Can solar panels share land with crops? Miljkovic says yes

7/22/2022

Mary Hill, News Nation

Nenad MiljkovicLower costs and government incentives make harvesting solar energy cheaper than growing crops in some places, but there is a worry that a solar boom would further destabilize the American food system.

Researchers behind a $10 million project led by the University of Illinois Urbana-Champaign say combining crops and solar power will increase the productivity of both.

Funded by the U.S. Department of Agriculture, university researchers, biologists and mechanical engineers have joined together in Illinois, Arizona and Colorado to show that “agrivoltaics” — growing crops under solar panels — can give farmers the best of both worlds.

NewsNation talked with Nenad Miljkovic, who leads the engineering team for the SCAPES Agrivoltaics Project, about what that could look like. This interview has been edited for clarity and length.

NewsNation: What does an agrivoltaics farm look like, and why does it have such potential?

Miljkovic: Many plants — whether it’s agricultural crop — corn, or wheat, or lettuce, but also trees or grass — are not photosynthetically 100% efficient, meaning that of the light that comes in from the sun, a small fraction of it is actually used for growth.

Because of that, we thought, can we integrate the two and have solar panels on top of crops? Add some spacing to allow some sunlight, but then crops growing underneath? Instead of just losing that fraction of light, you’re now using it to generate power.

In fact, we can actually make the crop growth even more efficient, because many times the sun is just beating down on the crop and it gets too hot, it loses water, it can dry out. The solar panels are helping protect it. There are certain crops that will grow very nicely in shade because they’re getting optimum sunlight and optimum growth conditions.

NewsNation: What are some of the challenges of designing an agrivoltaics field?

Miljkovic: If you’re going to grow corn, and it grows six feet tall, your solar panels are on the order of six feet high.

Let’s say you want to do soy or something where you need a tractor to harvest. How do you run your tractor through a field with solar panels? And so we’ve thought about, can we make it 12 feet tall instead? And what are the cost repercussions?

There’s lots of interesting considerations that have to be put into play. They are crop-dependent; they are region-dependent. If you prove it for a farmer in Illinois, that’s not the same thing as a farmer in Arizona or in Washington state or Florida.

NewsNation: How would you address critics of solar farming, who say farmland is needed for agriculture?

Miljkovic: If you look at solar energy — that’s been essentially exponential growth over the past 10 years. If you lose all that farmland, you lose the capacity to grow food for your people. But even within that, there’s an argument that you could actually get better yield or output by integrating the two.

You could take a farm and just do all solar farming, and (take) the farm next to it and just do all agriculture. If you were to take that same equivalent field and now integrate to do corn with solar panels above — you will actually grow more corn and you may generate the same amount of power.

NewsNation: What evidence shows that agrivoltaics will get the higher yields you want?

Miljkovic: There’s not a lot of experimental evidence for that particular fact, but we do have scientific grounding in our assumptions. There are methods to actually look at what light is being used by the crop itself. And then what is the output if you were to chop off (a part of the light coming from the sun) to use for a solar cell — and you can predict this.

Those are kind of the hypotheses or the scientific grounding to tell us that potentially we could have better yield than just two separate installations or fields. Now we have to actually go and prove it.

NewsNation: Is agrivoltaics the future? What would it take for mass adoption?

Miljkovic: Currently, we’re also looking at things like bifacial solar panels — where there’s also solar on the bottom side. And so whatever gets reflected from the backside goes to the solar panels as well. You get a 10-15% boost in terms of power efficiency.

The farmers are very interested, but part of the issue is they’re just not sure — “can you prove to me the benefit?” It’s just a matter of essentially sharing the findings with them, proving to them that this makes a lot of sense.

This story is reposted from News Nation.