Solar on Farms: Agrivoltaics

Is it possible to have solar power generation and agriculture sustainably and productively on the same land? Looking at solar farms from the roadside, it is hard to imagine; but agrivoltaics and ecovoltaics are proving you can. The US Departments of Energy and Agriculture have programs that promote the integration of agriculture, habitat restoration, ecosystem health and solar power.

The Department of Energy’s National Renewable Energy Laboratory (NREL) defines agrivoltaics as “the practice of bringing together agricultural activities and photovoltaics (PV)—using the same land to harvest solar energy and reap agricultural benefits, like grazing, crop production, increased pollinator habitat, and soil health. The Department of Agriculture specifies in its definition of agrivoltaics that “solar energy generation and sunlight-dependent agricultural activities are directly integrated and there is a layer of agricultural productivity within the boundaries of the solar infrastructure.” Therefore, things such as solar panels on barn roofs, or a solar array next to, but not integrated within a cow pasture would not count.

Ecovoltaics designs solar energy systems that balance priorities for ecosystem services (e.g., water conservation, biodiversity, air quality, etc.) with efficient power generation. It uses ecological principles and knowledge to guide how solar panels arrays are laid out, constructed, managed and maintained so that they contribute to ecosystem health.

NREL’s Innovative Solar Practices Integrated with Rural Economies and Ecosystems (InSPIRE) project documented that in November, 2024, there were close to 600 sites using agrivoltaics in the US, encompassing 60,000 acres and producing 10 GW of solar power. These sites combined solar power generation with grazing, crop production, native plant and pollinator habitat and greenhouses. Jack’s Solar Garden in Longmont, Colorado is one of the longest-running examples.

In Vermont, agrivoltaics has been used in grazing, crop production and native plant and pollinator habitats. Maple Ridge Meats, an organic meat farm, grazes cattle in among solar panels. The farm benefits from income provided by the power generation. The cattle provide mowing services, and benefit from the shade under the panels. According to the Vermont Agency of Agriculture Food and Markets, sheep grazing in one of the most popular kinds of agrivoltaic farming. University of Vermont’s North American Center for Saffron Research and Development studies using various kinds of solar panels in saffron fields.

Agrivoltaics offers a variety of benefits to farms and farmers. It provides farmers with a stable income source independent of volatile crop prices, as well as covering electricity costs of running the farm. For a variety of shade-tolerant crops, including many greens, root vegetables, berry plants, and perennial herbs, growing under and beside solar panels does not impede the quantity or quality of harvest. The panels provide cooling of the air and soil, which impedes evaporation and improves soil moisture.

Ecovoltaics capitalizes on detailed knowledge of plant biology, and ecology to inform solar array design and management. A new kind of advanced solar panel, the Vertically-mounted Bifacial Photovoltaic panel, has opened up opportunities to improve plant growth at the same time as increasing power generation efficiency. These panels absorb energy on both sides of the panel, from the sun overhead, as well as the reflected light, or albedo, from the below the panel. They can be mounted vertically, on a tilt, or on a tracker. When mounted vertically, they can take advantage of early morning and late afternoon light resulting in better power generation than conventional tilted panels. Botanists have determined that most plants photosynthesize best in the morning, a phenomenon known as midday photosynthetic depression, and exist in a state of stress tolerance in the afternoon. In other words, plants are actively building resources in the morning and getting by in the afternoon when it is dryer and hotter. Plant water stress and high air temperature exacerbate photosynthetic depression. By designing solar panel arrays that allow for maximum sunlight during the morning, and provide some shade in the afternoon, plant growth could be enhanced. Vertically-mounted and tracker mounted bifacial panels can be configured to provide these conditions. Further, increased power generation through denser panel placement would be possible compared to conventional panels.

Links to more information on agrivoltaics and ecovoltaics can be found here.