In rural America, shoulder-high corn is increasingly competing with a new cash crop: solar energy. Acres of solar panels shine brightly in fields along interstates and rural highways, signaling a shift in the way America’s farm country generates income. The need for a happy marriage between these old and new industries has inspired an explosion of innovation and a new word to describe the combination: Agrivoltaics.
The Inflation Reduction Act includes billions of dollars in renewable energy funds that will accelerate the adoption of solar and other renewable energy sources. Some of the new solar panels will land on rooftops, but most will be concentrated in large utility-scale arrays that could eventually cover an area the size of Massachusetts, Rhode Island and Connecticut, the US Department of Energy claims.
Solar panels work well in light winds, moderate temperatures and low humidity. Roof tiles share some of these characteristics. But nothing can enhance the combination of these features like farmland. For solar developers looking to get the most out of their investment, this makes farm country irresistible.
For farmers, the attraction is mutual. Depending on the location, solar can be one of the most profitable uses of land. Texas farmers can get up to $500 per acre annually from solar leases, and California’s Central Valley farmers sometimes see up to $1,000 per acre. It’s easy money compared to the complex and often uncertain business of agriculture.
But the potential scale of these new projects has rattled some farming communities, where opposition has grown and threatened efforts to decarbonize the U.S. energy supply.
Critics point to the drawbacks of converting farmland to solar power generation. Panels are typically placed 18 to 36 inches off the ground, preventing access to soil. Some don’t like the aesthetics and fear that large solar arrays will change the rural character of their communities. Meanwhile, fake, social media-driven conspiracies about the devices’ negative health effects are on the rise.
James McCall, a researcher at the Energy Department’s National Renewable Energy Laboratory, called from Denver to say whether the growing opposition to solar power in rural America is right or wrong, climate progress is at risk. “We need to find a middle ground,” he said.
Brad Heins, a professor of animal science at the University of Minnesota, is working on just such a compromise. He is a leading researcher on agrovoltaics, an emerging set of technologies and methods for harnessing synergies between energy production and agriculture. “We harvest the sun twice,” Heins explains as he opens the door to a large cattle pasture in west-central Minnesota near the border of North and South Dakota.
Solar power feeds pasture forage and crops side by side with solar panels. “It’s two income streams for farmers,” Heins said. This may mean planting plants that thrive in the shade cast by the panels. Or, in the Heins’ case, it could mean cooling cows in the shade of panels rather than resorting to expensive fans in the barn.
Heins and his colleagues are at the forefront of this new field, but they are not alone. Hundreds of agrovoltaic projects are underway in the United States. Some work better than others and some may not work at all. But the best will lead to a greener and more profitable rural America that embraces renewable energy as an asset.
The idea that solar panel shading can increase farm productivity dates back to the early 1980s. Japan, long dealing with limited land and energy resources, was among the first to discover this concept. Its first known agrovoltaic facility was established in 2004, and by 2019 there were 1,992 agrovoltaic farms in the country.
For example, the premium green tea plant ground into matcha is traditionally grown under shade nets for several weeks. Placing these nets is not only a labor-intensive process, but can also damage delicate and valuable plant shoots. Agrivoltaics offers an alternative. Farmers carefully position the solar panels to provide shade, thereby eliminating the need for a grid and the expensive labor involved in deploying it. Farmers who invest in the system not only save on production costs, but also earn money from renewable energy and a high-quality product that they can consistently market.
None of these Japanese systems were designed to cover Midwestern cornfields or Texas livestock operations spread over thousands of acres. Most Japanese farms are less than 3 hectares and support the cultivation of high-value, hand-harvested products that enjoy high-value markets in Japan. Their agrovoltaic projects are adapted to that model.
Starting small is a chance to prove the concept. Some of the most successful agrovoltaic pilots in the US also focus on hand-harvested crops. Researchers in Arizona recently found that tomato production doubles under sunlight and is 65% more efficient in water use. They also found that jalapenos were 167% more efficient than water, even though output remained the same. This is an important finding that saves money for agriculture in arid regions, especially as the climate warms.
