Agrivoltaics: It’s a word we’ll be hearing a lot more in years to come.
The Sonoran Desert is a perfect place to see agrivoltaics in action. It's a new way of combining renewable energy with agriculture in a hot, arid landscape, positioning elevated solar panels over an understory of plants.
At the University of Arizona, scientists are working on agrivoltaics projects just outside of Biosphere 2, the living laboratory where climate change has been the focus of interdisciplinary research in recent years.
In the Food-Energy-Water (FEW) Nexus, agrivoltaics delivers eco-friendly solutions:
1. The plants, protected by the solar panels from the worst of the midday sun’s rays, become little evaporative coolers on the landscape. They take up carbon for photosynthesis by opening up their pores, or stomata, while letting water escape from their leaves and create a cooler microclimate.
2. The solar panel modules can lose efficiency while operating under the blazing Sonoran sun. The panels perform at a higher level – thanks to this cooler microclimate afforded by the plants. The panels, in turn, protect the plants from sunburn and dehydration.
The end results: a better crop yield and more efficient performance of the solar array.
"This is the ultimate goal of this work. Part of it [agrivoltaics] is making renewable energy better. Part of it is bringing a new dimension to community agriculture, but a big part of it is reaching into those rural landscapes where a simple idea like growing your plants under solar panels can solve some important problems. This work truly is at the nexus of food, energy, and water science."
—Greg Barron-Gafford, Assistant Professor, UA School of Geography & Development
Researchers are testing the usefulness of agrivoltaics in latitudes and climates throughout the world. Simulations and studies have found electricity and shade-resistant crop production allow both to be simultaneously produced efficiently. In one study, lettuce grown with agrivoltaics was found to be comparable to monocultures.
Agrivoltaics work best for plants that grow well in partial shade. Potential functioning crops include hog peanut, alfalfa, yam, taro, cassava, sweet potato, along with lettuce. At Biosphere 2 in the Sonoran Desert, researchers have successfully grown tomatoes, chard, kale, cabbage and onions.
Shade-resistant crops such as wheat do not thrive in a low-light environment, and so would not work well with agrivoltaics. And, scientists have found that agrivoltaics do not yet work with greenhouses. When greenhouses with half the roof covered in panels were simulated, the resulting crop output reduced by 64 percent and panel productivity reduced by 84 percent.
At Biosphere 2, the scientists continue their agrivoltaics research, trying to reduce water use even further. They plan to eventually take their system to underserved populations in rural Arizona and northern Mexico – areas where there is no reliable water or power.
Agrivoltaics: How it works
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— Greg Barron-Gafford (@barrongafford) April 19, 2017