Analysis | Casting a shadow is solar power’s new superpower.

In rural America, shoulder-high corn is competing with a new cash crop; Solar energy. Acres of solar panels will shine brightly along interstates and rural highways, marking a change in how America’s farm country generates income. The need for a happy marriage between these old and new industries has inspired a new term to describe the explosion of innovation and synergy: Agrivoltaics.

The Depreciation Act includes billions of dollars in renewable energy funds that will accelerate the adoption of solar and other renewable plants. Some of the new solar panels will land on rooftops, but most will be focused on large utility-scale arrays, which the U.S. Department of Energy claims could eventually cover an area the size of Massachusetts, Rhode Island and Connecticut.

Solar panels work best in light winds, moderate temperatures and low humidity. Roofs share some of these characteristics. But nothing adds to that combination of qualities like a cropland. For solar developers looking to get the most out of their investments, this makes farm country irresistible.

For farmers, the attraction is mutual. Depending on the location, solar can be one of the most profitable land uses. Texas farmers can receive up to $500 an acre per year from solar leases, and California Central Valley farmers occasionally see up to $1,000 an acre. That’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 is mounting and threatens efforts to decarbonize America’s energy supply.

Critics focus on the problems of turning farmland into solar power. Panels are typically placed 18 to 36 inches below the ground, preventing penetration into the soil. Some dislike the aesthetics and fear that large-scale solar farms will change the rural character of their communities. Meanwhile, false, social media-backed conspiracies about the alleged health problems at the facilities are gaining ground.

Right or wrong, increasing solar resistance in rural America threatens climate change, James McCall, a researcher at the Energy Department’s National Renewable Energy Laboratory, said on a call from Denver. “We have to find a middle ground solution,” he said.

Brad Haynes, a professor of animal science at the University of Minnesota, is working on such a deal. He is a leading researcher in agrivoltaics, a set of technologies and methods designed to exploit the synergy between energy production and agriculture. “We harvest the sun twice,” Heins explains as he opens the door to a large cattle ranch in west-central Minnesota near the border of North and South Dakota.

Solar energy is used to feed pastures and crops side by side with solar panels. “It’s a dual income stream for farmers,” Haynes said. This may mean planting crops that grow in the shade cast by the panels. Or, in Haynes’ case, it could mean cooling cows in the shade of panels instead of using expensive fans in the barn.

Haynes and his colleagues are at the cutting edge of this new field, but they are not alone. There are hundreds of agrivoltex projects in the US. 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 the shade cast by solar panels could increase farm productivity dates back to the early 1980s. Among those who have explored the concept is Japan, a country that has long been concerned about its land and energy reserves. The first known agrivoltaic facility was established in 2004, and in 2019 there were 1,992 agrivoltaic farms in the country.

For example, the high-grade green tea plant that is ground into matcha is typically grown under shade nets for several weeks. Stretching those nets is not only a labor-intensive process, but can also damage delicate and valuable plant buds. Agrivoltex offers an alternative. Farmers carefully place solar panels to provide shade, thereby eliminating the need for netting and the expensive labor required to operate it. Farmers who invest in the system will save money on production costs from renewable energy and sustainably market premium crops.

None of these Japanese systems are designed to cover the cornfields of the Midwest or the thousands of acres of Texas ranching operations. Most Japanese farms are less than 3 hectares and support the cultivation of high-value, hand-harvested crops that enjoy major markets in Japan. Their agrivoltic projects fit that model.

Starting small is an opportunity to prove the concept. In the US, some of the most successful agrivoltex pilots also focus on hand-harvested crops. Researchers in Arizona recently found that tomato production doubled under solar power plants, and was 65% more efficient in water use. They also found that jalapenos were 167% more water efficient, even though the yield was the same. This is a valuable, money-saving breakthrough for agriculture in arid regions, especially when the climate is hot.

