Solar energy and agricultural production often find themselves competitors. Both have strong incentives to expand, and they share a key input: land. Solar developers continue ramping up solar installation worldwide to meet heightened clean energy targets aimed at combating climate change, while agribusiness faces pressure to expand food production to support a growing population. Because solar development and crop production thrive under similar land conditions, namely, large, contiguous parcels of traditionally agricultural land, the two industries often find themselves competing for space.
Agrivoltaics aims to transform this competition into synergy: farming operations and solar development can coexist and reap benefits by sharing land. These arrangements are called agrivoltaic systems, and their widespread implementation can help popularize solar energy in agriculture-dependent communities hesitant to welcome solar development.
Pairing Solar Fields and Cropland
Currently, solar developers have two primary options for solar panel configurations in crop-based agrivoltaic systems. They can either install elevated panels (at least six feet above grade) to allow for agricultural activity underneath, or they can install the panels a sufficient distance apart to allow for intercultural activity between panel rows. Each of these panel configurations has certain advantages and drawbacks. Elevated panels have been successfully paired with high-value crops, like delicate vegetables and berries, which benefit from the shade and protection provided by the panels. Elevated panels can also be installed over existing cropland. However, elevated configurations come with increased installation and maintenance costs, and additional vulnerability to high winds and snow.
Inter-row agrivoltaic configurations, on the other hand, use more traditional panel heights, which are more resilient and can be paired with plants requiring full sun. The spacing between the panels reduces the effect on the surrounding microclimate, benefiting the growing environment and making inter-row agrivoltaics more appealing to farmers. Studies pairing solar panels with typical rotation crops, such as corn and soybeans, are in the early stages, and research is ongoing to determine ideal panel design, crop pairings, and spacing.
Solar developers interested in agrivoltaic options should consider the implications and risks of farmers maneuvering farm equipment under or in between panels, irrigation plans, and the long-term monitoring of photosynthesis and soil quality. However, there is federal interest in researching and supporting agrivoltaic systems. The U.S. Department of Energy has been researching agrivoltaics since 2015, when it launched the Innovative Solar Practices Integrated with Rural Economics and Ecosystems (“InSPIRE”) research study. A technical report outlining InSPIRE’s findings was made publicly available in August 2022. In May 2023, Senators Martin Heinrich (D-NM) and Mike Braun (R-IN) introduced the Agrivoltaics Research and Demonstration Act of 2023, a bipartisan bill that would create a joint study by DOE and the U.S. Department of Agriculture on agrivoltaics. In addition to researching methods of harmonizing cropland with solar fields, the study aims to create a regulatory definition for agrivoltaics. Various states have also acted on agrivoltaics. For example, New Jersey and Colorado have funded agrivoltaics research, while Massachusetts has a feed-in tariff adder of $0.06/kWh for agrivoltaic projects. Researchers have also experimented with solar arrays designed to support agrivoltaic systems. Purdue University researchers have developed new solar panel structures that can rotate nearly vertically, seeking to optimize energy generation while allowing farm equipment to maneuver around the panels.
Alternative Arrangements: Grazing and Pollinator Habitat
The majority of the over 2.8 GW of energy generated in the U.S. on agrivoltaic sites currently does not pair solar generation with crops. As an alternative form of agrivoltaics, solar developers have adapted projects to support livestock grazing and/or pollinator habitats. Grazing arrangements allow sheep or other small animals to manage the vegetation under and around the panels. These animals will graze for free, or with a payment from the solar developer to the farmer, often creating a win-win-win system: the animals receive food and shade, farmers reduce cost and often receive a payment for managing vegetation, and developers reduce vegetation management cost. Sheep are often the preferred grazing animal, as they present a low risk of damaging solar panels and will not chew on metal and wiring, unlike goats.
Other agrivoltaic projects utilize solar fields to cultivate habitats for pollinators, like bees. This agrivoltaic system is both simple and flexible: it often only involves the developer installing solar arrays and seeding pollinator-friendly plants around and/or beneath the panels. While the plants may take several seasons to become established, their presence will ultimately benefit the surrounding agriculture, which depends on pollinators for crop yield. As a secondary benefit, these plants keep the solar panels cooler, increasing performance and longevity while reducing mowing and maintenance cost for developers.
While agrivoltaics research is still in relatively early stages, harmonizing agricultural and solar energy interests has the potential to greatly benefit both industries. According to a 2021 University of Oregon study, converting just 1% of U.S. farmland to agrivoltaic systems would allow solar developers to reach upcoming renewable energy targets. For farmers, agrivoltaics create the rare opportunity to make agricultural land dual-use, allowing farmers to diversify income streams while continuing crop production. As interest continues to grow, developers should expect new and varied opportunities to implement agrivoltaics in future projects.