZ

The planet is experiencing warming temperatures at an unprecedented rate, with a 1.1 degree Celsius temperature increase since the 1900s, and the effects are being seen on all levels of life. It brings into question whether the things we rely on to uplift our current ways of living are sustainable.

Scientists recently conducted a study and found that extreme hot zones currently occupy only

0.8% of our land area at the moment. However, these hot zones could expand to over 19% of the global land surface area by 2070. Looking specifically at dryland expansion, it’s expected that, relative to 1961–1990, arid-like conditions could grow to about 50% of total land mass.

Not only could these zones displace billions of individuals, but their growth raises the question: what will happen to our current agricultural model as desert-like land conditions become more common? Farmers will have to experience water shortages, warming temperatures, and other climate-related stressors more regularly. Taking this into account, the possibility of food scarcity in the future becomes likely.

Beyond expansion of arid-areas, agricultural land is being lost to population growth and further urbanization. Focusing on the U.S. specifically, American Farmland Trust recently used spatial mapping technology and found between 2001-2016 that 11 million acres of agricultural land was converted to residential or urban land use.

The agricultural system that relies heavily on excessive water usage, abundant fertile soil, steady labor, and stable conditions for crop production is now at risk as its requirements become scarce.

As human expansion, land-use conflict, and climate change continues to put extreme tension on local farmers, society has to rethink our approach to the current agricultural system.

This brings us to Arizona, where local researchers from the University of Arizona are taking it upon themselves to investigate how new technology, known as agrovoltaics, could expand crop production into desert-like locations, decrease water usage, increase efficiency of photovol- taic systems, and help resolve urban-rural land conflicts.

Kai Lepley, a PhD student at the University of Arizona’s School of Geography, Development and Environment, is currently researching this new technology and using remote sensing platforms to bring a better understanding to its impact going forward. In a one-on-one Q&A interview, Lepley, as an expert on sustainable agriculture, explains the effectiveness of our current agricultural model, the impacts of climate change on food production, and the potentials of innovative solutions such as agrovoltaic systems.

On a general note, can you go more in-depth into the sustainability and effectiveness of our current agricultural model in the Southwest?

Flood irrigation is still widely used. We simply flood the field with water, and part of it evaporates into the air before it even goes into the soil. That’s a lot of wasted water. In Arizona, we use Colorado River water. To get that water, it must be pumped up a hundreds of miles long canal using electricity, because it’s going up in elevation.

Therefore, pumping that water to our cities and agricultural farms uses the majority of our state’s electricity, and it’s all done in these open canals where it’s evaporating along the way. A lot of these outdated practices and systems contribute to water use inefficiency. Agriculture used to take 90% of the water in Arizona, but now it takes 74%.

On a global scale, the World Resources Institute recently found that 17 countries, accounting for a quarter of the population, currently have food systems under severe water stress and shortages due to climate change related factors. Going off this, how has climate change impacted our agricultural system in the Southwest region, and why is arid farming so integral to the future stability of our food systems?

We’ve already experienced over a degree Celsius of warming. The fact is that the warmer it is, the faster water evaporates. When it comes to plants growing in any environment, one of the key factors is vapor pressure deficit. Basically, the hotter it is, the quicker the air is going to dry out. And because the air is so dry, it’s pulling water out of the plants and out of the ground more quickly. When it comes to agriculture, it means we have to use more water. Also, it’s more stress on the plants. When you mix in high temperatures and extreme events, you have these plants that are pushed to their limit because of this added pressure.

Turning to a more locally defined view of these current agricultural issues, how has this affected the farming community specifically?

We have a lot of farmers who are struggling because of the pressures of climate change, the economics of farming, and the limitations with water supply — farmers this year have faced a 21% water cut. A solar developer will say, “We’ll buy your land and install a bunch of solar there.” It’s an easy way for a farmer to make a profit. Or, they might sell their land to residential development. In either case, you’re losing that farmland and that food production.

How does this connect to the origins of agrovoltaics?

Agrovoltaics is just the combination of the words ‘agriculture’ and ‘photovoltaics’. Agriculture is simply growing food, and photovoltaics is the actual process that makes solar panels possible. The whole idea behind agrovoltaics is what if we shared the sun between solar panels and between crops. Instead of having to use more land doing these activities separately, we use the same land for both. If you can combine those activities, then the farmer can keep their identity, continue farming, and can make some more money.

How are solar panels affected when incorporated into these agrovoltaic farms?

In a place where it gets hot, above 77 degrees Fahrenheit, the solar panels start losing efficiency with every degree you go higher. Once you’re at 100 degrees Fahrenheit, [the panels] lose about 10% of their efficiency. In agrovoltaics, we’re irrigating the ground beneath the solar panels, and the plants are essentially sucking up that water and then breathing it out through processes to cool the air above it.

