By now, most of us have seen a solar farm—a field of glistening photovoltaic (PV) panels silently generating electricity from sunlight. The first solar farms typically used bare soil, gravel, or grass as ground cover beneath the arrays. These days, however, that space under the panels could be filled with flower meadows, grazing sheep, or even tomato vines. The combination of PV panels and agriculture is known as agrivoltaics and has become an increasingly popular approach to provide land with more than just one purpose.
As we continue to strive to make the land we use as productive as possible, researchers have begun to assess the benefits of solar power and crop or livestock co-production. One study published in Nature Sustainability by the US Department of Energy’s National Renewable Energy Laboratory (NREL) concluded that the co-location of solar panels and agriculture could have synergistic effects that support both the production of food and energy. NREL’s study, which took place during a three-month growing season, found that certain crops like tomatoes produce greater yield when shaded by solar panels.
Additionally, water-use efficiency was improved since the shade and cooler temperatures decreased evaporation. Even the PV panels themselves experienced benefits in performance. The cooling “microclimate” that occurs in the presence of agriculture decreased panel surface heat and improved energy production compared to typical, ground-mounted panels. The lead researcher noted that “the promising results of this work have broad implications for how solar development and farming across the globe could be integrated to provide mutual benefits.”
Another study found that certain croplands are the “land covers with the greatest solar PV power potential” based on an analysis of incoming sunlight, air temperature, and relative humidity. Livestock, especially sheep, have also been found to benefit from the solar panels. The shade effectively reduces heat stress on animals while they graze.
Research indicates that solar arrays and farming have a synergistic relationship. Agriculture produces a cooling microclimate that increase solar efficiency while shade from the panels conserves water by reducing excess evaporation.
Research in the area is not only happening in the United States, but across the globe. In Germany, the Faunhofer Institute for Solar Energy Systems recently published guidelines for agrivoltaics in Germany, titled Agrivoltaics: Opportunities for Agriculture and the Energy Transition. This document aims to provide practical advice on agrivoltaics implementation to farmers, municipalities, and companies that are interested in the approach. On the advantages of combining solar generation and agriculture, Max Trommsdorff, Group Head of Agrivoltaics at Fraunhofer ISE, said the combination “reduces competition for arable land and contributes to more efficient land use.
In addition, agrivoltaics offers advantages such as protection against hail, frost, and drought damage, eliminating the need for protective foils and other materials. Also, a reduction in wind load and solar radiation underneath the PV modules can help to decrease water consumption in agriculture.” Similar to the NREL, the Fraunhofer ISE researchers also pointed toward increases in yields for some crop types and a significant reduction in water use.
Farmers who consider adopting agrivoltaics balance the pros and cons. Less land flexibility and the cost of adoption remain key concerns.
While there are some early adopters of agrivoltaics, most of the existing solar plus crop farms are at small scales and used for researching best practices. As with any innovative approach to technology implementation, there are still some limitations to keep in mind. In a study published in Agronomy, the authors interviewed several farmers to discuss their perceptions on the opportunities and barriers to adopting agrivoltaics.
The results of these interviews indicated that, while farmers where interested in learning about marrying PV panels and agriculture, barriers include: “(i) desired certainty of long-term land productivity, (ii) market potential, (iii) just compensation, and (iv) a need for predesigned system flexibility to accommodate different scales, types of operations, and changing farming practices.” More specifically, farmers expressed concerns over “putting in permanent structure,” which could make land use less flexible for different types of agriculture.
Ensuring the market potential of the crops or livestock grown or raised among the solar panels is critical. Other farmers pointed out that by leasing out land to solar developers they would be able to gain an additional profit, so long as a reasonable agreement could be reached between the two. Finally, farmers said that scale mattered, as solar arrays could impede the large machinery needed to harvest crops in bigger fields.
With increasing food and energy requirements and a growing population, agrivoltaics is certainly one approach to consider to meet demand while alleviating the competition for land resources. So, next time you pass by a glistening field of solar panels, check what is beneath them — there could be rabbits or jalapeños.
*Norman Shafto is a Senior Sustainability Analyst at the Electric Power Research Institute (EPRI), where he leads EPRI’s Sustainability Assessment Services. Mr. Shafto received a Bachelor of Arts in Sustainable Development and a Master of Public Administration in Environmental Science and Policy, both from Columbia University.