What is agrivoltaics, and can you really farm under solar panels?

The short answer: yes, if the crop and the layout fit

Agrivoltaics is the practice of farming under or between rows of solar panels, so one piece of land produces both food and electricity. It can work, but not for every crop and not with every solar layout. The panels shade the ground, and that shade helps some plants and hurts others. The real design question is how much light to give the crop and how much to keep for the panels.

A new extension fact sheet from Utah State University frames it from a farmer's point of view: land is under pressure from development, water is scarce, and production costs keep rising. Putting solar on working farmland, and keeping the farm running underneath it, is one way to hold on to the land and add a second income stream.

The four main kinds of agrivoltaic systems

The U.S. National Renewable Energy Laboratory (NREL) groups agrivoltaics into a few families. Crop production grows vegetables or other plants under raised panels or in the alleys between rows, usually harvested by hand or with small machines. Grazing lets sheep or cattle feed under and between the panels, which can replace mowing. Pollinator habitat, sometimes called ecovoltaics, plants native flowering vegetation that supports beneficial insects. Greenhouse systems build solar into the greenhouse itself.

Grazing is the easiest to fit onto an ordinary solar farm, because sheep do not need the panels raised. NREL's materials describe a Massachusetts solar grazing operation running on more than 100 acres of solar sites.

What happens to crops, water and the panels themselves

The best-known field trial came from the University of Arizona at Biosphere 2, published in Nature Sustainability in 2019. Researchers grew chiltepin peppers, jalapenos and cherry tomatoes under solar panels and on an open plot nearby, with the same irrigation on both. Under the panels, chiltepin fruit production was about three times higher and cherry tomato production about twice as high, while jalapenos produced about the same.

Water was the bigger story. Jalapeno plants under the panels lost 65 percent less water through transpiration. When watered every other day, the soil under the panels held about 15 percent more moisture than the open plot, and one watering kept plants going for days instead of hours. The shade lowered daytime air temperature and raised it slightly at night.

The panels gain too. Solar cells lose output as they heat up, and plants underneath release water vapor that cools the space around them. NREL's summary of the Arizona work puts the gain at about 2 percent more electricity per year. A bare-gravel solar farm, by contrast, can bake into a small heat island.

Why it is harder than it sounds

Raising panels high enough to farm under costs more to build for the same amount of power, and that upfront cost is the main barrier NREL lists. Spacing is the other tension. Standard utility-scale rows are too tight for full-size tractors. Taller panels and wider rows let equipment and light through, but produce less energy per acre. Vertical two-sided panels are the friendliest to machinery and carry the biggest energy penalty.

Results also depend heavily on place. Shade that rescues a pepper plant in the Arizona desert may starve a sun-loving grain in a cloudier climate. NREL notes that reported yield results vary by crop, by growing method, and even by where a plant sits within the array, and that many studies have not controlled for climate or layout. Other trade-offs include delayed harvests, soil compaction during construction, and uneven soil moisture under the drip edges of panels.

How much land could this involve

Research from Oregon State University, reported by pv magazine, estimated that pairing solar with agriculture could supply about 20 percent of U.S. electricity using roughly 1 percent of the country's farmland, with only a small effect on crop yield. NREL's InSPIRE project studies these systems across dozens of sites in many states. The practical takeaway is that agrivoltaics is not a single technology but a set of design choices, and the right one depends on the crop, the climate and the equipment a farm already uses.