In our research, we found at least a more than one degree Celsius cooling effect due to this agrovoltaic system. The closer those panels are to the soil, the greater the cooling effect, and you actually gain efficiency in the solar systems electrical production by growing plants underneath. It’s so cool how you have this dual benefit.

On the topic of water conservation, how does agrovoltaics work to efficiently minimize water usage?

It’s that effect of shade from solar panels cooling the soil and air slightly that prevents the mois- ture we get from these plants from evaporating so quickly. We have essentially side by side gardens with one in the full sun, like traditional agriculture, and one in the shade with solar panels on top of it.

In the summer in Arizona, when we water them both with the same amount of water, the garden in the sun is going to need water the next day, or else, those plants are going to die. In the shade of the solar panels, because that soil is cooler and it doesn’t have that intense sun, you’re gonna see that we can water and wait almost a whole week before watering again.

One of the main questions people might wonder is: how effective is it to grow staple crops under agrovoltaic systems as compared to traditional, mainstream agricultural methods?

That’s another big question: can we even grow crops in the shade? We’ve grown beans, potatoes, onions, tomatoes, basil, cilantro, carrots, eggplant, flowers, peppers, and more, and we’ve had success across the board with little differences when compared to traditional agricultural methods. However, one major difference is that we see a change in timing. The plants grown under the solar panels tend to be delayed when they start flowering. Possibly your crop is going to be done growing a few days to a week later. And that’s something farmers have to think about.

In terms of the yield, we’ve actually noticed little to no difference in yield. Sometimes we even find higher yields in the shade in the agrovoltaics, and that’s especially the case for Chiltepin Peppers.

How are farmers impacted from implementing these agrovoltaic systems?

Another thing to take into account with respect to farmworkers is when you are outside working in the sun all day, it’s life threatening. It’s a health crisis. But when you’re working in the shade, under solar panels, it’s night and day. Farmers experience severe health risks, especially undertaking their agricultural businesses in primarily arid, hotter regions such as Arizona. In that way, farmers stand to gain much from implementing agrovoltaic models.

Are there possible barriers or obstacles to entry for farmers looking to expand their services to include agrovoltaic models? More specifically, why hasn’t agrovoltaics become more mainstream in the agricultural field?

I think part of it is education. I think most people still have never heard of agrovoltaics. And then after that, I think we need policy. Every county has their own land use policy. Zoning, for instance, might allow or not allow for agrovoltaics to be possible. This is because energy and agriculture are two totally separate activities in our minds. There is the farm in Colorado that we are working with, and when the agrovoltaic concept was initiated, we actually had to work with the local government to create a new zoning code, so that they could combine agriculture and electrical production.

You also have utility companies. Every electrical utility in each different region has their own policy and practices, and it’s kind of at their whim. Do they want to allow this, because that means that they’re going to then be purchasing power from these farmers who are producing electricity or they’re going to be competing with these farmers to sell electricity to people. There’s just no standardization for enabling this technology to be quickly rolled out or adopted.

How do farmers specifically perceive this agrovoltaic idea?

There’s a big farming community just an hour north of us here in Tucson. They’ve had a lot of solar developers come in and buy out land from farmers and turn it into solar fields. The people there don’t like it. Sometimes, it’s just that they hate the way it looks. Other times, a neighbor made a ton of money by selling his land to this utility, but another cannot because they’re not close enough to the major power line.

What happens now is the majority of farmers in that community are very opposed to any type of solar. However, you then have a different community that’s totally on board. Therefore, it’s really this kind of patchwork landscape of thinking about where it can fit. I think a lot of the agrivoltaic farms that we’re gonna see pop up in the coming years are just going to be very opportunistic: someone who knows about it and then talks to the right people.

Before the idea for agrovoltaics came to the U.S., Kai Lepley describes how “back in 2020, we had the world’s first agrovoltaics conference. We went there, and some attendees from Japan said, ‘we have over 2000 agrovoltaic systems.’ Everyone was shocked. We had maybe three to five systems in the United States at this point. The thing is, there’s an incentive from the government. Because they have so little land and especially land that they can farm on, it was almost essential. If they wanted to adopt solar, it had to go over farmland. So it was just out of practicality.”

Agrovoltaics poses an alternative pathway forward for land cultivation. By rethinking how we utilize land, it can become multifunctional — these symbiotic relationships can evolve to make our current systems more efficient. While there might be boundaries to access, Japan’s example demonstrates a hopeful possibility for these technologies to become more integrated into these growing arid locations, such as Arizona. With this, we can modernize a network facing extreme pressures at the moment, our food system.