In 2019, Arizona researchers grew crops beneath solar panels: Chiltepin peppers produced 3 times more fru

In Arizona’s desert heat, solar panels are usually seen as a way to generate electricity, while farmland is used to grow food. In 2019, researchers at the University of Arizona’s Biosphere 2 began testing whether the two could work in the same space. They planted chiltepin peppers, jalapeños and cherry tomatoes beneath elevated solar panels and compared them with crops growing in full sunlight. The results were notable. Chiltepin peppers produced about three times more fruit under the panels, while cherry tomatoes produced roughly twice as much.The study published in Nature Sustainability examined the experiment as a form of agrivoltaics, where solar power and crop production share the same land. After tracking crop and panel performance across the season, the researchers found that the shaded peppers were less heat- and water-stressed, while the solar modules also ran cooler than those in the open field. The authors argue that this kind of co-location can create a genuine land-use win in hot, dry regions rather than forcing farmers to choose between food and power.The idea was particularly useful to test in Arizona, where farmers deal with intense sunlight, high temperatures and limited water.

Instead of setting aside separate areas for solar installations and crops, agrivoltaics places panels above the plants and uses the space for both purposes. The researchers wanted to see how the partial shade affected crops during the hottest part of the year. They monitored temperature, humidity, soil moisture and plant water use while keeping the growing conditions as consistent as possible. The goal was not just to see whether the crops could survive beneath the panels, but whether the altered environment could make growing conditions easier.Why some crops responded so well to the shadeThe panels changed the conditions around the plants throughout the day. They blocked some of the strongest sunlight, which lowered daytime temperatures beneath the array, while the panels also held in more warmth at night. The soil underneath stayed wetter, so the plants lost water more slowly than those exposed to full sun. The shaded plots had cooler daytime conditions, warmer nights and higher soil moisture.The response varied from one crop to another. Chiltepin peppers benefited the most, producing around three times as much fruit as plants grown in the open. Cherry tomatoes also performed strongly, with about twice the fruit production. Jalapeños showed a different result. Their yield was similar under the panels and in full sunlight, but the shaded plants lost 65% less water through transpiration. In other words, the panels did not make every crop produce more, but they changed the growing environment in ways that could help certain plants deal with Arizona’s heat.That difference is important because it means farmers cannot simply assume that any crop will perform better under solar panels. The result depends on the plant, the climate and the design of the system. A crop that benefits from protection against intense afternoon heat may respond very differently from one that needs more direct light. The Arizona experiment, therefore, offered a more useful lesson than a simple “solar panels increase crop yields” conclusion: the relationship between the panels and the plants depends on how the system is designed.

Aerial shot of the agrivoltaics pilot plan. Credits — Wikimedia Commons

Could the same land produce food and electricity?The experiment also raised a practical question about water. The shaded soil held more moisture, which could reduce some of the stress placed on crops during hot periods. That does not mean solar panels remove the need for irrigation, but it suggests that the panels can change how quickly water is lost from the growing area. For a dry region such as Arizona, keeping more moisture around plant roots could be valuable, particularly during the hottest part of the season.The panels themselves may benefit from the setup as well. Solar modules become less efficient as their temperature rises, while plants growing underneath can create a cooler microclimate. This creates the possibility of a small exchange: the panels provide shade for the crops, while the crops and soil may help keep the equipment cooler. Still, the researchers were careful not to suggest that this approach would work everywhere. The experiment took place at one site and involved only a small number of crops, so results could differ on commercial farms with different soils, climates and panel layouts.That caution has also appeared in broader research on agrivoltaics. A 2023 review of agrivoltaic systems found that combining solar generation with agriculture can offer benefits, but performance varies considerably depending on crop choice, local climate and system design. That is why experiments like the one in Arizona matter: they provide practical information instead of assuming that one setup will work for every farm.The 2019 study did not show that solar panels are a universal solution for agriculture, but it demonstrated that energy production and crop growing do not always have to compete for the same land. Under the right conditions, the shade from the panels can make the environment easier for some plants while the same structure produces electricity above them. Chiltepin peppers produced three times more fruit, tomatoes produced twice as much and jalapeños used less water. In a hot, dry state where both farmland and water are valuable, that combination gives agrivoltaics a reason to keep being tested.