Grazing Livestock on Solar Farms, with Stacie Peterson

What is Solar Grazing? The deployment of utility scale solar has often required clearing vegetation and then using fossil-fuel-powered mowers or toxic herbicides to prevent overgrowth. To reduce these harms, solar grazing is a dual land use approach where livestock is taken to solar farms to manage the vegetation that can grow and interfere with the panels. Solar grazing reduces maintenance emissions, provides a revenue stream for local ranchers, and promotes soil health. Why it Works: Sheep Solar grazing is a type of targeted grazing, which is, “the controlled application of specific livestock at a designated season, duration, and intensity to achieve specific landscape and vegetation management goals”. Those goals often include weed control, fire risk reduction, and wildlife habitat enhancement. Solar grazing specifically refers to livestock grazing on solar farms, or, under and around solar arrays. According to the American Solar Grazing Association (ASGA), other terms associated with solar grazing include agrivoltaics (the co-location of agriculture and solar), agrisolar, agri-pv, or rangevoltaics. One grazier compares solar grazing to silvopasture - or, grazing under trees - “Just with metal trees”. Sheep have been found to be an excellent match for the needs of solar grazing. Sheep are nimble and can work around solar installments, eliminating work that, without re-designing or raising solar panels, can be difficult for humans. The benefits of solar grazing extend beyond vegetation management: sheep have been measured to have lower body temperatures, both in their wool and skin, when they’re shaded by solar panels. Additionally, forage quality and moisture content are higher in the shade where water in the soil evaporates more slowly. Sheep have been shown to drink less water during solar grazing, which reduces water needs for graziers. Solar grazing also eliminates competition for land use between solar developers and graziers.  What’s Left to Learn Solar grazing has been expanding across the country for the last decade; however, long-term studies on the effects of grazing on biotic and abiotic factors - as well as changes in cost over time - have not been widely conducted. One of the highest costs in solar grazing is transportation and logistics, so in places like the US’s Northeast where most solar farms are around 11 acres, moving sheep makes grazing less affordable. In regions with large or interconnected farms, that cost is reduced; Stacie reports that many sheep are born and live out their lives on one farm. Solar grazing is often viewed as just “mowing with sheep” - not as an active agricultural practice. The American Farmland Trust emphasizes that, on the contrary, “It’s a way to grow food, build soil, create habitat, and generate renewable energy at once.” Stacie’s Points Stacie emphasizes that grazing - even in areas where animals have to be rotated between sites - contributes less fossil fuel emissions than mowers that run on diesel. Mowers and weed-whackers have other side effects: blades have a tendency to “throw” rocks, or pick up and eject rocks, which can damage panels and add costs to operation. Also, using any machine powered by combustion increases fire risk.  There’s a demographic shift supported by solar grazing. Often, the greatest financial hurdle to a grazing operation is buying or leasing pasture; for young people who won’t inherit pastureland, solar grazing lowers the barrier to entering the industry. Stacie says that polling done by ASGA shows a lower average age of participants compared to the national average, which sits around 65. Also, a greater proportion of women are involved. Another upside: solar graziers are contracted by solar farms - meaning, instead of paying to lease or buy land, they’re being paid for their service - which adds economic opportunity. On the climate side, Stacie underscores improvement in overall soil health, but especially carbon sequestration. The use of agrivoltaics tends to improve public acceptance of large-scale solar, a key strategy for reducing the country’s dependence on fossil fuels.  About our Guest Stacie Peterson is the Executive Director of the American Solar Grazing Association. She was a developer of the AgriSolar Clearinghouse for the Department of Energy and the Director of Energy Programs at the National Center for Appropriate Technology. Her environmental research includes the development of a protocol for domestic dogs to serve as bioindicators of metal contamination and cleanup efficacy. Resources Society for Rangeland Management, Targeted Grazing Fonseca et al, Solar Shade on Sheep American Farmland Trust, Grazing Between the Panels  Andrew et al, Sheep grazing as sustainable vegetation management for solar energy  For a transcript of this episode, visit https://climatebreak.org/grazing-livestock-on-solar-farms-with-stacie-peterson/