Can solar farms and crop farms coexist?

McCall: Argivortaics is a term that refers to the coexistence of sunlight and agricultural activities, such as grazing, crop production, and ecosystem restoration.

Sujit: Algivoltaics offers a range of benefits for farmers and solar developers alike.

McCall: If solar developers can prove that they are making the most of the land, they will be able to access more land and develop more solar.The other big factor is the farmers and landowners themselves.

Sujit: When land is leased for solar development, it is possible to continue income-generating activities such as growing crops or raising sheep.

McCall: Local communities also stand to benefit: they can create pollinator habitat and restore grasslands.

Mr. Choi Seok: It used to be common to leave the ground bare for solar construction, but that’s no longer the case.

Sujit: Covering land with vegetation can help prevent erosion and provide an opportunity to restore soil carbon.

McCall: There are currently about 530 artificial pastures in the U.S. (as of July 2024). The ratio of pollinator habitat to solar pasture is roughly half and half.

Mr. Choi Seok: There’s a lot of focus now on getting sheep to graze under solar panels, because they won’t jump on them or chew on electrical wires and things like that.

Sujit: Incorporating sheep grazing can also improve soil nutrition. We just completed a five-year study in the Midwestern United States, many of which are carbon-depleted due to intensive agriculture, and we found that managed sheep grazing can actually improve old carbon and soil nutrition.

McCall: And if it can be done at the same cost as mowing, and benefit both local herbivores and the environment, then why not make it part of their standard practice?

Sujit: So overall, there is a growing consensus that solar grazing has some value in many of these landscapes. But when it comes to crop production, there are many unknowns.

McCall: Of the 570 artificial solar farms, only 40 are actually dedicated to crop production, and many of these are small research facilities.

Sujit: So the first thing to consider is which crops grow better in what climate and geographical conditions. This is an important question because some crops grow well in shade while others will produce significantly less yield in shade.

McCall: This means that two varieties of the same tomato may respond completely differently to the microclimate that is actually created by solar panels, and weather patterns are not consistent from year to year, making it very difficult to generalize about when and where a crop will actually be harvested.

Mr. Choi Seok: But beyond that, crop production requires many engineering and design changes.

McCall: The panels would have to be mounted high enough to avoid shading, or spaced far enough apart to allow conventional farm machinery to pass. Essentially, all of the changes required come with cost tradeoffs, or you’ll get less energy. That’s why there’s been some hesitation in the U.S. market.

McCall: We’re not going to do every system design everywhere, but when and where does this actually make sense? And why would different stakeholders want to do this? We see climate change with decreased access to water and increased temperatures, so we need to integrate solar. A great example of this is wine grape production in California. Right now, it’s too hot to really produce certain grape varieties, so we need to put in shade structures. So why not also produce solar and get some benefit from that shade structure?

McCall: Well, there’s also a broader need to grow food closer to population centers.

Sujit: So now we’re trying to figure out what kind of solar power system configurations are suitable for urban areas. We’ve set up an experimental system at Temple University’s Ambler campus, which can be installed in places like vacant parking lots in urban areas. So the idea is to compare how solar panels are affecting crops. Maybe they actually improve the yield of leafy greens. So maybe you can produce one more cycle of lettuce. But we need to expand the study to other regions to see how the impact is different. Over the next 10 years, we’ll have a lot of information about different types of integration, which could be applicable to different parts of the world.

Mr. Choi Seok: That’s my dream, a place where I can point to a map and say, if we put panels here, this is where the climate will change and we’ll be able to grow this crop.

McCall: So it’s not a one-size-fits-all solution. It requires real thought. It requires taking the perspectives of a lot of different stakeholders. But increasing solar power also helps us meet our climate change goals, so it’s essential that we make the most of this land.