The benefits of agrivoltics are not limited to farmers. Arizona studies have shown that solar panels with a growing garden can stay cool and produce more energy. Such alliances are leading solar developers to work with farmers and encourage more investments in rural solar.

The question now is: Can promising techniques on small scale demonstration projects and hand-harvested farms be scaled up sufficiently for crops such as maize, livestock and the communities that thrive on them?

“Twelve years ago, when I started here, I never thought I’d be doing renewable energy,” Haynes told me, standing under a solar panel at the West Central Research and Development Center in Morris, Minnesota. He grew up on a dairy farm, and after earning his doctorate from the University of Minnesota, his research focused primarily on organic dairy production. “But the thing is, agriculture is very labor intensive,” he said. In the year In 2013, the research center began looking for ways to reduce its energy footprint. So, in addition to seeking efficiency gains, he began installing renewable energy systems, including solar arrays.

Agrivoltex was part of the mix from the beginning. The center has some traditional installations just a few inches off the ground. But it went to extra expense to raise the panels several feet into the air. Standing under an array shared with the University of Minnesota-Morris, Haynes points to cows grazing across the pasture. “Cows don’t do well in 80- and 90-degree heat,” he said. Among other problems, heat stress in cows can lead to increased body temperature and reduced milk production. A common solution is to put cows in a barn with fans. But this requires electricity.

Haynes and his colleagues tried a different approach: raising the panels at least six feet high enough to accommodate cows seeking shade. The cows did not hesitate to use it, and during the study, the cows became colder and began to breathe more slowly. In other words: it was less stressful. “This is a big problem with dairy cows,” Haynes said. Stressed dairy cows are less productive and ultimately less profitable. Haynes told me they’ve gotten calls from livestock farmers outside of Minnesota.

Not only Morris cows. During the morning tour, Haynes and Esther Jordan, executive director of the research center’s horticulture division, showed me the different plants and crops they are trying to grow in this pasture and others under the sunlight. There are good reasons to be optimistic about this work. A recent Yale study on Minnesota agrivoltaics projects shows that including pollinator-friendly plants can improve the efficiency of rooftop solar panels and spread benefits to pollinator-based farms. This is the type of effect that helps overcome opposition to solar power plants in US farm country, with direct economic benefits through improved crops.

For now, the discussion is in the early stages. Agrivoltex, at least on a large scale, remains more of a research subject than a business method. In addition, the effort to mount solar panels six to eight feet apart—instead of 18 inches—results in higher costs, especially since the cost of steel is so high. Still too heavy, even eight feet isn’t enough for most modern farm machines to work under. The large-scale farming operations that define much of American agriculture—and rely on large-scale planting and harvesting equipment—are unlikely candidates for these new techniques for now.

But these are short term issues. McCall, from the Energy Department’s Renewable Energy Laboratory, told me that interest in agrivoltics is high and growing. He said he’s hearing from landowners, state and local regulators, universities — “people who want to see these sites.” There is a lot of interest in local communities to develop demonstration sites.”

That’s good news for rural communities looking for ways to boost their economies, farmers looking to add another source of income, and anyone determined to see the US decarbonize its power grid. Agrivoltex won’t solve every economic problem in farm country or ensure that President Joe Biden’s solar goals are met. But it’s a valuable tool that farmers and solar developers are understanding and using.

In the coming years, Agrivoltex will link them together in efforts to build a more sustainable farming and energy system. This has led to a decline in long-term optimism for agriculture and rural America. More on Bloomberg opinion from other writers:

US green energy is surprisingly Republican: Denning and Davis

Saving the planet is more important than saving the birds: Tyler Cowen.

We must learn to love genetically modified crops: Amanda Small

This column does not necessarily reflect the views of the editorial board or Bloomberg LP and its owners.

Adam Minter is a Bloomberg opinion columnist covering Asia, technology and the environment. He is, most recently, the author of “Second: Journeys in the New Global Garage Sale.”

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