By Frank Morris
Solar power is the fastest growing source of electricity in the U.S., but some new solar installations are taking over productive farm ground. Scientists are trying to develop ways to get both calories and kilowatts from the same land, but that’s not as easy as it might seem.
When Scott Thellman looks at the bottom land near the Kaw River, he sees productive farmland.
This area north of Lawrence, Kansas, just across the river from an old coal-fired power plant has fantastic soil, according to Thellman, who lives nearby and grows organic vegetables and row crops.
“It’s absolutely the best our county, and frankly our region, has in terms of the water accessibility, the mineral glacial components of the soil,” Thellman said. “Plants are really able to thrive here.”
It also makes a good place to locate a solar farm. It’s flat, with easy access to roads and high voltage power lines.
This spring the Douglas County Commission approved a 1,105-acre solar farm.
Utility-scale solar is the fastest growing power source in the U.S., more than doubling in the last three years. Power companies built more solar farms last year than ever before, and they’ll likely hit another record expansion this year.
The increase in solar energy means solar farms and traditional farms are vying for some of the same acreage. The competition for land comes at a time when farmland is already losing one to two million acres a year. Now solar farms are a small but growing use for those fields.
One answer is agrivoltaics – the idea that production agriculture can coexist with utility-scale solar power.
Developers of the solar farm outside Lawrence, for instance, have promised to facilitate sheep grazing around and under solar panels. Farmer Scott Thellman said there’s better land for grazing nearby, that’s marginal for farming.
“We're looking at a field here that, you know, if built out would transition from very high-quality production to a solar array that currently has no actionable plan for agrivoltaics systems,” said Thellman.
How to harvest sun and food
At Iowa State University, a team of researchers is figuring how land can be used for both solar farming and just plain farming. Their work is concentrated on a 10-acre plot just south of Ames.
“It's a solar farm. We're producing electricity. It's 1.8 megawatts enough for 200 homes. But it's also a site for experiments,” said Matt O’Neal, an entomology professor involved in the project.
This solar farm was built specifically to test mixing solar power and farming.
The solar panels stand at different heights. Some of the fixed panels are two feet off the ground on the low end, while some rise five feet. Another bank of panels rotates to track the sun, including some from an industry standard 5 or 6 feet high and others 8 to 9 feet off the ground.
While O’Neal wants to see how native flowering plants and bees do under these various conditions, Ajay Nair, the incoming head of the horticulture department, is growing fruits and vegetables.
“These plants love full sun,” Nair said. “The first thing that strikes anybody is, ‘Is there enough light for the plants to grow? which is a valid question.”
Nair thinks there will be enough sunlight between rows of solar panels for some crops to thrive. Even the shade may help, he said, by keeping plants cooler in the heat of summer. Tomatoes, for instance, start to suffer when the temperature rises above about 91 degrees Fahrenheit.
“If a heat spell comes, maybe these plants will fare better in those conditions,” he said. “But if you can show that you can still profitably grow crops without affecting the yield, without affecting the quality, I think that's a good step forward.”
Yet other big questions remain.
The shade solar panels cast also boost humidity underneath and reduce the air flow. That may make the growing area under them more prone to plant diseases.
And farming around solar panels sharply limits the type and scale of machinery farmers can use. The huge tractors, harvesters and tillers that Iowa farmers rely on to grow corn and soybeans wouldn’t begin to fit between rows of solar panels.
That’s one of the reasons the team at Iowa State University is focusing on fruits, vegetables and bee-friendly plants. O’Neal said figuring out new ways to incorporate farming around solar panels will be necessary.
“So, are you going to have solar panels on farmland? Yes. Does that mean you can't farm? No. Are you going to be able to farm the way you used to? Probably not,” said O’Neal. “There's going to be some adjusting. But that farming could be different. And could it be profitable? Well, that's the question.”
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