The U.S. Department of Energy (DOE) believes solar could provide up to 40% of the country’s electricity by the year 2035. However, it’s estimated roughly 5.7 million acres of land will be needed.
“While that amount is a tiny fraction of U.S. land (0.3%) in the lower 48 states, it would need to be located near power transmission facilities and could add to recent encroachment on agricultural lands from other sources,” explains Stephanie Mercier, an agricultural policy consultant.
The DOE is pushing hard to help make it a reality. For instance, it just announced an investment of $1.3 billion dollars for six state transmission line projects aimed at bolstering the electric grid. Those projects connect Nevada, Utah, Arizona and New Mexico and also link New Hampshire and Vermont to Canada.
Projects Are Underway
Thousands of solar projects are already operating or under construction. The latest update from the Solar Energy Industries Association (SEIA) shows those sites, to the best of their knowledge, as of September. The yellow circles indicate projects already operating, orange circles are projects that are under development and red represents the construction phase.
“Millions of acres may be needed for solar energy production going into the next 20 to 30 years and some of that land, not all of it, could be farmland,” says Matt O’Neal, a professor in the department of plant pathology, entomology and microbiology at Iowa State and the Wallace Chair for Sustainable Agriculture. “That worries some people, especially those farmers in the Midwest.”
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That’s why more research is going into how to continue agriculture below and around solar panels — also known as agrivoltaics.
“Such research was launched in 1981 by two German scientists, Adolph Goetzberger and Armin Zastrow, who determined that constructing solar panels so they are elevated about 6' above the ground rather than being placed directly on the ground can allow for crops to be cultivated below the solar panel array,” Mercier says.
Agrivoltaics in Iowa
Iowa State is now starting some research of its own. The 10-acre, 1.35 megawatt Alliant Energy Solar Farm will study harvesting power from the sun while utilizing the land below.
“Iowa is a great place to study the combination of solar energy and agriculture,” O’Neal says. “We do a lot of things really well in Iowa, and one of them is agriculture.”
Over the next few years, ISU researchers will study the possibility of raising fruits and vegetables beneath those solar photovoltaic panels thanks to a $1.8 million dollar grant from the DOE.
“That shady environment might be conducive for some of those plants to survive, and maybe even thrive to the point where it becomes economically viable. We don’t know yet, and that’s the point of the experiment,” O’Neal says.
The research farm is installing multiple styles of panels including those that track or follow the sun, fixed panels and panels mounted higher above the ground.
“Very little research has been done in this area, and very little has been done in Iowa, if any at all,” O’Neal explains. “It’s an open question how much the difference in panel height and tilted versus fixed is going to affect vegetation.”
“This effort represents a paradigm that allows for continued agricultural production while generating renewable energy, defying the current notion that installation of solar panels on farmland requires removing that land from agriculture entirely,” Mercier says.
She says researchers are finding that for some crops, solar radiation is often too intense during the summer in some regions to thrive, so the shade provided reduces the intensity and improves prospects for those crops.
Click to watch a video about Iowa State University’s solar farm.
Studies Around the World
Mercier has found that recent estimates indicate there are currently more than 340 agrivoltaics sites in the U.S., mainly pairing solar with pollinator habitats or small ruminant grazing, such as sheep, across more than 33,000 acres while producing a total of 4.8 gigawatts of solar energy.
“Several agrivoltaic pilot programs, in partnership with mainly European research centers and agencies, are underway on the African continent,” she says.
Mercier adds according to a German research organization, Fraunhofer ISE, in 2022, early results from a project in the north African country of Algeria found that under an agrivoltaic installation there was an increase in yield of potatoes of roughly 16% versus the uncovered field.
“The value of this shade will only increase as average summer temperatures increase due to climate change,” Mercier says.
“We have a rich history and a diverse community of farmers in Iowa that grow fruits and vegetables,” O’Neal adds. “It’s possible that this site, and sites like this in the future, could contribute and build that sector of agriculture in Iowa.”