The benefits of agrovoltaics did not reach only farmers. Arizona research has found that solar panels with a garden growing underneath stay cooler and produce more energy. Such synergies are prompting solar manufacturers to look more closely at working with farmers and encourage further investment in rural solar.
Now the question: Can the techniques that show the most promise in small-scale demonstration projects and hand-picked farms be scaled up enough to work for crops like corn, cattle, and the communities that thrive on them?
“Twelve years ago, when I started here, I never imagined I would be involved in renewable energy,” says Heins, standing beneath a row of solar panels at the West Central Research and Development Center in Morris, Minnesota. He grew up on a dairy farm, and after receiving his PhD from the University of Minnesota, his research focused on organic dairy production. “But the thing is, farming takes a lot of energy,” he said. In 2013, the research center began looking for ways to reduce its energy footprint. So, in addition to gaining efficiency, it started installing renewable energy systems, including solar arrays.
Agrivoltaics were part of the mix from the start. In the center are some traditional fixtures a few inches off the ground. But so did the extra expense of raising the panels a few feet into the air. Standing under the array shared with the University of Minnesota-Morris, Heins points to cows grazing on the other side of the pasture. “Cows don’t do well in 80, 90-degree heat,” he said. Among other problems, heat stress in cows increases body temperature and reduces milk production. A common solution is to house the cows in a stall with fans. But it needs electricity.
Heins and his colleagues tried a different approach: They raised the panels at least six feet, high enough to accommodate cows in search of shade. The cows didn’t mind using it, and during the study, the cows stayed cooler and breathed more slowly. In other words: they were less stressed. “This is a big problem with dairy cows,” explains Heins. Stressed dairy cows are less productive and consequently less profitable. Heins tells me he’s gotten calls from livestock farmers outside of Minnesota wanting to know if solar arrays are compatible with their herds.
It’s not just about cows in Morris. During the morning tour, Heins and Esther Jordan, co-directors of the research center’s horticulture department, showed me some of the plants and crops they are trying to grow in this pasture and elsewhere under the sun’s rays. There are good reasons to be hopeful about this work. A recent Yale study of Minnesota agrovoltaic projects found that incorporating pollinator-friendly plants not only improves the efficiency of the solar panels above them, but also potentially benefits surrounding farms that depend on pollinators. That’s the result, along with direct economic benefits through improved products that could help overcome resistance to solar arrays in the agricultural country of the United States.
For now, the conversation is at an early stage. Agrivoltaics, at least on a large scale, remain more a subject of research than a method of doing business. Additionally, the effort to raise solar panels six to eight feet above the ground rather than 18 inches creates a significant cost burden, especially when the cost of steel is so high. More difficult, even eight feet is not high enough for many modern farm machines to work under. The large-scale farming operations that define much of US agriculture and depend on large planting and harvesting equipment will not yet be candidates for these new techniques.
But these are short-term problems. McCall of the Department of Energy’s renewable resources lab tells me that interest in agrovoltaics is high and growing. He said he’s heard from landowners, state and local regulators, universities — “people who want to see these sites. There’s a lot of interest in local communities to create demonstration facilities.”
That’s good news for rural communities looking for ways to diversify their economies, farmers looking to add another income stream, and anyone who wants to see the U.S. decarbonize its electricity grid. Agrivoltaics won’t solve every economic problem in farm country, and they won’t meet President Joe Biden’s solar goals. But it’s an important tool that farmers and solar power producers are just beginning to understand and use.
In the coming years, agrovoltaics will combine them to build more sustainable farming and energy systems. That’s reason for long-term optimism on the farm and in rural America. More from Other Writers at Bloomberg Opinion:
US Green Energy Is Surprisingly Republican: Denning and Davies
Saving the planet is more important than saving the birds: Tyler Cowen
We must learn to love genetically modified plants: Amanda Little
This column does not necessarily reflect the opinion of the editorial staff or Bloomberg LP and its owners.
Adam Minter is a Bloomberg Opinion columnist covering Asia, technology and the environment. He is the author of the most recent book, Secondhand: Journeys in the New Global Garage Sale.
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