Mixing solar and farming could be key to clean energy future
Black landscaping fabric now covers the bare soil between rows of solar panels on the Big Lake solar farm in rural Sherburne County.
But a couple of weeks ago, this solar farm was producing more than just energy.
Peter Schmitt, director of project management for US Solar, holds a basket overflowing with the last of the harvest: shiny green peppers, bunches of broccoli, kale and spinach, herbs and tomatillos.
“This is a former potato farm,” Schmitt said. “Now, with this pilot project, we are putting some crops back on it, just in kind of a different way.”
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US Solar owns the 1-megawatt Big Lake community solar garden and about 80 more in Minnesota. It’s part of a pilot project encouraging farmers to grow crops or graze livestock between and underneath solar arrays — a practice known as agrivoltaics.
Typically US Solar plants its solar farms with a mix of native wildflowers and prairie grasses that attract pollinators, such as bees and butterflies. But increasingly, the company is looking for ways to integrate farming into its solar energy sites, Schmitt said.
“It’s something where we can help the community, we can help build relationships with farmers,” he said. “One way or the other, we have to maintain the land under this site and we want to. But if there’s an opportunity to support local small farmers and provide them access, all the better for us.”
Interest in agrivoltaics is growing, along with the need for land for new solar farms, as Minnesota and the nation shift to cleaner energy. The U.S. Department of Energy estimates 10 million acres of solar panels will be needed by 2050 to meet the nation’s net zero-carbon goals.
Several hundred sites across the country are combining solar with everything from growing squash and blueberries to raising honeybees to grazing sheep, said Stacie Peterson, energy program director of the National Center for Appropriate Technology. It runs the AgriSolar Clearinghouse, a nationwide information-sharing hub.
“It popped up around the world over the last couple decades, and it’s become more common in the last decade,” Peterson said.
The partnerships benefit solar companies by helping manage vegetation, Peterson said. And farmers benefit from improved soil health and extra income.
“We’ve talked with a lot of farmers that (say) this is how they were able to pay for their family farm,” she said. “(With) the money that they get from the solar, they’re able to pay for their taxes. Or they’re able to set up a trust for their kids.”
Agrivoltaics offers other benefits: In hot, dry climates, solar panels provide shade for grazing livestock. Mixing crops with solar energy also can create a microclimate that decreases evapotranspiration, reducing plants’ need for water. And solar panels with crops underneath tend to stay cooler and produce electricity more efficiently, Peterson said.
Adding agriculture also can help increase public acceptance of solar in rural areas, where residents often raise concerns about the loss of farmland.
“We’re seeing pushback, people not wanting to see land drastically transformed or changed from what they knew it to be,” said Jordan Macknick, who is lead energy-water-land analyst with the U.S. Department of Energy’s Colorado-based National Renewable Energy Laboratory. NREL is conducting research on two dozen agrivoltaics sites across the country, including the one in Big Lake.
Combining solar with agriculture is a way to keep land in production and ease community concerns, Macknick said. He cited one example: In Delta County, Colorado, county commissioners opposed a solar farm until the developer revamped the proposal to add irrigation for sheep grazing.
“There’s real stories of agrivoltaics being the deciding factor that gets a project approved or not,” Macknick said.
Schmitt said US Solar wants to integrate solar in a way that benefits agriculture and the community.
“When I’m talking to farmers, they want this,” he said. “It’s good revenue from those land leases, but also it’s a way for them to still be doing agriculture, even if it’s not the same look of agriculture that it's been for the last few generations.”
Finding partners
Co-location also can help farmers gain access to land that they otherwise wouldn’t be able to find or afford.
US Solar and Connexus Energy joined with Big River Farms, an incubator farm in Marine on St. Croix that teaches beginning farmers — especially immigrants and people of color — how to grow sustainable, organic food and build their business.
Next summer, farmers in the program will be able to use plots of land at the Big Lake solar garden for free.
Sophia Lenarz-Coy, executive director of The Food Group nonprofit, said farmers were able to visit the demonstration project this summer, which helped spark interest.
“Because most people have not heard of agrivoltaics, it really helps farmers to see something in action to imagine what this could be like,” she said.
The Big Lake solar farm also housed bee hives owned by Bare Honey, a Minnesota beekeeping company that produces and distributes local honey throughout the Upper Midwest.
Bare Honey has bee hives on dozens of solar energy farms planted with pollinator habitat, and also on some sites where crops are grown, said owner Dustin Vanasse.
Solar farms that include vegetables and other crops provide direct health benefits for the bees by providing a variety of types of pollen, Vanasse said. Healthier bees increase the strength and longevity of the hive, he said.
“You can think of it like eating just Trix cereal for your entire life as you’re growing up, compared to having a variety of vegetables available and a varied diet,” Vanasse said.
Overcoming challenges
There are potential hurdles to co-locating solar and agriculture becoming a widespread practice.
Retrofitting older solar farms can be trickier, because some were built with arrays closer together, leaving less space for crops or equipment. Also, adding solar panels to farm land sometimes can require local government officials to approve a change in zoning.
The pilot project is helping the company better understand how farming and solar can co-exist, Schmitt said. At one Carver County site, they’ve learned that sheep will happily graze between solar arrays without causing mischief, but goats are a different story.
The University of Minnesota Morris began experimenting with agrivoltaics about a decade ago by putting solar panels on top of swine barns, said Brad Heins, animal science professor at the university’s West Central Research and Outreach Center.
In 2018, the center started putting solar panels in cow pastures. Researchers just wrapped up a two-year study where they grew different grasses and crops such as oats, wheat, corn and soybeans under the panels, Heins said.
How well different crops grow depends on how much sunlight the solar designs allow, Heins said. During a drought, the solar panels seem to hold in the moisture, he said.
“So we see more grass growth underneath the solar panels where there’s some shade, compared to areas that have more sunlight,” Heins said.
Researchers also found that cows spend a lot of time under the solar panels during the hot times of the day, which reduced their heat stress.
However, the panels were raised about 8 feet in the air to allow the animals room to graze. Given today’s inflationary prices, that could increase the cost.
But Heins thinks that agrivoltaics is a promising way to address concerns about solar energy projects built on valuable agricultural land.
“I’m not a big fan of driving around and seeing solar take up a lot of good farmland either,” he said. “So I think this is a viable option.”
Advocates say the obstacles aren’t insurmountable, given what’s at stake.
Farmers are regularly seeing the results of climate change, whether it be drought, extreme heat or unpredictable rainfall, Lenarz-Coy said, so it makes sense to build partnerships between sustainable agriculture and clean energy.
“It just opens up additional doors for groups that have so much in common, but maybe haven't gotten to be in that direct partnership in the past,” she said.